/rpython/jit/metainterp/optimizeopt/test/test_optimizebasic.py

import py
from rpython.rlib.objectmodel import instantiate
from rpython.jit.metainterp.optimizeopt.test.test_util import (
    LLtypeMixin, BaseTest, FakeMetaInterpStaticData, convert_old_style_to_targets)
from rpython.jit.metainterp.history import TargetToken, JitCellToken
from rpython.jit.metainterp.test.test_compile import FakeLogger
import rpython.jit.metainterp.optimizeopt.optimizer as optimizeopt
import rpython.jit.metainterp.optimizeopt.virtualize as virtualize
from rpython.jit.metainterp.optimize import InvalidLoop
from rpython.jit.metainterp.history import AbstractDescr, ConstInt, BoxInt, get_const_ptr_for_string
from rpython.jit.metainterp import executor, compile, resume, history
from rpython.jit.metainterp.resoperation import rop, opname, ResOperation
from rpython.rlib.rarithmetic import LONG_BIT

def test_store_final_boxes_in_guard():
    from rpython.jit.metainterp.compile import ResumeGuardDescr
    from rpython.jit.metainterp.resume import tag, TAGBOX
    b0 = BoxInt()
    b1 = BoxInt()
    opt = optimizeopt.Optimizer(FakeMetaInterpStaticData(LLtypeMixin.cpu),
                                None)
    fdescr = ResumeGuardDescr()
    op = ResOperation(rop.GUARD_TRUE, ['dummy'], None, descr=fdescr)
    # setup rd data
    fi0 = resume.FrameInfo(None, "code0", 11)
    fdescr.rd_frame_info_list = resume.FrameInfo(fi0, "code1", 33)
    snapshot0 = resume.Snapshot(None, [b0])
    fdescr.rd_snapshot = resume.Snapshot(snapshot0, [b1])
    #
    opt.store_final_boxes_in_guard(op)
    if op.getfailargs() == [b0, b1]:
        assert list(fdescr.rd_numb.nums)      == [tag(1, TAGBOX)]
        assert list(fdescr.rd_numb.prev.nums) == [tag(0, TAGBOX)]
    else:
        assert op.getfailargs() == [b1, b0]
        assert list(fdescr.rd_numb.nums)      == [tag(0, TAGBOX)]
        assert list(fdescr.rd_numb.prev.nums) == [tag(1, TAGBOX)]
    assert fdescr.rd_virtuals is None
    assert fdescr.rd_consts == []

def test_sharing_field_lists_of_virtual():
    class FakeOptimizer(object):
        class optimizer(object):
            class cpu(object):
                pass
    opt = FakeOptimizer()
    virt1 = virtualize.AbstractVirtualStructValue(opt, None)
    lst1 = virt1._get_field_descr_list()
    assert lst1 == []
    lst2 = virt1._get_field_descr_list()
    assert lst1 is lst2
    virt1.setfield(LLtypeMixin.valuedescr, optimizeopt.OptValue(None))
    lst3 = virt1._get_field_descr_list()
    assert lst3 == [LLtypeMixin.valuedescr]
    lst4 = virt1._get_field_descr_list()
    assert lst3 is lst4

    virt2 = virtualize.AbstractVirtualStructValue(opt, None)
    lst5 = virt2._get_field_descr_list()
    assert lst5 is lst1
    virt2.setfield(LLtypeMixin.valuedescr, optimizeopt.OptValue(None))
    lst6 = virt1._get_field_descr_list()
    assert lst6 is lst3

def test_reuse_vinfo():
    class FakeVInfo(object):
        def set_content(self, fieldnums):
            self.fieldnums = fieldnums
        def equals(self, fieldnums):
            return self.fieldnums == fieldnums
    class FakeVirtualValue(virtualize.AbstractVirtualValue):
        def _make_virtual(self, *args):
            return FakeVInfo()
    v1 = FakeVirtualValue(None, None)
    vinfo1 = v1.make_virtual_info(None, [1, 2, 4])
    vinfo2 = v1.make_virtual_info(None, [1, 2, 4])
    assert vinfo1 is vinfo2
    vinfo3 = v1.make_virtual_info(None, [1, 2, 6])
    assert vinfo3 is not vinfo2
    vinfo4 = v1.make_virtual_info(None, [1, 2, 6])
    assert vinfo3 is vinfo4

def test_descrlist_dict():
    from rpython.jit.metainterp.optimizeopt import util as optimizeutil
    h1 = optimizeutil.descrlist_hash([])
    h2 = optimizeutil.descrlist_hash([LLtypeMixin.valuedescr])
    h3 = optimizeutil.descrlist_hash(
            [LLtypeMixin.valuedescr, LLtypeMixin.nextdescr])
    assert h1 != h2
    assert h2 != h3
    assert optimizeutil.descrlist_eq([], [])
    assert not optimizeutil.descrlist_eq([], [LLtypeMixin.valuedescr])
    assert optimizeutil.descrlist_eq([LLtypeMixin.valuedescr],
                                     [LLtypeMixin.valuedescr])
    assert not optimizeutil.descrlist_eq([LLtypeMixin.valuedescr],
                                         [LLtypeMixin.nextdescr])
    assert optimizeutil.descrlist_eq([LLtypeMixin.valuedescr, LLtypeMixin.nextdescr],
                                     [LLtypeMixin.valuedescr, LLtypeMixin.nextdescr])
    assert not optimizeutil.descrlist_eq([LLtypeMixin.nextdescr, LLtypeMixin.valuedescr],
                                         [LLtypeMixin.valuedescr, LLtypeMixin.nextdescr])

    # descrlist_eq should compare by identity of the descrs, not by the result
    # of sort_key
    class FakeDescr(object):
        def sort_key(self):
            return 1

    assert not optimizeutil.descrlist_eq([FakeDescr()], [FakeDescr()])


# ____________________________________________________________


class BaseTestBasic(BaseTest):

    enable_opts = "intbounds:rewrite:virtualize:string:earlyforce:pure:heap"

    def optimize_loop(self, ops, optops, call_pure_results=None):
        loop = self.parse(ops)
        token = JitCellToken()
        loop.operations = [ResOperation(rop.LABEL, loop.inputargs, None, descr=TargetToken(token))] + \
                          loop.operations
        if loop.operations[-1].getopnum() == rop.JUMP:
            loop.operations[-1].setdescr(token)
        expected = convert_old_style_to_targets(self.parse(optops), jump=True)
        self._do_optimize_loop(loop, call_pure_results)
        print '\n'.join([str(o) for o in loop.operations])
        self.assert_equal(loop, expected)

    def setup_method(self, meth=None):
        class FailDescr(compile.ResumeGuardDescr):
            oparse = None
            def _oparser_uses_descr_of_guard(self, oparse, fail_args):
                # typically called 3 times: once when parsing 'ops',
                # once when parsing 'preamble', once when parsing 'expected'.
                self.oparse = oparse
                self.rd_frame_info_list, self.rd_snapshot = snapshot(fail_args)
            def _clone_if_mutable(self):
                assert self is fdescr
                return fdescr2
            def __repr__(self):
                if self is fdescr:
                    return 'fdescr'
                if self is fdescr2:
                    return 'fdescr2'
                return compile.ResumeGuardDescr.__repr__(self)
        #
        def snapshot(fail_args, got=[]):
            if not got:    # only the first time, i.e. when parsing 'ops'
                rd_frame_info_list = resume.FrameInfo(None, "code", 11)
                rd_snapshot = resume.Snapshot(None, fail_args)
                got.append(rd_frame_info_list)
                got.append(rd_snapshot)
            return got
        #
        fdescr = instantiate(FailDescr)
        self.namespace['fdescr'] = fdescr
        fdescr2 = instantiate(FailDescr)
        self.namespace['fdescr2'] = fdescr2

    def teardown_method(self, meth):
        self.namespace.pop('fdescr', None)
        self.namespace.pop('fdescr2', None)



class BaseTestOptimizeBasic(BaseTestBasic):

    def test_simple(self):
        ops = """
        [i]
        i0 = int_sub(i, 1)
        guard_value(i0, 0) [i0]
        jump(i)
        """
        expected = """
        [i]
        i0 = int_sub(i, 1)
        guard_value(i0, 0) [i0]
        jump(1)
        """
        self.optimize_loop(ops, expected)

    def test_constant_propagate(self):
        ops = """
        []
        i0 = int_add(2, 3)
        i1 = int_is_true(i0)
        guard_true(i1) []
        i2 = int_is_zero(i1)
        guard_false(i2) []
        guard_value(i0, 5) []
        jump()
        """
        expected = """
        []
        jump()
        """
        self.optimize_loop(ops, expected)

    def test_constant_propagate_ovf(self):
        ops = """
        []
        i0 = int_add_ovf(2, 3)
        guard_no_overflow() []
        i1 = int_is_true(i0)
        guard_true(i1) []
        i2 = int_is_zero(i1)
        guard_false(i2) []
        guard_value(i0, 5) []
        jump()
        """
        expected = """
        []
        jump()
        """
        self.optimize_loop(ops, expected)

    # ----------

    def test_remove_guard_class_1(self):
        ops = """
        [p0]
        guard_class(p0, ConstClass(node_vtable)) []
        guard_class(p0, ConstClass(node_vtable)) []
        jump(p0)
        """
        expected = """
        [p0]
        guard_class(p0, ConstClass(node_vtable)) []
        jump(p0)
        """
        self.optimize_loop(ops, expected)

    def test_remove_guard_class_2(self):
        ops = """
        [i0]
        p0 = new_with_vtable(ConstClass(node_vtable))
        escape(p0)
        guard_class(p0, ConstClass(node_vtable)) []
        jump(i0)
        """
        expected = """
        [i0]
        p0 = new_with_vtable(ConstClass(node_vtable))
        escape(p0)
        jump(i0)
        """
        self.optimize_loop(ops, expected)

    def test_remove_guard_class_constant(self):
        ops = """
        [i0]
        p0 = same_as(ConstPtr(myptr))
        guard_class(p0, ConstClass(node_vtable)) []
        jump(i0)
        """
        expected = """
        [i0]
        jump(i0)
        """
        self.optimize_loop(ops, expected)

    def test_constant_boolrewrite_lt(self):
        ops = """
        [i0]
        i1 = int_lt(i0, 0)
        guard_true(i1) []
        i2 = int_ge(i0, 0)
        guard_false(i2) []
        jump(i0)
        """
        expected = """
        [i0]
        i1 = int_lt(i0, 0)
        guard_true(i1) []
        jump(i0)
        """
        self.optimize_loop(ops, expected)

    def test_constant_boolrewrite_gt(self):
        ops = """
        [i0]
        i1 = int_gt(i0, 0)
        guard_true(i1) []
        i2 = int_le(i0, 0)
        guard_false(i2) []
        jump(i0)
        """
        expected = """
        [i0]
        i1 = int_gt(i0, 0)
        guard_true(i1) []
        jump(i0)
        """
        self.optimize_loop(ops, expected)

    def test_constant_boolrewrite_reflex(self):
        ops = """
        [i0]
        i1 = int_gt(i0, 0)
        guard_true(i1) []
        i2 = int_lt(0, i0)
        guard_true(i2) []
        jump(i0)
        """
        expected = """
        [i0]
        i1 = int_gt(i0, 0)
        guard_true(i1) []
        jump(i0)
        """
        self.optimize_loop(ops, expected)

    def test_constant_boolrewrite_reflex_invers(self):
        ops = """
        [i0]
        i1 = int_gt(i0, 0)
        guard_true(i1) []
        i2 = int_ge(0, i0)
        guard_false(i2) []
        jump(i0)
        """
        expected = """
        [i0]
        i1 = int_gt(i0, 0)
        guard_true(i1) []
        jump(i0)
        """
        self.optimize_loop(ops, expected)

    def test_remove_consecutive_guard_value_constfold(self):
        ops = """
        []
        i0 = escape()
        guard_value(i0, 0) []
        i1 = int_add(i0, 1)
        guard_value(i1, 1) []
        i2 = int_add(i1, 2)
        escape(i2)
        jump()
        """
        expected = """
        []
        i0 = escape()
        guard_value(i0, 0) []
        escape(3)
        jump()
        """
        self.optimize_loop(ops, expected)

    def test_remove_guard_value_if_constant(self):
        ops = """
        [p1]
        guard_value(p1, ConstPtr(myptr)) []
        jump(ConstPtr(myptr))
        """
        expected = """
        []
        jump()
        """
        py.test.skip("XXX")
        self.optimize_loop(ops, 'Constant(myptr)', expected)

    def test_ooisnull_oononnull_1(self):
        ops = """
        [p0]
        guard_class(p0, ConstClass(node_vtable)) []
        guard_nonnull(p0) []
        jump(p0)
        """
        expected = """
        [p0]
        guard_class(p0, ConstClass(node_vtable)) []
        jump(p0)
        """
        self.optimize_loop(ops, expected)

    def test_int_is_true_1(self):
        ops = """
        [i0]
        i1 = int_is_true(i0)
        guard_true(i1) []
        i2 = int_is_true(i0)
        guard_true(i2) []
        jump(i0)
        """
        expected = """
        [i0]
        i1 = int_is_true(i0)
        guard_true(i1) []
        jump(i0)
        """
        self.optimize_loop(ops, expected)

    def test_int_is_true_is_zero(self):
        py.test.skip("XXX implement me")
        ops = """
        [i0]
        i1 = int_is_true(i0)
        guard_true(i1) []
        i2 = int_is_zero(i0)
        guard_false(i2) []
        jump(i0)
        """
        expected = """
        [i0]
        i1 = int_is_true(i0)
        guard_true(i1) []
        jump(i0)
        """
        self.optimize_loop(ops, expected)

    def test_int_is_zero_int_is_true(self):
        ops = """
        [i0]
        i1 = int_is_zero(i0)
        guard_true(i1) []
        i2 = int_is_true(i0)
        guard_false(i2) []
        jump(i0)
        """
        expected = """
        [i0]
        i1 = int_is_zero(i0)
        guard_true(i1) []
        jump(0)
        """
        self.optimize_loop(ops, expected)

    def test_ooisnull_oononnull_2(self):
        ops = """
        [p0]
        guard_nonnull(p0) []
        guard_nonnull(p0) []
        jump(p0)
        """
        expected = """
        [p0]
        guard_nonnull(p0) []
        jump(p0)
        """
        self.optimize_loop(ops, expected)

    def test_ooisnull_on_null_ptr_1(self):
        ops = """
        []
        p0 = escape()
        guard_isnull(p0) []
        guard_isnull(p0) []
        jump()
        """
        expected = """
        []
        p0 = escape()
        guard_isnull(p0) []
        jump()
        """
        self.optimize_loop(ops, expected)

    def test_ooisnull_oononnull_via_virtual(self):
        ops = """
        [p0]
        pv = new_with_vtable(ConstClass(node_vtable))
        setfield_gc(pv, p0, descr=valuedescr)
        guard_nonnull(p0) []
        p1 = getfield_gc(pv, descr=valuedescr)
        guard_nonnull(p1) []
        jump(p0)
        """
        expected = """
        [p0]
        guard_nonnull(p0) []
        jump(p0)
        """
        self.optimize_loop(ops, expected)

    def test_oois_1(self):
        ops = """
        [p0]
        guard_class(p0, ConstClass(node_vtable)) []
        i0 = instance_ptr_ne(p0, NULL)
        guard_true(i0) []
        i1 = instance_ptr_eq(p0, NULL)
        guard_false(i1) []
        i2 = instance_ptr_ne(NULL, p0)
        guard_true(i0) []
        i3 = instance_ptr_eq(NULL, p0)
        guard_false(i1) []
        jump(p0)
        """
        expected = """
        [p0]
        guard_class(p0, ConstClass(node_vtable)) []
        jump(p0)
        """
        self.optimize_loop(ops, expected)

    def test_nonnull_1(self):
        ops = """
        [p0]
        setfield_gc(p0, 5, descr=valuedescr)     # forces p0 != NULL
        i0 = ptr_ne(p0, NULL)
        guard_true(i0) []
        i1 = ptr_eq(p0, NULL)
        guard_false(i1) []
        i2 = ptr_ne(NULL, p0)
        guard_true(i0) []
        i3 = ptr_eq(NULL, p0)
        guard_false(i1) []
        guard_nonnull(p0) []
        jump(p0)
        """
        expected = """
        [p0]
        setfield_gc(p0, 5, descr=valuedescr)
        jump(p0)
        """
        self.optimize_loop(ops, expected)

    def test_const_guard_value(self):
        ops = """
        []
        i = int_add(5, 3)
        guard_value(i, 8) []
        jump()
        """
        expected = """
        []
        jump()
        """
        self.optimize_loop(ops, expected)

    def test_constptr_guard_value(self):
        ops = """
        []
        p1 = escape()
        guard_value(p1, ConstPtr(myptr)) []
        jump()
        """
        self.optimize_loop(ops, ops)

    def test_guard_value_to_guard_true(self):
        ops = """
        [i]
        i1 = int_lt(i, 3)
        guard_value(i1, 1) [i]
        jump(i)
        """
        expected = """
        [i]
        i1 = int_lt(i, 3)
        guard_true(i1) [i]
        jump(i)
        """
        self.optimize_loop(ops, expected)

    def test_guard_value_to_guard_false(self):
        ops = """
        [i]
        i1 = int_is_true(i)
        guard_value(i1, 0) [i]
        jump(i)
        """
        expected = """
        [i]
        i1 = int_is_true(i)
        guard_false(i1) [i]
        jump(i)
        """
        self.optimize_loop(ops, expected)

    def test_guard_value_on_nonbool(self):
        ops = """
        [i]
        i1 = int_add(i, 3)
        guard_value(i1, 0) [i]
        jump(i)
        """
        expected = """
        [i]
        i1 = int_add(i, 3)
        guard_value(i1, 0) [i]
        jump(-3)
        """
        self.optimize_loop(ops, expected)

    def test_int_is_true_of_bool(self):
        ops = """
        [i0, i1]
        i2 = int_gt(i0, i1)
        i3 = int_is_true(i2)
        i4 = int_is_true(i3)
        guard_value(i4, 0) [i0, i1]
        jump(i0, i1)
        """
        expected = """
        [i0, i1]
        i2 = int_gt(i0, i1)
        guard_false(i2) [i0, i1]
        jump(i0, i1)
        """
        self.optimize_loop(ops, expected)




    def test_p123_simple(self):
        ops = """
        [i1, p2, p3]
        i3 = getfield_gc(p3, descr=valuedescr)
        escape(i3)
        p1 = new_with_vtable(ConstClass(node_vtable))
        setfield_gc(p1, i1, descr=valuedescr)
        jump(i1, p1, p2)
        """
        # We cannot track virtuals that survive for more than two iterations.
        self.optimize_loop(ops, ops)

    def test_p123_nested(self):
        ops = """
        [i1, p2, p3]
        i3 = getfield_gc(p3, descr=valuedescr)
        escape(i3)
        p1 = new_with_vtable(ConstClass(node_vtable))
        p1sub = new_with_vtable(ConstClass(node_vtable2))
        setfield_gc(p1sub, i1, descr=valuedescr)
        setfield_gc(p1, i1, descr=valuedescr)
        setfield_gc(p1, p1sub, descr=nextdescr)
        jump(i1, p1, p2)
        """
        # The same as test_p123_simple, but with a virtual containing another
        # virtual.
        self.optimize_loop(ops, ops)

    def test_p123_anti_nested(self):
        ops = """
        [i1, p2, p3]
        p3sub = getfield_gc(p3, descr=nextdescr)
        i3 = getfield_gc(p3sub, descr=valuedescr)
        escape(i3)
        p1 = new_with_vtable(ConstClass(node_vtable))
        p2sub = new_with_vtable(ConstClass(node_vtable2))
        setfield_gc(p2sub, i1, descr=valuedescr)
        setfield_gc(p2, p2sub, descr=nextdescr)
        jump(i1, p1, p2)
        """
        # The same as test_p123_simple, but in the end the "old" p2 contains
        # a "young" virtual p2sub.  Make sure it is all forced.
        self.optimize_loop(ops, ops)

