match.pd: Restrict division combining to trunc_div and exact_div.

2014-12-02  Richard Biener  <rguenther@suse.de>

	* match.pd: Restrict division combining to trunc_div and
	exact_div.

From-SVN: r218260

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 8924c7aa95eed25b9cc9403ff5735209f5446e64..aed08f432991abe6d72e0fc509b3e2e3616216d1 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2014-12-02  Richard Biener  <rguenther@suse.de>
+
+       * match.pd: Restrict division combining to trunc_div and
+       exact_div.
+
 2014-12-02  Jakub Jelinek  <jakub@redhat.com>
 
        * config/sparc/sparc.c (sparc_atomic_assign_expand_fenv):

diff --git a/gcc/match.pd b/gcc/match.pd
index ee9bbc65fafe853178db6d5ebd64c2d3674901f2..b36aa2fe76a3c67e2e1e916a79e116deb2019d0c 100644 (file)
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -129,8 +129,9 @@ along with GCC; see the file COPYING3.  If not see
       && TYPE_UNSIGNED (type))
   (trunc_div @0 @1)))
 
-/* Combine two successive divisions.  */
-(for div (trunc_div ceil_div floor_div round_div exact_div)
+/* Combine two successive divisions.  Note that combining ceil_div
+   and floor_div is trickier and combining round_div even more so.  */
+(for div (trunc_div exact_div)
  (simplify
   (div (div @0 INTEGER_CST@1) INTEGER_CST@2)
   (with {