[PATCH] Reduce garbage produced by fold_truthop

[Richard Guenther]

This fixes fold_truthop not returning an unmodified tree.

Bootstrapped and tested on x86_64-unknown-linux-gnu.

Ok for mainline?

Thanks,
Richard.

:ADDPATCH middle-end:

2006-06-15  Michael Matz  <matz@suse.de>
	Richard Guenther  <rguenther@suse.de>

	* fold-const.c (fold_truthop): Only return new tree node if
	we canonicalized something.

Index: fold-const.c
===================================================================
--- fold-const.c	(revision 114599)
+++ fold-const.c	(working copy)
@@ -4841,6 +4841,8 @@ fold_truthop (enum tree_code code, tree 
   tree lntype, rntype, result;
   int first_bit, end_bit;
   int volatilep;
+  tree orig_lhs = lhs, orig_rhs = rhs;
+  enum tree_code orig_code = code;
 
   /* Start by getting the comparison codes.  Fail if anything is volatile.
      If one operand is a BIT_AND_EXPR with the constant one, treat it as if
@@ -4934,7 +4936,11 @@ fold_truthop (enum tree_code code, tree 
 		       build_int_cst (TREE_TYPE (ll_arg), 0));
 
       if (LOGICAL_OP_NON_SHORT_CIRCUIT)
-	return build2 (code, truth_type, lhs, rhs);
+	{
+	  if (code != orig_code || lhs != orig_lhs || rhs != orig_rhs)
+	    return build2 (code, truth_type, lhs, rhs);
+	  return NULL_TREE;
+	}
     }
 
   /* See if the comparisons can be merged.  Then get all the parameters for