    # ----------

    def test_keep_guard_no_exception(self):
        ops = """
        [i1]
        i2 = call(i1, descr=nonwritedescr)
        guard_no_exception() [i1, i2]
        jump(i2)
        """
        self.optimize_loop(ops, ops)

    def test_keep_guard_no_exception_with_call_pure_that_is_not_folded(self):
        ops = """
        [i1]
        i2 = call_pure(123456, i1, descr=nonwritedescr)
        guard_no_exception() [i1, i2]
        jump(i2)
        """
        expected = """
        [i1]
        i2 = call(123456, i1, descr=nonwritedescr)
        guard_no_exception() [i1, i2]
        jump(i2)
        """
        self.optimize_loop(ops, expected)

    def test_remove_guard_no_exception_with_call_pure_on_constant_args(self):
        arg_consts = [ConstInt(i) for i in (123456, 81)]
        call_pure_results = {tuple(arg_consts): ConstInt(5)}
        ops = """
        [i1]
        i3 = same_as(81)
        i2 = call_pure(123456, i3, descr=nonwritedescr)
        guard_no_exception() [i1, i2]
        jump(i2)
        """
        expected = """
        [i1]
        jump(5)
        """
        self.optimize_loop(ops, expected, call_pure_results)

    def test_remove_guard_no_exception_with_duplicated_call_pure(self):
        ops = """
        [i1]
        i2 = call_pure(123456, i1, descr=nonwritedescr)
        guard_no_exception() [i1, i2]
        i3 = call_pure(123456, i1, descr=nonwritedescr)
        guard_no_exception() [i1, i2, i3]
        jump(i3)
        """
        expected = """
        [i1]
        i2 = call(123456, i1, descr=nonwritedescr)
        guard_no_exception() [i1, i2]
        jump(i2)
        """
        self.optimize_loop(ops, expected)

    # ----------

    def test_call_loopinvariant(self):
        ops = """
        [i1]
        i2 = call_loopinvariant(1, i1, descr=nonwritedescr)
        guard_no_exception() []
        guard_value(i2, 1) []
        i3 = call_loopinvariant(1, i1, descr=nonwritedescr)
        guard_no_exception() []
        guard_value(i3, 1) []
        i4 = call_loopinvariant(1, i1, descr=nonwritedescr)
        guard_no_exception() []
        guard_value(i4, 1) []
        jump(i1)
        """
        expected = """
        [i1]
        i2 = call(1, i1, descr=nonwritedescr)
        guard_no_exception() []
        guard_value(i2, 1) []
        jump(i1)
        """
        self.optimize_loop(ops, expected)


    # ----------

    def test_virtual_1(self):
        ops = """
        [i, p0]
        i0 = getfield_gc(p0, descr=valuedescr)
        i1 = int_add(i0, i)
        setfield_gc(p0, i1, descr=valuedescr)
        jump(i, p0)
        """
        expected = """
        [i, i2]
        i1 = int_add(i2, i)
        jump(i, i1)
        """
        py.test.skip("XXX")
        self.optimize_loop(ops, 'Not, Virtual(node_vtable, valuedescr=Not)',
                           expected)

    def test_virtual_float(self):
        ops = """
        [f, p0]
        f0 = getfield_gc(p0, descr=floatdescr)
        f1 = float_add(f0, f)
        setfield_gc(p0, f1, descr=floatdescr)
        jump(f, p0)
        """
        expected = """
        [f, f2]
        f1 = float_add(f2, f)
        jump(f, f1)
        """
        py.test.skip("XXX")
        self.optimize_loop(ops, 'Not, Virtual(node_vtable, floatdescr=Not)',
                           expected)

    def test_virtual_2(self):
        ops = """
        [i, p0]
        i0 = getfield_gc(p0, descr=valuedescr)
        i1 = int_add(i0, i)
        p1 = new_with_vtable(ConstClass(node_vtable))
        setfield_gc(p1, i1, descr=valuedescr)
        jump(i, p1)
        """
        expected = """
        [i, i2]
        i1 = int_add(i2, i)
        jump(i, i1)
        """
        py.test.skip("XXX")
        self.optimize_loop(ops, 'Not, Virtual(node_vtable, valuedescr=Not)',
                           expected)

    def test_virtual_oois(self):
        ops = """
        [p0, p1, p2]
        guard_nonnull(p0) []
        i3 = ptr_ne(p0, NULL)
        guard_true(i3) []
        i4 = ptr_eq(p0, NULL)
        guard_false(i4) []
        i5 = ptr_ne(NULL, p0)
        guard_true(i5) []
        i6 = ptr_eq(NULL, p0)
        guard_false(i6) []
        i7 = ptr_ne(p0, p1)
        guard_true(i7) []
        i8 = ptr_eq(p0, p1)
        guard_false(i8) []
        i9 = ptr_ne(p0, p2)
        guard_true(i9) []
        i10 = ptr_eq(p0, p2)
        guard_false(i10) []
        i11 = ptr_ne(p2, p1)
        guard_true(i11) []
        i12 = ptr_eq(p2, p1)
        guard_false(i12) []
        jump(p0, p1, p2)
        """
        expected = """
        [p2]
        # all constant-folded :-)
        jump(p2)
        """
        py.test.skip("XXX")
        self.optimize_loop(ops, '''Virtual(node_vtable),
                                   Virtual(node_vtable),
                                   Not''',
                           expected)
        #
        # to be complete, we also check the no-opt case where most comparisons
        # are not removed.  The exact set of comparisons removed depends on
        # the details of the algorithm...
        expected2 = """
        [p0, p1, p2]
        guard_nonnull(p0) []
        i7 = ptr_ne(p0, p1)
        guard_true(i7) []
        i9 = ptr_ne(p0, p2)
        guard_true(i9) []
        i11 = ptr_ne(p2, p1)
        guard_true(i11) []
        jump(p0, p1, p2)
        """
        self.optimize_loop(ops, expected2)

    def test_virtual_default_field(self):
        ops = """
        [p0]
        i0 = getfield_gc(p0, descr=valuedescr)
        guard_value(i0, 0) []
        p1 = new_with_vtable(ConstClass(node_vtable))
        # the field 'value' has its default value of 0
        jump(p1)
        """
        expected = """
        [i]
        guard_value(i, 0) []
        jump(0)
        """
        # the 'expected' is sub-optimal, but it should be done by another later
        # optimization step.  See test_find_nodes_default_field() for why.
        py.test.skip("XXX")
        self.optimize_loop(ops, 'Virtual(node_vtable, valuedescr=Not)',
                           expected)

    def test_virtual_3(self):
        ops = """
        [i]
        p1 = new_with_vtable(ConstClass(node_vtable))
        setfield_gc(p1, i, descr=valuedescr)
        i0 = getfield_gc(p1, descr=valuedescr)
        i1 = int_add(i0, 1)
        jump(i1)
        """
        expected = """
        [i]
        i1 = int_add(i, 1)
        jump(i1)
        """
        self.optimize_loop(ops, expected)

    def test_virtual_4(self):
        ops = """
        [i0, p0]
        guard_class(p0, ConstClass(node_vtable)) []
        i1 = getfield_gc(p0, descr=valuedescr)
        i2 = int_sub(i1, 1)
        i3 = int_add(i0, i1)
        p1 = new_with_vtable(ConstClass(node_vtable))
        setfield_gc(p1, i2, descr=valuedescr)
        jump(i3, p1)
        """
        expected = """
        [i0, i1]
        i2 = int_sub(i1, 1)
        i3 = int_add(i0, i1)
        jump(i3, i2)
        """
        py.test.skip("XXX")
        self.optimize_loop(ops, 'Not, Virtual(node_vtable, valuedescr=Not)',
                           expected)

    def test_virtual_5(self):
        ops = """
        [i0, p0]
        guard_class(p0, ConstClass(node_vtable)) []
        i1 = getfield_gc(p0, descr=valuedescr)
        i2 = int_sub(i1, 1)
        i3 = int_add(i0, i1)
        p2 = new_with_vtable(ConstClass(node_vtable2))
        setfield_gc(p2, i1, descr=valuedescr)
        p1 = new_with_vtable(ConstClass(node_vtable))
        setfield_gc(p1, i2, descr=valuedescr)
        setfield_gc(p1, p2, descr=nextdescr)
        jump(i3, p1)
        """
        expected = """
        [i0, i1, i1bis]
        i2 = int_sub(i1, 1)
        i3 = int_add(i0, i1)
        jump(i3, i2, i1)
        """
        py.test.skip("XXX")
        self.optimize_loop(ops,
            '''Not, Virtual(node_vtable,
                            valuedescr=Not,
                            nextdescr=Virtual(node_vtable2,
                                              valuedescr=Not))''',
                           expected)

    def test_virtual_constant_isnull(self):
        ops = """
        [i0]
        p0 = new_with_vtable(ConstClass(node_vtable))
        setfield_gc(p0, NULL, descr=nextdescr)
        p2 = getfield_gc(p0, descr=nextdescr)
        i1 = ptr_eq(p2, NULL)
        jump(i1)
        """
        expected = """
        [i0]
        jump(1)
        """
        self.optimize_loop(ops, expected)

    def test_virtual_constant_isnonnull(self):
        ops = """
        [i0]
        p0 = new_with_vtable(ConstClass(node_vtable))
        setfield_gc(p0, ConstPtr(myptr), descr=nextdescr)
        p2 = getfield_gc(p0, descr=nextdescr)
        i1 = ptr_eq(p2, NULL)
        jump(i1)
        """
        expected = """
        [i0]
        jump(0)
        """
        self.optimize_loop(ops, expected)

    def test_virtual_array_of_struct(self):
        ops = """
        [f0, f1, f2, f3]
        p0 = new_array(2, descr=complexarraydescr)
        setinteriorfield_gc(p0, 0, f1, descr=compleximagdescr)
        setinteriorfield_gc(p0, 0, f0, descr=complexrealdescr)
        setinteriorfield_gc(p0, 1, f3, descr=compleximagdescr)
        setinteriorfield_gc(p0, 1, f2, descr=complexrealdescr)
        f4 = getinteriorfield_gc(p0, 0, descr=complexrealdescr)
        f5 = getinteriorfield_gc(p0, 1, descr=complexrealdescr)
        f6 = float_mul(f4, f5)
        f7 = getinteriorfield_gc(p0, 0, descr=compleximagdescr)
        f8 = getinteriorfield_gc(p0, 1, descr=compleximagdescr)
        f9 = float_mul(f7, f8)
        f10 = float_add(f6, f9)
        finish(f10)
        """
        expected = """
        [f0, f1, f2, f3]
        f4 = float_mul(f0, f2)
        f5 = float_mul(f1, f3)
        f6 = float_add(f4, f5)
        finish(f6)
        """
        self.optimize_loop(ops, expected)

    def test_virtual_array_of_struct_forced(self):
        ops = """
        [f0, f1]
        p0 = new_array(1, descr=complexarraydescr)
        setinteriorfield_gc(p0, 0, f0, descr=complexrealdescr)
        setinteriorfield_gc(p0, 0, f1, descr=compleximagdescr)
        f2 = getinteriorfield_gc(p0, 0, descr=complexrealdescr)
        f3 = getinteriorfield_gc(p0, 0, descr=compleximagdescr)
        f4 = float_mul(f2, f3)
        i0 = escape(f4, p0)
        finish(i0)
        """
        expected = """
        [f0, f1]
        f2 = float_mul(f0, f1)
        p0 = new_array(1, descr=complexarraydescr)
        setinteriorfield_gc(p0, 0, f1, descr=compleximagdescr)
        setinteriorfield_gc(p0, 0, f0, descr=complexrealdescr)
        i0 = escape(f2, p0)
        finish(i0)
        """
        self.optimize_loop(ops, expected)

    def test_nonvirtual_1(self):
        ops = """
        [i]
        p1 = new_with_vtable(ConstClass(node_vtable))
        setfield_gc(p1, i, descr=valuedescr)
        i0 = getfield_gc(p1, descr=valuedescr)
        i1 = int_add(i0, 1)
        escape(p1)
        escape(p1)
        jump(i1)
        """
        expected = """
        [i]
        i1 = int_add(i, 1)
        p1 = new_with_vtable(ConstClass(node_vtable))
        setfield_gc(p1, i, descr=valuedescr)
        escape(p1)
        escape(p1)
        jump(i1)
        """
        self.optimize_loop(ops, expected)

    def test_nonvirtual_2(self):
        ops = """
        [i, p0]
        i0 = getfield_gc(p0, descr=valuedescr)
        escape(p0)
        i1 = int_add(i0, i)
        p1 = new_with_vtable(ConstClass(node_vtable))
        setfield_gc(p1, i1, descr=valuedescr)
        jump(i, p1)
        """
        expected = ops
        self.optimize_loop(ops, expected)

    def test_nonvirtual_later(self):
        ops = """
        [i]
        p1 = new_with_vtable(ConstClass(node_vtable))
        setfield_gc(p1, i, descr=valuedescr)
        i1 = getfield_gc(p1, descr=valuedescr)
        escape(p1)
        i2 = getfield_gc(p1, descr=valuedescr)
        i3 = int_add(i1, i2)
        jump(i3)
        """
        expected = """
        [i]
        p1 = new_with_vtable(ConstClass(node_vtable))
        setfield_gc(p1, i, descr=valuedescr)
        escape(p1)
        i2 = getfield_gc(p1, descr=valuedescr)
        i3 = int_add(i, i2)
        jump(i3)
        """
        self.optimize_loop(ops, expected)

    def test_nonvirtual_dont_write_null_fields_on_force(self):
        ops = """
        [i]
        p1 = new_with_vtable(ConstClass(node_vtable))
        setfield_gc(p1, i, descr=valuedescr)
        i1 = getfield_gc(p1, descr=valuedescr)
        setfield_gc(p1, 0, descr=valuedescr)
        escape(p1)
        i2 = getfield_gc(p1, descr=valuedescr)
        jump(i2)
        """
        expected = """
        [i]
        p1 = new_with_vtable(ConstClass(node_vtable))
        escape(p1)
        i2 = getfield_gc(p1, descr=valuedescr)
        jump(i2)
        """
        self.optimize_loop(ops, expected)

    def test_getfield_gc_pure_1(self):
        ops = """
        [i]
        p1 = new_with_vtable(ConstClass(node_vtable))
        setfield_gc(p1, i, descr=valuedescr)
        i1 = getfield_gc_pure(p1, descr=valuedescr)
        jump(i1)
        """
        expected = """
        [i]
        jump(i)
        """
        self.optimize_loop(ops, expected)

    def test_getfield_gc_pure_2(self):
        ops = """
        [i]
        i1 = getfield_gc_pure(ConstPtr(myptr), descr=valuedescr)
        jump(i1)
        """
        expected = """
        [i]
        jump(5)
        """
        self.node.value = 5
        self.optimize_loop(ops, expected)

    def test_getfield_gc_nonpure_2(self):
        ops = """
        [i]
        i1 = getfield_gc(ConstPtr(myptr), descr=valuedescr)
        jump(i1)
        """
        expected = ops
        self.optimize_loop(ops, expected)

    def test_varray_1(self):
        ops = """
        [i1]
        p1 = new_array(3, descr=arraydescr)
        i3 = arraylen_gc(p1, descr=arraydescr)
        guard_value(i3, 3) []
        setarrayitem_gc(p1, 1, i1, descr=arraydescr)
        setarrayitem_gc(p1, 0, 25, descr=arraydescr)
        i2 = getarrayitem_gc(p1, 1, descr=arraydescr)
        jump(i2)
        """
        expected = """
        [i1]
        jump(i1)
        """
        self.optimize_loop(ops, expected)

    def test_varray_alloc_and_set(self):
        ops = """
        [i1]
        p1 = new_array(2, descr=arraydescr)
        setarrayitem_gc(p1, 0, 25, descr=arraydescr)
        i2 = getarrayitem_gc(p1, 1, descr=arraydescr)
        jump(i2)
        """
        expected = """
        [i1]
        jump(0)
        """
        self.optimize_loop(ops, expected)

    def test_varray_float(self):
        ops = """
        [f1]
        p1 = new_array(3, descr=floatarraydescr)
        i3 = arraylen_gc(p1, descr=floatarraydescr)
        guard_value(i3, 3) []
        setarrayitem_gc(p1, 1, f1, descr=floatarraydescr)
        setarrayitem_gc(p1, 0, 3.5, descr=floatarraydescr)
        f2 = getarrayitem_gc(p1, 1, descr=floatarraydescr)
        jump(f2)
        """
        expected = """
        [f1]
        jump(f1)
        """
        self.optimize_loop(ops, expected)

    def test_array_non_optimized(self):
        ops = """
        [i1, p0]
        setarrayitem_gc(p0, 0, i1, descr=arraydescr)
        guard_nonnull(p0) []
        p1 = new_array(i1, descr=arraydescr)
        jump(i1, p1)
        """
        expected = """
        [i1, p0]
        p1 = new_array(i1, descr=arraydescr)
        setarrayitem_gc(p0, 0, i1, descr=arraydescr)
        jump(i1, p1)
        """
        self.optimize_loop(ops, expected)

    def test_nonvirtual_array_dont_write_null_fields_on_force(self):
        ops = """
        [i1]
        p1 = new_array(5, descr=arraydescr)
        setarrayitem_gc(p1, 0, i1, descr=arraydescr)
        setarrayitem_gc(p1, 1, 0, descr=arraydescr)
        escape(p1)
        jump(i1)
        """
        expected = """
        [i1]
        p1 = new_array(5, descr=arraydescr)
        setarrayitem_gc(p1, 0, i1, descr=arraydescr)
        escape(p1)
        jump(i1)
        """
        self.optimize_loop(ops, expected)

    def test_varray_2(self):
        ops = """
        [i0, p1]
        i1 = getarrayitem_gc(p1, 0, descr=arraydescr)
        i2 = getarrayitem_gc(p1, 1, descr=arraydescr)
        i3 = int_sub(i1, i2)
        guard_value(i3, 15) []
        p2 = new_array(2, descr=arraydescr)
        setarrayitem_gc(p2, 1, i0, descr=arraydescr)
        setarrayitem_gc(p2, 0, 20, descr=arraydescr)
        jump(i0, p2)
        """
        expected = """
        [i0, i1, i2]
        i3 = int_sub(i1, i2)
        guard_value(i3, 15) []
        jump(i0, 20, i0)
        """
        py.test.skip("XXX")
        self.optimize_loop(ops, 'Not, VArray(arraydescr, Not, Not)', expected)

    def test_p123_array(self):
        ops = """
        [i1, p2, p3]
        i3 = getarrayitem_gc(p3, 0, descr=arraydescr)
        escape(i3)
        p1 = new_array(1, descr=arraydescr)
        setarrayitem_gc(p1, 0, i1, descr=arraydescr)
        jump(i1, p1, p2)
        """
        # We cannot track virtuals that survive for more than two iterations.
        self.optimize_loop(ops, ops)

    def test_varray_forced_1(self):
        ops = """
        []
        p2 = new_with_vtable(ConstClass(node_vtable))
        setfield_gc(p2, 3, descr=valuedescr)
        i1 = getfield_gc(p2, descr=valuedescr)    # i1 = const 3
        p1 = new_array(i1, descr=arraydescr)
        escape(p1)
        i2 = arraylen_gc(p1)
        escape(i2)
        jump()
        """
        expected = """
        []
        p1 = new_array(3, descr=arraydescr)
        escape(p1)
        i2 = arraylen_gc(p1)
        escape(i2)
        jump()
        """
        self.optimize_loop(ops, expected)

    def test_vstruct_1(self):
        ops = """
        [i1, p2]
        i2 = getfield_gc(p2, descr=adescr)
        escape(i2)
        p3 = new(descr=ssize)
        setfield_gc(p3, i1, descr=adescr)
        jump(i1, p3)
        """
        expected = """
        [i1, i2]
        escape(i2)
        jump(i1, i1)
        """
        py.test.skip("XXX")
        self.optimize_loop(ops, 'Not, VStruct(ssize, adescr=Not)', expected)

    def test_p123_vstruct(self):
        ops = """
        [i1, p2, p3]
        i3 = getfield_gc(p3, descr=adescr)
        escape(i3)
        p1 = new(descr=ssize)
        setfield_gc(p1, i1, descr=adescr)
        jump(i1, p1, p2)
        """
        # We cannot track virtuals that survive for more than two iterations.
        self.optimize_loop(ops, ops)

