/gcc/d/expr.cc

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/* expr.cc -- Lower D frontend expressions to GCC trees.
   Copyright (C) 2015-2018 Free Software Foundation, Inc.

GCC is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3, or (at your option)
any later version.

GCC is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3.  If not see
<http://www.gnu.org/licenses/>.  */

#include "config.h"
#include "system.h"
#include "coretypes.h"

#include "dmd/aggregate.h"
#include "dmd/ctfe.h"
#include "dmd/declaration.h"
#include "dmd/expression.h"
#include "dmd/identifier.h"
#include "dmd/init.h"
#include "dmd/module.h"
#include "dmd/mtype.h"
#include "dmd/template.h"

#include "tree.h"
#include "fold-const.h"
#include "diagnostic.h"
#include "langhooks.h"
#include "tm.h"
#include "function.h"
#include "toplev.h"
#include "varasm.h"
#include "predict.h"
#include "stor-layout.h"

#include "d-tree.h"


/* Implements the visitor interface to build the GCC trees of all Expression
   AST classes emitted from the D Front-end.
   All visit methods accept one parameter E, which holds the frontend AST
   of the expression to compile.  They also don't return any value, instead
   generated code is cached in RESULT_ and returned from the caller.  */

class ExprVisitor : public Visitor
{
  using Visitor::visit;

  tree result_;
  bool constp_;

  /* Determine if type is a struct that has a postblit.  */

  bool needs_postblit (Type *t)
  {
    t = t->baseElemOf ();

    if (t->ty == Tstruct)
      {
	StructDeclaration *sd = ((TypeStruct *) t)->sym;
	if (sd->postblit)
	  return true;
      }

    return false;
  }

  /* Determine if type is a struct that has a destructor.  */

  bool needs_dtor (Type *t)
  {
    t = t->baseElemOf ();

    if (t->ty == Tstruct)
      {
	StructDeclaration *sd = ((TypeStruct *) t)->sym;
	if (sd->dtor)
	  return true;
      }

    return false;
  }

  /* Determine if expression is suitable lvalue.  */

  bool lvalue_p (Expression *e)
  {
    return ((e->op != TOKslice && e->isLvalue ())
	    || (e->op == TOKslice && ((UnaExp *) e)->e1->isLvalue ())
	    || (e->op == TOKcast && ((UnaExp *) e)->e1->isLvalue ()));
  }

  /* Build an expression of code CODE, data type TYPE, and operands ARG0 and
     ARG1.  Perform relevant conversions needed for correct code operations.  */

  tree binary_op (tree_code code, tree type, tree arg0, tree arg1)
  {
    tree t0 = TREE_TYPE (arg0);
    tree t1 = TREE_TYPE (arg1);
    tree ret = NULL_TREE;

    bool unsignedp = TYPE_UNSIGNED (t0) || TYPE_UNSIGNED (t1);

    /* Deal with float mod expressions immediately.  */
    if (code == FLOAT_MOD_EXPR)
      return build_float_modulus (type, arg0, arg1);

    if (POINTER_TYPE_P (t0) && INTEGRAL_TYPE_P (t1))
      return build_nop (type, build_offset_op (code, arg0, arg1));

    if (INTEGRAL_TYPE_P (t0) && POINTER_TYPE_P (t1))
      return build_nop (type, build_offset_op (code, arg1, arg0));

    if (POINTER_TYPE_P (t0) && POINTER_TYPE_P (t1))
      {
	gcc_assert (code == MINUS_EXPR);
	tree ptrtype = lang_hooks.types.type_for_mode (ptr_mode, 0);

	/* POINTER_DIFF_EXPR requires a signed integer type of the same size as
	   pointers.  If some platform cannot provide that, or has a larger
	   ptrdiff_type to support differences larger than half the address
	   space, cast the pointers to some larger integer type and do the
	   computations in that type.  */
	if (TYPE_PRECISION (ptrtype) > TYPE_PRECISION (t0))
	  ret = fold_build2 (MINUS_EXPR, ptrtype,
			     d_convert (ptrtype, arg0),
			     d_convert (ptrtype, arg1));
	else
	  ret = fold_build2 (POINTER_DIFF_EXPR, ptrtype, arg0, arg1);
      }
    else if (INTEGRAL_TYPE_P (type) && (TYPE_UNSIGNED (type) != unsignedp))
      {
	tree inttype = (unsignedp)
	  ? d_unsigned_type (type) : d_signed_type (type);
	ret = fold_build2 (code, inttype, arg0, arg1);
      }
    else
      {
	/* If the operation needs excess precision.  */
	tree eptype = excess_precision_type (type);
	if (eptype != NULL_TREE)
	  {
	    arg0 = d_convert (eptype, arg0);
	    arg1 = d_convert (eptype, arg1);
	  }
	else
	  {
	    /* Front-end does not do this conversion and GCC does not
	       always do it right.  */
	    if (COMPLEX_FLOAT_TYPE_P (t0) && !COMPLEX_FLOAT_TYPE_P (t1))
	      arg1 = d_convert (t0, arg1);
	    else if (COMPLEX_FLOAT_TYPE_P (t1) && !COMPLEX_FLOAT_TYPE_P (t0))
	      arg0 = d_convert (t1, arg0);

	    eptype = type;
	  }

	ret = fold_build2 (code, eptype, arg0, arg1);
      }

    return d_convert (type, ret);
  }

  /* Build a binary expression of code CODE, assigning the result into E1.  */

  tree binop_assignment (tree_code code, Expression *e1, Expression *e2)
  {
    /* Skip casts for lhs assignment.  */
    Expression *e1b = e1;
    while (e1b->op == TOKcast)
      {
	CastExp *ce = (CastExp *) e1b;
	gcc_assert (same_type_p (ce->type, ce->to));
	e1b = ce->e1;
      }

    /* Stabilize LHS for assignment.  */
    tree lhs = build_expr (e1b);
    tree lexpr = stabilize_expr (&lhs);

    /* The LHS expression could be an assignment, to which its operation gets
       lost during gimplification.  */
    if (TREE_CODE (lhs) == MODIFY_EXPR)
      {
	/* If LHS has side effects, call stabilize_reference on it, so it can
	   be evaluated multiple times.  */
	if (TREE_SIDE_EFFECTS (TREE_OPERAND (lhs, 0)))
	  lhs = build_assign (MODIFY_EXPR,
			      stabilize_reference (TREE_OPERAND (lhs, 0)),
			      TREE_OPERAND (lhs, 1));

	lexpr = compound_expr (lexpr, lhs);
	lhs = TREE_OPERAND (lhs, 0);
      }

    lhs = stabilize_reference (lhs);

