re PR rtl-optimization/69291 (wrong code at -O1 for ruby-2.3.0/regcomp.c:985:compile_...

2016-02-11  Richard Biener  <rguenther@suse.de>

	PR rtl-optimization/69291
	* ifcvt.c (noce_try_store_flag_constants): Do not allow
	subexpressions affected by changing the result.

From-SVN: r233316

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index b4495d8..6037782 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2016-02-11  Richard Biener  <rguenther@suse.de>
+
+       PR rtl-optimization/69291
+       * ifcvt.c (noce_try_store_flag_constants): Do not allow
+       subexpressions affected by changing the result.
+
 2016-02-10  Vladimir Makarov  <vmakarov@redhat.com>
 
        PR target/69148

diff --git a/gcc/ifcvt.c b/gcc/ifcvt.c
index a50e33d..2055909 100644 (file)
--- a/gcc/ifcvt.c
+++ b/gcc/ifcvt.c
@@ -1274,7 +1274,10 @@ noce_try_store_flag_constants (struct noce_if_info *if_info)
       && CONST_INT_P (XEXP (a, 1))
       && CONST_INT_P (XEXP (b, 1))
       && rtx_equal_p (XEXP (a, 0), XEXP (b, 0))
-      && noce_operand_ok (XEXP (a, 0))
+      /* Allow expressions that are not using the result or plain
+         registers where we handle overlap below.  */
+      && (REG_P (XEXP (a, 0))
+         || ! reg_overlap_mentioned_p (if_info->x, XEXP (a, 0)))
       && if_info->branch_cost >= 2)
     {
       common = XEXP (a, 0);