* [PATCH] aarch64: Fix typo in aarch64-ldp-fusion.cc:combine_reg_notes [PR114936]
@ 2024-05-03 14:45 Alex Coplan
2024-05-07 14:40 ` Richard Earnshaw (lists)
0 siblings, 1 reply; 2+ messages in thread
From: Alex Coplan @ 2024-05-03 14:45 UTC (permalink / raw)
To: gcc-patches; +Cc: Richard Earnshaw, Richard Sandiford
[-- Attachment #1: Type: text/plain, Size: 1219 bytes --]
This fixes a typo in combine_reg_notes in the load/store pair fusion
pass. As it stands, the calls to filter_notes store any
REG_FRAME_RELATED_EXPR to fr_expr with the following association:
- i2 -> fr_expr[0]
- i1 -> fr_expr[1]
but then the checks inside the following if statement expect the
opposite (more natural) association, i.e.:
- i2 -> fr_expr[1]
- i1 -> fr_expr[0]
this patch fixes the oversight by swapping the fr_expr indices in the
calls to filter_notes.
In hindsight it would probably have been less confusing / error-prone to
have combine_reg_notes take an array of two insns, then we wouldn't have
to mix 1-based and 0-based indexing as well as remembering to call
filter_notes in reverse program order. This however is a minimal fix
for backporting purposes.
Many thanks to Matthew for spotting this typo and pointing it out to me.
Bootstrapped/regtested on aarch64-linux-gnu, OK for trunk and the 14
branch after the 14.1 release?
Thanks,
Alex
gcc/ChangeLog:
PR target/114936
* config/aarch64/aarch64-ldp-fusion.cc (combine_reg_notes):
Ensure insn iN has its REG_FRAME_RELATED_EXPR (if any) stored in
FR_EXPR[N-1], thus matching the correspondence expected by the
copy_rtx calls.
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diff --git a/gcc/config/aarch64/aarch64-ldp-fusion.cc b/gcc/config/aarch64/aarch64-ldp-fusion.cc
index 0bc225dae7b..12ef305d8d3 100644
--- a/gcc/config/aarch64/aarch64-ldp-fusion.cc
+++ b/gcc/config/aarch64/aarch64-ldp-fusion.cc
@@ -1085,9 +1085,9 @@ combine_reg_notes (insn_info *i1, insn_info *i2, bool load_p)
bool found_eh_region = false;
rtx result = NULL_RTX;
result = filter_notes (REG_NOTES (i2->rtl ()), result,
- &found_eh_region, fr_expr);
- result = filter_notes (REG_NOTES (i1->rtl ()), result,
&found_eh_region, fr_expr + 1);
+ result = filter_notes (REG_NOTES (i1->rtl ()), result,
+ &found_eh_region, fr_expr);
if (!load_p)
{
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] aarch64: Fix typo in aarch64-ldp-fusion.cc:combine_reg_notes [PR114936]
2024-05-03 14:45 [PATCH] aarch64: Fix typo in aarch64-ldp-fusion.cc:combine_reg_notes [PR114936] Alex Coplan
@ 2024-05-07 14:40 ` Richard Earnshaw (lists)
0 siblings, 0 replies; 2+ messages in thread
From: Richard Earnshaw (lists) @ 2024-05-07 14:40 UTC (permalink / raw)
To: Alex Coplan, gcc-patches; +Cc: Richard Sandiford
On 03/05/2024 15:45, Alex Coplan wrote:
> This fixes a typo in combine_reg_notes in the load/store pair fusion
> pass. As it stands, the calls to filter_notes store any
> REG_FRAME_RELATED_EXPR to fr_expr with the following association:
>
> - i2 -> fr_expr[0]
> - i1 -> fr_expr[1]
>
> but then the checks inside the following if statement expect the
> opposite (more natural) association, i.e.:
>
> - i2 -> fr_expr[1]
> - i1 -> fr_expr[0]
>
> this patch fixes the oversight by swapping the fr_expr indices in the
> calls to filter_notes.
>
> In hindsight it would probably have been less confusing / error-prone to
> have combine_reg_notes take an array of two insns, then we wouldn't have
> to mix 1-based and 0-based indexing as well as remembering to call
> filter_notes in reverse program order. This however is a minimal fix
> for backporting purposes.
>
> Many thanks to Matthew for spotting this typo and pointing it out to me.
>
> Bootstrapped/regtested on aarch64-linux-gnu, OK for trunk and the 14
> branch after the 14.1 release?
>
> Thanks,
> Alex
>
> gcc/ChangeLog:
>
> PR target/114936
> * config/aarch64/aarch64-ldp-fusion.cc (combine_reg_notes):
> Ensure insn iN has its REG_FRAME_RELATED_EXPR (if any) stored in
> FR_EXPR[N-1], thus matching the correspondence expected by the
> copy_rtx calls.
OK.
R.
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