    /* Save RHS, to ensure that the expression is evaluated before LHS.  */
    tree rhs = build_expr (e2);
    tree rexpr = d_save_expr (rhs);

    rhs = this->binary_op (code, build_ctype (e1->type),
			   convert_expr (lhs, e1b->type, e1->type), rexpr);
    if (TREE_SIDE_EFFECTS (rhs))
      rhs = compound_expr (rexpr, rhs);

    tree expr = modify_expr (lhs, convert_expr (rhs, e1->type, e1b->type));
    return compound_expr (lexpr, expr);
  }

public:
  ExprVisitor (bool constp)
  {
    this->result_ = NULL_TREE;
    this->constp_ = constp;
  }

  tree result (void)
  {
    return this->result_;
  }

  /* Visitor interfaces, each Expression class should have
     overridden the default.  */

  void visit (Expression *)
  {
    gcc_unreachable ();
  }

  /* Build a conditional expression.  If either the second or third
     expression is void, then the resulting type is void.  Otherwise
     they are implicitly converted to a common type.  */

  void visit (CondExp *e)
  {
    tree cond = convert_for_condition (build_expr (e->econd),
				       e->econd->type);
    tree t1 = build_expr (e->e1);
    tree t2 = build_expr (e->e2);

    if (e->type->ty != Tvoid)
      {
	t1 = convert_expr (t1, e->e1->type, e->type);
	t2 = convert_expr (t2, e->e2->type, e->type);
      }

    this->result_ = build_condition (build_ctype (e->type), cond, t1, t2);
  }

  /* Build an identity comparison expression.  Operands go through the
     usual conversions to bring them to a common type before comparison.
     The result type is bool.  */

  void visit (IdentityExp *e)
  {
    tree_code code = (e->op == TOKidentity) ? EQ_EXPR : NE_EXPR;
    Type *tb1 = e->e1->type->toBasetype ();
    Type *tb2 = e->e2->type->toBasetype ();

    if ((tb1->ty == Tsarray || tb1->ty == Tarray)
	&& (tb2->ty == Tsarray || tb2->ty == Tarray))
      {
	/* For static and dynamic arrays, identity is defined as referring to
	   the same array elements and the same number of elements.  */
	tree t1 = d_array_convert (e->e1);
	tree t2 = d_array_convert (e->e2);
	this->result_ = d_convert (build_ctype (e->type),
				   build_boolop (code, t1, t2));
      }
    else if (tb1->isfloating () && tb1->ty != Tvector)
      {
	/* For floating-point values, identity is defined as the bits in the
	   operands being identical.  */
	tree t1 = d_save_expr (build_expr (e->e1));
	tree t2 = d_save_expr (build_expr (e->e2));

	tree tmemcmp = builtin_decl_explicit (BUILT_IN_MEMCMP);
	tree size = size_int (TYPE_PRECISION (TREE_TYPE (t1)) / BITS_PER_UNIT);

	tree result = build_call_expr (tmemcmp, 3, build_address (t1),
				       build_address (t2), size);
	this->result_ = build_boolop (code, result, integer_zero_node);
      }
    else if (tb1->ty == Tstruct)
      {
	/* For struct objects, identity is defined as bits in operands being
	   identical also.  Alignment holes in structs are ignored.  */
	StructDeclaration *sd = ((TypeStruct *) tb1)->sym;
	tree t1 = build_expr (e->e1);
	tree t2 = build_expr (e->e2);

	gcc_assert (same_type_p (tb1, tb2));

	this->result_ = build_struct_comparison (code, sd, t1, t2);
      }
    else
      {
	/* For operands of other types, identity is defined as being the
	   same as equality expressions.  */
	tree t1 = build_expr (e->e1);
	tree t2 = build_expr (e->e2);
	this->result_ = d_convert (build_ctype (e->type),
				   build_boolop (code, t1, t2));
      }
  }

  /* Build an equality expression, which compare the two operands for either
     equality or inequality.  Operands go through the usual conversions to bring
     them to a common type before comparison.  The result type is bool.  */

  void visit (EqualExp *e)
  {
    Type *tb1 = e->e1->type->toBasetype ();
    Type *tb2 = e->e2->type->toBasetype ();
    tree_code code = (e->op == TOKequal) ? EQ_EXPR : NE_EXPR;

    if ((tb1->ty == Tsarray || tb1->ty == Tarray)
	&& (tb2->ty == Tsarray || tb2->ty == Tarray))
      {
	/* For static and dynamic arrays, equality is defined as the lengths of
	   the arrays matching, and all the elements are equal.  */
	Type *t1elem = tb1->nextOf ()->toBasetype ();
	Type *t2elem = tb1->nextOf ()->toBasetype ();

	/* Check if comparisons of arrays can be optimized using memcmp.
	   This will inline EQ expressions as:
		e1.length == e2.length && memcmp(e1.ptr, e2.ptr, size) == 0;
	    Or when generating a NE expression:
		e1.length != e2.length || memcmp(e1.ptr, e2.ptr, size) != 0;  */
	if ((t1elem->isintegral () || t1elem->ty == Tvoid
	     || (t1elem->ty == Tstruct && !((TypeStruct *)t1elem)->sym->xeq))
	    && t1elem->ty == t2elem->ty)
	  {
	    tree t1 = d_array_convert (e->e1);
	    tree t2 = d_array_convert (e->e2);
	    tree result;

	    /* Make temporaries to prevent multiple evaluations.  */
	    tree t1saved = d_save_expr (t1);
	    tree t2saved = d_save_expr (t2);

	    /* Length of arrays, for comparisons done before calling memcmp.  */
	    tree t1len = d_array_length (t1saved);
	    tree t2len = d_array_length (t2saved);

	    /* Reference to array data.  */
	    tree t1ptr = d_array_ptr (t1saved);
	    tree t2ptr = d_array_ptr (t2saved);

	    /* Compare arrays using memcmp if possible, otherwise for structs,
	       each field is compared inline.  */
	    if (t1elem->ty != Tstruct
		|| identity_compare_p (((TypeStruct *) t1elem)->sym))
	      {
		tree size = size_mult_expr (t1len, size_int (t1elem->size ()));
		tree tmemcmp = builtin_decl_explicit (BUILT_IN_MEMCMP);

		result = build_call_expr (tmemcmp, 3, t1ptr, t2ptr, size);
		result = build_boolop (code, result, integer_zero_node);
	      }
	    else
	      {
		StructDeclaration *sd = ((TypeStruct *) t1elem)->sym;

		result = build_array_struct_comparison (code, sd, t1len,
							t1ptr, t2ptr);
	      }

	    /* Check array length first before passing to memcmp.
	       For equality expressions, this becomes:
		    (e1.length == 0 || memcmp);
	       Otherwise for inequality:
		    (e1.length != 0 && memcmp);  */
	    tree tsizecmp = build_boolop (code, t1len, size_zero_node);
	    if (e->op == TOKequal)
	      result = build_boolop (TRUTH_ORIF_EXPR, tsizecmp, result);
	    else
	      result = build_boolop (TRUTH_ANDIF_EXPR, tsizecmp, result);

	    /* Finally, check if lengths of both arrays match if dynamic.
	       The frontend should have already guaranteed that static arrays
	       have same size.  */
	    if (tb1->ty == Tsarray && tb2->ty == Tsarray)
	      gcc_assert (tb1->size () == tb2->size ());
	    else
	      {
		tree tlencmp = build_boolop (code, t1len, t2len);
		if (e->op == TOKequal)
		  result = build_boolop (TRUTH_ANDIF_EXPR, tlencmp, result);
		else
		  result = build_boolop (TRUTH_ORIF_EXPR, tlencmp, result);
	      }

