postreload.c (reload_combine): Mark reg_state as invalid at volatile insns if…

postreload.c (reload_combine): Mark reg_state as invalid at volatile insns if there has been a use already.

2011-11-22  Andreas Krebbel  <Andreas.Krebbel@de.ibm.com>

	* postreload.c (reload_combine): Mark reg_state as invalid at
	volatile insns if there has been a use already.

From-SVN: r181631

gcc/ChangeLog

+2011-11-22  Andreas Krebbel  <Andreas.Krebbel@de.ibm.com>
+
+	* postreload.c (reload_combine): Mark reg_state as invalid at
+	volatile insns if there has been a use already.
+
 2011-11-21  Aldy Hernandez  <aldyh@redhat.com>
 
 	* opts.c (finish_options): Do not fail for -fgnu-tm.

gcc/postreload.c

@@ -1312,11 +1312,21 @@ 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)
-	       || (INSN_P (insn) && volatile_insn_p (PATTERN (insn))))
+      else if (BARRIER_P (insn))
+	{
+	  /* Crossing a barrier resets all the use information.  */
 	  for (r = 0; r < FIRST_PSEUDO_REGISTER; r++)
 	    if (! fixed_regs[r])
 	      reg_state[r].use_index = RELOAD_COMBINE_MAX_USES;
+	}
+      else if (INSN_P (insn) && volatile_insn_p (PATTERN (insn)))
+	/* Optimizations across insns being marked as volatile must be
+	   prevented.  All the usage information is invalidated
+	   here.  */
+	for (r = 0; r < FIRST_PSEUDO_REGISTER; r++)
+	  if (! fixed_regs[r]
+	      && reg_state[r].use_index != RELOAD_COMBINE_MAX_USES)
+	    reg_state[r].use_index = -1;
 
       if (! NONDEBUG_INSN_P (insn))
 	continue;