* [PATCH] vect: Don't retry if the previous analysis fails
@ 2023-05-17 6:05 Kewen.Lin
2023-05-17 6:32 ` Richard Biener
0 siblings, 1 reply; 3+ messages in thread
From: Kewen.Lin @ 2023-05-17 6:05 UTC (permalink / raw)
To: GCC Patches
Cc: Richard Biener, Richard Sandiford, Segher Boessenkool, Peter Bergner
Hi,
When working on a cost tweaking patch, I found that a newly
added test case has different dumpings with stage-1 and
bootstrapped gcc. By looking into it, the apparent reason
is vect_analyze_loop_2 doesn't get slp_done_for_suggested_uf
set expectedly, the following retrying will use the garbage
slp_done_for_suggested_uf instead. In fact, the setting of
slp_done_for_suggested_uf only happens when the previous
analysis succeeds, for the mentioned test case, its previous
analysis does fail, it's unexpected to use the value of
slp_done_for_suggested_uf any more.
In function vect_analyze_loop_1, we only return success when
res is true, which is the result of 1st analysis. It means
we never try to vectorize with unroll_vinfo if the previous
analysis fails. So this patch shouldn't break anything, and
just stop some useless analysis early.
Bootstrapped and regtested on x86_64-redhat-linux,
aarch64-linux-gnu and powerpc64{,le}-linux-gnu.
Is it ok for trunk?
BR,
Kewen
-----
gcc/ChangeLog:
* tree-vect-loop.cc (vect_analyze_loop_1): Don't retry analysis with
suggested unroll factor once the previous analysis fails.
---
gcc/tree-vect-loop.cc | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc
index ed0166fedab..905145ae97b 100644
--- a/gcc/tree-vect-loop.cc
+++ b/gcc/tree-vect-loop.cc
@@ -3044,7 +3044,7 @@ vect_analyze_loop_1 (class loop *loop, vec_info_shared *shared,
res ? "succeeded" : " failed",
GET_MODE_NAME (loop_vinfo->vector_mode));
- if (!main_loop_vinfo && suggested_unroll_factor > 1)
+ if (res && !main_loop_vinfo && suggested_unroll_factor > 1)
{
if (dump_enabled_p ())
dump_printf_loc (MSG_NOTE, vect_location,
--
2.31.1
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] vect: Don't retry if the previous analysis fails
2023-05-17 6:05 [PATCH] vect: Don't retry if the previous analysis fails Kewen.Lin
@ 2023-05-17 6:32 ` Richard Biener
2023-05-22 5:36 ` Kewen.Lin
0 siblings, 1 reply; 3+ messages in thread
From: Richard Biener @ 2023-05-17 6:32 UTC (permalink / raw)
To: Kewen.Lin
Cc: GCC Patches, Richard Sandiford, Segher Boessenkool, Peter Bergner
On Wed, May 17, 2023 at 8:06 AM Kewen.Lin <linkw@linux.ibm.com> wrote:
>
> Hi,
>
> When working on a cost tweaking patch, I found that a newly
> added test case has different dumpings with stage-1 and
> bootstrapped gcc. By looking into it, the apparent reason
> is vect_analyze_loop_2 doesn't get slp_done_for_suggested_uf
> set expectedly, the following retrying will use the garbage
> slp_done_for_suggested_uf instead. In fact, the setting of
> slp_done_for_suggested_uf only happens when the previous
> analysis succeeds, for the mentioned test case, its previous
> analysis does fail, it's unexpected to use the value of
> slp_done_for_suggested_uf any more.
>
> In function vect_analyze_loop_1, we only return success when
> res is true, which is the result of 1st analysis. It means
> we never try to vectorize with unroll_vinfo if the previous
> analysis fails. So this patch shouldn't break anything, and
> just stop some useless analysis early.
>
> Bootstrapped and regtested on x86_64-redhat-linux,
> aarch64-linux-gnu and powerpc64{,le}-linux-gnu.
>
> Is it ok for trunk?
OK for trunk and affected branches.
Richard.
> BR,
> Kewen
> -----
> gcc/ChangeLog:
>
> * tree-vect-loop.cc (vect_analyze_loop_1): Don't retry analysis with
> suggested unroll factor once the previous analysis fails.
> ---
> gcc/tree-vect-loop.cc | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc
> index ed0166fedab..905145ae97b 100644
> --- a/gcc/tree-vect-loop.cc
> +++ b/gcc/tree-vect-loop.cc
> @@ -3044,7 +3044,7 @@ vect_analyze_loop_1 (class loop *loop, vec_info_shared *shared,
> res ? "succeeded" : " failed",
> GET_MODE_NAME (loop_vinfo->vector_mode));
>
> - if (!main_loop_vinfo && suggested_unroll_factor > 1)
> + if (res && !main_loop_vinfo && suggested_unroll_factor > 1)
> {
> if (dump_enabled_p ())
> dump_printf_loc (MSG_NOTE, vect_location,
> --
> 2.31.1
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] vect: Don't retry if the previous analysis fails
2023-05-17 6:32 ` Richard Biener
@ 2023-05-22 5:36 ` Kewen.Lin
0 siblings, 0 replies; 3+ messages in thread
From: Kewen.Lin @ 2023-05-22 5:36 UTC (permalink / raw)
To: Richard Biener
Cc: GCC Patches, Richard Sandiford, Segher Boessenkool, Peter Bergner
on 2023/5/17 14:32, Richard Biener wrote:
> On Wed, May 17, 2023 at 8:06 AM Kewen.Lin <linkw@linux.ibm.com> wrote:
>>
>> Hi,
>>
>> When working on a cost tweaking patch, I found that a newly
>> added test case has different dumpings with stage-1 and
>> bootstrapped gcc. By looking into it, the apparent reason
>> is vect_analyze_loop_2 doesn't get slp_done_for_suggested_uf
>> set expectedly, the following retrying will use the garbage
>> slp_done_for_suggested_uf instead. In fact, the setting of
>> slp_done_for_suggested_uf only happens when the previous
>> analysis succeeds, for the mentioned test case, its previous
>> analysis does fail, it's unexpected to use the value of
>> slp_done_for_suggested_uf any more.
>>
>> In function vect_analyze_loop_1, we only return success when
>> res is true, which is the result of 1st analysis. It means
>> we never try to vectorize with unroll_vinfo if the previous
>> analysis fails. So this patch shouldn't break anything, and
>> just stop some useless analysis early.
>>
>> Bootstrapped and regtested on x86_64-redhat-linux,
>> aarch64-linux-gnu and powerpc64{,le}-linux-gnu.
>>
>> Is it ok for trunk?
>
> OK for trunk and affected branches.
Pushed as r14-926 and backported in r13-7364 & r12-9633. Thanks!
BR,
Kewen
^ permalink raw reply [flat|nested] 3+ messages in thread
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2023-05-17 6:32 ` Richard Biener
2023-05-22 5:36 ` Kewen.Lin
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