	    /* Ensure left-to-right order of evaluation.  */
	    if (TREE_SIDE_EFFECTS (t2))
	      result = compound_expr (t2saved, result);

	    if (TREE_SIDE_EFFECTS (t1))
	      result = compound_expr (t1saved, result);

	    this->result_ = result;
	  }
	else
	  {
	    /* Use _adEq2() to compare each element.  */
	    Type *t1array = t1elem->arrayOf ();
	    tree result = build_libcall (LIBCALL_ADEQ2, e->type, 3,
					 d_array_convert (e->e1),
					 d_array_convert (e->e2),
					 build_typeinfo (e->loc, t1array));

	    if (e->op == TOKnotequal)
	      result = build1 (TRUTH_NOT_EXPR, build_ctype (e->type), result);

	    this->result_ = result;
	  }
      }
    else if (tb1->ty == Tstruct)
      {
	/* Equality for struct objects means the logical product of all
	   equality results of the corresponding object fields.  */
	StructDeclaration *sd = ((TypeStruct *) tb1)->sym;
	tree t1 = build_expr (e->e1);
	tree t2 = build_expr (e->e2);

	gcc_assert (same_type_p (tb1, tb2));

	this->result_ = build_struct_comparison (code, sd, t1, t2);
      }
    else if (tb1->ty == Taarray && tb2->ty == Taarray)
      {
	/* Use _aaEqual() for associative arrays.  */
	TypeAArray *taa1 = (TypeAArray *) tb1;
	tree result = build_libcall (LIBCALL_AAEQUAL, e->type, 3,
				     build_typeinfo (e->loc, taa1),
				     build_expr (e->e1),
				     build_expr (e->e2));

	if (e->op == TOKnotequal)
	  result = build1 (TRUTH_NOT_EXPR, build_ctype (e->type), result);

	this->result_ = result;
      }
    else
      {
	/* For operands of other types, equality is defined as the bit pattern
	   of the type matches exactly.  */
	tree t1 = build_expr (e->e1);
	tree t2 = build_expr (e->e2);

	this->result_ = d_convert (build_ctype (e->type),
				   build_boolop (code, t1, t2));
      }
  }

  /* Build an `in' expression.  This is a condition to see if an element
     exists in an associative array.  The result is a pointer to the
     element, or null if false.  */

  void visit (InExp *e)
  {
    Type *tb2 = e->e2->type->toBasetype ();
    gcc_assert (tb2->ty == Taarray);

    Type *tkey = ((TypeAArray *) tb2)->index->toBasetype ();
    tree key = convert_expr (build_expr (e->e1), e->e1->type, tkey);

    /* Build a call to _aaInX().  */
    this->result_ = build_libcall (LIBCALL_AAINX, e->type, 3,
				   build_expr (e->e2),
				   build_typeinfo (e->loc, tkey),
				   build_address (key));
  }

  /* Build a relational expression.  The result type is bool.  */

  void visit (CmpExp *e)
  {
    Type *tb1 = e->e1->type->toBasetype ();
    Type *tb2 = e->e2->type->toBasetype ();

    tree result;
    tree_code code;

    switch (e->op)
      {
      case TOKle:
	code = LE_EXPR;
	break;

      case TOKlt:
	code = LT_EXPR;
	break;

      case TOKge:
	code = GE_EXPR;
	break;

      case TOKgt:
	code = GT_EXPR;
	break;

      default:
	gcc_unreachable ();
      }

    /* For static and dynamic arrays, the relational op is turned into a
       library call.  It is not lowered during codegen.  */
    if ((tb1->ty == Tsarray || tb1->ty == Tarray)
	&& (tb2->ty == Tsarray || tb2->ty == Tarray))
      {
	error ("cannot handle comparison of type %<%s == %s%>",
	       tb1->toChars (), tb2->toChars ());
	gcc_unreachable ();
      }

    /* Simple comparison.  */
    result = build_boolop (code, build_expr (e->e1), build_expr (e->e2));
    this->result_ = d_convert (build_ctype (e->type), result);
  }

  /* Build a logical `and if' or `or if' expression.  If the right operand
     expression is void, then the resulting type is void.  Otherwise the
     result is bool.  */

  void visit (LogicalExp *e)
  {
    tree_code code = (e->op == TOKandand) ? TRUTH_ANDIF_EXPR : TRUTH_ORIF_EXPR;

    if (e->e2->type->toBasetype ()->ty != Tvoid)
      {
	tree t1 = build_expr (e->e1);
	tree t2 = build_expr (e->e2);

	t1 = convert_for_condition (t1, e->e1->type);
	t2 = convert_for_condition (t2, e->e2->type);

	this->result_ = d_convert (build_ctype (e->type),
				   build_boolop (code, t1, t2));
      }
    else
      {
	tree t1 = convert_for_condition (build_expr (e->e1), e->e1->type);
	tree t2 = build_expr_dtor (e->e2);

	/* Invert condition for logical or if expression.  */
	if (e->op == TOKoror)
	  t1 = build1 (TRUTH_NOT_EXPR, d_bool_type, t1);

	this->result_ = build_condition (build_ctype (e->type),
					 t1, t2, void_node);
      }
  }

  /* Build a binary operand expression.  Operands go through usual arithmetic
     conversions to bring them to a common type before evaluating.  */

  void visit (BinExp *e)
  {
    tree_code code;

    switch (e->op)
      {
      case TOKadd:
      case TOKmin:
	if ((e->e1->type->isreal () && e->e2->type->isimaginary ())
	    || (e->e1->type->isimaginary () && e->e2->type->isreal ()))
	  {
	    /* If the result is complex, then we can shortcut binary_op.
	       Frontend should have already validated types and sizes.  */
	    tree t1 = build_expr (e->e1);
	    tree t2 = build_expr (e->e2);

	    if (e->op == TOKmin)
	      t2 = build1 (NEGATE_EXPR, TREE_TYPE (t2), t2);

	    if (e->e1->type->isreal ())
	      this->result_ = complex_expr (build_ctype (e->type), t1, t2);
	    else
	      this->result_ = complex_expr (build_ctype (e->type), t2, t1);

	    return;
	  }
	else
	  code = (e->op == TOKadd)
	    ? PLUS_EXPR : MINUS_EXPR;
	break;

      case TOKmul:
	code = MULT_EXPR;
	break;

      case TOKdiv:
	code = e->e1->type->isintegral ()
	  ? TRUNC_DIV_EXPR : RDIV_EXPR;
	break;

      case TOKmod:
	code = e->e1->type->isfloating ()
	  ? FLOAT_MOD_EXPR : TRUNC_MOD_EXPR;
	break;

      case TOKand:
	code = BIT_AND_EXPR;
	break;

      case TOKor:
	code = BIT_IOR_EXPR;
	break;

      case TOKxor:
	code = BIT_XOR_EXPR;
	break;

      case TOKshl:
	code = LSHIFT_EXPR;
	  break;

      case TOKshr:
	code = RSHIFT_EXPR;
	break;

      case TOKushr:
	code = UNSIGNED_RSHIFT_EXPR;
	break;

      default:
	gcc_unreachable ();
      }

    this->result_ = this->binary_op (code, build_ctype (e->type),
				     build_expr (e->e1), build_expr (e->e2));
  }