    def test_duplicate_getfield_1(self):
        ops = """
        [p1, p2]
        i1 = getfield_gc(p1, descr=valuedescr)
        i2 = getfield_gc(p2, descr=valuedescr)
        i3 = getfield_gc(p1, descr=valuedescr)
        i4 = getfield_gc(p2, descr=valuedescr)
        escape(i1)
        escape(i2)
        escape(i3)
        escape(i4)
        jump(p1, p2)
        """
        expected = """
        [p1, p2]
        i1 = getfield_gc(p1, descr=valuedescr)
        i2 = getfield_gc(p2, descr=valuedescr)
        escape(i1)
        escape(i2)
        escape(i1)
        escape(i2)
        jump(p1, p2)
        """
        self.optimize_loop(ops, expected)

    def test_getfield_after_setfield(self):
        ops = """
        [p1, i1]
        setfield_gc(p1, i1, descr=valuedescr)
        i2 = getfield_gc(p1, descr=valuedescr)
        escape(i2)
        jump(p1, i1)
        """
        expected = """
        [p1, i1]
        setfield_gc(p1, i1, descr=valuedescr)
        escape(i1)
        jump(p1, i1)
        """
        self.optimize_loop(ops, expected)

    def test_setfield_of_different_type_does_not_clear(self):
        ops = """
        [p1, p2, i1]
        setfield_gc(p1, i1, descr=valuedescr)
        setfield_gc(p2, p1, descr=nextdescr)
        i2 = getfield_gc(p1, descr=valuedescr)
        escape(i2)
        jump(p1, p2, i1)
        """
        expected = """
        [p1, p2, i1]
        setfield_gc(p1, i1, descr=valuedescr)
        setfield_gc(p2, p1, descr=nextdescr)
        escape(i1)
        jump(p1, p2, i1)
        """
        self.optimize_loop(ops, expected)

    def test_setfield_of_same_type_clears(self):
        ops = """
        [p1, p2, i1, i2]
        setfield_gc(p1, i1, descr=valuedescr)
        setfield_gc(p2, i2, descr=valuedescr)
        i3 = getfield_gc(p1, descr=valuedescr)
        escape(i3)
        jump(p1, p2, i1, i3)
        """
        self.optimize_loop(ops, ops)

    def test_duplicate_getfield_mergepoint_has_no_side_effects(self):
        ops = """
        [p1]
        i1 = getfield_gc(p1, descr=valuedescr)
        debug_merge_point(15, 0)
        i2 = getfield_gc(p1, descr=valuedescr)
        escape(i1)
        escape(i2)
        jump(p1)
        """
        expected = """
        [p1]
        i1 = getfield_gc(p1, descr=valuedescr)
        debug_merge_point(15, 0)
        escape(i1)
        escape(i1)
        jump(p1)
        """
        self.optimize_loop(ops, expected)

    def test_duplicate_getfield_ovf_op_does_not_clear(self):
        ops = """
        [p1]
        i1 = getfield_gc(p1, descr=valuedescr)
        i2 = int_add_ovf(i1, 14)
        guard_no_overflow() []
        i3 = getfield_gc(p1, descr=valuedescr)
        escape(i2)
        escape(i3)
        jump(p1)
        """
        expected = """
        [p1]
        i1 = getfield_gc(p1, descr=valuedescr)
        i2 = int_add_ovf(i1, 14)
        guard_no_overflow() []
        escape(i2)
        escape(i1)
        jump(p1)
        """
        self.optimize_loop(ops, expected)

    def test_duplicate_getfield_setarrayitem_does_not_clear(self):
        ops = """
        [p1, p2]
        i1 = getfield_gc(p1, descr=valuedescr)
        setarrayitem_gc(p2, 0, p1, descr=arraydescr2)
        i3 = getfield_gc(p1, descr=valuedescr)
        escape(i1)
        escape(i3)
        jump(p1, p2)
        """
        expected = """
        [p1, p2]
        i1 = getfield_gc(p1, descr=valuedescr)
        setarrayitem_gc(p2, 0, p1, descr=arraydescr2)
        escape(i1)
        escape(i1)
        jump(p1, p2)
        """
        self.optimize_loop(ops, expected)

    def test_duplicate_getfield_constant(self):
        ops = """
        []
        i1 = getfield_gc(ConstPtr(myptr), descr=valuedescr)
        i2 = getfield_gc(ConstPtr(myptr), descr=valuedescr)
        escape(i1)
        escape(i2)
        jump()
        """
        expected = """
        []
        i1 = getfield_gc(ConstPtr(myptr), descr=valuedescr)
        escape(i1)
        escape(i1)
        jump()
        """
        self.optimize_loop(ops, expected)

    def test_duplicate_getfield_guard_value_const(self):
        ops = """
        [p1]
        guard_value(p1, ConstPtr(myptr)) []
        i1 = getfield_gc(p1, descr=valuedescr)
        i2 = getfield_gc(ConstPtr(myptr), descr=valuedescr)
        escape(i1)
        escape(i2)
        jump(p1)
        """
        expected = """
        []
        i1 = getfield_gc(ConstPtr(myptr), descr=valuedescr)
        escape(i1)
        escape(i1)
        jump()
        """
        py.test.skip("XXX")
        self.optimize_loop(ops, 'Constant(myptr)', expected)

    def test_duplicate_getfield_sideeffects_1(self):
        ops = """
        [p1]
        i1 = getfield_gc(p1, descr=valuedescr)
        escape()
        i2 = getfield_gc(p1, descr=valuedescr)
        escape(i1)
        escape(i2)
        jump(p1)
        """
        self.optimize_loop(ops, ops)

    def test_duplicate_getfield_sideeffects_2(self):
        ops = """
        [p1, i1]
        setfield_gc(p1, i1, descr=valuedescr)
        escape()
        i2 = getfield_gc(p1, descr=valuedescr)
        escape(i2)
        jump(p1, i1)
        """
        self.optimize_loop(ops, ops)

    def test_duplicate_setfield_1(self):
        ops = """
        [p1, i1, i2]
        setfield_gc(p1, i1, descr=valuedescr)
        setfield_gc(p1, i2, descr=valuedescr)
        jump(p1, i1, i2)
        """
        expected = """
        [p1, i1, i2]
        setfield_gc(p1, i2, descr=valuedescr)
        jump(p1, i1, i2)
        """
        self.optimize_loop(ops, expected)

    def test_duplicate_setfield_2(self):
        ops = """
        [p1, i1, i3]
        setfield_gc(p1, i1, descr=valuedescr)
        i2 = getfield_gc(p1, descr=valuedescr)
        setfield_gc(p1, i3, descr=valuedescr)
        escape(i2)
        jump(p1, i1, i3)
        """
        expected = """
        [p1, i1, i3]
        setfield_gc(p1, i3, descr=valuedescr)
        escape(i1)
        jump(p1, i1, i3)
        """
        self.optimize_loop(ops, expected)

    def test_duplicate_setfield_3(self):
        ops = """
        [p1, p2, i1, i3]
        setfield_gc(p1, i1, descr=valuedescr)
        i2 = getfield_gc(p2, descr=valuedescr)
        setfield_gc(p1, i3, descr=valuedescr)
        escape(i2)
        jump(p1, p2, i1, i3)
        """
        # potential aliasing of p1 and p2 means that we cannot kill the
        # the setfield_gc
        self.optimize_loop(ops, ops)

    def test_duplicate_setfield_4(self):
        ops = """
        [p1, i1, i2, p3]
        setfield_gc(p1, i1, descr=valuedescr)
        #
        # some operations on which the above setfield_gc cannot have effect
        i3 = getarrayitem_gc_pure(p3, 1, descr=arraydescr)
        i4 = getarrayitem_gc(p3, i3, descr=arraydescr)
        i5 = int_add(i3, i4)
        setarrayitem_gc(p3, 0, i5, descr=arraydescr)
        setfield_gc(p1, i4, descr=nextdescr)
        #
        setfield_gc(p1, i2, descr=valuedescr)
        jump(p1, i1, i2, p3)
        """
        expected = """
        [p1, i1, i2, p3]
        #
        i3 = getarrayitem_gc_pure(p3, 1, descr=arraydescr)
        i4 = getarrayitem_gc(p3, i3, descr=arraydescr)
        i5 = int_add(i3, i4)
        #
        setfield_gc(p1, i2, descr=valuedescr)
        setarrayitem_gc(p3, 0, i5, descr=arraydescr)
        setfield_gc(p1, i4, descr=nextdescr)
        jump(p1, i1, i2, p3)
        """
        self.optimize_loop(ops, expected)

    def test_duplicate_setfield_5(self):
        ops = """
        [p0, i1]
        p1 = new_with_vtable(ConstClass(node_vtable))
        setfield_gc(p1, i1, descr=valuedescr)
        setfield_gc(p0, p1, descr=nextdescr)
        setfield_raw(i1, i1, descr=valuedescr)    # random op with side-effects
        p2 = getfield_gc(p0, descr=nextdescr)
        i2 = getfield_gc(p2, descr=valuedescr)
        setfield_gc(p0, NULL, descr=nextdescr)
        escape(i2)
        jump(p0, i1)
        """
        expected = """
        [p0, i1]
        setfield_raw(i1, i1, descr=valuedescr)
        setfield_gc(p0, NULL, descr=nextdescr)
        escape(i1)
        jump(p0, i1)
        """
        self.optimize_loop(ops, expected)

    def test_duplicate_setfield_sideeffects_1(self):
        ops = """
        [p1, i1, i2]
        setfield_gc(p1, i1, descr=valuedescr)
        escape()
        setfield_gc(p1, i2, descr=valuedescr)
        jump(p1, i1, i2)
        """
        self.optimize_loop(ops, ops)

    def test_duplicate_setfield_residual_guard_1(self):
        ops = """
        [p1, i1, i2, i3]
        setfield_gc(p1, i1, descr=valuedescr)
        guard_true(i3) []
        i4 = int_neg(i2)
        setfield_gc(p1, i2, descr=valuedescr)
        jump(p1, i1, i2, i4)
        """
        self.optimize_loop(ops, ops)

    def test_duplicate_setfield_residual_guard_2(self):
        # the difference with the previous test is that the field value is
        # a virtual, which we try hard to keep virtual
        ops = """
        [p1, i2, i3]
        p2 = new_with_vtable(ConstClass(node_vtable))
        setfield_gc(p1, p2, descr=nextdescr)
        guard_true(i3) []
        i4 = int_neg(i2)
        setfield_gc(p1, NULL, descr=nextdescr)
        jump(p1, i2, i4)
        """
        expected = """
        [p1, i2, i3]
        guard_true(i3) [p1]
        i4 = int_neg(i2)
        setfield_gc(p1, NULL, descr=nextdescr)
        jump(p1, i2, i4)
        """
        self.optimize_loop(ops, expected)

    def test_duplicate_setfield_residual_guard_3(self):
        ops = """
        [p1, i2, i3]
        p2 = new_with_vtable(ConstClass(node_vtable))
        setfield_gc(p2, i2, descr=valuedescr)
        setfield_gc(p1, p2, descr=nextdescr)
        guard_true(i3) []
        i4 = int_neg(i2)
        setfield_gc(p1, NULL, descr=nextdescr)
        jump(p1, i2, i4)
        """
        expected = """
        [p1, i2, i3]
        guard_true(i3) [i2, p1]
        i4 = int_neg(i2)
        setfield_gc(p1, NULL, descr=nextdescr)
        jump(p1, i2, i4)
        """
        self.optimize_loop(ops, expected)

    def test_duplicate_setfield_residual_guard_4(self):
        # test that the setfield_gc does not end up between int_eq and
        # the following guard_true
        ops = """
        [p1, i1, i2, i3]
        setfield_gc(p1, i1, descr=valuedescr)
        i5 = int_eq(i3, 5)
        guard_true(i5) []
        i4 = int_neg(i2)
        setfield_gc(p1, i2, descr=valuedescr)
        jump(p1, i1, i2, i4)
        """
        self.optimize_loop(ops, ops)

    def test_duplicate_setfield_aliasing(self):
        # a case where aliasing issues (and not enough cleverness) mean
        # that we fail to remove any setfield_gc
        ops = """
        [p1, p2, i1, i2, i3]
        setfield_gc(p1, i1, descr=valuedescr)
        setfield_gc(p2, i2, descr=valuedescr)
        setfield_gc(p1, i3, descr=valuedescr)
        jump(p1, p2, i1, i2, i3)
        """
        self.optimize_loop(ops, ops)

    def test_duplicate_setfield_guard_value_const(self):
        ops = """
        [p1, i1, i2]
        guard_value(p1, ConstPtr(myptr)) []
        setfield_gc(p1, i1, descr=valuedescr)
        setfield_gc(ConstPtr(myptr), i2, descr=valuedescr)
        jump(p1, i1, i2)
        """
        expected = """
        [i1, i2]
        setfield_gc(ConstPtr(myptr), i2, descr=valuedescr)
        jump(i1, i2)
        """
        py.test.skip("XXX")
        self.optimize_loop(ops, 'Constant(myptr), Not, Not', expected)

    def test_duplicate_getarrayitem_1(self):
        ops = """
        [p1]
        p2 = getarrayitem_gc(p1, 0, descr=arraydescr2)
        p3 = getarrayitem_gc(p1, 1, descr=arraydescr2)
        p4 = getarrayitem_gc(p1, 0, descr=arraydescr2)
        p5 = getarrayitem_gc(p1, 1, descr=arraydescr2)
        escape(p2)
        escape(p3)
        escape(p4)
        escape(p5)
        jump(p1)
        """
        expected = """
        [p1]
        p2 = getarrayitem_gc(p1, 0, descr=arraydescr2)
        p3 = getarrayitem_gc(p1, 1, descr=arraydescr2)
        escape(p2)
        escape(p3)
        escape(p2)
        escape(p3)
        jump(p1)
        """
        self.optimize_loop(ops, expected)

    def test_duplicate_getarrayitem_after_setarrayitem_1(self):
        ops = """
        [p1, p2]
        setarrayitem_gc(p1, 0, p2, descr=arraydescr2)
        p3 = getarrayitem_gc(p1, 0, descr=arraydescr2)
        escape(p3)
        jump(p1, p3)
        """
        expected = """
        [p1, p2]
        setarrayitem_gc(p1, 0, p2, descr=arraydescr2)
        escape(p2)
        jump(p1, p2)
        """
        self.optimize_loop(ops, expected)

    def test_duplicate_getarrayitem_after_setarrayitem_2(self):
        py.test.skip("setarrayitem with variable index")
        ops = """
        [p1, p2, p3, i1]
        setarrayitem_gc(p1, 0, p2, descr=arraydescr2)
        setarrayitem_gc(p1, i1, p3, descr=arraydescr2)
        p4 = getarrayitem_gc(p1, 0, descr=arraydescr2)
        p5 = getarrayitem_gc(p1, i1, descr=arraydescr2)
        escape(p4)
        escape(p5)
        jump(p1, p2, p3, i1)
        """
        expected = """
        [p1, p2, p3, i1]
        setarrayitem_gc(p1, 0, p2, descr=arraydescr2)
        setarrayitem_gc(p1, i1, p3, descr=arraydescr2)
        p4 = getarrayitem_gc(p1, 0, descr=arraydescr2)
        escape(p4)
        escape(p3)
        jump(p1, p2, p3, i1)
        """
        self.optimize_loop(ops, expected)

    def test_duplicate_getarrayitem_after_setarrayitem_3(self):
        ops = """
        [p1, p2, p3, p4, i1]
        setarrayitem_gc(p1, i1, p2, descr=arraydescr2)
        setarrayitem_gc(p1, 0, p3, descr=arraydescr2)
        setarrayitem_gc(p1, 1, p4, descr=arraydescr2)
        p5 = getarrayitem_gc(p1, i1, descr=arraydescr2)
        p6 = getarrayitem_gc(p1, 0, descr=arraydescr2)
        p7 = getarrayitem_gc(p1, 1, descr=arraydescr2)
        escape(p5)
        escape(p6)
        escape(p7)
        jump(p1, p2, p3, p4, i1)
        """
        expected = """
        [p1, p2, p3, p4, i1]
        setarrayitem_gc(p1, i1, p2, descr=arraydescr2)
        setarrayitem_gc(p1, 0, p3, descr=arraydescr2)
        setarrayitem_gc(p1, 1, p4, descr=arraydescr2)
        p5 = getarrayitem_gc(p1, i1, descr=arraydescr2)
        escape(p5)
        escape(p3)
        escape(p4)
        jump(p1, p2, p3, p4, i1)
        """
        self.optimize_loop(ops, expected)

    def test_getarrayitem_pure_does_not_invalidate(self):
        ops = """
        [p1, p2]
        p3 = getarrayitem_gc(p1, 0, descr=arraydescr2)
        i4 = getfield_gc_pure(ConstPtr(myptr), descr=valuedescr)
        p5 = getarrayitem_gc(p1, 0, descr=arraydescr2)
        escape(p3)
        escape(i4)
        escape(p5)
        jump(p1, p2)
        """
        expected = """
        [p1, p2]
        p3 = getarrayitem_gc(p1, 0, descr=arraydescr2)
        escape(p3)
        escape(5)
        escape(p3)
        jump(p1, p2)
        """
        self.optimize_loop(ops, expected)

    def test_duplicate_getarrayitem_after_setarrayitem_two_arrays(self):
        ops = """
        [p1, p2, p3, p4, i1]
        setarrayitem_gc(p1, 0, p3, descr=arraydescr2)
        setarrayitem_gc(p2, 1, p4, descr=arraydescr2)
        p5 = getarrayitem_gc(p1, 0, descr=arraydescr2)
        p6 = getarrayitem_gc(p2, 1, descr=arraydescr2)
        escape(p5)
        escape(p6)
        jump(p1, p2, p3, p4, i1)
        """
        expected = """
        [p1, p2, p3, p4, i1]
        setarrayitem_gc(p1, 0, p3, descr=arraydescr2)
        setarrayitem_gc(p2, 1, p4, descr=arraydescr2)
        escape(p3)
        escape(p4)
        jump(p1, p2, p3, p4, i1)
        """
        self.optimize_loop(ops, expected)

    def test_duplicate_getarrayitem_after_setarrayitem_bug(self):
        ops = """
        [p0, i0, i1]
        setarrayitem_gc(p0, 0, i0, descr=arraydescr)
        i6 = int_add(i0, 1)
        setarrayitem_gc(p0, i1, i6, descr=arraydescr)
        i10 = getarrayitem_gc(p0, 0, descr=arraydescr)
        i11 = int_add(i10, i0)
        jump(p0, i11, i1)
        """
        expected = """
        [p0, i0, i1]
        i6 = int_add(i0, 1)
        setarrayitem_gc(p0, 0, i0, descr=arraydescr)
        setarrayitem_gc(p0, i1, i6, descr=arraydescr)
        i10 = getarrayitem_gc(p0, 0, descr=arraydescr)
        i11 = int_add(i10, i0)
        jump(p0, i11, i1)
        """
        self.optimize_loop(ops, expected)

    def test_duplicate_getarrayitem_after_setarrayitem_bug2(self):
        ops = """
        [p0, i0, i1]
        i2 = getarrayitem_gc(p0, 0, descr=arraydescr)
        i6 = int_add(i0, 1)
        setarrayitem_gc(p0, i1, i6, descr=arraydescr)
        i10 = getarrayitem_gc(p0, 0, descr=arraydescr)
        i11 = int_add(i10, i2)
        jump(p0, i11, i1)
        """
        expected = """
        [p0, i0, i1]
        i2 = getarrayitem_gc(p0, 0, descr=arraydescr)
        i6 = int_add(i0, 1)
        setarrayitem_gc(p0, i1, i6, descr=arraydescr)
        i10 = getarrayitem_gc(p0, 0, descr=arraydescr)
        i11 = int_add(i10, i2)
        jump(p0, i11, i1)
        """
        self.optimize_loop(ops, expected)

    def test_bug_1(self):
        ops = """
        [i0, p1]
        p4 = getfield_gc(p1, descr=nextdescr)
        guard_nonnull(p4) []
        escape(p4)
        #
        p2 = new_with_vtable(ConstClass(node_vtable))
        p3 = escape()
        setfield_gc(p2, p3, descr=nextdescr)
        jump(i0, p2)
        """
        expected = """
        [i0, p4]
        guard_nonnull(p4) []
        escape(p4)
        #
        p3 = escape()
        jump(i0, p3)
        """
        py.test.skip("XXX")
        self.optimize_loop(ops, 'Not, Virtual(node_vtable, nextdescr=Not)',
                           expected)

