Patchwork [rs6000] Correctly set rs6000_always_hint for ppc476

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Submitter Peter Bergner
Date Jan. 26, 2012, 10:30 p.m.
Message ID <1327617025.14063.5.camel@otta>
Download mbox | patch
Permalink /patch/138077/
State New
Headers show

Comments

Peter Bergner - Jan. 26, 2012, 10:30 p.m.
The 476 cpu has dynamic branch prediction, so we don't want to always
use static branch prediction hints.  Is the following patch ok assuming
my currently running bootstrap/regtesting doesn't uncover any regressions?

Is this appropriate for the 4.6 and 4.5 branches as well?

Peter


	* config/rs6000/rs6000.c (rs6000_option_override_internal):
	Set rs6000_always_hint to false for 476.
David Edelsohn - Jan. 27, 2012, 12:13 a.m.
On Thu, Jan 26, 2012 at 5:30 PM, Peter Bergner <bergner@vnet.ibm.com> wrote:
> The 476 cpu has dynamic branch prediction, so we don't want to always
> use static branch prediction hints.  Is the following patch ok assuming
> my currently running bootstrap/regtesting doesn't uncover any regressions?
>
> Is this appropriate for the 4.6 and 4.5 branches as well?

The patch is okay.

It is not appropriate for 4.5 and 4.6 branches because it is not a bug fix.

Thanks, David
Peter Bergner - Jan. 27, 2012, 2:49 a.m.
On Thu, 2012-01-26 at 19:13 -0500, David Edelsohn wrote:
> On Thu, Jan 26, 2012 at 5:30 PM, Peter Bergner <bergner@vnet.ibm.com> wrote:
> > The 476 cpu has dynamic branch prediction, so we don't want to always
> > use static branch prediction hints.  Is the following patch ok assuming
> > my currently running bootstrap/regtesting doesn't uncover any regressions?
> 
> The patch is okay.

Ok, I committed it to mainline as revision 183601.  Thanks.


Peter

Patch

Index: config/rs6000/rs6000.c
===================================================================
--- config/rs6000/rs6000.c	(revision 183456)
+++ config/rs6000/rs6000.c	(working copy)
@@ -2960,7 +2960,8 @@  rs6000_option_override_internal (bool gl
 			&& rs6000_cpu != PROCESSOR_POWER6
 			&& rs6000_cpu != PROCESSOR_POWER7
 			&& rs6000_cpu != PROCESSOR_PPCA2
-			&& rs6000_cpu != PROCESSOR_CELL);
+			&& rs6000_cpu != PROCESSOR_CELL
+			&& rs6000_cpu != PROCESSOR_PPC476);
   rs6000_sched_groups = (rs6000_cpu == PROCESSOR_POWER4
 			 || rs6000_cpu == PROCESSOR_POWER5
 			 || rs6000_cpu == PROCESSOR_POWER7);