[PATCH] PR49452, prevent post reload combining cross blockage insn

[PATCH] PR49452, prevent post reload combining cross blockage insn

[Carrot Wei]

Hi

We should not combine insns cross volatile insns. Combine.c already does this
check, postreload should also do so.

Bootstrapped and regtested on x86_64-unknown-linux-gnu.
Regtested on arm qemu.

thanks
Carrot


ChangeLog:
2011-09-19  Wei Guozhi  <carrot@google.com>

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


Index: postreload.c
===================================================================
--- postreload.c	(revision 178938)
+++ postreload.c	(working copy)
@@ -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;

Re: [PATCH] PR49452, prevent post reload combining cross blockage insn

[Jeff Law]

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On 09/19/11 02:51, Carrot Wei wrote:
> Hi
> 
> We should not combine insns cross volatile insns. Combine.c already
> does this check, postreload should also do so.
> 
> Bootstrapped and regtested on x86_64-unknown-linux-gnu. Regtested
> on arm qemu.
> 
> thanks Carrot
> 
> 
> ChangeLog: 2011-09-19  Wei Guozhi  <carrot@google.com>
> 
> PR 49452 * postreload.c (reload_combine): Invalidate use
> information when across volatile insn.
OK.
jeff
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Re: [PATCH] PR49452, prevent post reload combining cross blockage insn

[Eric Botcazou]

> 2011-09-19  Wei Guozhi  <carrot@google.com>
>
>         PR 49452
>         * postreload.c (reload_combine): Invalidate use information when
> across volatile insn.

PR rtl-optimization/49452, otherwise I'm not sure the commit will be xref'ed.

-- 
Eric Botcazou