    def test_bug_2(self):
        ops = """
        [i0, p1]
        p4 = getarrayitem_gc(p1, 0, descr=arraydescr2)
        guard_nonnull(p4) []
        escape(p4)
        #
        p2 = new_array(1, descr=arraydescr2)
        p3 = escape()
        setarrayitem_gc(p2, 0, p3, descr=arraydescr2)
        jump(i0, p2)
        """
        expected = """
        [i0, p4]
        guard_nonnull(p4) []
        escape(p4)
        #
        p3 = escape()
        jump(i0, p3)
        """
        py.test.skip("XXX")
        self.optimize_loop(ops, 'Not, VArray(arraydescr2, Not)',
                           expected)

    def test_bug_3(self):
        ops = """
        [p1]
        guard_nonnull(p1) []
        guard_class(p1, ConstClass(node_vtable2)) []
        p2 = getfield_gc(p1, descr=nextdescr)
        guard_nonnull(12) []
        guard_class(p2, ConstClass(node_vtable)) []
        p3 = getfield_gc(p1, descr=otherdescr)
        guard_nonnull(12) []
        guard_class(p3, ConstClass(node_vtable)) []
        setfield_gc(p3, p2, descr=otherdescr)
        p1a = new_with_vtable(ConstClass(node_vtable2))
        p2a = new_with_vtable(ConstClass(node_vtable))
        p3a = new_with_vtable(ConstClass(node_vtable))
        escape(p3a)
        setfield_gc(p1a, p2a, descr=nextdescr)
        setfield_gc(p1a, p3a, descr=otherdescr)
        jump(p1a)
        """
        expected = """
        [p2, p3]
        guard_class(p2, ConstClass(node_vtable)) []
        guard_class(p3, ConstClass(node_vtable)) []
        setfield_gc(p3, p2, descr=otherdescr)
        p3a = new_with_vtable(ConstClass(node_vtable))
        escape(p3a)
        p2a = new_with_vtable(ConstClass(node_vtable))
        jump(p2a, p3a)
        """
        py.test.skip("XXX")
        self.optimize_loop(ops, 'Virtual(node_vtable2, nextdescr=Not, otherdescr=Not)', expected)

    def test_bug_3bis(self):
        ops = """
        [p1]
        guard_nonnull(p1) []
        guard_class(p1, ConstClass(node_vtable2)) []
        p2 = getfield_gc(p1, descr=nextdescr)
        guard_nonnull(12) []
        guard_class(p2, ConstClass(node_vtable)) []
        p3 = getfield_gc(p1, descr=otherdescr)
        guard_nonnull(12) []
        guard_class(p3, ConstClass(node_vtable)) []
        p1a = new_with_vtable(ConstClass(node_vtable2))
        p2a = new_with_vtable(ConstClass(node_vtable))
        setfield_gc(p3, p2a, descr=otherdescr)
        p3a = new_with_vtable(ConstClass(node_vtable))
        escape(p3a)
        setfield_gc(p1a, p2a, descr=nextdescr)
        setfield_gc(p1a, p3a, descr=otherdescr)
        jump(p1a)
        """
        expected = """
        [p2, p3]
        guard_class(p2, ConstClass(node_vtable)) []
        guard_class(p3, ConstClass(node_vtable)) []
        p2a = new_with_vtable(ConstClass(node_vtable))
        setfield_gc(p3, p2a, descr=otherdescr)
        p3a = new_with_vtable(ConstClass(node_vtable))
        escape(p3a)
        jump(p2a, p3a)
        """
        py.test.skip("XXX")
        self.optimize_loop(ops, 'Virtual(node_vtable2, nextdescr=Not, otherdescr=Not)', expected)

    def test_invalid_loop_1(self):
        ops = """
        [p1]
        guard_isnull(p1) []
        #
        p2 = new_with_vtable(ConstClass(node_vtable))
        jump(p2)
        """
        py.test.skip("XXX")
        py.test.raises(InvalidLoop, self.optimize_loop,
                       ops, 'Virtual(node_vtable)', None)

    def test_invalid_loop_2(self):
        py.test.skip("this would fail if we had Fixed again in the specnodes")
        ops = """
        [p1]
        guard_class(p1, ConstClass(node_vtable2)) []
        #
        p2 = new_with_vtable(ConstClass(node_vtable))
        escape(p2)      # prevent it from staying Virtual
        jump(p2)
        """
        py.test.raises(InvalidLoop, self.optimize_loop,
                       ops, '...', None)

    def test_invalid_loop_3(self):
        ops = """
        [p1]
        p2 = getfield_gc(p1, descr=nextdescr)
        guard_isnull(p2) []
        #
        p3 = new_with_vtable(ConstClass(node_vtable))
        p4 = new_with_vtable(ConstClass(node_vtable))
        setfield_gc(p3, p4, descr=nextdescr)
        jump(p3)
        """
        py.test.skip("XXX")
        py.test.raises(InvalidLoop, self.optimize_loop, ops,
                       'Virtual(node_vtable, nextdescr=Virtual(node_vtable))',
                       None)

    def test_merge_guard_class_guard_value(self):
        ops = """
        [p1, i0, i1, i2, p2]
        guard_class(p1, ConstClass(node_vtable)) [i0]
        i3 = int_add(i1, i2)
        guard_value(p1, ConstPtr(myptr)) [i1]
        jump(p2, i0, i1, i3, p2)
        """
        expected = """
        [p1, i0, i1, i2, p2]
        guard_value(p1, ConstPtr(myptr)) [i0]
        i3 = int_add(i1, i2)
        jump(p2, i0, i1, i3, p2)
        """
        self.optimize_loop(ops, expected)

    def test_merge_guard_nonnull_guard_class(self):
        ops = """
        [p1, i0, i1, i2, p2]
        guard_nonnull(p1, descr=fdescr) [i0]
        i3 = int_add(i1, i2)
        guard_class(p1, ConstClass(node_vtable)) [i1]
        jump(p2, i0, i1, i3, p2)
        """
        expected = """
        [p1, i0, i1, i2, p2]
        guard_nonnull_class(p1, ConstClass(node_vtable), descr=fdescr) [i0]
        i3 = int_add(i1, i2)
        jump(p2, i0, i1, i3, p2)
        """
        self.optimize_loop(ops, expected)
        self.check_expanded_fail_descr("i0", rop.GUARD_NONNULL_CLASS)

    def test_merge_guard_nonnull_guard_value(self):
        ops = """
        [p1, i0, i1, i2, p2]
        guard_nonnull(p1, descr=fdescr) [i0]
        i3 = int_add(i1, i2)
        guard_value(p1, ConstPtr(myptr)) [i1]
        jump(p2, i0, i1, i3, p2)
        """
        expected = """
        [p1, i0, i1, i2, p2]
        guard_value(p1, ConstPtr(myptr), descr=fdescr) [i0]
        i3 = int_add(i1, i2)
        jump(p2, i0, i1, i3, p2)
        """
        self.optimize_loop(ops, expected)
        self.check_expanded_fail_descr("i0", rop.GUARD_VALUE)

    def test_merge_guard_nonnull_guard_class_guard_value(self):
        ops = """
        [p1, i0, i1, i2, p2]
        guard_nonnull(p1, descr=fdescr) [i0]
        i3 = int_add(i1, i2)
        guard_class(p1, ConstClass(node_vtable)) [i2]
        i4 = int_sub(i3, 1)
        guard_value(p1, ConstPtr(myptr)) [i1]
        jump(p2, i0, i1, i4, p2)
        """
        expected = """
        [p1, i0, i1, i2, p2]
        guard_value(p1, ConstPtr(myptr), descr=fdescr) [i0]
        i3 = int_add(i1, i2)
        i4 = int_sub(i3, 1)
        jump(p2, i0, i1, i4, p2)
        """
        self.optimize_loop(ops, expected)
        self.check_expanded_fail_descr("i0", rop.GUARD_VALUE)

    def test_guard_class_oois(self):
        ops = """
        [p1]
        guard_class(p1, ConstClass(node_vtable2)) []
        i = instance_ptr_ne(ConstPtr(myptr), p1)
        guard_true(i) []
        jump(p1)
        """
        expected = """
        [p1]
        guard_class(p1, ConstClass(node_vtable2)) []
        jump(p1)
        """
        self.optimize_loop(ops, expected)

    def test_oois_of_itself(self):
        ops = """
        [p0]
        p1 = getfield_gc(p0, descr=nextdescr)
        p2 = getfield_gc(p0, descr=nextdescr)
        i1 = ptr_eq(p1, p2)
        guard_true(i1) []
        i2 = ptr_ne(p1, p2)
        guard_false(i2) []
        jump(p0)
        """
        expected = """
        [p0]
        p1 = getfield_gc(p0, descr=nextdescr)
        jump(p0)
        """
        self.optimize_loop(ops, expected)

    def test_remove_duplicate_pure_op(self):
        ops = """
        [p1, p2]
        i1 = ptr_eq(p1, p2)
        i2 = ptr_eq(p1, p2)
        i3 = int_add(i1, 1)
        i3b = int_is_true(i3)
        guard_true(i3b) []
        i4 = int_add(i2, 1)
        i4b = int_is_true(i4)
        guard_true(i4b) []
        escape(i3)
        escape(i4)
        guard_true(i1) []
        guard_true(i2) []
        jump(p1, p2)
        """
        expected = """
        [p1, p2]
        i1 = ptr_eq(p1, p2)
        i3 = int_add(i1, 1)
        i3b = int_is_true(i3)
        guard_true(i3b) []
        escape(i3)
        escape(i3)
        guard_true(i1) []
        jump(p1, p2)
        """
        self.optimize_loop(ops, expected)

    def test_remove_duplicate_pure_op_with_descr(self):
        ops = """
        [p1]
        i0 = arraylen_gc(p1, descr=arraydescr)
        i1 = int_gt(i0, 0)
        guard_true(i1) []
        i2 = arraylen_gc(p1, descr=arraydescr)
        i3 = int_gt(i0, 0)
        guard_true(i3) []
        jump(p1)
        """
        expected = """
        [p1]
        i0 = arraylen_gc(p1, descr=arraydescr)
        i1 = int_gt(i0, 0)
        guard_true(i1) []
        jump(p1)
        """
        self.optimize_loop(ops, expected)

    def test_remove_duplicate_pure_op_ovf(self):
        ops = """
        [i1]
        i3 = int_add_ovf(i1, 1)
        guard_no_overflow() []
        i3b = int_is_true(i3)
        guard_true(i3b) []
        i4 = int_add_ovf(i1, 1)
        guard_no_overflow() []
        i4b = int_is_true(i4)
        guard_true(i4b) []
        escape(i3)
        escape(i4)
        jump(i1)
        """
        expected = """
        [i1]
        i3 = int_add_ovf(i1, 1)
        guard_no_overflow() []
        i3b = int_is_true(i3)
        guard_true(i3b) []
        escape(i3)
        escape(i3)
        jump(i1)
        """
        self.optimize_loop(ops, expected)

    def test_int_and_or_with_zero(self):
        ops = """
        [i0, i1]
        i2 = int_and(i0, 0)
        i3 = int_and(0, i2)
        i4 = int_or(i2, i1)
        i5 = int_or(i0, i3)
        jump(i4, i5)
        """
        expected = """
        [i0, i1]
        jump(i1, i0)
        """
        self.optimize_loop(ops, expected)

    def test_fold_partially_constant_ops(self):
        ops = """
        [i0]
        i1 = int_sub(i0, 0)
        jump(i1)
        """
        expected = """
        [i0]
        jump(i0)
        """
        self.optimize_loop(ops, expected)

        ops = """
        [i0]
        i1 = int_add(i0, 0)
        jump(i1)
        """
        expected = """
        [i0]
        jump(i0)
        """
        self.optimize_loop(ops, expected)

        ops = """
        [i0]
        i1 = int_add(0, i0)
        jump(i1)
        """
        expected = """
        [i0]
        jump(i0)
        """
        self.optimize_loop(ops, expected)

        ops = """
        [i0]
        i1 = int_floordiv(0, i0)
        jump(i1)
        """
        expected = """
        [i0]
        jump(0)
        """
        self.optimize_loop(ops, expected)

    def test_fold_partially_constant_ops_ovf(self):
        ops = """
        [i0]
        i1 = int_sub_ovf(i0, 0)
        guard_no_overflow() []
        jump(i1)
        """
        expected = """
        [i0]
        jump(i0)
        """
        self.optimize_loop(ops, expected)

        ops = """
        [i0]
        i1 = int_add_ovf(i0, 0)
        guard_no_overflow() []
        jump(i1)
        """
        expected = """
        [i0]
        jump(i0)
        """
        self.optimize_loop(ops, expected)

        ops = """
        [i0]
        i1 = int_add_ovf(0, i0)
        guard_no_overflow() []
        jump(i1)
        """
        expected = """
        [i0]
        jump(i0)
        """
        self.optimize_loop(ops, expected)

    def test_fold_constant_partial_ops_float(self):
        ops = """
        [f0]
        f1 = float_mul(f0, 1.0)
        f2 = escape(f1)
        jump(f2)
        """
        expected = """
        [f0]
        f2 = escape(f0)
        jump(f2)
        """
        self.optimize_loop(ops, expected)

        ops = """
        [f0]
        f1 = float_mul(1.0, f0)
        f2 = escape(f1)
        jump(f2)
        """
        expected = """
        [f0]
        f2 = escape(f0)
        jump(f2)
        """
        self.optimize_loop(ops, expected)


        ops = """
        [f0]
        f1 = float_mul(f0, -1.0)
        f2 = escape(f1)
        jump(f2)
        """
        expected = """
        [f0]
        f1 = float_neg(f0)
        f2 = escape(f1)
        jump(f2)
        """
        self.optimize_loop(ops, expected)

        ops = """
        [f0]
        f1 = float_mul(-1.0, f0)
        f2 = escape(f1)
        jump(f2)
        """
        expected = """
        [f0]
        f1 = float_neg(f0)
        f2 = escape(f1)
        jump(f2)
        """
        self.optimize_loop(ops, expected)

    def test_fold_repeated_float_neg(self):
        ops = """
        [f0]
        f1 = float_neg(f0)
        f2 = float_neg(f1)
        f3 = float_neg(f2)
        f4 = float_neg(f3)
        escape(f4)
        jump(f4)
        """
        expected = """
        [f0]
        # The backend removes this dead op.
        f1 = float_neg(f0)
        escape(f0)
        jump(f0)
        """
        self.optimize_loop(ops, expected)

    # ----------

    def _verify_fail_args(self, boxes, oparse, text):
        import re
        r = re.compile(r"\bwhere\s+(\w+)\s+is a\s+(\w+)")
        parts = list(r.finditer(text))
        ends = [match.start() for match in parts] + [len(text)]
        #
        virtuals = {}
        for match, end in zip(parts, ends[1:]):
            pvar = match.group(1)
            fieldstext = text[match.end():end]
            if match.group(2) == 'varray':
                arrayname, fieldstext = fieldstext.split(':', 1)
                tag = ('varray', self.namespace[arrayname.strip()])
            elif match.group(2) == 'vstruct':
                if ',' in fieldstext:
                    structname, fieldstext = fieldstext.split(',', 1)
                else:
                    structname, fieldstext = fieldstext, ''
                tag = ('vstruct', self.namespace[structname.strip()])
            else:
                tag = ('virtual', self.namespace[match.group(2)])
            virtuals[pvar] = (tag, None, fieldstext)
        #
        r2 = re.compile(r"([\w\d()]+)[.](\w+)\s*=\s*([\w\d()]+)")
        pendingfields = []
        for match in r2.finditer(text):
            pvar = match.group(1)
            pfieldname = match.group(2)
            pfieldvar = match.group(3)
            pendingfields.append((pvar, pfieldname, pfieldvar))
        #
        def _variables_equal(box, varname, strict):
            if varname not in virtuals:
                if strict:
                    assert box.same_box(oparse.getvar(varname))
                else:
                    assert box.value == oparse.getvar(varname).value
            else:
                tag, resolved, fieldstext = virtuals[varname]
                if tag[0] == 'virtual':
                    assert self.get_class_of_box(box) == tag[1]
                elif tag[0] == 'varray':
                    pass    # xxx check arraydescr
                elif tag[0] == 'vstruct':
                    pass    # xxx check typedescr
                else:
                    assert 0
                if resolved is not None:
                    assert resolved.value == box.value
                else:
                    virtuals[varname] = tag, box, fieldstext
        #
        basetext = text.splitlines()[0]
        varnames = [s.strip() for s in basetext.split(',')]
        if varnames == ['']:
            varnames = []
        assert len(boxes) == len(varnames)
        for box, varname in zip(boxes, varnames):
            _variables_equal(box, varname, strict=True)
        for pvar, pfieldname, pfieldvar in pendingfields:
            box = oparse.getvar(pvar)
            fielddescr = self.namespace[pfieldname.strip()]
            fieldbox = executor.execute(self.cpu, None,
                                        rop.GETFIELD_GC,
                                        fielddescr,
                                        box)
            _variables_equal(fieldbox, pfieldvar, strict=True)
        #
        for match in parts:
            pvar = match.group(1)
            tag, resolved, fieldstext = virtuals[pvar]
            assert resolved is not None
            index = 0
            for fieldtext in fieldstext.split(','):
                fieldtext = fieldtext.strip()
                if not fieldtext:
                    continue
                if tag[0] in ('virtual', 'vstruct'):
                    fieldname, fieldvalue = fieldtext.split('=')
                    fielddescr = self.namespace[fieldname.strip()]
                    fieldbox = executor.execute(self.cpu, None,
                                                rop.GETFIELD_GC,
                                                fielddescr,
                                                resolved)
                elif tag[0] == 'varray':
                    fieldvalue = fieldtext
                    fieldbox = executor.execute(self.cpu, None,
                                                rop.GETARRAYITEM_GC,
                                                tag[1],
                                                resolved, ConstInt(index))
                else:
                    assert 0
                _variables_equal(fieldbox, fieldvalue.strip(), strict=False)
                index += 1

    def check_expanded_fail_descr(self, expectedtext, guard_opnum):
        from rpython.jit.metainterp.test.test_resume import ResumeDataFakeReader
        from rpython.jit.metainterp.test.test_resume import MyMetaInterp
        guard_op, = [op for op in self.loop.operations if op.is_guard()]
        fail_args = guard_op.getfailargs()
        fdescr = guard_op.getdescr()
        assert fdescr.guard_opnum == guard_opnum
        reader = ResumeDataFakeReader(fdescr, fail_args,
                                      MyMetaInterp(self.cpu))
        boxes = reader.consume_boxes()
        self._verify_fail_args(boxes, fdescr.oparse, expectedtext)

    def test_expand_fail_1(self):
        ops = """
        [i1, i3]
        # first rename i3 into i4
        p1 = new_with_vtable(ConstClass(node_vtable))
        setfield_gc(p1, i3, descr=valuedescr)
        i4 = getfield_gc(p1, descr=valuedescr)
        #
        i2 = int_add(10, 5)
        guard_true(i1, descr=fdescr) [i2, i4]
        jump(i1, i4)
        """
        expected = """
        [i1, i3]
        guard_true(i1, descr=fdescr) [i3]
        jump(1, i3)
        """
        self.optimize_loop(ops, expected)
        self.check_expanded_fail_descr('15, i3', rop.GUARD_TRUE)

    def test_expand_fail_2(self):
        ops = """
        [i1, i2]
        p1 = new_with_vtable(ConstClass(node_vtable))
        setfield_gc(p1, i2, descr=valuedescr)
        setfield_gc(p1, p1, descr=nextdescr)
        guard_true(i1, descr=fdescr) [p1]
        jump(i1, i2)
        """
        expected = """
        [i1, i2]
        guard_true(i1, descr=fdescr) [i2]
        jump(1, i2)
        """
        self.optimize_loop(ops, expected)
        self.check_expanded_fail_descr('''ptr
            where ptr is a node_vtable, valuedescr=i2
            ''', rop.GUARD_TRUE)

    def test_expand_fail_3(self):
        ops = """
        [i1, i2, i3, p3]
        p1 = new_with_vtable(ConstClass(node_vtable))
        p2 = new_with_vtable(ConstClass(node_vtable))
        setfield_gc(p1, 1, descr=valuedescr)
        setfield_gc(p1, p2, descr=nextdescr)
        setfield_gc(p2, i2, descr=valuedescr)
        setfield_gc(p2, p3, descr=nextdescr)
        guard_true(i1, descr=fdescr) [i3, p1]
        jump(i2, i1, i3, p3)
        """
        expected = """
        [i1, i2, i3, p3]
        guard_true(i1, descr=fdescr) [i3, i2, p3]
        jump(i2, 1, i3, p3)
        """
        self.optimize_loop(ops, expected)
        self.check_expanded_fail_descr('''i3, p1
            where p1 is a node_vtable, valuedescr=1, nextdescr=p2
            where p2 is a node_vtable, valuedescr=i2, nextdescr=p3
            ''', rop.GUARD_TRUE)

