* [PATCH, rs6000] PR71800, use correct constraint for stxsiwx
@ 2016-07-07 20:43 Pat Haugen
2016-07-08 5:43 ` Segher Boessenkool
0 siblings, 1 reply; 3+ messages in thread
From: Pat Haugen @ 2016-07-07 20:43 UTC (permalink / raw)
To: GCC Patches, Segher Boessenkool, David Edelsohn
The following patch corrects the constraint so that we only generate 'stxsiwx' on Power8 or later hardware. Ok for trunk after successful bootstrap/regtest?
-Pat
2016-07-07 Pat Haugen <pthaugen@us.ibm.com>
PR target/71800
* config/rs6000/rs6000.md (stfiwx): Change constraint to 'wu' to
prevent generation of 'stxsiwx' on pre Power8 hardware.
Index: config/rs6000/rs6000.md
===================================================================
--- config/rs6000/rs6000.md (revision 238117)
+++ config/rs6000/rs6000.md (working copy)
@@ -5748,7 +5748,7 @@ (define_expand "lround<mode>di2"
; An UNSPEC is used so we don't have to support SImode in FP registers.
(define_insn "stfiwx"
[(set (match_operand:SI 0 "memory_operand" "=Z,Z")
- (unspec:SI [(match_operand:DI 1 "gpc_reg_operand" "d,wv")]
+ (unspec:SI [(match_operand:DI 1 "gpc_reg_operand" "d,wu")]
UNSPEC_STFIWX))]
"TARGET_PPC_GFXOPT"
"@
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH, rs6000] PR71800, use correct constraint for stxsiwx
2016-07-07 20:43 [PATCH, rs6000] PR71800, use correct constraint for stxsiwx Pat Haugen
@ 2016-07-08 5:43 ` Segher Boessenkool
2016-07-08 14:53 ` Segher Boessenkool
0 siblings, 1 reply; 3+ messages in thread
From: Segher Boessenkool @ 2016-07-08 5:43 UTC (permalink / raw)
To: Pat Haugen; +Cc: GCC Patches, David Edelsohn
Hi Pat,
On Thu, Jul 07, 2016 at 03:42:55PM -0500, Pat Haugen wrote:
> The following patch corrects the constraint so that we only generate 'stxsiwx' on Power8 or later hardware. Ok for trunk after successful bootstrap/regtest?
I don't really understand this. Before, it required UPPER_REGS_DF (which
seems correct), and now it requires UPPER_REGS_SF, which seems wrong.
Could you explain a bit more please?
Segher
> 2016-07-07 Pat Haugen <pthaugen@us.ibm.com>
>
> PR target/71800
> * config/rs6000/rs6000.md (stfiwx): Change constraint to 'wu' to
> prevent generation of 'stxsiwx' on pre Power8 hardware.
>
>
> Index: config/rs6000/rs6000.md
> ===================================================================
> --- config/rs6000/rs6000.md (revision 238117)
> +++ config/rs6000/rs6000.md (working copy)
> @@ -5748,7 +5748,7 @@ (define_expand "lround<mode>di2"
> ; An UNSPEC is used so we don't have to support SImode in FP registers.
> (define_insn "stfiwx"
> [(set (match_operand:SI 0 "memory_operand" "=Z,Z")
> - (unspec:SI [(match_operand:DI 1 "gpc_reg_operand" "d,wv")]
> + (unspec:SI [(match_operand:DI 1 "gpc_reg_operand" "d,wu")]
> UNSPEC_STFIWX))]
> "TARGET_PPC_GFXOPT"
> "@
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH, rs6000] PR71800, use correct constraint for stxsiwx
2016-07-08 5:43 ` Segher Boessenkool
@ 2016-07-08 14:53 ` Segher Boessenkool
0 siblings, 0 replies; 3+ messages in thread
From: Segher Boessenkool @ 2016-07-08 14:53 UTC (permalink / raw)
To: Pat Haugen; +Cc: GCC Patches, David Edelsohn
On Fri, Jul 08, 2016 at 12:43:35AM -0500, Segher Boessenkool wrote:
> On Thu, Jul 07, 2016 at 03:42:55PM -0500, Pat Haugen wrote:
> > The following patch corrects the constraint so that we only generate 'stxsiwx' on Power8 or later hardware. Ok for trunk after successful bootstrap/regtest?
>
> I don't really understand this. Before, it required UPPER_REGS_DF (which
> seems correct), and now it requires UPPER_REGS_SF, which seems wrong.
After some discussion... Okay, so it is a bit sub-optimal, but it does
work. Okay for trunk, with a comment on why it is "wu" ("because "wu"
requires power8").
Thanks,
Segher
> > --- config/rs6000/rs6000.md (revision 238117)
> > +++ config/rs6000/rs6000.md (working copy)
> > @@ -5748,7 +5748,7 @@ (define_expand "lround<mode>di2"
> > ; An UNSPEC is used so we don't have to support SImode in FP registers.
> > (define_insn "stfiwx"
> > [(set (match_operand:SI 0 "memory_operand" "=Z,Z")
> > - (unspec:SI [(match_operand:DI 1 "gpc_reg_operand" "d,wv")]
> > + (unspec:SI [(match_operand:DI 1 "gpc_reg_operand" "d,wu")]
> > UNSPEC_STFIWX))]
> > "TARGET_PPC_GFXOPT"
> > "@
^ permalink raw reply [flat|nested] 3+ messages in thread
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2016-07-07 20:43 [PATCH, rs6000] PR71800, use correct constraint for stxsiwx Pat Haugen
2016-07-08 5:43 ` Segher Boessenkool
2016-07-08 14:53 ` Segher Boessenkool
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