* [PATCH] S/390: Increase register move costs for CC_REGS
@ 2018-11-05 14:38 Robin Dapp
2018-11-05 16:39 ` Andreas Krebbel
0 siblings, 1 reply; 2+ messages in thread
From: Robin Dapp @ 2018-11-05 14:38 UTC (permalink / raw)
To: GCC Patches; +Cc: Andreas Krebbel, Ilya Leoshkevich
[-- Attachment #1: Type: text/plain, Size: 317 bytes --]
Hi,
the attached patch increases the move costs for moves involving the CC
register. This saves us some instructions in SPEC CPU2006.
Regards
Robin
--
gcc/ChangeLog:
2018-11-05 Robin Dapp <rdapp@linux.ibm.com>
* config/s390/s390.c (s390_register_move_cost): Increase costs
for moves involving the CC reg.
[-- Attachment #2: gcc-no-cc-reg-move.diff --]
[-- Type: text/x-patch, Size: 475 bytes --]
diff --git a/gcc/config/s390/s390.c b/gcc/config/s390/s390.c
index 762c6bff07b..0f33101d779 100644
--- a/gcc/config/s390/s390.c
+++ b/gcc/config/s390/s390.c
@@ -3416,6 +3416,11 @@ s390_register_move_cost (machine_mode mode,
&& reg_classes_intersect_p (to, GENERAL_REGS)))
return 10;
+ /* We usually do not want to copy via CC. */
+ if (reg_classes_intersect_p (from, CC_REGS)
+ || reg_classes_intersect_p (to, CC_REGS))
+ return 5;
+
return 1;
}
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] S/390: Increase register move costs for CC_REGS
2018-11-05 14:38 [PATCH] S/390: Increase register move costs for CC_REGS Robin Dapp
@ 2018-11-05 16:39 ` Andreas Krebbel
0 siblings, 0 replies; 2+ messages in thread
From: Andreas Krebbel @ 2018-11-05 16:39 UTC (permalink / raw)
To: Robin Dapp, GCC Patches; +Cc: Ilya Leoshkevich
On 05.11.18 15:38, Robin Dapp wrote:
> Hi,
>
> the attached patch increases the move costs for moves involving the CC
> register. This saves us some instructions in SPEC CPU2006.
>
> Regards
> Robin
>
> --
>
> gcc/ChangeLog:
>
> 2018-11-05 Robin Dapp <rdapp@linux.ibm.com>
>
> * config/s390/s390.c (s390_register_move_cost): Increase costs
> for moves involving the CC reg.
>
Ok. Thanks!
Andreas
^ permalink raw reply [flat|nested] 2+ messages in thread
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