d: Move d_gimplify_expr and dependencies to d-gimplify.cc

gcc/d/ChangeLog:

	* Make-lang.in (D_OBJS): Add d-gimplify.o.
	* d-lang.cc (empty_modify_p): Move to d-gimplify.cc.
	(d_gimplify_expr): Likewise.
	* d-tree.h (d_gimplify_expr): Declare.
	* d-gimplify.cc: New file.

1 files changed, 187 insertions, 0 deletions

diff --git a/gcc/d/d-gimplify.cc b/gcc/d/d-gimplify.cc
new file mode 100644
index 0000000..ed49e5f
--- /dev/null
+++ b/gcc/d/d-gimplify.cc
@@ -0,0 +1,187 @@
+/* D-specific tree lowering bits; see also gimple.c.
+   Copyright (C) 2020 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/globals.h"
+
+#include "tree.h"
+#include "gimple-expr.h"
+#include "gimplify.h"
+
+#include "d-tree.h"
+
+
+/* Return TRUE if an operand OP of a given TYPE being copied has no data.
+   The middle-end does a similar check with zero sized types.  */
+
+static bool
+empty_modify_p (tree type, tree op)
+{
+  tree_code code = TREE_CODE (op);
+  switch (code)
+    {
+    case COMPOUND_EXPR:
+      return empty_modify_p (type, TREE_OPERAND (op, 1));
+
+    case CONSTRUCTOR:
+      /* Non-empty construcors are valid.  */
+      if (CONSTRUCTOR_NELTS (op) != 0 || TREE_CLOBBER_P (op))
+	return false;
+      break;
+
+    case CALL_EXPR:
+      /* Leave nrvo alone because it isn't a copy.  */
+      if (CALL_EXPR_RETURN_SLOT_OPT (op))
+	return false;
+      break;
+
+    default:
+      /* If the operand doesn't have a simple form.  */
+      if (!is_gimple_lvalue (op) && !INDIRECT_REF_P (op))
+	return false;
+      break;
+    }
+
+  return empty_aggregate_p (type);
+}
+
+/* Implements the lang_hooks.gimplify_expr routine for language D.
+   Do gimplification of D specific expression trees in EXPR_P.  */
+
+int
+d_gimplify_expr (tree *expr_p, gimple_seq *pre_p,
+		 gimple_seq *post_p ATTRIBUTE_UNUSED)
+{
+  tree_code code = TREE_CODE (*expr_p);
+  enum gimplify_status ret = GS_UNHANDLED;
+  tree op0, op1;
+  tree type;
+
+  switch (code)
+    {
+    case INIT_EXPR:
+    case MODIFY_EXPR:
+      op0 = TREE_OPERAND (*expr_p, 0);
+      op1 = TREE_OPERAND (*expr_p, 1);
+
+      if (!error_operand_p (op0) && !error_operand_p (op1)
+	  && (AGGREGATE_TYPE_P (TREE_TYPE (op0))
+	      || AGGREGATE_TYPE_P (TREE_TYPE (op1)))
+	  && !useless_type_conversion_p (TREE_TYPE (op1), TREE_TYPE (op0)))
+	{
+	  /* If the back end isn't clever enough to know that the lhs and rhs
+	     types are the same, add an explicit conversion.  */
+	  TREE_OPERAND (*expr_p, 1) = build1 (VIEW_CONVERT_EXPR,
+					      TREE_TYPE (op0), op1);
+	  ret = GS_OK;
+	}
+      else if (empty_modify_p (TREE_TYPE (op0), op1))
+	{
+	  /* Remove any copies of empty aggregates.  */
+	  gimplify_expr (&TREE_OPERAND (*expr_p, 0), pre_p, post_p,
+			 is_gimple_lvalue, fb_lvalue);
+
+	  if (TREE_SIDE_EFFECTS (op1))
+	    gimplify_and_add (op1, pre_p);
+
+	  *expr_p = TREE_OPERAND (*expr_p, 0);
+	  ret = GS_OK;
+	}
+      break;
+
+    case ADDR_EXPR:
+      op0 = TREE_OPERAND (*expr_p, 0);
+      /* Constructors are not lvalues, so make them one.  */
+      if (TREE_CODE (op0) == CONSTRUCTOR)
+	{
+	  TREE_OPERAND (*expr_p, 0) = force_target_expr (op0);
+	  ret = GS_OK;
+	}
+      break;
+
+    case CALL_EXPR:
+      if (CALL_EXPR_ARGS_ORDERED (*expr_p))
+	{
+	  /* Strictly evaluate all arguments from left to right.  */
+	  int nargs = call_expr_nargs (*expr_p);
+	  location_t loc = EXPR_LOC_OR_LOC (*expr_p, input_location);
+
+	  /* No need to enforce evaluation order if only one argument.  */
+	  if (nargs < 2)
+	    break;
+
+	  /* Or if all arguments are already free of side-effects.  */
+	  bool has_side_effects = false;
+	  for (int i = 0; i < nargs; i++)
+	    {
+	      if (TREE_SIDE_EFFECTS (CALL_EXPR_ARG (*expr_p, i)))
+		{
+		  has_side_effects = true;
+		  break;
+		}
+	    }
+
+	  if (!has_side_effects)
+	    break;
+
+	  /* Leave the last argument for gimplify_call_expr.  */
+	  for (int i = 0; i < nargs - 1; i++)
+	    {
+	      tree new_arg = CALL_EXPR_ARG (*expr_p, i);
+
+	      /* If argument has a side-effect, gimplify_arg will handle it.  */
+	      if (gimplify_arg (&new_arg, pre_p, loc) == GS_ERROR)
+		ret = GS_ERROR;
+
+	      /* Even if an argument itself doesn't have any side-effects, it
+		 might be altered by another argument in the list.  */
+	      if (new_arg == CALL_EXPR_ARG (*expr_p, i)
+		  && !really_constant_p (new_arg))
+		new_arg = get_formal_tmp_var (new_arg, pre_p);
+
+	      CALL_EXPR_ARG (*expr_p, i) = new_arg;
+	    }
+
+	  if (ret != GS_ERROR)
+	    ret = GS_OK;
+	}
+      break;
+
+    case UNSIGNED_RSHIFT_EXPR:
+      /* Convert op0 to an unsigned type.  */
+      op0 = TREE_OPERAND (*expr_p, 0);
+      op1 = TREE_OPERAND (*expr_p, 1);
+
+      type = d_unsigned_type (TREE_TYPE (op0));
+
+      *expr_p = convert (TREE_TYPE (*expr_p),
+			 build2 (RSHIFT_EXPR, type, convert (type, op0), op1));
+      ret = GS_OK;
+      break;
+
+    case FLOAT_MOD_EXPR:
+      gcc_unreachable ();
+
+    default:
+      break;
+    }
+
+  return ret;
+}