* [PATCH][ARM] Tweak HONOR_REG_ALLOC_ORDER
@ 2019-09-09 17:05 Wilco Dijkstra
2019-10-10 17:26 ` Wilco Dijkstra
2019-10-10 22:55 ` Ramana Radhakrishnan
0 siblings, 2 replies; 5+ messages in thread
From: Wilco Dijkstra @ 2019-09-09 17:05 UTC (permalink / raw)
To: GCC Patches, Kyrylo Tkachov, Richard Earnshaw; +Cc: nd
Setting HONOR_REG_ALLOC_ORDER improves codesize with -Os, however it generates
slower and larger code with -O2 and higher. So only set it when optimizing for
size. On Cortex-A57 this improves SPECINT2006 by 0.15% and SPECFP2006 by 0.25%
while reducing codesize.
Bootstrap OK, OK for commit?
ChangeLog:
2019-09-09 Wilco Dijkstra <wdijkstr@arm.com>
* config/arm/arm.h (HONOR_REG_ALLOC_ORDER): Set when optimizing for size.
--
diff --git a/gcc/config/arm/arm.h b/gcc/config/arm/arm.h
index 8d023389eec469ad9c8a4e88edebdad5f3c23769..e3473e29fbbb964ff1136c226fbe30d35dbf7b39 100644
--- a/gcc/config/arm/arm.h
+++ b/gcc/config/arm/arm.h
@@ -1065,9 +1065,8 @@ extern int arm_regs_in_sequence[];
/* Use different register alloc ordering for Thumb. */
#define ADJUST_REG_ALLOC_ORDER arm_order_regs_for_local_alloc ()
-/* Tell IRA to use the order we define rather than messing it up with its
- own cost calculations. */
-#define HONOR_REG_ALLOC_ORDER 1
+/* Tell IRA to use the order we define when optimizing for size. */
+#define HONOR_REG_ALLOC_ORDER optimize_size
/* Interrupt functions can only use registers that have already been
saved by the prologue, even if they would normally be
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH][ARM] Tweak HONOR_REG_ALLOC_ORDER
2019-09-09 17:05 [PATCH][ARM] Tweak HONOR_REG_ALLOC_ORDER Wilco Dijkstra
@ 2019-10-10 17:26 ` Wilco Dijkstra
2019-10-10 22:55 ` Ramana Radhakrishnan
1 sibling, 0 replies; 5+ messages in thread
From: Wilco Dijkstra @ 2019-10-10 17:26 UTC (permalink / raw)
To: GCC Patches, Kyrylo Tkachov, Richard Earnshaw, Richard Sandiford; +Cc: nd
ping
Setting HONOR_REG_ALLOC_ORDER improves codesize with -Os, however it generates
slower and larger code with -O2 and higher. So only set it when optimizing for
size. On Cortex-A57 this improves SPECINT2006 by 0.15% and SPECFP2006 by 0.25%
while reducing codesize.
Bootstrap OK, OK for commit?
ChangeLog:
2019-09-09 Wilco Dijkstra <wdijkstr@arm.com>
* config/arm/arm.h (HONOR_REG_ALLOC_ORDER): Set when optimizing for size.
--
diff --git a/gcc/config/arm/arm.h b/gcc/config/arm/arm.h
index 8d023389eec469ad9c8a4e88edebdad5f3c23769..e3473e29fbbb964ff1136c226fbe30d35dbf7b39 100644
--- a/gcc/config/arm/arm.h
+++ b/gcc/config/arm/arm.h
@@ -1065,9 +1065,8 @@ extern int arm_regs_in_sequence[];
/* Use different register alloc ordering for Thumb. */
#define ADJUST_REG_ALLOC_ORDER arm_order_regs_for_local_alloc ()
-/* Tell IRA to use the order we define rather than messing it up with its
- own cost calculations. */
-#define HONOR_REG_ALLOC_ORDER 1
+/* Tell IRA to use the order we define when optimizing for size. */
+#define HONOR_REG_ALLOC_ORDER optimize_size
/* Interrupt functions can only use registers that have already been
saved by the prologue, even if they would normally be
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH][ARM] Tweak HONOR_REG_ALLOC_ORDER
2019-09-09 17:05 [PATCH][ARM] Tweak HONOR_REG_ALLOC_ORDER Wilco Dijkstra
2019-10-10 17:26 ` Wilco Dijkstra
@ 2019-10-10 22:55 ` Ramana Radhakrishnan
2019-10-11 14:53 ` Wilco Dijkstra
1 sibling, 1 reply; 5+ messages in thread
From: Ramana Radhakrishnan @ 2019-10-10 22:55 UTC (permalink / raw)
To: Wilco Dijkstra; +Cc: GCC Patches, Kyrylo Tkachov, Richard Earnshaw, nd
On Mon, Sep 9, 2019 at 6:05 PM Wilco Dijkstra <Wilco.Dijkstra@arm.com> wrote:
>
> Setting HONOR_REG_ALLOC_ORDER improves codesize with -Os, however it generates
> slower and larger code with -O2 and higher. So only set it when optimizing for
> size. On Cortex-A57 this improves SPECINT2006 by 0.15% and SPECFP2006 by 0.25%
> while reducing codesize.
>
> Bootstrap OK, OK for commit?
>
> ChangeLog:
> 2019-09-09 Wilco Dijkstra <wdijkstr@arm.com>
>
> * config/arm/arm.h (HONOR_REG_ALLOC_ORDER): Set when optimizing for size.