  /* Build a concat expression, which concatenates two or more arrays of the
     same type, producing a dynamic array with the result.  If one operand
     is an element type, that element is converted to an array of length 1.  */

  void visit (CatExp *e)
  {
    Type *tb1 = e->e1->type->toBasetype ();
    Type *tb2 = e->e2->type->toBasetype ();
    Type *etype;

    if (tb1->ty == Tarray || tb1->ty == Tsarray)
      etype = tb1->nextOf ();
    else
      etype = tb2->nextOf ();

    vec<tree, va_gc> *elemvars = NULL;
    tree result;

    if (e->e1->op == TOKcat)
      {
	/* Flatten multiple concatenations to an array.
	   So the expression ((a ~ b) ~ c) becomes [a, b, c]  */
	int ndims = 2;

	for (Expression *ex = e->e1; ex->op == TOKcat;)
	  {
	    if (ex->op == TOKcat)
	      {
		ex = ((CatExp *) ex)->e1;
		ndims++;
	      }
	  }

	/* Store all concatenation args to a temporary byte[][ndims] array.  */
	Type *targselem = Type::tint8->arrayOf ();
	tree var = create_temporary_var (make_array_type (targselem, ndims));
	tree init = build_constructor (TREE_TYPE (var), NULL);
	vec_safe_push (elemvars, var);

	/* Loop through each concatenation from right to left.  */
	vec<constructor_elt, va_gc> *elms = NULL;
	CatExp *ce = e;
	int dim = ndims - 1;

	for (Expression *oe = ce->e2; oe != NULL;
	     (ce->e1->op != TOKcat
	      ? (oe = ce->e1)
	      : (ce = (CatExp *)ce->e1, oe = ce->e2)))
	  {
	    tree arg = d_array_convert (etype, oe, &elemvars);
	    tree index = size_int (dim);
	    CONSTRUCTOR_APPEND_ELT (elms, index, d_save_expr (arg));

	    /* Finished pushing all arrays.  */
	    if (oe == ce->e1)
	      break;

	    dim -= 1;
	  }

	/* Check there is no logic bug in constructing byte[][] of arrays.  */
	gcc_assert (dim == 0);
	CONSTRUCTOR_ELTS (init) = elms;
	DECL_INITIAL (var) = init;

	tree arrs = d_array_value (build_ctype (targselem->arrayOf ()),
				   size_int (ndims), build_address (var));

	result = build_libcall (LIBCALL_ARRAYCATNTX, e->type, 2,
				build_typeinfo (e->loc, e->type), arrs);
      }
    else
      {
	/* Handle single concatenation (a ~ b).  */
	result = build_libcall (LIBCALL_ARRAYCATT, e->type, 3,
				build_typeinfo (e->loc, e->type),
				d_array_convert (etype, e->e1, &elemvars),
				d_array_convert (etype, e->e2, &elemvars));
      }

    for (size_t i = 0; i < vec_safe_length (elemvars); ++i)
      result = bind_expr ((*elemvars)[i], result);

    this->result_ = result;
  }

  /* Build an assignment operator expression.  The right operand is implicitly
     converted to the type of the left operand, and assigned to it.  */

  void visit (BinAssignExp *e)
  {
    tree_code code;
    Expression *e1b = e->e1;

    switch (e->op)
      {
      case TOKaddass:
	code = PLUS_EXPR;
	break;

      case TOKminass:
	code = MINUS_EXPR;
	break;

      case TOKmulass:
	code = MULT_EXPR;
	break;

      case TOKdivass:
	code = e->e1->type->isintegral ()
	  ? TRUNC_DIV_EXPR : RDIV_EXPR;
	break;

      case TOKmodass:
	code = e->e1->type->isfloating ()
	  ? FLOAT_MOD_EXPR : TRUNC_MOD_EXPR;
	break;

      case TOKandass:
	code = BIT_AND_EXPR;
	break;

      case TOKorass:
	code = BIT_IOR_EXPR;
	break;

      case TOKxorass:
	code = BIT_XOR_EXPR;
	break;

      case TOKpowass:
	gcc_unreachable ();

      case TOKshlass:
	code = LSHIFT_EXPR;
	break;

      case TOKshrass:
      case TOKushrass:
	/* Use the original lhs type before it was promoted.  The left operand
	   of `>>>=' does not undergo integral promotions before shifting.
	   Strip off casts just incase anyway.  */
	while (e1b->op == TOKcast)
	  {
	    CastExp *ce = (CastExp *) e1b;
	    gcc_assert (same_type_p (ce->type, ce->to));
	    e1b = ce->e1;
	  }
	code = (e->op == TOKshrass) ? RSHIFT_EXPR : UNSIGNED_RSHIFT_EXPR;
	break;

      default:
	gcc_unreachable ();
      }

    tree exp = this->binop_assignment (code, e1b, e->e2);
    this->result_ = convert_expr (exp, e1b->type, e->type);
  }

  /* Build a concat assignment expression.  The right operand is appended
     to the the left operand.  */

  void visit (CatAssignExp *e)
  {
    Type *tb1 = e->e1->type->toBasetype ();
    Type *tb2 = e->e2->type->toBasetype ();
    Type *etype = tb1->nextOf ()->toBasetype ();

    if (tb1->ty == Tarray && tb2->ty == Tdchar
	&& (etype->ty == Tchar || etype->ty == Twchar))
      {
	/* Append a dchar to a char[] or wchar[]  */
	libcall_fn libcall = (etype->ty == Tchar)
	  ? LIBCALL_ARRAYAPPENDCD : LIBCALL_ARRAYAPPENDWD;

	this->result_ = build_libcall (libcall, e->type, 2,
				       build_address (build_expr (e->e1)),
				       build_expr (e->e2));
      }
    else
      {
	gcc_assert (tb1->ty == Tarray || tb2->ty == Tsarray);

	tree tinfo = build_typeinfo (e->loc, e->type);
	tree ptr = build_address (build_expr (e->e1));

	if ((tb2->ty == Tarray || tb2->ty == Tsarray)
	    && same_type_p (etype, tb2->nextOf ()->toBasetype ()))
	  {
	    /* Append an array.  */
	    this->result_ = build_libcall (LIBCALL_ARRAYAPPENDT, e->type, 3,
					   tinfo, ptr, d_array_convert (e->e2));

	  }
	else if (same_type_p (etype, tb2))
	  {
	    /* Append an element.  */
	    tree result = build_libcall (LIBCALL_ARRAYAPPENDCTX, e->type, 3,
					 tinfo, ptr, size_one_node);
	    result = d_save_expr (result);

	    /* Assign e2 to last element.  */
	    tree offexp = d_array_length (result);
	    offexp = build2 (MINUS_EXPR, TREE_TYPE (offexp),
			     offexp, size_one_node);
	    offexp = d_save_expr (offexp);

	    tree ptrexp = d_array_ptr (result);
	    ptrexp = void_okay_p (ptrexp);
	    ptrexp = build_array_index (ptrexp, offexp);

	    /* Evaluate expression before appending.  */
	    tree t2 = build_expr (e->e2);
	    tree expr = stabilize_expr (&t2);

	    t2 = d_save_expr (t2);
	    result = modify_expr (build_deref (ptrexp), t2);
	    result = compound_expr (t2, result);

	    this->result_ = compound_expr (expr, result);
	  }
	else
	  gcc_unreachable ();
      }
  }

  /* Build an assignment expression.  The right operand is implicitly
     converted to the type of the left operand, and assigned to it.  */

  void visit (AssignExp *e)
  {
    /* First, handle special assignment semantics.  */

    /* Look for array.length = n;  */
    if (e->e1->op == TOKarraylength)
      {
	/* Assignment to an array's length property; resize the array.  */
	ArrayLengthExp *ale = (ArrayLengthExp *) e->e1;
	tree newlength = convert_expr (build_expr (e->e2), e->e2->type,
				       Type::tsize_t);
	tree ptr = build_address (build_expr (ale->e1));