    def test_expand_fail_4(self):
        for arg in ['p1', 'i2,p1', 'p1,p2', 'p2,p1',
                    'i2,p1,p2', 'i2,p2,p1']:
            self.setup_method() # humpf
            ops = """
            [i1, i2, i3]
            p1 = new_with_vtable(ConstClass(node_vtable))
            setfield_gc(p1, i3, descr=valuedescr)
            i4 = getfield_gc(p1, descr=valuedescr)   # copy of i3
            p2 = new_with_vtable(ConstClass(node_vtable))
            setfield_gc(p1, i2, descr=valuedescr)
            setfield_gc(p1, p2, descr=nextdescr)
            setfield_gc(p2, i2, descr=valuedescr)
            guard_true(i1, descr=fdescr) [i4, i3, %s]
            jump(i1, i2, i3)
            """
            expected = """
            [i1, i2, i3]
            guard_true(i1, descr=fdescr) [i3, i2]
            jump(1, i2, i3)
            """
            self.optimize_loop(ops % arg, expected)
            self.check_expanded_fail_descr('''i3, i3, %s
                where p1 is a node_vtable, valuedescr=i2, nextdescr=p2
                where p2 is a node_vtable, valuedescr=i2''' % arg,
                                           rop.GUARD_TRUE)

    def test_expand_fail_5(self):
        ops = """
        [i1, i2, i3, i4]
        p1 = new_with_vtable(ConstClass(node_vtable))
        p2 = new_with_vtable(ConstClass(node_vtable))
        setfield_gc(p1, i4, descr=valuedescr)
        setfield_gc(p1, p2, descr=nextdescr)
        setfield_gc(p2, i2, descr=valuedescr)
        setfield_gc(p2, p1, descr=nextdescr)      # a cycle
        guard_true(i1, descr=fdescr) [i3, i4, p1, p2]
        jump(i2, i1, i3, i4)
        """
        expected = """
        [i1, i2, i3, i4]
        guard_true(i1, descr=fdescr) [i3, i4, i2]
        jump(i2, 1, i3, i4)
        """
        self.optimize_loop(ops, expected)
        self.check_expanded_fail_descr('''i3, i4, p1, p2
            where p1 is a node_vtable, valuedescr=i4, nextdescr=p2
            where p2 is a node_vtable, valuedescr=i2, nextdescr=p1
            ''', rop.GUARD_TRUE)

    def test_expand_fail_6(self):
        ops = """
        [p0, i0, i1]
        guard_true(i0, descr=fdescr) [p0]
        p1 = new_with_vtable(ConstClass(node_vtable))
        setfield_gc(p1, i1, descr=valuedescr)
        jump(p1, i1, i1)
        """
        expected = """
        [i1b, i0, i1]
        guard_true(i0, descr=fdescr) [i1b]
        jump(i1, i1, i1)
        """
        py.test.skip("XXX")
        self.optimize_loop(ops, '''Virtual(node_vtable, valuedescr=Not),
                                   Not, Not''', expected)
        self.check_expanded_fail_descr('''p0
            where p0 is a node_vtable, valuedescr=i1b
            ''', rop.GUARD_TRUE)

    def test_expand_fail_varray(self):
        ops = """
        [i1]
        p1 = new_array(3, descr=arraydescr)
        setarrayitem_gc(p1, 1, i1, descr=arraydescr)
        setarrayitem_gc(p1, 0, 25, descr=arraydescr)
        guard_true(i1, descr=fdescr) [p1]
        i2 = getarrayitem_gc(p1, 1, descr=arraydescr)
        jump(i2)
        """
        expected = """
        [i1]
        guard_true(i1, descr=fdescr) [i1]
        jump(1)
        """
        self.optimize_loop(ops, expected)
        self.check_expanded_fail_descr('''p1
            where p1 is a varray arraydescr: 25, i1
            ''', rop.GUARD_TRUE)

    def test_expand_fail_vstruct(self):
        ops = """
        [i1, p1]
        p2 = new(descr=ssize)
        setfield_gc(p2, i1, descr=adescr)
        setfield_gc(p2, p1, descr=bdescr)
        guard_true(i1, descr=fdescr) [p2]
        i3 = getfield_gc(p2, descr=adescr)
        p3 = getfield_gc(p2, descr=bdescr)
        jump(i3, p3)
        """
        expected = """
        [i1, p1]
        guard_true(i1, descr=fdescr) [i1, p1]
        jump(1, p1)
        """
        self.optimize_loop(ops, expected)
        self.check_expanded_fail_descr('''p2
            where p2 is a vstruct ssize, adescr=i1, bdescr=p1
            ''', rop.GUARD_TRUE)

    def test_expand_fail_v_all_1(self):
        ops = """
        [i1, p1a, i2]
        p6s = getarrayitem_gc(p1a, 0, descr=arraydescr2)
        p7v = getfield_gc(p6s, descr=bdescr)
        p5s = new(descr=ssize)
        setfield_gc(p5s, i2, descr=adescr)
        setfield_gc(p5s, p7v, descr=bdescr)
        setarrayitem_gc(p1a, 1, p5s, descr=arraydescr2)
        guard_true(i1, descr=fdescr) [p1a]
        p2s = new(descr=ssize)
        p3v = new_with_vtable(ConstClass(node_vtable))
        p4a = new_array(2, descr=arraydescr2)
        setfield_gc(p2s, i1, descr=adescr)
        setfield_gc(p2s, p3v, descr=bdescr)
        setfield_gc(p3v, i2, descr=valuedescr)
        setarrayitem_gc(p4a, 0, p2s, descr=arraydescr2)
        jump(i1, p4a, i2)
        """
        expected = """
        [i1, ia, iv, pnull, i2]
        guard_true(i1, descr=fdescr) [ia, iv, i2]
        jump(1, 1, i2, NULL, i2)
        """
        py.test.skip("XXX")
        self.optimize_loop(ops, '''
            Not,
            VArray(arraydescr2,
                   VStruct(ssize,
                           adescr=Not,
                           bdescr=Virtual(node_vtable,
                                          valuedescr=Not)),
                   Not),
            Not''', expected)
        self.check_expanded_fail_descr('''p1a
            where p1a is a varray arraydescr2: p6s, p5s
            where p6s is a vstruct ssize, adescr=ia, bdescr=p7v
            where p5s is a vstruct ssize, adescr=i2, bdescr=p7v
            where p7v is a node_vtable, valuedescr=iv
            ''', rop.GUARD_TRUE)

    def test_expand_fail_lazy_setfield_1(self):
        ops = """
        [p1, i2, i3]
        p2 = new_with_vtable(ConstClass(node_vtable))
        setfield_gc(p2, i2, descr=valuedescr)
        setfield_gc(p1, p2, descr=nextdescr)
        guard_true(i3, descr=fdescr) []
        i4 = int_neg(i2)
        setfield_gc(p1, NULL, descr=nextdescr)
        jump(p1, i2, i4)
        """
        expected = """
        [p1, i2, i3]
        guard_true(i3, descr=fdescr) [p1, i2]
        i4 = int_neg(i2)
        setfield_gc(p1, NULL, descr=nextdescr)
        jump(p1, i2, i4)
        """
        self.optimize_loop(ops, expected)
        self.loop.inputargs[0].value = self.nodebox.value
        self.check_expanded_fail_descr('''
            p1.nextdescr = p2
            where p2 is a node_vtable, valuedescr=i2
            ''', rop.GUARD_TRUE)

    def test_expand_fail_lazy_setfield_2(self):
        ops = """
        [i2, i3]
        p2 = new_with_vtable(ConstClass(node_vtable))
        setfield_gc(p2, i2, descr=valuedescr)
        setfield_gc(ConstPtr(myptr), p2, descr=nextdescr)
        guard_true(i3, descr=fdescr) []
        i4 = int_neg(i2)
        setfield_gc(ConstPtr(myptr), NULL, descr=nextdescr)
        jump(i2, i4)
        """
        expected = """
        [i2, i3]
        guard_true(i3, descr=fdescr) [i2]
        i4 = int_neg(i2)
        setfield_gc(ConstPtr(myptr), NULL, descr=nextdescr)
        jump(i2, i4)
        """
        self.optimize_loop(ops, expected)
        self.check_expanded_fail_descr('''
            ConstPtr(myptr).nextdescr = p2
            where p2 is a node_vtable, valuedescr=i2
            ''', rop.GUARD_TRUE)

    def test_residual_call_does_not_invalidate_caches(self):
        ops = """
        [p1, p2]
        i1 = getfield_gc(p1, descr=valuedescr)
        i2 = call(i1, descr=nonwritedescr)
        i3 = getfield_gc(p1, descr=valuedescr)
        escape(i1)
        escape(i3)
        jump(p1, p2)
        """
        expected = """
        [p1, p2]
        i1 = getfield_gc(p1, descr=valuedescr)
        i2 = call(i1, descr=nonwritedescr)
        escape(i1)
        escape(i1)
        jump(p1, p2)
        """
        self.optimize_loop(ops, expected)

    def test_residual_call_invalidate_some_caches(self):
        ops = """
        [p1, p2]
        i1 = getfield_gc(p1, descr=adescr)
        i2 = getfield_gc(p1, descr=bdescr)
        i3 = call(i1, descr=writeadescr)
        i4 = getfield_gc(p1, descr=adescr)
        i5 = getfield_gc(p1, descr=bdescr)
        escape(i1)
        escape(i2)
        escape(i4)
        escape(i5)
        jump(p1, p2)
        """
        expected = """
        [p1, p2]
        i1 = getfield_gc(p1, descr=adescr)
        i2 = getfield_gc(p1, descr=bdescr)
        i3 = call(i1, descr=writeadescr)
        i4 = getfield_gc(p1, descr=adescr)
        escape(i1)
        escape(i2)
        escape(i4)
        escape(i2)
        jump(p1, p2)
        """
        self.optimize_loop(ops, expected)

    def test_residual_call_invalidate_arrays(self):
        ops = """
        [p1, p2, i1]
        p3 = getarrayitem_gc(p1, 0, descr=arraydescr2)
        p4 = getarrayitem_gc(p2, 1, descr=arraydescr2)
        i3 = call(i1, descr=writeadescr)
        p5 = getarrayitem_gc(p1, 0, descr=arraydescr2)
        p6 = getarrayitem_gc(p2, 1, descr=arraydescr2)
        escape(p3)
        escape(p4)
        escape(p5)
        escape(p6)
        jump(p1, p2, i1)
        """
        expected = """
        [p1, p2, i1]
        p3 = getarrayitem_gc(p1, 0, descr=arraydescr2)
        p4 = getarrayitem_gc(p2, 1, descr=arraydescr2)
        i3 = call(i1, descr=writeadescr)
        escape(p3)
        escape(p4)
        escape(p3)
        escape(p4)
        jump(p1, p2, i1)
        """
        self.optimize_loop(ops, expected)

    def test_residual_call_invalidate_some_arrays(self):
        ops = """
        [p1, p2, i1]
        p3 = getarrayitem_gc(p2, 0, descr=arraydescr2)
        p4 = getarrayitem_gc(p2, 1, descr=arraydescr2)
        i2 = getarrayitem_gc(p1, 1, descr=arraydescr)
        i3 = call(i1, descr=writearraydescr)
        p5 = getarrayitem_gc(p2, 0, descr=arraydescr2)
        p6 = getarrayitem_gc(p2, 1, descr=arraydescr2)
        i4 = getarrayitem_gc(p1, 1, descr=arraydescr)
        escape(p3)
        escape(p4)
        escape(p5)
        escape(p6)
        escape(i2)
        escape(i4)
        jump(p1, p2, i1)
        """
        expected = """
        [p1, p2, i1]
        p3 = getarrayitem_gc(p2, 0, descr=arraydescr2)
        p4 = getarrayitem_gc(p2, 1, descr=arraydescr2)
        i2 = getarrayitem_gc(p1, 1, descr=arraydescr)
        i3 = call(i1, descr=writearraydescr)
        i4 = getarrayitem_gc(p1, 1, descr=arraydescr)
        escape(p3)
        escape(p4)
        escape(p3)
        escape(p4)
        escape(i2)
        escape(i4)
        jump(p1, p2, i1)
        """
        self.optimize_loop(ops, expected)

    def test_residual_call_invalidates_some_read_caches_1(self):
        ops = """
        [p1, i1, p2, i2]
        setfield_gc(p1, i1, descr=valuedescr)
        setfield_gc(p2, i2, descr=adescr)
        i3 = call(i1, descr=readadescr)
        setfield_gc(p1, i3, descr=valuedescr)
        setfield_gc(p2, i3, descr=adescr)
        jump(p1, i1, p2, i2)
        """
        expected = """
        [p1, i1, p2, i2]
        setfield_gc(p2, i2, descr=adescr)
        i3 = call(i1, descr=readadescr)
        setfield_gc(p1, i3, descr=valuedescr)
        setfield_gc(p2, i3, descr=adescr)
        jump(p1, i1, p2, i2)
        """
        self.optimize_loop(ops, expected)

    def test_residual_call_invalidates_some_read_caches_2(self):
        ops = """
        [p1, i1, p2, i2]
        setfield_gc(p1, i1, descr=valuedescr)
        setfield_gc(p2, i2, descr=adescr)
        i3 = call(i1, descr=writeadescr)
        setfield_gc(p1, i3, descr=valuedescr)
        setfield_gc(p2, i3, descr=adescr)
        jump(p1, i1, p2, i2)
        """
        expected = """
        [p1, i1, p2, i2]
        setfield_gc(p2, i2, descr=adescr)
        i3 = call(i1, descr=writeadescr)
        setfield_gc(p1, i3, descr=valuedescr)
        setfield_gc(p2, i3, descr=adescr)
        jump(p1, i1, p2, i2)
        """
        self.optimize_loop(ops, expected)

    def test_residual_call_invalidates_some_read_caches_3(self):
        ops = """
        [p1, i1, p2, i2]
        setfield_gc(p1, i1, descr=valuedescr)
        setfield_gc(p2, i2, descr=adescr)
        i3 = call(i1, descr=plaincalldescr)
        setfield_gc(p1, i3, descr=valuedescr)
        setfield_gc(p2, i3, descr=adescr)
        jump(p1, i1, p2, i2)
        """
        self.optimize_loop(ops, ops)

    def test_call_assembler_invalidates_caches(self):
        ops = '''
        [p1, i1]
        setfield_gc(p1, i1, descr=valuedescr)
        i3 = call_assembler(i1, descr=asmdescr)
        setfield_gc(p1, i3, descr=valuedescr)
        jump(p1, i3)
        '''
        self.optimize_loop(ops, ops)

    def test_call_pure_invalidates_caches(self):
        # CALL_PURE should still force the setfield_gc() to occur before it
        ops = '''
        [p1, i1]
        setfield_gc(p1, i1, descr=valuedescr)
        i3 = call_pure(p1, descr=plaincalldescr)
        setfield_gc(p1, i3, descr=valuedescr)
        jump(p1, i3)
        '''
        expected = '''
        [p1, i1]
        setfield_gc(p1, i1, descr=valuedescr)
        i3 = call(p1, descr=plaincalldescr)
        setfield_gc(p1, i3, descr=valuedescr)
        jump(p1, i3)
        '''
        self.optimize_loop(ops, expected)

    def test_call_pure_constant_folding(self):
        # CALL_PURE is not marked as is_always_pure(), because it is wrong
        # to call the function arbitrary many times at arbitrary points in
        # time.  Check that it is either constant-folded (and replaced by
        # the result of the call, recorded as the first arg), or turned into
        # a regular CALL.
        arg_consts = [ConstInt(i) for i in (123456, 4, 5, 6)]
        call_pure_results = {tuple(arg_consts): ConstInt(42)}
        ops = '''
        [i0, i1, i2]
        escape(i1)
        escape(i2)
        i3 = call_pure(123456, 4, 5, 6, descr=plaincalldescr)
        i4 = call_pure(123456, 4, i0, 6, descr=plaincalldescr)
        jump(i0, i3, i4)
        '''
        expected = '''
        [i0, i1, i2]
        escape(i1)
        escape(i2)
        i4 = call(123456, 4, i0, 6, descr=plaincalldescr)
        jump(i0, 42, i4)
        '''
        self.optimize_loop(ops, expected, call_pure_results)

    def test_vref_nonvirtual_nonescape(self):
        ops = """
        [p1]
        p2 = virtual_ref(p1, 5)
        virtual_ref_finish(p2, p1)
        jump(p1)
        """
        expected = """
        [p1]
        p0 = force_token()
        jump(p1)
        """
        self.optimize_loop(ops, expected)

    def test_vref_nonvirtual_escape(self):
        ops = """
        [p1]
        p2 = virtual_ref(p1, 5)
        escape(p2)
        virtual_ref_finish(p2, p1)
        jump(p1)
        """
        expected = """
        [p1]
        p0 = force_token()
        p2 = new_with_vtable(ConstClass(jit_virtual_ref_vtable))
        setfield_gc(p2, p0, descr=virtualtokendescr)
        escape(p2)
        setfield_gc(p2, p1, descr=virtualforceddescr)
        setfield_gc(p2, NULL, descr=virtualtokendescr)
        jump(p1)
        """
        # XXX we should optimize a bit more the case of a nonvirtual.
        # in theory it is enough to just do 'p2 = p1'.
        self.optimize_loop(ops, expected)

    def test_vref_virtual_1(self):
        ops = """
        [p0, i1]
        #
        p1 = new_with_vtable(ConstClass(node_vtable))
        p1b = new_with_vtable(ConstClass(node_vtable))
        setfield_gc(p1b, 252, descr=valuedescr)
        setfield_gc(p1, p1b, descr=nextdescr)
        #
        p2 = virtual_ref(p1, 3)
        setfield_gc(p0, p2, descr=nextdescr)
        call_may_force(i1, descr=mayforcevirtdescr)
        guard_not_forced() [i1]
        virtual_ref_finish(p2, p1)
        setfield_gc(p0, NULL, descr=nextdescr)
        jump(p0, i1)
        """
        expected = """
        [p0, i1]
        p3 = force_token()
        #
        p2 = new_with_vtable(ConstClass(jit_virtual_ref_vtable))
        setfield_gc(p2, p3, descr=virtualtokendescr)
        setfield_gc(p0, p2, descr=nextdescr)
        #
        call_may_force(i1, descr=mayforcevirtdescr)
        guard_not_forced() [i1]
        #
        setfield_gc(p0, NULL, descr=nextdescr)
        p1 = new_with_vtable(ConstClass(node_vtable))
        p1b = new_with_vtable(ConstClass(node_vtable))
        setfield_gc(p1b, 252, descr=valuedescr)
        setfield_gc(p1, p1b, descr=nextdescr)
        setfield_gc(p2, p1, descr=virtualforceddescr)
        setfield_gc(p2, NULL, descr=virtualtokendescr)
        jump(p0, i1)
        """
        self.optimize_loop(ops, expected)

    def test_vref_virtual_2(self):
        ops = """
        [p0, i1]
        #
        p1 = new_with_vtable(ConstClass(node_vtable))
        p1b = new_with_vtable(ConstClass(node_vtable))
        setfield_gc(p1b, i1, descr=valuedescr)
        setfield_gc(p1, p1b, descr=nextdescr)
        #
        p2 = virtual_ref(p1, 2)
        setfield_gc(p0, p2, descr=nextdescr)
        call_may_force(i1, descr=mayforcevirtdescr)
        guard_not_forced(descr=fdescr) [p2, p1]
        virtual_ref_finish(p2, p1)
        setfield_gc(p0, NULL, descr=nextdescr)
        jump(p0, i1)
        """
        expected = """
        [p0, i1]
        p3 = force_token()
        #
        p2 = new_with_vtable(ConstClass(jit_virtual_ref_vtable))
        setfield_gc(p2, p3, descr=virtualtokendescr)
        setfield_gc(p0, p2, descr=nextdescr)
        #
        call_may_force(i1, descr=mayforcevirtdescr)
        guard_not_forced(descr=fdescr) [p2, i1]
        #
        setfield_gc(p0, NULL, descr=nextdescr)
        p1 = new_with_vtable(ConstClass(node_vtable))
        p1b = new_with_vtable(ConstClass(node_vtable))
        setfield_gc(p1b, i1, descr=valuedescr)
        setfield_gc(p1, p1b, descr=nextdescr)
        setfield_gc(p2, p1, descr=virtualforceddescr)
        setfield_gc(p2, NULL, descr=virtualtokendescr)
        jump(p0, i1)
        """
        # the point of this test is that 'i1' should show up in the fail_args
        # of 'guard_not_forced', because it was stored in the virtual 'p1b'.
        self.optimize_loop(ops, expected)
        self.check_expanded_fail_descr('''p2, p1
            where p1 is a node_vtable, nextdescr=p1b
            where p1b is a node_vtable, valuedescr=i1
            ''', rop.GUARD_NOT_FORCED)