>
> --
> diff --git a/gcc/config/arm/arm.h b/gcc/config/arm/arm.h
> index 8d023389eec469ad9c8a4e88edebdad5f3c23769..e3473e29fbbb964ff1136c226fbe30d35dbf7b39 100644
> --- a/gcc/config/arm/arm.h
> +++ b/gcc/config/arm/arm.h
> @@ -1065,9 +1065,8 @@ extern int arm_regs_in_sequence[];
> /* Use different register alloc ordering for Thumb. */
> #define ADJUST_REG_ALLOC_ORDER arm_order_regs_for_local_alloc ()
>
> -/* Tell IRA to use the order we define rather than messing it up with its
> - own cost calculations. */
> -#define HONOR_REG_ALLOC_ORDER 1
> +/* Tell IRA to use the order we define when optimizing for size. */
> +#define HONOR_REG_ALLOC_ORDER optimize_size
My only question would be whether it's more suitable to use
optimize_function_for_size_p(cfun) instead as IIRC that gives us a
chance with lto rather than the global optimize_size.
Otherwise ok .
regards
Ramana
>
> /* Interrupt functions can only use registers that have already been
> saved by the prologue, even if they would normally be
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH][ARM] Tweak HONOR_REG_ALLOC_ORDER
2019-10-10 22:55 ` Ramana Radhakrishnan
@ 2019-10-11 14:53 ` Wilco Dijkstra
2019-10-11 19:47 ` Ramana Radhakrishnan
0 siblings, 1 reply; 5+ messages in thread
From: Wilco Dijkstra @ 2019-10-11 14:53 UTC (permalink / raw)
To: Ramana Radhakrishnan; +Cc: GCC Patches, Kyrylo Tkachov, Richard Earnshaw, nd
Hi Ramana,
> My only question would be whether it's more suitable to use
> optimize_function_for_size_p(cfun) instead as IIRC that gives us a
> chance with lto rather than the global optimize_size.
Yes that is even better and that defaults to optimize_size if cfun isn't
set. I've committed this:
diff --git a/gcc/config/arm/arm.h b/gcc/config/arm/arm.h
index 8b67c9c3657b312be223ab60c01969958baa9ed3..5fad1e5bcc2bc448489fdc8239c676246bbc8879 100644
--- a/gcc/config/arm/arm.h
+++ b/gcc/config/arm/arm.h
@@ -1068,9 +1068,8 @@ extern int arm_regs_in_sequence[];
/* Use different register alloc ordering for Thumb. */
#define ADJUST_REG_ALLOC_ORDER arm_order_regs_for_local_alloc ()
-/* Tell IRA to use the order we define rather than messing it up with its
- own cost calculations. */
-#define HONOR_REG_ALLOC_ORDER 1
+/* Tell IRA to use the order we define when optimizing for size. */
+#define HONOR_REG_ALLOC_ORDER optimize_function_for_size_p (cfun)
/* Interrupt functions can only use registers that have already been
saved by the prologue, even if they would normally be
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH][ARM] Tweak HONOR_REG_ALLOC_ORDER
2019-10-11 14:53 ` Wilco Dijkstra
@ 2019-10-11 19:47 ` Ramana Radhakrishnan
0 siblings, 0 replies; 5+ messages in thread
From: Ramana Radhakrishnan @ 2019-10-11 19:47 UTC (permalink / raw)
To: Wilco Dijkstra; +Cc: GCC Patches, Kyrylo Tkachov, Richard Earnshaw, nd
On Fri, Oct 11, 2019 at 3:52 PM Wilco Dijkstra <Wilco.Dijkstra@arm.com> wrote:
>
> Hi Ramana,
>
> > My only question would be whether it's more suitable to use
> > optimize_function_for_size_p(cfun) instead as IIRC that gives us a
> > chance with lto rather than the global optimize_size.
>
> Yes that is even better and that defaults to optimize_size if cfun isn't
> set. I've committed this:
>
> diff --git a/gcc/config/arm/arm.h b/gcc/config/arm/arm.h
> index 8b67c9c3657b312be223ab60c01969958baa9ed3..5fad1e5bcc2bc448489fdc8239c676246bbc8879 100644
> --- a/gcc/config/arm/arm.h
> +++ b/gcc/config/arm/arm.h
> @@ -1068,9 +1068,8 @@ extern int arm_regs_in_sequence[];
> /* Use different register alloc ordering for Thumb. */
> #define ADJUST_REG_ALLOC_ORDER arm_order_regs_for_local_alloc ()
>
> -/* Tell IRA to use the order we define rather than messing it up with its
> - own cost calculations. */
> -#define HONOR_REG_ALLOC_ORDER 1
> +/* Tell IRA to use the order we define when optimizing for size. */
> +#define HONOR_REG_ALLOC_ORDER optimize_function_for_size_p (cfun)
I'd be happy with a patch that goes and looks at more such uses in the
backend in your copious free time. hint hint.
R
>
> /* Interrupt functions can only use registers that have already been
> saved by the prologue, even if they would normally be
^ permalink raw reply [flat|nested] 5+ messages in thread
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2019-09-09 17:05 [PATCH][ARM] Tweak HONOR_REG_ALLOC_ORDER Wilco Dijkstra
2019-10-10 17:26 ` Wilco Dijkstra
2019-10-10 22:55 ` Ramana Radhakrishnan
2019-10-11 14:53 ` Wilco Dijkstra
2019-10-11 19:47 ` Ramana Radhakrishnan
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