	/* Don't want the basetype for the element type.  */
	Type *etype = ale->e1->type->toBasetype ()->nextOf ();
	libcall_fn libcall = etype->isZeroInit ()
	  ? LIBCALL_ARRAYSETLENGTHT : LIBCALL_ARRAYSETLENGTHIT;

	tree result = build_libcall (libcall, ale->e1->type, 3,
				     build_typeinfo (ale->loc, ale->e1->type),
				     newlength, ptr);

	this->result_ = d_array_length (result);
	return;
      }

    /* Look for array[] = n;  */
    if (e->e1->op == TOKslice)
      {
	SliceExp *se = (SliceExp *) e->e1;
	Type *stype = se->e1->type->toBasetype ();
	Type *etype = stype->nextOf ()->toBasetype ();

	/* Determine if we need to run postblit or dtor.  */
	bool postblit = this->needs_postblit (etype) && this->lvalue_p (e->e2);
	bool destructor = this->needs_dtor (etype);

	if (e->memset & blockAssign)
	  {
	    /* Set a range of elements to one value.  */
	    tree t1 = d_save_expr (build_expr (e->e1));
	    tree t2 = build_expr (e->e2);
	    tree result;

	    if ((postblit || destructor) && e->op != TOKblit)
	      {
		libcall_fn libcall = (e->op == TOKconstruct)
		  ? LIBCALL_ARRAYSETCTOR : LIBCALL_ARRAYSETASSIGN;
		/* So we can call postblits on const/immutable objects.  */
		Type *tm = etype->unSharedOf ()->mutableOf ();
		tree ti = build_typeinfo (e->loc, tm);

		tree result = build_libcall (libcall, Type::tvoid, 4,
					     d_array_ptr (t1),
					     build_address (t2),
					     d_array_length (t1), ti);
		this->result_ = compound_expr (result, t1);
		return;
	      }

	    if (integer_zerop (t2))
	      {
		tree tmemset = builtin_decl_explicit (BUILT_IN_MEMSET);
		tree size = size_mult_expr (d_array_length (t1),
					    size_int (etype->size ()));

		result = build_call_expr (tmemset, 3, d_array_ptr (t1),
					  integer_zero_node, size);
	      }
	    else
	      result = build_array_set (d_array_ptr (t1),
					d_array_length (t1), t2);

	    this->result_ = compound_expr (result, t1);
	  }
	else
	  {
	    /* Perform a memcpy operation.  */
	    gcc_assert (e->e2->type->ty != Tpointer);

	    if (!postblit && !destructor && !array_bounds_check ())
	      {
		tree t1 = d_save_expr (d_array_convert (e->e1));
		tree t2 = d_array_convert (e->e2);
		tree tmemcpy = builtin_decl_explicit (BUILT_IN_MEMCPY);
		tree size = size_mult_expr (d_array_length (t1),
					    size_int (etype->size ()));

		tree result = build_call_expr (tmemcpy, 3, d_array_ptr (t1),
					       d_array_ptr (t2), size);
		this->result_ = compound_expr (result, t1);
	      }
	    else if ((postblit || destructor) && e->op != TOKblit)
	      {
		/* Generate: _d_arrayassign(ti, from, to)
			 or: _d_arrayctor(ti, from, to)  */
		libcall_fn libcall = (e->op == TOKconstruct)
		  ? LIBCALL_ARRAYCTOR : LIBCALL_ARRAYASSIGN;

		this->result_ = build_libcall (libcall, e->type, 3,
					       build_typeinfo (e->loc, etype),
					       d_array_convert (e->e2),
					       d_array_convert (e->e1));
	      }
	    else
	      {
		/* Generate: _d_arraycopy()  */
		this->result_ = build_libcall (LIBCALL_ARRAYCOPY, e->type, 3,
					       size_int (etype->size ()),
					       d_array_convert (e->e2),
					       d_array_convert (e->e1));
	      }
	  }

	return;
      }

    /* Look for reference initializations.  */
    if (e->memset & referenceInit)
      {
	gcc_assert (e->op == TOKconstruct || e->op == TOKblit);
	gcc_assert (e->e1->op == TOKvar);

	Declaration *decl = ((VarExp *) e->e1)->var;
	if (decl->storage_class & (STCout | STCref))
	  {
	    tree t2 = convert_for_assignment (build_expr (e->e2),
					      e->e2->type, e->e1->type);
	    tree t1 = build_expr (e->e1);
	    /* Want reference to lhs, not indirect ref.  */
	    t1 = TREE_OPERAND (t1, 0);
	    t2 = build_address (t2);

	    this->result_ = indirect_ref (build_ctype (e->type),
					  build_assign (INIT_EXPR, t1, t2));
	    return;
	  }
      }

    /* Other types of assignments that may require post construction.  */
    Type *tb1 = e->e1->type->toBasetype ();
    tree_code modifycode = (e->op == TOKconstruct) ? INIT_EXPR : MODIFY_EXPR;

    /* Look for struct assignment.  */
    if (tb1->ty == Tstruct)
      {
	tree t1 = build_expr (e->e1);
	tree t2 = convert_for_assignment (build_expr (e->e2),
					  e->e2->type, e->e1->type);

	/* Look for struct = 0.  */
	if (e->e2->op == TOKint64)
	  {
	    /* Use memset to fill struct.  */
	    gcc_assert (e->op == TOKblit);
	    StructDeclaration *sd = ((TypeStruct *) tb1)->sym;

	    tree tmemset = builtin_decl_explicit (BUILT_IN_MEMSET);
	    tree result = build_call_expr (tmemset, 3, build_address (t1),
					   t2, size_int (sd->structsize));

	    /* Maybe set-up hidden pointer to outer scope context.  */
	    if (sd->isNested ())
	      {
		tree field = get_symbol_decl (sd->vthis);
		tree value = build_vthis (sd);

		tree vthis_exp = modify_expr (component_ref (t1, field), value);
		result = compound_expr (result, vthis_exp);
	      }

	    this->result_ = compound_expr (result, t1);
	  }
	else
	  this->result_ = build_assign (modifycode, t1, t2);

	return;
      }

    /* Look for static array assignment.  */
    if (tb1->ty == Tsarray)
      {
	/* Look for array = 0.  */
	if (e->e2->op == TOKint64)
	  {
	    /* Use memset to fill the array.  */
	    gcc_assert (e->op == TOKblit);

	    tree t1 = build_expr (e->e1);
	    tree t2 = convert_for_assignment (build_expr (e->e2),
					      e->e2->type, e->e1->type);
	    tree size = size_int (e->e1->type->size ());

	    tree tmemset = builtin_decl_explicit (BUILT_IN_MEMSET);
	    this->result_ = build_call_expr (tmemset, 3, build_address (t1),
					     t2, size);
	    return;
	  }

	Type *etype = tb1->nextOf ();
	gcc_assert (e->e2->type->toBasetype ()->ty == Tsarray);

	/* Determine if we need to run postblit.  */
	bool postblit = this->needs_postblit (etype);
	bool destructor = this->needs_dtor (etype);
	bool lvalue_p = this->lvalue_p (e->e2);