    def test_vref_virtual_and_lazy_setfield(self):
        ops = """
        [p0, i1]
        #
        p1 = new_with_vtable(ConstClass(node_vtable))
        p1b = new_with_vtable(ConstClass(node_vtable))
        setfield_gc(p1b, i1, descr=valuedescr)
        setfield_gc(p1, p1b, descr=nextdescr)
        #
        p2 = virtual_ref(p1, 2)
        setfield_gc(p0, p2, descr=refdescr)
        call(i1, descr=nonwritedescr)
        guard_no_exception(descr=fdescr) [p2, p1]
        virtual_ref_finish(p2, p1)
        setfield_gc(p0, NULL, descr=refdescr)
        jump(p0, i1)
        """
        expected = """
        [p0, i1]
        p3 = force_token()
        call(i1, descr=nonwritedescr)
        guard_no_exception(descr=fdescr) [p3, i1, p0]
        setfield_gc(p0, NULL, descr=refdescr)
        jump(p0, i1)
        """
        self.optimize_loop(ops, expected)
        # the fail_args contain [p3, i1, p0]:
        #  - p3 is from the virtual expansion of p2
        #  - i1 is from the virtual expansion of p1
        #  - p0 is from the extra pendingfields
        self.loop.inputargs[0].value = self.nodeobjvalue
        self.check_expanded_fail_descr('''p2, p1
            p0.refdescr = p2
            where p2 is a jit_virtual_ref_vtable, virtualtokendescr=p3
            where p1 is a node_vtable, nextdescr=p1b
            where p1b is a node_vtable, valuedescr=i1
            ''', rop.GUARD_NO_EXCEPTION)

    def test_vref_virtual_after_finish(self):
        ops = """
        [i1]
        p1 = new_with_vtable(ConstClass(node_vtable))
        p2 = virtual_ref(p1, 7)
        escape(p2)
        virtual_ref_finish(p2, p1)
        call_may_force(i1, descr=mayforcevirtdescr)
        guard_not_forced() []
        jump(i1)
        """
        expected = """
        [i1]
        p3 = force_token()
        p2 = new_with_vtable(ConstClass(jit_virtual_ref_vtable))
        setfield_gc(p2, p3, descr=virtualtokendescr)
        escape(p2)
        p1 = new_with_vtable(ConstClass(node_vtable))
        setfield_gc(p2, p1, descr=virtualforceddescr)
        setfield_gc(p2, NULL, descr=virtualtokendescr)
        call_may_force(i1, descr=mayforcevirtdescr)
        guard_not_forced() []
        jump(i1)
        """
        self.optimize_loop(ops, expected)

    def test_vref_nonvirtual_and_lazy_setfield(self):
        ops = """
        [i1, p1]
        p2 = virtual_ref(p1, 23)
        escape(p2)
        virtual_ref_finish(p2, p1)
        call_may_force(i1, descr=mayforcevirtdescr)
        guard_not_forced() [i1]
        jump(i1, p1)
        """
        expected = """
        [i1, p1]
        p3 = force_token()
        p2 = new_with_vtable(ConstClass(jit_virtual_ref_vtable))
        setfield_gc(p2, p3, descr=virtualtokendescr)
        escape(p2)
        setfield_gc(p2, p1, descr=virtualforceddescr)
        setfield_gc(p2, NULL, descr=virtualtokendescr)
        call_may_force(i1, descr=mayforcevirtdescr)
        guard_not_forced() [i1]
        jump(i1, p1)
        """
        self.optimize_loop(ops, expected)

    def test_arraycopy_1(self):
        ops = '''
        [i0]
        p1 = new_array(3, descr=arraydescr)
        setarrayitem_gc(p1, 1, 1, descr=arraydescr)
        p2 = new_array(3, descr=arraydescr)
        setarrayitem_gc(p2, 1, 3, descr=arraydescr)
        call(0, p1, p2, 1, 1, 2, descr=arraycopydescr)
        i2 = getarrayitem_gc(p2, 1, descr=arraydescr)
        jump(i2)
        '''
        expected = '''
        [i0]
        jump(1)
        '''
        self.optimize_loop(ops, expected)

    def test_arraycopy_2(self):
        ops = '''
        [i0]
        p1 = new_array(3, descr=arraydescr)
        p2 = new_array(3, descr=arraydescr)
        setarrayitem_gc(p1, 0, i0, descr=arraydescr)
        setarrayitem_gc(p2, 0, 3, descr=arraydescr)
        call(0, p1, p2, 1, 1, 2, descr=arraycopydescr)
        i2 = getarrayitem_gc(p2, 0, descr=arraydescr)
        jump(i2)
        '''
        expected = '''
        [i0]
        jump(3)
        '''
        self.optimize_loop(ops, expected)

    def test_arraycopy_not_virtual(self):
        ops = '''
        [p0]
        p1 = new_array(3, descr=arraydescr)
        p2 = new_array(3, descr=arraydescr)
        setarrayitem_gc(p1, 2, 10, descr=arraydescr)
        setarrayitem_gc(p2, 2, 13, descr=arraydescr)
        call(0, p1, p2, 0, 0, 3, descr=arraycopydescr)
        jump(p2)
        '''
        expected = '''
        [p0]
        p2 = new_array(3, descr=arraydescr)
        setarrayitem_gc(p2, 2, 10, descr=arraydescr)
        jump(p2)
        '''
        self.optimize_loop(ops, expected)

    def test_arraycopy_not_virtual_2(self):
        ops = '''
        [p0]
        p1 = new_array(3, descr=arraydescr)
        call(0, p0, p1, 0, 0, 3, descr=arraycopydescr)
        i0 = getarrayitem_gc(p1, 0, descr=arraydescr)
        jump(i0)
        '''
        expected = '''
        [p0]
        i0 = getarrayitem_gc(p0, 0, descr=arraydescr)
        i1 = getarrayitem_gc(p0, 1, descr=arraydescr) # removed by the backend
        i2 = getarrayitem_gc(p0, 2, descr=arraydescr) # removed by the backend
        jump(i0)
        '''
        self.optimize_loop(ops, expected)

    def test_arraycopy_not_virtual_3(self):
        ops = '''
        [p0, p1]
        call(0, p0, p1, 0, 0, 3, descr=arraycopydescr)
        i0 = getarrayitem_gc(p1, 0, descr=arraydescr)
        jump(i0)
        '''
        expected = '''
        [p0, p1]
        i0 = getarrayitem_gc(p0, 0, descr=arraydescr)
        i1 = getarrayitem_gc(p0, 1, descr=arraydescr)
        i2 = getarrayitem_gc(p0, 2, descr=arraydescr)
        setarrayitem_gc(p1, 0, i0, descr=arraydescr)
        setarrayitem_gc(p1, 1, i1, descr=arraydescr)
        setarrayitem_gc(p1, 2, i2, descr=arraydescr)
        jump(i0)
        '''
        self.optimize_loop(ops, expected)

    def test_arraycopy_no_elem(self):
        """ this was actually observed in the wild
        """
        ops = '''
        [p1]
        p0 = new_array(0, descr=arraydescr)
        call(0, p0, p1, 0, 0, 0, descr=arraycopydescr)
        jump(p1)
        '''
        expected = '''
        [p1]
        jump(p1)
        '''
        self.optimize_loop(ops, expected)

    def test_bound_lt(self):
        ops = """
        [i0]
        i1 = int_lt(i0, 4)
        guard_true(i1) []
        i2 = int_lt(i0, 5)
        guard_true(i2) []
        jump(i0)
        """
        expected = """
        [i0]
        i1 = int_lt(i0, 4)
        guard_true(i1) []
        jump(i0)
        """
        self.optimize_loop(ops, expected)

    def test_bound_lt_noguard(self):
        ops = """
        [i0]
        i1 = int_lt(i0, 4)
        i2 = int_lt(i0, 5)
        jump(i2)
        """
        expected = """
        [i0]
        i1 = int_lt(i0, 4)
        i2 = int_lt(i0, 5)
        jump(i2)
        """
        self.optimize_loop(ops, expected)

    def test_bound_lt_noopt(self):
        ops = """
        [i0]
        i1 = int_lt(i0, 4)
        guard_false(i1) []
        i2 = int_lt(i0, 5)
        guard_true(i2) []
        jump(i0)
        """
        expected = """
        [i0]
        i1 = int_lt(i0, 4)
        guard_false(i1) []
        i2 = int_lt(i0, 5)
        guard_true(i2) []
        jump(4)
        """
        self.optimize_loop(ops, expected)

    def test_bound_lt_rev(self):
        ops = """
        [i0]
        i1 = int_lt(i0, 4)
        guard_false(i1) []
        i2 = int_gt(i0, 3)
        guard_true(i2) []
        jump(i0)
        """
        expected = """
        [i0]
        i1 = int_lt(i0, 4)
        guard_false(i1) []
        jump(i0)
        """
        self.optimize_loop(ops, expected)

    def test_bound_lt_tripple(self):
        ops = """
        [i0]
        i1 = int_lt(i0, 0)
        guard_true(i1) []
        i2 = int_lt(i0, 7)
        guard_true(i2) []
        i3 = int_lt(i0, 5)
        guard_true(i3) []
        jump(i0)
        """
        expected = """
        [i0]
        i1 = int_lt(i0, 0)
        guard_true(i1) []
        jump(i0)
        """
        self.optimize_loop(ops, expected)

    def test_bound_lt_add(self):
        ops = """
        [i0]
        i1 = int_lt(i0, 4)
        guard_true(i1) []
        i2 = int_add(i0, 10)
        i3 = int_lt(i2, 15)
        guard_true(i3) []
        jump(i0)
        """
        expected = """
        [i0]
        i1 = int_lt(i0, 4)
        guard_true(i1) []
        i2 = int_add(i0, 10)
        jump(i0)
        """
        self.optimize_loop(ops, expected)

    def test_bound_lt_add_before(self):
        ops = """
        [i0]
        i2 = int_add(i0, 10)
        i3 = int_lt(i2, 15)
        guard_true(i3) []
        i1 = int_lt(i0, 6)
        guard_true(i1) []
        jump(i0)
        """
        expected = """
        [i0]
        i2 = int_add(i0, 10)
        i3 = int_lt(i2, 15)
        guard_true(i3) []
        jump(i0)
        """
        self.optimize_loop(ops, expected)

    def test_bound_lt_add_ovf(self):
        ops = """
        [i0]
        i1 = int_lt(i0, 4)
        guard_true(i1) []
        i2 = int_add_ovf(i0, 10)
        guard_no_overflow() []
        i3 = int_lt(i2, 15)
        guard_true(i3) []
        jump(i0)
        """
        expected = """
        [i0]
        i1 = int_lt(i0, 4)
        guard_true(i1) []
        i2 = int_add(i0, 10)
        jump(i0)
        """
        self.optimize_loop(ops, expected)

    def test_bound_lt_add_ovf_before(self):
        ops = """
        [i0]
        i2 = int_add_ovf(i0, 10)
        guard_no_overflow() []
        i3 = int_lt(i2, 15)
        guard_true(i3) []
        i1 = int_lt(i0, 6)
        guard_true(i1) []
        jump(i0)
        """
        expected = """
        [i0]
        i2 = int_add_ovf(i0, 10)
        guard_no_overflow() []
        i3 = int_lt(i2, 15)
        guard_true(i3) []
        jump(i0)
        """
        self.optimize_loop(ops, expected)

    def test_bound_lt_sub(self):
        ops = """
        [i0]
        i1 = int_lt(i0, 4)
        guard_true(i1) []
        i1p = int_gt(i0, -4)
        guard_true(i1p) []
        i2 = int_sub(i0, 10)
        i3 = int_lt(i2, -5)
        guard_true(i3) []
        jump(i0)
        """
        expected = """
        [i0]
        i1 = int_lt(i0, 4)
        guard_true(i1) []
        i1p = int_gt(i0, -4)
        guard_true(i1p) []
        i2 = int_sub(i0, 10)
        jump(i0)
        """
        self.optimize_loop(ops, expected)

    def test_bound_lt_sub_before(self):
        ops = """
        [i0]
        i2 = int_sub(i0, 10)
        i3 = int_lt(i2, -5)
        guard_true(i3) []
        i1 = int_lt(i0, 5)
        guard_true(i1) []
        jump(i0)
        """
        expected = """
        [i0]
        i2 = int_sub(i0, 10)
        i3 = int_lt(i2, -5)
        guard_true(i3) []
        jump(i0)
        """
        self.optimize_loop(ops, expected)

    def test_bound_ltle(self):
        ops = """
        [i0]
        i1 = int_lt(i0, 4)
        guard_true(i1) []
        i2 = int_le(i0, 3)
        guard_true(i2) []
        jump(i0)
        """
        expected = """
        [i0]
        i1 = int_lt(i0, 4)
        guard_true(i1) []
        jump(i0)
        """
        self.optimize_loop(ops, expected)

    def test_bound_lelt(self):
        ops = """
        [i0]
        i1 = int_le(i0, 4)
        guard_true(i1) []
        i2 = int_lt(i0, 5)
        guard_true(i2) []
        jump(i0)
        """
        expected = """
        [i0]
        i1 = int_le(i0, 4)
        guard_true(i1) []
        jump(i0)
        """
        self.optimize_loop(ops, expected)

    def test_bound_gt(self):
        ops = """
        [i0]
        i1 = int_gt(i0, 5)
        guard_true(i1) []
        i2 = int_gt(i0, 4)
        guard_true(i2) []
        jump(i0)
        """
        expected = """
        [i0]
        i1 = int_gt(i0, 5)
        guard_true(i1) []
        jump(i0)
        """
        self.optimize_loop(ops, expected)

    def test_bound_gtge(self):
        ops = """
        [i0]
        i1 = int_gt(i0, 5)
        guard_true(i1) []
        i2 = int_ge(i0, 6)
        guard_true(i2) []
        jump(i0)
        """
        expected = """
        [i0]
        i1 = int_gt(i0, 5)
        guard_true(i1) []
        jump(i0)
        """
        self.optimize_loop(ops, expected)

    def test_bound_gegt(self):
        ops = """
        [i0]
        i1 = int_ge(i0, 5)
        guard_true(i1) []
        i2 = int_gt(i0, 4)
        guard_true(i2) []
        jump(i0)
        """
        expected = """
        [i0]
        i1 = int_ge(i0, 5)
        guard_true(i1) []
        jump(i0)
        """
        self.optimize_loop(ops, expected)

    def test_bound_ovf(self):
        ops = """
        [i0]
        i1 = int_ge(i0, 0)
        guard_true(i1) []
        i2 = int_lt(i0, 10)
        guard_true(i2) []
        i3 = int_add_ovf(i0, 1)
        guard_no_overflow() []
        jump(i3)
        """
        expected = """
        [i0]
        i1 = int_ge(i0, 0)
        guard_true(i1) []
        i2 = int_lt(i0, 10)
        guard_true(i2) []
        i3 = int_add(i0, 1)
        jump(i3)
        """
        self.optimize_loop(ops, expected)

    def test_bound_arraylen(self):
        ops = """
        [i0, p0]
        p1 = new_array(i0, descr=arraydescr)
        i1 = arraylen_gc(p1)
        i2 = int_gt(i1, -1)
        guard_true(i2) []
        setarrayitem_gc(p0, 0, p1)
        jump(i0, p0)
        """
        # The dead arraylen_gc will be eliminated by the backend.
        expected = """
        [i0, p0]
        p1 = new_array(i0, descr=arraydescr)
        i1 = arraylen_gc(p1)
        setarrayitem_gc(p0, 0, p1)
        jump(i0, p0)
        """
        self.optimize_loop(ops, expected)

    def test_bound_strlen(self):
        ops = """
        [p0]
        i0 = strlen(p0)
        i1 = int_ge(i0, 0)
        guard_true(i1) []
        jump(p0)
        """
        # The dead strlen will be eliminated be the backend.
        expected = """
        [p0]
        i0 = strlen(p0)
        jump(p0)
        """
        self.optimize_strunicode_loop(ops, expected)

    def test_addsub_const(self):
        ops = """
        [i0]
        i1 = int_add(i0, 1)
        i2 = int_sub(i1, 1)
        i3 = int_add(i2, 1)
        i4 = int_mul(i2, i3)
        jump(i4)
        """
        expected = """
        [i0]
        i1 = int_add(i0, 1)
        i4 = int_mul(i0, i1)
        jump(i4)
        """
        self.optimize_loop(ops, expected)

    def test_addsub_int(self):
        ops = """
        [i0, i10]
        i1 = int_add(i0, i10)
        i2 = int_sub(i1, i10)
        i3 = int_add(i2, i10)
        i4 = int_add(i2, i3)
        jump(i4, i10)
        """
        expected = """
        [i0, i10]
        i1 = int_add(i0, i10)
        i4 = int_add(i0, i1)
        jump(i4, i10)
        """
        self.optimize_loop(ops, expected)

    def test_addsub_int2(self):
        ops = """
        [i0, i10]
        i1 = int_add(i10, i0)
        i2 = int_sub(i1, i10)
        i3 = int_add(i10, i2)
        i4 = int_add(i2, i3)
        jump(i4, i10)
        """
        expected = """
        [i0, i10]
        i1 = int_add(i10, i0)
        i4 = int_add(i0, i1)
        jump(i4, i10)
        """
        self.optimize_loop(ops, expected)

    def test_framestackdepth_overhead(self):
        ops = """
        [p0, i22]
        i1 = getfield_gc(p0, descr=valuedescr)
        i2 = int_gt(i1, i22)
        guard_false(i2) []
        i3 = int_add(i1, 1)
        setfield_gc(p0, i3, descr=valuedescr)
        i4 = int_sub(i3, 1)
        setfield_gc(p0, i4, descr=valuedescr)
        i5 = int_gt(i4, i22)
        guard_false(i5) []
        i6 = int_add(i4, 1)
        p331 = force_token()
        i7 = int_sub(i6, 1)
        setfield_gc(p0, i7, descr=valuedescr)
        jump(p0, i22)
        """
        expected = """
        [p0, i22]
        i1 = getfield_gc(p0, descr=valuedescr)
        i2 = int_gt(i1, i22)
        guard_false(i2) []
        i3 = int_add(i1, 1)
        p331 = force_token()
        jump(p0, i22)
        """
        self.optimize_loop(ops, expected)

    def test_addsub_ovf(self):
        ops = """
        [i0]
        i1 = int_add_ovf(i0, 10)
        guard_no_overflow() []
        i2 = int_sub_ovf(i1, 5)
        guard_no_overflow() []
        jump(i2)
        """
        expected = """
        [i0]
        i1 = int_add_ovf(i0, 10)
        guard_no_overflow() []
        i2 = int_sub(i1, 5)
        jump(i2)
        """
        self.optimize_loop(ops, expected)

    def test_subadd_ovf(self):
        ops = """
        [i0]
        i1 = int_sub_ovf(i0, 10)
        guard_no_overflow() []
        i2 = int_add_ovf(i1, 5)
        guard_no_overflow() []
        jump(i2)
        """
        expected = """
        [i0]
        i1 = int_sub_ovf(i0, 10)
        guard_no_overflow() []
        i2 = int_add(i1, 5)
        jump(i2)
        """
        self.optimize_loop(ops, expected)

    def test_bound_and(self):
        ops = """
        [i0]
        i1 = int_and(i0, 255)
        i2 = int_lt(i1, 500)
        guard_true(i2) []
        i3 = int_le(i1, 255)
        guard_true(i3) []
        i4 = int_gt(i1, -1)
        guard_true(i4) []
        i5 = int_ge(i1, 0)
        guard_true(i5) []
        i6 = int_lt(i1, 0)
        guard_false(i6) []
        i7 = int_le(i1, -1)
        guard_false(i7) []
        i8 = int_gt(i1, 255)
        guard_false(i8) []
        i9 = int_ge(i1, 500)
        guard_false(i9) []
        i12 = int_lt(i1, 100)
        guard_true(i12) []
        i13 = int_le(i1, 90)
        guard_true(i13) []
        i14 = int_gt(i1, 10)
        guard_true(i14) []
        i15 = int_ge(i1, 20)
        guard_true(i15) []
        jump(i1)
        """
        expected = """
        [i0]
        i1 = int_and(i0, 255)
        i12 = int_lt(i1, 100)
        guard_true(i12) []
        i13 = int_le(i1, 90)
        guard_true(i13) []
        i14 = int_gt(i1, 10)
        guard_true(i14) []
        i15 = int_ge(i1, 20)
        guard_true(i15) []
        jump(i1)
        """
        self.optimize_loop(ops, expected)

    def test_subsub_ovf(self):
        ops = """
        [i0]
        i1 = int_sub_ovf(1, i0)
        guard_no_overflow() []
        i2 = int_gt(i1, 1)
        guard_true(i2) []
        i3 = int_sub_ovf(1, i0)
        guard_no_overflow() []
        i4 = int_gt(i3, 1)
        guard_true(i4) []
        jump(i0)
        """
        expected = """
        [i0]
        i1 = int_sub_ovf(1, i0)
        guard_no_overflow() []
        i2 = int_gt(i1, 1)
        guard_true(i2) []
        jump(i0)
        """
        self.optimize_loop(ops, expected)

    def test_bound_eq(self):
        ops = """
        [i0, i1]
        i2 = int_le(i0, 4)
        guard_true(i2) []
        i3 = int_eq(i0, i1)
        guard_true(i3) []
        i4 = int_lt(i1, 5)
        guard_true(i4) []
        jump(i0, i1)
        """
        expected = """
        [i0, i1]
        i2 = int_le(i0, 4)
        guard_true(i2) []
        i3 = int_eq(i0, i1)
        guard_true(i3) []
        jump(i0, i1)
        """
        self.optimize_loop(ops, expected)

    def test_bound_eq_const(self):
        ops = """
        [i0]
        i1 = int_eq(i0, 7)
        guard_true(i1) []
        i2 = int_add(i0, 3)
        jump(i2)
        """
        expected = """
        [i0]
        i1 = int_eq(i0, 7)
        guard_true(i1) []
        jump(10)

