re PR rtl-optimization/49452 (comp-goto-2.c regresses in testing)

	PR rtl-optimization/49452
	* postreload.c (reload_combine): Invalidate use information when across
	volatile insn.

From-SVN: r178995

gcc/ChangeLog

+2011-09-20  Wei Guozhi  <carrot@google.com>
+
+	PR rtl-optimization/49452
+	* postreload.c (reload_combine): Invalidate use information when across
+	volatile insn.
+
 2011-09-19  Maxim Kuvyrkov  <maxim@codesourcery.com>
 
 	* haifa-sched.c (has_edge_p, prev_non_location_insn, check_cfg):

gcc/postreload.c

@@ -1312,7 +1312,8 @@ reload_combine (void)
 	 is and then later disable any optimization that would cross it.  */
       if (LABEL_P (insn))
 	last_label_ruid = reload_combine_ruid;
-      else if (BARRIER_P (insn))
+      else if (BARRIER_P (insn)
+	       || (INSN_P (insn) && volatile_insn_p (PATTERN (insn))))
 	for (r = 0; r < FIRST_PSEUDO_REGISTER; r++)
 	  if (! fixed_regs[r])
 	      reg_state[r].use_index = RELOAD_COMBINE_MAX_USES;