fold-const.c (split_tree): Associate floatig-point expressions if flag_associative_math is set.

2008-02-20  Richard Guenther  <rguenther@suse.de>

	* fold-const.c (split_tree): Associate floatig-point expressions
	if flag_associative_math is set.

	* gcc.dg/fold-reassoc-1.c: New testcase.
	* gcc.dg/tree-ssa/recip-3.c: Adjust to not compute d/d.

From-SVN: r132481

gcc/ChangeLog

 2008-02-20  Richard Guenther  <rguenther@suse.de>
 
+	* fold-const.c (split_tree): Associate floatig-point expressions
+	if flag_associative_math is set.
+
+2008-02-20  Richard Guenther  <rguenther@suse.de>
+
 	* tree.h (fold_real_zero_addition_p): Declare.
 	* fold-const.c (fold_real_zero_addition_p): Export.
 	* tree-ssa-reassoc.c (eliminate_using_constants): Also handle

gcc/fold-const.c

@@ -1491,7 +1491,7 @@ split_tree (tree in, enum tree_code code, tree *conp, tree *litp,
       || TREE_CODE (in) == FIXED_CST)
     *litp = in;
   else if (TREE_CODE (in) == code
-	   || (! FLOAT_TYPE_P (TREE_TYPE (in))
+	   || ((! FLOAT_TYPE_P (TREE_TYPE (in)) || flag_associative_math)
 	       && ! SAT_FIXED_POINT_TYPE_P (TREE_TYPE (in))
 	       /* We can associate addition and subtraction together (even
 		  though the C standard doesn't say so) for integers because

gcc/testsuite/ChangeLog

 2008-02-20  Richard Guenther  <rguenther@suse.de>
 
+	* gcc.dg/fold-reassoc-1.c: New testcase.
+	* gcc.dg/tree-ssa/recip-3.c: Adjust to not compute d/d.
+
+2008-02-20  Richard Guenther  <rguenther@suse.de>
+
 	* gcc.dg/tree-ssa/reassoc-13.c: New testcase.
 
 2008-02-20  Ira Rosen  <irar@il.ibm.com>

gcc/testsuite/gcc.dg/fold-reassoc-1.c

+/* { dg-do compile } */
+/* { dg-options "-O -ffast-math -fdump-tree-original" } */
+
+double foo (double x)
+{
+  return (x + 0.5 - x - 0.5);
+}
+
+/* { dg-final { scan-tree-dump "return 0.0;" "original" } } */
+/* { dg-final { cleanup-tree-dump "original" } } */

gcc/testsuite/gcc.dg/tree-ssa/recip-3.c

@@ -9,7 +9,7 @@ float h ()
 	int i;
 	double E, W, P, d;
 
-	W = 1.;
+	W = 1.1;
 	d = 2.*e;
 	E = 1. - d;