        """
        self.optimize_loop(ops, expected)

    def test_bound_eq_const_not(self):
        ops = """
        [i0]
        i1 = int_eq(i0, 7)
        guard_false(i1) []
        i2 = int_add(i0, 3)
        jump(i2)
        """
        expected = """
        [i0]
        i1 = int_eq(i0, 7)
        guard_false(i1) []
        i2 = int_add(i0, 3)
        jump(i2)

        """
        self.optimize_loop(ops, expected)

    def test_bound_ne_const(self):
        ops = """
        [i0]
        i1 = int_ne(i0, 7)
        guard_false(i1) []
        i2 = int_add(i0, 3)
        jump(i2)
        """
        expected = """
        [i0]
        i1 = int_ne(i0, 7)
        guard_false(i1) []
        jump(10)

        """
        self.optimize_loop(ops, expected)

    def test_bound_ne_const_not(self):
        ops = """
        [i0]
        i1 = int_ne(i0, 7)
        guard_true(i1) []
        i2 = int_add(i0, 3)
        jump(i2)
        """
        expected = """
        [i0]
        i1 = int_ne(i0, 7)
        guard_true(i1) []
        i2 = int_add(i0, 3)
        jump(i2)
        """
        self.optimize_loop(ops, expected)

    def test_bound_ltne(self):
        ops = """
        [i0, i1]
        i2 = int_lt(i0, 7)
        guard_true(i2) []
        i3 = int_ne(i0, 10)
        guard_true(i2) []
        jump(i0, i1)
        """
        expected = """
        [i0, i1]
        i2 = int_lt(i0, 7)
        guard_true(i2) []
        jump(i0, i1)
        """
        self.optimize_loop(ops, expected)

    def test_bound_lege_const(self):
        ops = """
        [i0]
        i1 = int_ge(i0, 7)
        guard_true(i1) []
        i2 = int_le(i0, 7)
        guard_true(i2) []
        i3 = int_add(i0, 3)
        jump(i3)
        """
        expected = """
        [i0]
        i1 = int_ge(i0, 7)
        guard_true(i1) []
        i2 = int_le(i0, 7)
        guard_true(i2) []
        jump(10)

        """
        self.optimize_loop(ops, expected)

    def test_mul_ovf(self):
        ops = """
        [i0, i1]
        i2 = int_and(i0, 255)
        i3 = int_lt(i1, 5)
        guard_true(i3) []
        i4 = int_gt(i1, -10)
        guard_true(i4) []
        i5 = int_mul_ovf(i2, i1)
        guard_no_overflow() []
        i6 = int_lt(i5, -2550)
        guard_false(i6) []
        i7 = int_ge(i5, 1276)
        guard_false(i7) []
        i8 = int_gt(i5, 126)
        guard_true(i8) []
        jump(i0, i1)
        """
        expected = """
        [i0, i1]
        i2 = int_and(i0, 255)
        i3 = int_lt(i1, 5)
        guard_true(i3) []
        i4 = int_gt(i1, -10)
        guard_true(i4) []
        i5 = int_mul(i2, i1)
        i8 = int_gt(i5, 126)
        guard_true(i8) []
        jump(i0, i1)
        """
        self.optimize_loop(ops, expected)

    def test_mul_ovf_before(self):
        ops = """
        [i0, i1]
        i2 = int_and(i0, 255)
        i22 = int_add(i2, 1)
        i3 = int_mul_ovf(i22, i1)
        guard_no_overflow() []
        i4 = int_lt(i3, 10)
        guard_true(i4) []
        i5 = int_gt(i3, 2)
        guard_true(i5) []
        i6 = int_lt(i1, 0)
        guard_false(i6) []
        jump(i0, i1)
        """
        expected = """
        [i0, i1]
        i2 = int_and(i0, 255)
        i22 = int_add(i2, 1)
        i3 = int_mul_ovf(i22, i1)
        guard_no_overflow() []
        i4 = int_lt(i3, 10)
        guard_true(i4) []
        i5 = int_gt(i3, 2)
        guard_true(i5) []
        jump(i0, i1)
        """
        self.optimize_loop(ops, expected)

    def test_sub_ovf_before(self):
        ops = """
        [i0, i1]
        i2 = int_and(i0, 255)
        i3 = int_sub_ovf(i2, i1)
        guard_no_overflow() []
        i4 = int_le(i3, 10)
        guard_true(i4) []
        i5 = int_ge(i3, 2)
        guard_true(i5) []
        i6 = int_lt(i1, -10)
        guard_false(i6) []
        i7 = int_gt(i1, 253)
        guard_false(i7) []
        jump(i0, i1)
        """
        expected = """
        [i0, i1]
        i2 = int_and(i0, 255)
        i3 = int_sub_ovf(i2, i1)
        guard_no_overflow() []
        i4 = int_le(i3, 10)
        guard_true(i4) []
        i5 = int_ge(i3, 2)
        guard_true(i5) []
        jump(i0, i1)
        """
        self.optimize_loop(ops, expected)

    # ----------
    def optimize_strunicode_loop(self, ops, optops):
        # check with the arguments passed in
        self.optimize_loop(ops, optops)
        # check with replacing 'str' with 'unicode' everywhere
        self.optimize_loop(ops.replace('str','unicode').replace('s"', 'u"'),
                           optops.replace('str','unicode').replace('s"', 'u"'))

    def test_newstr_1(self):
        ops = """
        [i0]
        p1 = newstr(1)
        strsetitem(p1, 0, i0)
        i1 = strgetitem(p1, 0)
        jump(i1)
        """
        expected = """
        [i0]
        jump(i0)
        """
        self.optimize_strunicode_loop(ops, expected)

    def test_newstr_2(self):
        ops = """
        [i0, i1]
        p1 = newstr(2)
        strsetitem(p1, 0, i0)
        strsetitem(p1, 1, i1)
        i2 = strgetitem(p1, 1)
        i3 = strgetitem(p1, 0)
        jump(i2, i3)
        """
        expected = """
        [i0, i1]
        jump(i1, i0)
        """
        self.optimize_strunicode_loop(ops, expected)

    def test_str_concat_1(self):
        ops = """
        [p1, p2]
        p3 = call(0, p1, p2, descr=strconcatdescr)
        jump(p2, p3)
        """
        expected = """
        [p1, p2]
        i1 = strlen(p1)
        i2 = strlen(p2)
        i3 = int_add(i1, i2)
        p3 = newstr(i3)
        copystrcontent(p1, p3, 0, 0, i1)
        copystrcontent(p2, p3, 0, i1, i2)
        jump(p2, p3)
        """
        self.optimize_strunicode_loop(ops, expected)

    def test_str_concat_vstr2_str(self):
        ops = """
        [i0, i1, p2]
        p1 = newstr(2)
        strsetitem(p1, 0, i0)
        strsetitem(p1, 1, i1)
        p3 = call(0, p1, p2, descr=strconcatdescr)
        jump(i1, i0, p3)
        """
        expected = """
        [i0, i1, p2]
        i2 = strlen(p2)
        i3 = int_add(2, i2)
        p3 = newstr(i3)
        strsetitem(p3, 0, i0)
        strsetitem(p3, 1, i1)
        copystrcontent(p2, p3, 0, 2, i2)
        jump(i1, i0, p3)
        """
        self.optimize_strunicode_loop(ops, expected)

    def test_str_concat_str_vstr2(self):
        ops = """
        [i0, i1, p2]
        p1 = newstr(2)
        strsetitem(p1, 0, i0)
        strsetitem(p1, 1, i1)
        p3 = call(0, p2, p1, descr=strconcatdescr)
        jump(i1, i0, p3)
        """
        expected = """
        [i0, i1, p2]
        i2 = strlen(p2)
        i3 = int_add(i2, 2)
        p3 = newstr(i3)
        copystrcontent(p2, p3, 0, 0, i2)
        strsetitem(p3, i2, i0)
        i5 = int_add(i2, 1)
        strsetitem(p3, i5, i1)
        i6 = int_add(i5, 1)      # will be killed by the backend
        jump(i1, i0, p3)
        """
        self.optimize_strunicode_loop(ops, expected)

    def test_str_concat_str_str_str(self):
        ops = """
        [p1, p2, p3]
        p4 = call(0, p1, p2, descr=strconcatdescr)
        p5 = call(0, p4, p3, descr=strconcatdescr)
        jump(p2, p3, p5)
        """
        expected = """
        [p1, p2, p3]
        i1 = strlen(p1)
        i2 = strlen(p2)
        i12 = int_add(i1, i2)
        i3 = strlen(p3)
        i123 = int_add(i12, i3)
        p5 = newstr(i123)
        copystrcontent(p1, p5, 0, 0, i1)
        copystrcontent(p2, p5, 0, i1, i2)
        copystrcontent(p3, p5, 0, i12, i3)
        jump(p2, p3, p5)
        """
        self.optimize_strunicode_loop(ops, expected)

    def test_str_concat_str_cstr1(self):
        ops = """
        [p2]
        p3 = call(0, p2, s"x", descr=strconcatdescr)
        jump(p3)
        """
        expected = """
        [p2]
        i2 = strlen(p2)
        i3 = int_add(i2, 1)
        p3 = newstr(i3)
        copystrcontent(p2, p3, 0, 0, i2)
        strsetitem(p3, i2, 120)     # == ord('x')
        jump(p3)
        """
        self.optimize_strunicode_loop(ops, expected)

    def test_str_concat_consts(self):
        ops = """
        []
        p1 = same_as(s"ab")
        p2 = same_as(s"cde")
        p3 = call(0, p1, p2, descr=strconcatdescr)
        escape(p3)
        jump()
        """
        expected = """
        []
        escape(s"abcde")
        jump()
        """
        self.optimize_strunicode_loop(ops, expected)

    def test_str_concat_constant_lengths(self):
        ops = """
        [i0]
        p0 = newstr(1)
        strsetitem(p0, 0, i0)
        p1 = newstr(0)
        p2 = call(0, p0, p1, descr=strconcatdescr)
        i1 = call(0, p2, p0, descr=strequaldescr)
        finish(i1)
        """
        expected = """
        [i0]
        finish(1)
        """
        self.optimize_strunicode_loop(ops, expected)

    def test_str_concat_constant_lengths_2(self):
        ops = """
        [i0]
        p0 = newstr(0)
        p1 = newstr(1)
        strsetitem(p1, 0, i0)
        p2 = call(0, p0, p1, descr=strconcatdescr)
        i1 = call(0, p2, p1, descr=strequaldescr)
        finish(i1)
        """
        expected = """
        [i0]
        finish(1)
        """
        self.optimize_strunicode_loop(ops, expected)

    def test_str_slice_1(self):
        ops = """
        [p1, i1, i2]
        p2 = call(0, p1, i1, i2, descr=strslicedescr)
        jump(p2, i1, i2)
        """
        expected = """
        [p1, i1, i2]
        i3 = int_sub(i2, i1)
        p2 = newstr(i3)
        copystrcontent(p1, p2, i1, 0, i3)
        jump(p2, i1, i2)
        """
        self.optimize_strunicode_loop(ops, expected)

    def test_str_slice_2(self):
        ops = """
        [p1, i2]
        p2 = call(0, p1, 0, i2, descr=strslicedescr)
        jump(p2, i2)
        """
        expected = """
        [p1, i2]
        p2 = newstr(i2)
        copystrcontent(p1, p2, 0, 0, i2)
        jump(p2, i2)
        """
        self.optimize_strunicode_loop(ops, expected)

    def test_str_slice_3(self):
        ops = """
        [p1, i1, i2, i3, i4]
        p2 = call(0, p1, i1, i2, descr=strslicedescr)
        p3 = call(0, p2, i3, i4, descr=strslicedescr)
        jump(p3, i1, i2, i3, i4)
        """
        expected = """
        [p1, i1, i2, i3, i4]
        i0 = int_sub(i2, i1)     # killed by the backend
        i5 = int_sub(i4, i3)
        i6 = int_add(i1, i3)
        p3 = newstr(i5)
        copystrcontent(p1, p3, i6, 0, i5)
        jump(p3, i1, i2, i3, i4)
        """
        self.optimize_strunicode_loop(ops, expected)

    def test_str_slice_getitem1(self):
        ops = """
        [p1, i1, i2, i3]
        p2 = call(0, p1, i1, i2, descr=strslicedescr)
        i4 = strgetitem(p2, i3)
        escape(i4)
        jump(p1, i1, i2, i3)
        """
        expected = """
        [p1, i1, i2, i3]
        i6 = int_sub(i2, i1)      # killed by the backend
        i5 = int_add(i1, i3)
        i4 = strgetitem(p1, i5)
        escape(i4)
        jump(p1, i1, i2, i3)
        """
        self.optimize_strunicode_loop(ops, expected)

    def test_str_slice_plain(self):
        ops = """
        [i3, i4]
        p1 = newstr(2)
        strsetitem(p1, 0, i3)
        strsetitem(p1, 1, i4)
        p2 = call(0, p1, 1, 2, descr=strslicedescr)
        i5 = strgetitem(p2, 0)
        escape(i5)
        jump(i3, i4)
        """
        expected = """
        [i3, i4]
        escape(i4)
        jump(i3, i4)
        """
        self.optimize_strunicode_loop(ops, expected)

    def test_str_slice_concat(self):
        ops = """
        [p1, i1, i2, p2]
        p3 = call(0, p1, i1, i2, descr=strslicedescr)
        p4 = call(0, p3, p2, descr=strconcatdescr)
        jump(p4, i1, i2, p2)
        """
        expected = """
        [p1, i1, i2, p2]
        i3 = int_sub(i2, i1)     # length of p3
        i4 = strlen(p2)
        i5 = int_add(i3, i4)
        p4 = newstr(i5)
        copystrcontent(p1, p4, i1, 0, i3)
        copystrcontent(p2, p4, 0, i3, i4)
        jump(p4, i1, i2, p2)
        """
        self.optimize_strunicode_loop(ops, expected)

    def test_str_slice_plain_virtual(self):
        ops = """
        []
        p0 = newstr(11)
        copystrcontent(s"hello world", p0, 0, 0, 11)
        p1 = call(0, p0, 0, 5, descr=strslicedescr)
        finish(p1)
        """
        expected = """
        []
        finish(s"hello")
        """
        self.optimize_strunicode_loop(ops, expected)

    # ----------
    def optimize_strunicode_loop_extradescrs(self, ops, optops):
        class FakeCallInfoCollection:
            def callinfo_for_oopspec(self, oopspecindex):
                calldescrtype = type(LLtypeMixin.strequaldescr)
                effectinfotype = type(LLtypeMixin.strequaldescr.get_extra_info())
                for value in LLtypeMixin.__dict__.values():
                    if isinstance(value, calldescrtype):
                        extra = value.get_extra_info()
                        if (extra and isinstance(extra, effectinfotype) and
                            extra.oopspecindex == oopspecindex):
                            # returns 0 for 'func' in this test
                            return value, 0
                raise AssertionError("not found: oopspecindex=%d" %
                                     oopspecindex)
        #
        self.callinfocollection = FakeCallInfoCollection()
        self.optimize_strunicode_loop(ops, optops)

    def test_str_equal_noop1(self):
        ops = """
        [p1, p2]
        i0 = call(0, p1, p2, descr=strequaldescr)
        escape(i0)
        jump(p1, p2)
        """
        self.optimize_strunicode_loop_extradescrs(ops, ops)

    def test_str_equal_noop2(self):
        ops = """
        [p1, p2, p3]
        p4 = call(0, p1, p2, descr=strconcatdescr)
        i0 = call(0, p3, p4, descr=strequaldescr)
        escape(i0)
        jump(p1, p2, p3)
        """
        expected = """
        [p1, p2, p3]
        i1 = strlen(p1)
        i2 = strlen(p2)
        i3 = int_add(i1, i2)
        p4 = newstr(i3)
        copystrcontent(p1, p4, 0, 0, i1)
        copystrcontent(p2, p4, 0, i1, i2)
        i0 = call(0, p3, p4, descr=strequaldescr)
        escape(i0)
        jump(p1, p2, p3)
        """
        self.optimize_strunicode_loop_extradescrs(ops, expected)

    def test_str_equal_slice1(self):
        ops = """
        [p1, i1, i2, p3]
        p4 = call(0, p1, i1, i2, descr=strslicedescr)
        i0 = call(0, p4, p3, descr=strequaldescr)
        escape(i0)
        jump(p1, i1, i2, p3)
        """
        expected = """
        [p1, i1, i2, p3]
        i3 = int_sub(i2, i1)
        i0 = call(0, p1, i1, i3, p3, descr=streq_slice_checknull_descr)
        escape(i0)
        jump(p1, i1, i2, p3)
        """
        self.optimize_strunicode_loop_extradescrs(ops, expected)

    def test_str_equal_slice2(self):
        ops = """
        [p1, i1, i2, p3]
        p4 = call(0, p1, i1, i2, descr=strslicedescr)
        i0 = call(0, p3, p4, descr=strequaldescr)
        escape(i0)
        jump(p1, i1, i2, p3)
        """
        expected = """
        [p1, i1, i2, p3]
        i4 = int_sub(i2, i1)
        i0 = call(0, p1, i1, i4, p3, descr=streq_slice_checknull_descr)
        escape(i0)
        jump(p1, i1, i2, p3)
        """
        self.optimize_strunicode_loop_extradescrs(ops, expected)

    def test_str_equal_slice3(self):
        ops = """
        [p1, i1, i2, p3]
        guard_nonnull(p3) []
        p4 = call(0, p1, i1, i2, descr=strslicedescr)
        i0 = call(0, p3, p4, descr=strequaldescr)
        escape(i0)
        jump(p1, i1, i2, p3)
        """
        expected = """
        [p1, i1, i2, p3]
        guard_nonnull(p3) []
        i4 = int_sub(i2, i1)
        i0 = call(0, p1, i1, i4, p3, descr=streq_slice_nonnull_descr)
        escape(i0)
        jump(p1, i1, i2, p3)
        """
        self.optimize_strunicode_loop_extradescrs(ops, expected)

