fold-const.c (split_tree): Associate floatig-point expressions if flag_associative_ma...

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

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 18dd9dc4a31b106a2a43d6e959486580d3b0ac5e..91bd7e24de29c508a098b61b118d0cc88fa9412e 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+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.

diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index aba71b6bf41d157aea171c6479066af4620d747f..5d64c1773e7efb771370e8763652c268caaf0e1e 100644 (file)
--- a/gcc/fold-const.c
+++ b/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

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 7e947ec4b27968b37c6a9c3ea3cd9b54d83077a1..8b9fb37624da2587a5b59c23c9e1adfd864a000d 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+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.

diff --git a/gcc/testsuite/gcc.dg/fold-reassoc-1.c b/gcc/testsuite/gcc.dg/fold-reassoc-1.c
new file mode 100644 (file)
index 0000000..88d5dd8
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/fold-reassoc-1.c
@@ -0,0 +1,10 @@
+/* { 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" } } */

diff --git a/gcc/testsuite/gcc.dg/tree-ssa/recip-3.c b/gcc/testsuite/gcc.dg/tree-ssa/recip-3.c
index 45c8db148ac554736cd7344c829d23480e8a9564..04b40f32a732b2f086af2254f6453d03178560b9 100644 (file)
--- a/gcc/testsuite/gcc.dg/tree-ssa/recip-3.c
+++ b/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;