	/* Even if the elements in rhs are all rvalues and don't have
	   to call postblits, this assignment should call dtors on old
	   assigned elements.  */
	if ((!postblit && !destructor)
	    || (e->op == TOKconstruct && !lvalue_p && postblit)
	    || (e->op == TOKblit || e->e1->type->size () == 0))
	  {
	    tree t1 = build_expr (e->e1);
	    tree t2 = convert_for_assignment (build_expr (e->e2),
					      e->e2->type, e->e1->type);

	    this->result_ = build_assign (modifycode, t1, t2);
	    return;
	  }

	Type *arrtype = (e->type->ty == Tsarray) ? etype->arrayOf () : e->type;
	tree result;

	if (e->op == TOKconstruct)
	  {
	    /* Generate: _d_arrayctor(ti, from, to)  */
	    result = build_libcall (LIBCALL_ARRAYCTOR, arrtype, 3,
				    build_typeinfo (e->loc, etype),
				    d_array_convert (e->e2),
				    d_array_convert (e->e1));
	  }
	else
	  {
	    /* Generate: _d_arrayassign_l()
		     or: _d_arrayassign_r()  */
	    libcall_fn libcall = (lvalue_p)
	      ? LIBCALL_ARRAYASSIGN_L : LIBCALL_ARRAYASSIGN_R;
	    tree elembuf = build_local_temp (build_ctype (etype));

	    result = build_libcall (libcall, arrtype, 4,
				    build_typeinfo (e->loc, etype),
				    d_array_convert (e->e2),
				    d_array_convert (e->e1),
				    build_address (elembuf));
	  }

	/* Cast the libcall result back to a static array.  */
	if (e->type->ty == Tsarray)
	  result = indirect_ref (build_ctype (e->type),
				 d_array_ptr (result));

	this->result_ = result;
	return;
      }

    /* Simple assignment.  */
    tree t1 = build_expr (e->e1);
    tree t2 = convert_for_assignment (build_expr (e->e2),
				      e->e2->type, e->e1->type);

    this->result_ = build_assign (modifycode, t1, t2);
  }

  /* Build a postfix expression.  */

  void visit (PostExp *e)
  {
    tree result;

    if (e->op == TOKplusplus)
      {
	result = build2 (POSTINCREMENT_EXPR, build_ctype (e->type),
			 build_expr (e->e1), build_expr (e->e2));
      }
    else if (e->op == TOKminusminus)
      {
	result = build2 (POSTDECREMENT_EXPR, build_ctype (e->type),
			 build_expr (e->e1), build_expr (e->e2));
      }
    else
      gcc_unreachable ();

    TREE_SIDE_EFFECTS (result) = 1;
    this->result_ = result;
  }

  /* Build an index expression.  */

  void visit (IndexExp *e)
  {
    Type *tb1 = e->e1->type->toBasetype ();

    if (tb1->ty == Taarray)
      {
	/* Get the key for the associative array.  */
	Type *tkey = ((TypeAArray *) tb1)->index->toBasetype ();
	tree key = convert_expr (build_expr (e->e2), e->e2->type, tkey);
	libcall_fn libcall;
	tree tinfo, ptr;

	if (e->modifiable)
	  {
	    libcall = LIBCALL_AAGETY;
	    ptr = build_address (build_expr (e->e1));
	    tinfo = build_typeinfo (e->loc, tb1->unSharedOf ()->mutableOf ());
	  }
	else
	  {
	    libcall = LIBCALL_AAGETRVALUEX;
	    ptr = build_expr (e->e1);
	    tinfo = build_typeinfo (e->loc, tkey);
	  }

	/* Index the associative array.  */
	tree result = build_libcall (libcall, e->type->pointerTo (), 4,
				     ptr, tinfo,
				     size_int (tb1->nextOf ()->size ()),
				     build_address (key));

	if (!e->indexIsInBounds && array_bounds_check ())
	  {
	    tree tassert = (global.params.checkAction == CHECKACTION_C)
	      ? build_call_expr (builtin_decl_explicit (BUILT_IN_TRAP), 0)
	      : d_assert_call (e->loc, LIBCALL_ARRAY_BOUNDS);

	    result = d_save_expr (result);
	    result = build_condition (TREE_TYPE (result),
				      d_truthvalue_conversion (result),
				      result, tassert);
	  }

	this->result_ = indirect_ref (build_ctype (e->type), result);
      }
    else
      {
	/* Get the data pointer and length for static and dynamic arrays.  */
	tree array = d_save_expr (build_expr (e->e1));
	tree ptr = convert_expr (array, tb1, tb1->nextOf ()->pointerTo ());

	tree length = NULL_TREE;
	if (tb1->ty != Tpointer)
	  length = get_array_length (array, tb1);
	else
	  gcc_assert (e->lengthVar == NULL);

	/* The __dollar variable just becomes a placeholder for the
	   actual length.  */
	if (e->lengthVar)
	  e->lengthVar->csym = length;

	/* Generate the index.  */
	tree index = build_expr (e->e2);

	/* If it's a static array and the index is constant, the front end has
	   already checked the bounds.  */
	if (tb1->ty != Tpointer && !e->indexIsInBounds)
	  index = build_bounds_condition (e->e2->loc, index, length, false);

	/* Index the .ptr.  */
	ptr = void_okay_p (ptr);
	this->result_ = indirect_ref (TREE_TYPE (TREE_TYPE (ptr)),
				      build_array_index (ptr, index));
      }
  }

  /* Build a comma expression.  The type is the type of the right operand.  */

  void visit (CommaExp *e)
  {
    tree t1 = build_expr (e->e1);
    tree t2 = build_expr (e->e2);
    tree type = e->type ? build_ctype (e->type) : void_type_node;

    this->result_ = build2 (COMPOUND_EXPR, type, t1, t2);
  }

  /* Build an array length expression.  Returns the number of elements
     in the array.  The result is of type size_t.  */

  void visit (ArrayLengthExp *e)
  {
    if (e->e1->type->toBasetype ()->ty == Tarray)
      this->result_ = d_array_length (build_expr (e->e1));
    else
      {
	/* Static arrays have already been handled by the front-end.  */
	error ("unexpected type for array length: %qs", e->type->toChars ());
	this->result_ = error_mark_node;
      }
  }

  /* Build a delegate pointer expression.  This will return the frame
     pointer value as a type void*.  */

  void visit (DelegatePtrExp *e)
  {
    tree t1 = build_expr (e->e1);
    this->result_ = delegate_object (t1);
  }

  /* Build a delegate function pointer expression.  This will return the
     function pointer value as a function type.  */

  void visit (DelegateFuncptrExp *e)
  {
    tree t1 = build_expr (e->e1);
    this->result_ = delegate_method (t1);
  }

  /* Build a slice expression.  */

  void visit (SliceExp *e)
  {
    Type *tb = e->type->toBasetype ();
    Type *tb1 = e->e1->type->toBasetype ();
    gcc_assert (tb->ty == Tarray || tb->ty == Tsarray);

    /* Use convert-to-dynamic-array code if possible.  */
    if (!e->lwr)
      {
	tree result = build_expr (e->e1);
	if (e->e1->type->toBasetype ()->ty == Tsarray)
	  result = convert_expr (result, e->e1->type, e->type);

	this->result_ = result;
	return;
      }
    else
      gcc_assert (e->upr != NULL);

