From: Eric Botcazou <ebotcazou@adacore.com>
Date: Thu, 6 Nov 2008 11:28:07 +0000 (+0000)
Subject: re PR ada/19419 (Overlapping memcpy with array slices)
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=8b659f794a1613b10333fa6826c0ed41d802ce8b;p=gcc.git

re PR ada/19419 (Overlapping memcpy with array slices)

	PR ada/19419
	* gcc-interface/trans.c (gnat_to_gnu) <N_Assignment_Statement>:
	Generate a call to memmove for an assignment between overlapping
	array slices.

From-SVN: r141637
---

diff --git a/gcc/ada/ChangeLog b/gcc/ada/ChangeLog
index ba94a5e9a7f..67300939fe0 100644
--- a/gcc/ada/ChangeLog
+++ b/gcc/ada/ChangeLog
@@ -1,3 +1,10 @@
+2008-11-06  Eric Botcazou  <ebotcazou@adacore.com>
+
+	PR ada/19419
+	* gcc-interface/trans.c (gnat_to_gnu) <N_Assignment_Statement>:
+	Generate a call to memmove for an assignment between overlapping
+	array slices.
+
 2008-11-02  Andreas Krebbel  <Andreas.Krebbel@de.ibm.com>
 
 	PR target/37977
diff --git a/gcc/ada/gcc-interface/trans.c b/gcc/ada/gcc-interface/trans.c
index 6ade56869d9..9f050bdc5d1 100644
--- a/gcc/ada/gcc-interface/trans.c
+++ b/gcc/ada/gcc-interface/trans.c
@@ -4159,12 +4159,33 @@ gnat_to_gnu (Node_Id gnat_node)
 	  gnu_rhs
 	    = maybe_unconstrained_array (gnat_to_gnu (Expression (gnat_node)));
 
-	  /* If range check is needed, emit code to generate it */
+	  /* If range check is needed, emit code to generate it.  */
 	  if (Do_Range_Check (Expression (gnat_node)))
 	    gnu_rhs = emit_range_check (gnu_rhs, Etype (Name (gnat_node)));
 
 	  gnu_result
 	    = build_binary_op (MODIFY_EXPR, NULL_TREE, gnu_lhs, gnu_rhs);
+
+	  /* If the type being assigned is an array type and the two sides
+	     are not completely disjoint, play safe and use memmove.  */
+	  if (TREE_CODE (gnu_result) == MODIFY_EXPR
+	      && Is_Array_Type (Etype (Name (gnat_node)))
+	      && !(Forwards_OK (gnat_node) && Backwards_OK (gnat_node)))
+	    {
+	      tree to, from, size, to_ptr, from_ptr, t;
+
+	      to = TREE_OPERAND (gnu_result, 0);
+	      from = TREE_OPERAND (gnu_result, 1);
+
+	      size = TYPE_SIZE_UNIT (TREE_TYPE (from));
+	      size = SUBSTITUTE_PLACEHOLDER_IN_EXPR (size, from);
+
+	      to_ptr = build_fold_addr_expr (to);
+	      from_ptr = build_fold_addr_expr (from);
+
+	      t = implicit_built_in_decls[BUILT_IN_MEMMOVE];
+	      gnu_result = build_call_expr (t, 3, to_ptr, from_ptr, size);
+	   }
 	}
       break;