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

Large files files are truncated, but you can click here to view the full file

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

def test_store_final_boxes_in_guard():
    from pypy.jit.metainterp.compile import ResumeGuardDescr
    from pypy.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 pypy.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_constfold_all(self):
        from pypy.jit.backend.llgraph.llimpl import TYPES     # xxx fish
        from pypy.jit.metainterp.executor import execute_nonspec
        from pypy.jit.metainterp.history import BoxInt
        import random
        for opnum in range(rop.INT_ADD, rop.SAME_AS+1):
            try:
                op = opname[opnum]
            except KeyError:
                continue
            if 'FLOAT' in op:
                continue
            argtypes, restype = TYPES[op.lower()]
            args = []
            for argtype in argtypes:
                assert argtype in ('int', 'bool')
                args.append(random.randrange(1, 20))
            assert restype in ('int', 'bool')
            ops = """
            []
            i1 = %s(%s)
            escape(i1)
            jump()
            """ % (op.lower(), ', '.join(map(str, args)))
            argboxes = [BoxInt(a) for a in args]
            expected_value = execute_nonspec(self.cpu, None, opnum,
                                             argboxes).getint()
            expected = """
            []
            escape(%d)
            jump()
            """ % expected_value
            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(p1, i1, descr=valuedescr)
        setfield_gc(p1sub, 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, f0, descr=complexrealdescr)
        setinteriorfield_gc(p0, 0, f1, descr=compleximagdescr)
        setinteriorfield_gc(p0, 1, f2, descr=complexrealdescr)
        setinteriorfield_gc(p0, 1, f3, descr=compleximagdescr)
        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, f0, descr=complexrealdescr)
        setinteriorfield_gc(p0, 0, f1, descr=compleximagdescr)
        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, des…