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[PATCH] Fix optimization regression in constant folder


Hi,

The fix for PR middle-end/30364 disabled association of expressions with more 
than 1 variable if the type doesn't wrap.  This is a bit problematic for Ada 
because variable-sized types generate lots of size calculations and we want 
to simplify them at compile time as much as possible.

Bootstrapped/regtested on i586-suse-linux, OK for mainline?


2007-09-17  Eric Botcazou  <ebotcazou@adacore.com>

	* fold-const.c (fold_binary): Associate again expressions with more
	than one variable for size types.


-- 
Eric Botcazou
Index: fold-const.c
===================================================================
--- fold-const.c	(revision 128432)
+++ fold-const.c	(working copy)
@@ -9924,10 +9924,13 @@ fold_binary (enum tree_code code, tree t
 	  var1 = split_tree (arg1, code, &con1, &lit1, &minus_lit1,
 			     code == MINUS_EXPR);
 
-	  /* With undefined overflow we can only associate constants
-	     with one variable.  */
+	  /* With undefined overflow we can only associate constants with one
+	     variable, but this restriction doesn't apply to size types.  */
 	  if ((POINTER_TYPE_P (type)
-	       || (INTEGRAL_TYPE_P (type) && !TYPE_OVERFLOW_WRAPS (type)))
+	       || (INTEGRAL_TYPE_P (type)
+		   && !TYPE_OVERFLOW_WRAPS (type)
+		   && !(TREE_CODE (type) == INTEGER_TYPE
+			&& TYPE_IS_SIZETYPE (type))))
 	      && var0 && var1)
 	    {
 	      tree tmp0 = var0;

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