    /* Get the data pointer and length for static and dynamic arrays.  */
    tree array = d_save_expr (build_expr (e->e1));
    tree ptr = convert_expr (array, tb1, tb1->nextOf ()->pointerTo ());
    tree length = NULL_TREE;

    /* Our array is already a SAVE_EXPR if necessary, so we don't make length
       a SAVE_EXPR which is, at most, a COMPONENT_REF on top of array.  */
    if (tb1->ty != Tpointer)
      length = get_array_length (array, tb1);
    else
      gcc_assert (e->lengthVar == NULL);

    /* The __dollar variable just becomes a placeholder for the
       actual length.  */
    if (e->lengthVar)
      e->lengthVar->csym = length;

    /* Generate upper and lower bounds.  */
    tree lwr_tree = d_save_expr (build_expr (e->lwr));
    tree upr_tree = d_save_expr (build_expr (e->upr));

    /* If the upper bound has any side effects, then the lower bound should be
       copied to a temporary always.  */
    if (TREE_CODE (upr_tree) == SAVE_EXPR && TREE_CODE (lwr_tree) != SAVE_EXPR)
      lwr_tree = save_expr (lwr_tree);

    /* Adjust the .ptr offset.  */
    if (!integer_zerop (lwr_tree))
      {
	tree ptrtype = TREE_TYPE (ptr);
	ptr = build_array_index (void_okay_p (ptr), lwr_tree);
	ptr = build_nop (ptrtype, ptr);
      }
    else
      lwr_tree = NULL_TREE;

    /* Nothing more to do for static arrays, their bounds checking has been
       done at compile-time.  */
    if (tb->ty == Tsarray)
      {
	this->result_ = indirect_ref (build_ctype (e->type), ptr);
	return;
      }
    else
      gcc_assert (tb->ty == Tarray);

    /* Generate bounds checking code.  */
    tree newlength;

    if (!e->upperIsInBounds)
      {
	if (length)
	  {
	    newlength = build_bounds_condition (e->upr->loc, upr_tree,
						length, true);
	  }
	else
	  {
	    /* Still need to check bounds lwr <= upr for pointers.  */
	    gcc_assert (tb1->ty == Tpointer);
	    newlength = upr_tree;
	  }
      }
    else
      newlength = upr_tree;

    if (lwr_tree)
      {
	/* Enforces lwr <= upr.  No need to check lwr <= length as
	   we've already ensured that upr <= length.  */
	if (!e->lowerIsLessThanUpper)
	  {
	    tree cond = build_bounds_condition (e->lwr->loc, lwr_tree,
						upr_tree, true);

	    /* When bounds checking is off, the index value is
	       returned directly.  */
	    if (cond != lwr_tree)
	      newlength = compound_expr (cond, newlength);
	  }

	/* Need to ensure lwr always gets evaluated first, as it may be a
	   function call.  Generates (lwr, upr) - lwr.  */
	newlength = fold_build2 (MINUS_EXPR, TREE_TYPE (newlength),
				 compound_expr (lwr_tree, newlength), lwr_tree);
      }

    tree result = d_array_value (build_ctype (e->type), newlength, ptr);
    this->result_ = compound_expr (array, result);
  }

  /* Build a cast expression, which converts the given unary expression to the
     type of result.  */

  void visit (CastExp *e)
  {
    Type *ebtype = e->e1->type->toBasetype ();
    Type *tbtype = e->to->toBasetype ();
    tree result = build_expr (e->e1, this->constp_);

    /* Just evaluate e1 if it has any side effects.  */
    if (tbtype->ty == Tvoid)
      this->result_ = build_nop (build_ctype (tbtype), result);
    else
      this->result_ = convert_expr (result, ebtype, tbtype);
  }

  /* Build a delete expression.  */

  void visit (DeleteExp *e)
  {
    tree t1 = build_expr (e->e1);
    Type *tb1 = e->e1->type->toBasetype ();

    if (tb1->ty == Tclass)
      {
	/* For class object references, if there is a destructor for that class,
	   the destructor is called for the object instance.  */
	libcall_fn libcall;

	if (e->e1->op == TOKvar)
	  {
	    VarDeclaration *v = ((VarExp *) e->e1)->var->isVarDeclaration ();
	    if (v && v->onstack)
	      {
		libcall = tb1->isClassHandle ()->isInterfaceDeclaration ()
		  ? LIBCALL_CALLINTERFACEFINALIZER : LIBCALL_CALLFINALIZER;

		this->result_ = build_libcall (libcall, Type::tvoid, 1, t1);
		return;
	      }
	  }

	/* Otherwise, the garbage collector is called to immediately free the
	   memory allocated for the class instance.  */
	libcall = tb1->isClassHandle ()->isInterfaceDeclaration ()
	  ? LIBCALL_DELINTERFACE : LIBCALL_DELCLASS;

	t1 = build_address (t1);
	this->result_ = build_libcall (libcall, Type::tvoid, 1, t1);
      }
    else if (tb1->ty == Tarray)
      {
	/* For dynamic arrays, the garbage collector is called to immediately
	   release the memory.  */
	Type *telem = tb1->nextOf ()->baseElemOf ();
	tree ti = null_pointer_node;

	if (telem->ty == Tstruct)
	  {
	    /* Might need to run destructor on array contents.  */
	    TypeStruct *ts = (TypeStruct *) telem;
	    if (ts->sym->dtor)
	      ti = build_typeinfo (e->loc, tb1->nextOf ());
	  }

	/* Generate: _delarray_t (&t1, ti);  */
	this->result_ = build_libcall (LIBCALL_DELARRAYT, Type::tvoid, 2,
				       build_address (t1), ti);
      }
    else if (tb1->ty == Tpointer)
      {
	/* For pointers to a struct instance, if the struct has overloaded
	   operator delete, then that operator is called.  */
	t1 = build_address (t1);
	Type *tnext = ((TypePointer *)tb1)->next->toBasetype ();

	if (tnext->ty == Tstruct)
	  {
	    TypeStruct *ts = (TypeStruct *)tnext;
	    if (ts->sym->dtor)
	      {
		tree ti = build_typeinfo (e->loc, tnext);
		this->result_ = build_libcall (LIBCALL_DELSTRUCT, Type::tvoid,
					       2, t1, ti);
		return;
	      }
	  }

	/* Otherwise, the garbage collector is called to immediately free the
	   memory allocated for the pointer.  */
	this->result_ = build_libcall (LIBCALL_DELMEMORY, Type::tvoid, 1, t1);
      }
    else
      {
	error ("don't know how to delete %qs", e->e1->toChars ());
	this->result_ = error_mark_node;
      }
  }

  /* Build a remove expression, which removes a particular key from an
     associative array.  */

  void visit (RemoveExp *e)
  {
    /* Check that the array is actually an associative array.  */
    if (e->e1->type->toBasetype ()->ty == Taarray)
      {
	Type *tb = e->e1->type->toBasetype ();
	Type *tkey = ((TypeAArray *) tb)->index->toBasetype ();
	tree index = convert_expr (build_expr (e->e2), e->e2->type, tkey);

	this->result_ = build_libcall (LIBCALL_AADELX, Type::tbool, 3,
				       build_expr (e->e1),
				       build_typeinfo (e->loc, tkey),
				       build_address (index));
      }
    else
      {
	error ("%qs is not an associative array", e->e1->toChars ());
	this->result_ = error_mark_node;
      }
  }