    def test_str_equal_slice4(self):
        ops = """
        [p1, i1, i2]
        p3 = call(0, p1, i1, i2, descr=strslicedescr)
        i0 = call(0, p3, s"x", descr=strequaldescr)
        escape(i0)
        jump(p1, i1, i2)
        """
        expected = """
        [p1, i1, i2]
        i3 = int_sub(i2, i1)
        i0 = call(0, p1, i1, i3, 120, descr=streq_slice_char_descr)
        escape(i0)
        jump(p1, i1, i2)
        """
        self.optimize_strunicode_loop_extradescrs(ops, expected)

    def test_str_equal_slice5(self):
        ops = """
        [p1, i1, i2, i3]
        p4 = call(0, p1, i1, i2, descr=strslicedescr)
        p5 = newstr(1)
        strsetitem(p5, 0, i3)
        i0 = call(0, p5, p4, descr=strequaldescr)
        escape(i0)
        jump(p1, i1, i2, i3)
        """
        expected = """
        [p1, i1, i2, i3]
        i4 = int_sub(i2, i1)
        i0 = call(0, p1, i1, i4, i3, descr=streq_slice_char_descr)
        escape(i0)
        jump(p1, i1, i2, i3)
        """
        self.optimize_strunicode_loop_extradescrs(ops, expected)

    def test_str_equal_none1(self):
        ops = """
        [p1]
        i0 = call(0, p1, NULL, descr=strequaldescr)
        escape(i0)
        jump(p1)
        """
        expected = """
        [p1]
        i0 = ptr_eq(p1, NULL)
        escape(i0)
        jump(p1)
        """
        self.optimize_strunicode_loop_extradescrs(ops, expected)

    def test_str_equal_none2(self):
        ops = """
        [p1]
        i0 = call(0, NULL, p1, descr=strequaldescr)
        escape(i0)
        jump(p1)
        """
        expected = """
        [p1]
        i0 = ptr_eq(p1, NULL)
        escape(i0)
        jump(p1)
        """
        self.optimize_strunicode_loop_extradescrs(ops, expected)

    def test_str_equal_nonnull1(self):
        ops = """
        [p1]
        guard_nonnull(p1) []
        i0 = call(0, p1, s"hello world", descr=strequaldescr)
        escape(i0)
        jump(p1)
        """
        expected = """
        [p1]
        guard_nonnull(p1) []
        i0 = call(0, p1, s"hello world", descr=streq_nonnull_descr)
        escape(i0)
        jump(p1)
        """
        self.optimize_strunicode_loop_extradescrs(ops, expected)

    def test_str_equal_nonnull2(self):
        ops = """
        [p1]
        guard_nonnull(p1) []
        i0 = call(0, p1, s"", descr=strequaldescr)
        escape(i0)
        jump(p1)
        """
        expected = """
        [p1]
        guard_nonnull(p1) []
        i1 = strlen(p1)
        i0 = int_eq(i1, 0)
        escape(i0)
        jump(p1)
        """
        self.optimize_strunicode_loop_extradescrs(ops, expected)

    def test_str_equal_nonnull3(self):
        ops = """
        [p1]
        guard_nonnull(p1) []
        i0 = call(0, p1, s"x", descr=strequaldescr)
        escape(i0)
        jump(p1)
        """
        expected = """
        [p1]
        guard_nonnull(p1) []
        i0 = call(0, p1, 120, descr=streq_nonnull_char_descr)
        escape(i0)
        jump(p1)
        """
        self.optimize_strunicode_loop_extradescrs(ops, expected)

    def test_str_equal_nonnull4(self):
        ops = """
        [p1, p2]
        p4 = call(0, p1, p2, descr=strconcatdescr)
        i0 = call(0, s"hello world", p4, descr=strequaldescr)
        escape(i0)
        jump(p1, p2)
        """
        expected = """
        [p1, p2]
        i1 = strlen(p1)
        i2 = strlen(p2)
        i3 = int_add(i1, i2)
        p4 = newstr(i3)
        copystrcontent(p1, p4, 0, 0, i1)
        copystrcontent(p2, p4, 0, i1, i2)
        i0 = call(0, s"hello world", p4, descr=streq_nonnull_descr)
        escape(i0)
        jump(p1, p2)
        """
        self.optimize_strunicode_loop_extradescrs(ops, expected)

    def test_str_equal_chars0(self):
        ops = """
        [i1]
        p1 = newstr(0)
        i0 = call(0, p1, s"", descr=strequaldescr)
        escape(i0)
        jump(i1)
        """
        expected = """
        [i1]
        escape(1)
        jump(i1)
        """
        self.optimize_strunicode_loop_extradescrs(ops, expected)

    def test_str_equal_chars1(self):
        ops = """
        [i1]
        p1 = newstr(1)
        strsetitem(p1, 0, i1)
        i0 = call(0, p1, s"x", descr=strequaldescr)
        escape(i0)
        jump(i1)
        """
        expected = """
        [i1]
        i0 = int_eq(i1, 120)     # ord('x')
        escape(i0)
        jump(i1)
        """
        self.optimize_strunicode_loop_extradescrs(ops, expected)

    def test_str_equal_chars2(self):
        ops = """
        [i1, i2]
        p1 = newstr(2)
        strsetitem(p1, 0, i1)
        strsetitem(p1, 1, i2)
        i0 = call(0, p1, s"xy", descr=strequaldescr)
        escape(i0)
        jump(i1, i2)
        """
        expected = """
        [i1, i2]
        p1 = newstr(2)
        strsetitem(p1, 0, i1)
        strsetitem(p1, 1, i2)
        i0 = call(0, p1, s"xy", descr=streq_lengthok_descr)
        escape(i0)
        jump(i1, i2)
        """
        self.optimize_strunicode_loop_extradescrs(ops, expected)

    def test_str_equal_chars3(self):
        ops = """
        [p1]
        i0 = call(0, s"x", p1, descr=strequaldescr)
        escape(i0)
        jump(p1)
        """
        expected = """
        [p1]
        i0 = call(0, p1, 120, descr=streq_checknull_char_descr)
        escape(i0)
        jump(p1)
        """
        self.optimize_strunicode_loop_extradescrs(ops, expected)

    def test_str_equal_lengthmismatch1(self):
        ops = """
        [i1]
        p1 = newstr(1)
        strsetitem(p1, 0, i1)
        i0 = call(0, s"xy", p1, descr=strequaldescr)
        escape(i0)
        jump(i1)
        """
        expected = """
        [i1]
        escape(0)
        jump(i1)
        """
        self.optimize_strunicode_loop_extradescrs(ops, expected)

    def test_str2unicode_constant(self):
        ops = """
        []
        p0 = call(0, "xy", descr=s2u_descr)      # string -> unicode
        escape(p0)
        jump()
        """
        expected = """
        []
        escape(u"xy")
        jump()
        """
        self.optimize_strunicode_loop_extradescrs(ops, expected)

    def test_str2unicode_nonconstant(self):
        ops = """
        [p0]
        p1 = call(0, p0, descr=s2u_descr)      # string -> unicode
        escape(p1)
        jump(p1)
        """
        self.optimize_strunicode_loop_extradescrs(ops, ops)
        # more generally, supporting non-constant but virtual cases is
        # not obvious, because of the exception UnicodeDecodeError that
        # can be raised by ll_str2unicode()

    def test_strgetitem_repeated(self):
        ops = """
        [p0, i0]
        i1 = strgetitem(p0, i0)
        i2 = strgetitem(p0, i0)
        i3 = int_eq(i1, i2)
        guard_true(i3) []
        escape(i2)
        jump(p0, i0)
        """
        expected = """
        [p0, i0]
        i1 = strgetitem(p0, i0)
        escape(i1)
        jump(p0, i0)
        """
        self.optimize_strunicode_loop(ops, expected)

    def test_int_is_true_bounds(self):
        ops = """
        [p0]
        i0 = strlen(p0)
        i1 = int_is_true(i0)
        guard_true(i1) []
        i2 = int_ge(0, i0)
        guard_false(i2) []
        jump(p0)
        """
        expected = """
        [p0]
        i0 = strlen(p0)
        i1 = int_is_true(i0)
        guard_true(i1) []
        jump(p0)
        """
        self.optimize_strunicode_loop(ops, expected)

    def test_strslice_subtraction_folds(self):
        ops = """
        [p0, i0]
        i1 = int_add(i0, 1)
        p1 = call(0, p0, i0, i1, descr=strslicedescr)
        escape(p1)
        jump(p0, i1)
        """
        expected = """
        [p0, i0]
        i1 = int_add(i0, 1)
        p1 = newstr(1)
        i2 = strgetitem(p0, i0)
        strsetitem(p1, 0, i2)
        escape(p1)
        jump(p0, i1)
        """
        self.optimize_strunicode_loop(ops, expected)

    def test_float_mul_reversed(self):
        ops = """
        [f0, f1]
        f2 = float_mul(f0, f1)
        f3 = float_mul(f1, f0)
        jump(f2, f3)
        """
        expected = """
        [f0, f1]
        f2 = float_mul(f0, f1)
        jump(f2, f2)
        """
        self.optimize_loop(ops, expected)

    def test_null_char_str(self):
        ops = """
        [p0]
        p1 = newstr(4)
        setfield_gc(p0, p1, descr=valuedescr)
        jump(p0)
        """
        # It used to be the case that this would have a series of
        # strsetitem(p1, idx, 0), which was silly because memory is 0 filled
        # when allocated.
        expected = """
        [p0]
        p1 = newstr(4)
        setfield_gc(p0, p1, descr=valuedescr)
        jump(p0)
        """
        self.optimize_strunicode_loop(ops, expected)

    def test_newstr_strlen(self):
        ops = """
        [i0]
        p0 = newstr(i0)
        escape(p0)
        i1 = strlen(p0)
        i2 = int_add(i1, 1)
        jump(i2)
        """
        expected = """
        [i0]
        p0 = newstr(i0)
        escape(p0)
        i1 = int_add(i0, 1)
        jump(i1)
        """
        self.optimize_strunicode_loop(ops, expected)

    def test_intmod_bounds(self):
        ops = """
        [i0, i1]
        i2 = int_mod(i0, 12)
        i3 = int_gt(i2, 12)
        guard_false(i3) []
        i4 = int_lt(i2, -12)
        guard_false(i4) []
        i5 = int_mod(i1, -12)
        i6 = int_lt(i5, -12)
        guard_false(i6) []
        i7 = int_gt(i5, 12)
        guard_false(i7) []
        jump(i2, i5)
        """
        expected = """
        [i0, i1]
        i2 = int_mod(i0, 12)
        i5 = int_mod(i1, -12)
        jump(i2, i5)
        """
        self.optimize_loop(ops, expected)

        # This the sequence of resoperations that is generated for a Python
        # app-level int % int.  When the modulus is constant and when i0
        # is known non-negative it should be optimized to a single int_mod.
        ops = """
        [i0]
        i5 = int_ge(i0, 0)
        guard_true(i5) []
        i1 = int_mod(i0, 42)
        i2 = int_rshift(i1, %d)
        i3 = int_and(42, i2)
        i4 = int_add(i1, i3)
        finish(i4)
        """ % (LONG_BIT-1)
        expected = """
        [i0]
        i5 = int_ge(i0, 0)
        guard_true(i5) []
        i1 = int_mod(i0, 42)
        finish(i1)
        """
        self.optimize_loop(ops, expected)

        # 'n % power-of-two' can be turned into int_and(); at least that's
        # easy to do now if n is known to be non-negative.
        ops = """
        [i0]
        i5 = int_ge(i0, 0)
        guard_true(i5) []
        i1 = int_mod(i0, 8)
        i2 = int_rshift(i1, %d)
        i3 = int_and(42, i2)
        i4 = int_add(i1, i3)
        finish(i4)
        """ % (LONG_BIT-1)
        expected = """
        [i0]
        i5 = int_ge(i0, 0)
        guard_true(i5) []
        i1 = int_and(i0, 7)
        finish(i1)
        """
        self.optimize_loop(ops, expected)

        # Of course any 'maybe-negative % power-of-two' can be turned into
        # int_and(), but that's a bit harder to detect here because it turns
        # into several operations, and of course it is wrong to just turn
        # int_mod(i0, 16) into int_and(i0, 15).
        ops = """
        [i0]
        i1 = int_mod(i0, 16)
        i2 = int_rshift(i1, %d)
        i3 = int_and(16, i2)
        i4 = int_add(i1, i3)
        finish(i4)
        """ % (LONG_BIT-1)
        expected = """
        [i0]
        i4 = int_and(i0, 15)
        finish(i4)
        """
        py.test.skip("harder")
        self.optimize_loop(ops, expected)

    def test_intmod_bounds_bug1(self):
        ops = """
        [i0]
        i1 = int_mod(i0, %d)
        i2 = int_eq(i1, 0)
        guard_false(i2) []
        finish()
        """ % (-(1<<(LONG_BIT-1)),)
        self.optimize_loop(ops, ops)

    def test_bounded_lazy_setfield(self):
        ops = """
        [p0, i0]
        i1 = int_gt(i0, 2)
        guard_true(i1) []
        setarrayitem_gc(p0, 0, 3)
        setarrayitem_gc(p0, 2, 4)
        setarrayitem_gc(p0, i0, 15)
        i2 = getarrayitem_gc(p0, 2)
        jump(p0, i2)
        """
        # Remove the getarrayitem_gc, because we know that p[i0] does not alias
        # p0[2]
        expected = """
        [p0, i0]
        i1 = int_gt(i0, 2)
        guard_true(i1) []
        setarrayitem_gc(p0, i0, 15)
        setarrayitem_gc(p0, 0, 3)
        setarrayitem_gc(p0, 2, 4)
        jump(p0, 4)
        """
        self.optimize_loop(ops, expected)

    def test_empty_copystrunicontent(self):
        ops = """
        [p0, p1, i0, i2, i3]
        i4 = int_eq(i3, 0)
        guard_true(i4) []
        copystrcontent(p0, p1, i0, i2, i3)
        jump(p0, p1, i0, i2, i3)
        """
        expected = """
        [p0, p1, i0, i2, i3]
        i4 = int_eq(i3, 0)
        guard_true(i4) []
        jump(p0, p1, i0, i2, 0)
        """
        self.optimize_strunicode_loop(ops, expected)

    def test_empty_copystrunicontent_virtual(self):
        ops = """
        [p0]
        p1 = newstr(23)
        copystrcontent(p0, p1, 0, 0, 0)
        jump(p0)
        """
        expected = """
        [p0]
        jump(p0)
        """
        self.optimize_strunicode_loop(ops, expected)

    def test_forced_virtuals_aliasing(self):
        ops = """
        [i0, i1]
        p0 = new(descr=ssize)
        p1 = new(descr=ssize)
        escape(p0)
        escape(p1)
        setfield_gc(p0, i0, descr=adescr)
        setfield_gc(p1, i1, descr=adescr)
        i2 = getfield_gc(p0, descr=adescr)
        jump(i2, i2)
        """
        expected = """
        [i0, i1]
        p0 = new(descr=ssize)
        escape(p0)
        p1 = new(descr=ssize)
        escape(p1)
        setfield_gc(p0, i0, descr=adescr)
        setfield_gc(p1, i1, descr=adescr)
        jump(i0, i0)
        """
        py.test.skip("not implemented")
        # setfields on things that used to be virtual still can't alias each
        # other
        self.optimize_loop(ops, expected)

    def test_plain_virtual_string_copy_content(self):
        ops = """
        [i1]
        p0 = newstr(6)
        copystrcontent(s"hello!", p0, 0, 0, 6)
        p1 = call(0, p0, s"abc123", descr=strconcatdescr)
        i0 = strgetitem(p1, i1)
        finish(i0)
        """
        expected = """
        [i1]
        i0 = strgetitem(s"hello!abc123", i1)
        finish(i0)
        """
        self.optimize_strunicode_loop(ops, expected)

    def test_plain_virtual_string_copy_content_2(self):
        ops = """
        []
        p0 = newstr(6)
        copystrcontent(s"hello!", p0, 0, 0, 6)
        p1 = call(0, p0, s"abc123", descr=strconcatdescr)
        i0 = strgetitem(p1, 0)
        finish(i0)
        """
        expected = """
        []
        finish(104)
        """
        self.optimize_strunicode_loop(ops, expected)

    def test_ptr_eq_str_constant(self):
        ops = """
        []
        i0 = ptr_eq(s"abc", s"\x00")
        finish(i0)
        """
        expected = """
        []
        finish(0)
        """
        self.optimize_loop(ops, expected)

    def test_known_equal_ints(self):
        py.test.skip("in-progress")
        ops = """
        [i0, i1, i2, p0]
        i3 = int_eq(i0, i1)
        guard_true(i3) []

        i4 = int_lt(i2, i0)
        guard_true(i4) []
        i5 = int_lt(i2, i1)
        guard_true(i5) []

        i6 = getarrayitem_gc(p0, i2)
        finish(i6)
        """
        expected = """
        [i0, i1, i2, p0]
        i3 = int_eq(i0, i1)
        guard_true(i3) []

        i4 = int_lt(i2, i0)
        guard_true(i4) []

        i6 = getarrayitem_gc(p0, i3)
        finish(i6)
        """
        self.optimize_loop(ops, expected)

    def test_str_copy_virtual(self):
        ops = """
        [i0]
        p0 = newstr(8)
        strsetitem(p0, 0, i0)
        strsetitem(p0, 1, i0)
        strsetitem(p0, 2, i0)
        strsetitem(p0, 3, i0)
        strsetitem(p0, 4, i0)
        strsetitem(p0, 5, i0)
        strsetitem(p0, 6, i0)
        strsetitem(p0, 7, i0)
        p1 = newstr(12)
        copystrcontent(p0, p1, 0, 0, 8)
        strsetitem(p1, 8, 3)
        strsetitem(p1, 9, 0)
        strsetitem(p1, 10, 0)
        strsetitem(p1, 11, 0)
        finish(p1)
        """
        expected = """
        [i0]
        p1 = newstr(12)
        strsetitem(p1, 0, i0)
        strsetitem(p1, 1, i0)
        strsetitem(p1, 2, i0)
        strsetitem(p1, 3, i0)
        strsetitem(p1, 4, i0)
        strsetitem(p1, 5, i0)
        strsetitem(p1, 6, i0)
        strsetitem(p1, 7, i0)
        strsetitem(p1, 8, 3)
        finish(p1)
        """
        self.optimize_strunicode_loop(ops, expected)

    def test_str_copy_constant_virtual(self):
        ops = """
        []
        p0 = newstr(10)
        copystrcontent(s"abcd", p0, 0, 0, 4)
        strsetitem(p0, 4, 101)
        copystrcontent(s"fghij", p0, 0, 5, 5)
        finish(p0)
        """
        expected = """
        []
        finish(s"abcdefghij")
        """
        self.optimize_strunicode_loop(ops, expected)

    def test_call_pure_vstring_const(self):
        py.test.skip("implement me")
        ops = """
        []
        p0 = newstr(3)
        strsetitem(p0, 0, 97)
        strsetitem(p0, 1, 98)
        strsetitem(p0, 2, 99)
        i0 = call_pure(123, p0, descr=nonwritedescr)
        finish(i0)
        """
        expected = """
        []
        finish(5)
        """
        call_pure_results = {
            (ConstInt(123), get_const_ptr_for_string("abc"),): ConstInt(5),
        }
        self.optimize_loop(ops, expected, call_pure_results)


class TestLLtype(BaseTestOptimizeBasic, LLtypeMixin):
    pass

##class TestOOtype(BaseTestOptimizeBasic, OOtypeMixin):

##    def test_instanceof(self):
##        ops = """
##        [i0]
##        p0 = new_with_vtable(ConstClass(node_vtable))
##        i1 = instanceof(p0, descr=nodesize)
##        jump(i1)
##        """
##        expected = """
##        [i0]
##        jump(1)
##        """
##        self.optimize_loop(ops, expected)

##    def test_instanceof_guard_class(self):
##        ops = """
##        [i0, p0]
##        guard_class(p0, ConstClass(node_vtable)) []
##        i1 = instanceof(p0, descr=nodesize)
##        jump(i1, p0)
##        """
##        expected = """
##        [i0, p0]
##        guard_class(p0, ConstClass(node_vtable)) []
##        jump(1, p0)
##        """
##        self.optimize_loop(ops, expected)