  /* Build an unary not expression.  */

  void visit (NotExp *e)
  {
    tree result = convert_for_condition (build_expr (e->e1), e->e1->type);
    /* Need to convert to boolean type or this will fail.  */
    result = fold_build1 (TRUTH_NOT_EXPR, d_bool_type, result);

    this->result_ = d_convert (build_ctype (e->type), result);
  }

  /* Build a compliment expression, where all the bits in the value are
     complemented.  Note: unlike in C, the usual integral promotions
     are not performed prior to the complement operation.  */

  void visit (ComExp *e)
  {
    TY ty1 = e->e1->type->toBasetype ()->ty;
    gcc_assert (ty1 != Tarray && ty1 != Tsarray);

    this->result_ = fold_build1 (BIT_NOT_EXPR, build_ctype (e->type),
				 build_expr (e->e1));
  }

  /* Build an unary negation expression.  */

  void visit (NegExp *e)
  {
    TY ty1 = e->e1->type->toBasetype ()->ty;
    gcc_assert (ty1 != Tarray && ty1 != Tsarray);

    tree type = build_ctype (e->type);
    tree expr = build_expr (e->e1);

    /* If the operation needs excess precision.  */
    tree eptype = excess_precision_type (type);
    if (eptype != NULL_TREE)
      expr = d_convert (eptype, expr);
    else
      eptype = type;

    tree ret = fold_build1 (NEGATE_EXPR, eptype, expr);
    this->result_ = d_convert (type, ret);
  }

  /* Build a pointer index expression.  */

  void visit (PtrExp *e)
  {
    Type *tnext = NULL;
    size_t offset;
    tree result;

    if (e->e1->op == TOKadd)
      {
	BinExp *be = (BinExp *) e->e1;
	if (be->e1->op == TOKaddress
	    && be->e2->isConst () && be->e2->type->isintegral ())
	  {
	    Expression *ae = ((AddrExp *) be->e1)->e1;
	    tnext = ae->type->toBasetype ();
	    result = build_expr (ae);
	    offset = be->e2->toUInteger ();
	  }
      }
    else if (e->e1->op == TOKsymoff)
      {
	SymOffExp *se = (SymOffExp *) e->e1;
	if (!declaration_reference_p (se->var))
	  {
	    tnext = se->var->type->toBasetype ();
	    result = get_decl_tree (se->var);
	    offset = se->offset;
	  }
      }

    /* Produce better code by converting *(#record + n) to
       COMPONENT_REFERENCE.  Otherwise, the variable will always be
       allocated in memory because its address is taken.  */
    if (tnext && tnext->ty == Tstruct)
      {
	StructDeclaration *sd = ((TypeStruct *) tnext)->sym;

	for (size_t i = 0; i < sd->fields.dim; i++)
	  {
	    VarDeclaration *field = sd->fields[i];

	    if (field->offset == offset
		&& same_type_p (field->type, e->type))
	      {
		/* Catch errors, backend will ICE otherwise.  */
		if (error_operand_p (result))
		  this->result_ = result;
		else
		  {
		    result  = component_ref (result, get_symbol_decl (field));
		    this->result_ = result;
		  }
		return;
	      }
	    else if (field->offset > offset)
	      break;
	  }
      }

    this->result_ = indirect_ref (build_ctype (e->type), build_expr (e->e1));
  }

  /* Build an unary address expression.  */

  void visit (AddrExp *e)
  {
    tree type = build_ctype (e->type);
    tree exp;

    /* The frontend optimizer can convert const symbol into a struct literal.
       Taking the address of a struct literal is otherwise illegal.  */
    if (e->e1->op == TOKstructliteral)
      {
	StructLiteralExp *sle = ((StructLiteralExp *) e->e1)->origin;
	gcc_assert (sle != NULL);

	/* Build the reference symbol, the decl is built first as the
	   initializer may have recursive references.  */
	if (!sle->sym)
	  {
	    sle->sym = build_artificial_decl (build_ctype (sle->type),
					      NULL_TREE, "S");
	    DECL_INITIAL (sle->sym) = build_expr (sle, true);
	    d_pushdecl (sle->sym);
	    rest_of_decl_compilation (sle->sym, 1, 0);
	  }

	exp = sle->sym;
      }
    else
      exp = build_expr (e->e1, this->constp_);

    TREE_CONSTANT (exp) = 0;
    this->result_ = d_convert (type, build_address (exp));
  }

  /* Build a function call expression.  */

  void visit (CallExp *e)
  {
    Type *tb = e->e1->type->toBasetype ();
    Expression *e1b = e->e1;

    tree callee = NULL_TREE;
    tree object = NULL_TREE;
    tree cleanup = NULL_TREE;
    TypeFunction *tf = NULL;

    /* Calls to delegates can sometimes look like this.  */
    if (e1b->op == TOKcomma)
      {
	e1b = ((CommaExp *) e1b)->e2;
	gcc_assert (e1b->op == TOKvar);

	Declaration *var = ((VarExp *) e1b)->var;
	gcc_assert (var->isFuncDeclaration () && !var->needThis ());
      }

    if (e1b->op == TOKdotvar && tb->ty != Tdelegate)
      {
	DotVarExp *dve = (DotVarExp *) e1b;

	/* Don't modify the static initializer for struct literals.  */
	if (dve->e1->op == TOKstructliteral)
	  {
	    StructLiteralExp *sle = (StructLiteralExp *) dve->e1;
	    sle->useStaticInit = false;
	  }

	FuncDeclaration *fd = dve->var->isFuncDeclaration ();
	if (fd != NULL)
	  {
	    /* Get the correct callee from the DotVarExp object.  */
	    tree fndecl = get_symbol_decl (fd);
	    AggregateDeclaration *ad = fd->isThis ();

	    /* Static method; ignore the object instance.  */
	    if (!ad)
	      callee = build_address (fndecl);
	    else
	      {
		tree thisexp = build_expr (dve->e1);

		/* When constructing temporaries, if the constructor throws,
		   then the object is destructed even though it is not a fully
		   constructed object yet.  And so this call will need to be
		   moved inside the TARGET_EXPR_INITIAL slot.  */
		if (fd->isCtorDeclaration ()
		    && TREE_CODE (thisexp) == COMPOUND_EXPR
		    && TREE_CODE (TREE_OPERAND (thisexp, 0)) == TARGET_EXPR
		    && TARGET_EXPR_CLEANUP (TREE_OPERAND (thisexp, 0)))
		  {
		    cleanup = TREE_OPERAND (thisexp, 0);
		    thisexp = TREE_OPERAND (thisexp, 1);
		  }

		/* Want reference to 'this' object.  */
		if (!POINTER_TYPE_P (TREE_TYPE (thisexp)))
		  thisexp = build_address (thisexp);

		/* Make the callee a virtual call.  */
		if (fd->isVirtual () && !fd->isFinalFunc () && !e->directcall)
		  {
		    tree fntype = build_pointer_type (TREE_TYPE (fndecl));
		    tree thistype = build_ctype (ad->handleType ());
		    thisexp = build_nop (thistype, d_save_expr (thisexp));
		    fndecl = build_vindex_ref (thisexp, fntype, fd->vtblIndex);
		  }
		else
		  fndecl = build_address (fndecl);

		callee = build_method_call (fndecl, thisexp, fd->type);
	      }
	  }
      }

    if (callee == NULL_TREE)…