* [PATCH] [PR40457] [arm] expand SI-aligned movdi into pair of movsi
@ 2022-12-02 9:29 Alexandre Oliva
2023-01-11 18:34 ` Richard Earnshaw
0 siblings, 1 reply; 2+ messages in thread
From: Alexandre Oliva @ 2022-12-02 9:29 UTC (permalink / raw)
To: gcc-patches
Cc: Nick Clifton, Richard Earnshaw, Ramana Radhakrishnan, Kyrylo Tkachov
When expanding a misaligned DImode move, emit aligned SImode moves if
the parts are sufficiently aligned. This enables neighboring stores
to be peephole-combined into stm, as expected by the PR40457 testcase,
even after SLP vectorizes the originally aligned SImode stores into a
misaligned DImode store.
Regstraped on x86_64-linux-gnu, also tested with crosses to riscv64-elf
and arm-eabi (tms570). Ok to install?
for gcc/ChangeLog
PR target/40457
* config/arm/arm.md (movmisaligndi): Prefer aligned SImode
moves.
---
gcc/config/arm/arm.md | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/gcc/config/arm/arm.md b/gcc/config/arm/arm.md
index 69bf343fb0ed6..a9eb0299aa761 100644
--- a/gcc/config/arm/arm.md
+++ b/gcc/config/arm/arm.md
@@ -12783,8 +12783,16 @@ (define_expand "movmisaligndi"
rtx hi_op0 = gen_highpart_mode (SImode, DImode, operands[0]);
rtx hi_op1 = gen_highpart_mode (SImode, DImode, operands[1]);
- emit_insn (gen_movmisalignsi (lo_op0, lo_op1));
- emit_insn (gen_movmisalignsi (hi_op0, hi_op1));
+ if (aligned_operand (lo_op0, SImode) && aligned_operand (lo_op1, SImode))
+ {
+ emit_move_insn (lo_op0, lo_op1);
+ emit_move_insn (hi_op0, hi_op1);
+ }
+ else
+ {
+ emit_insn (gen_movmisalignsi (lo_op0, lo_op1));
+ emit_insn (gen_movmisalignsi (hi_op0, hi_op1));
+ }
DONE;
})
--
Alexandre Oliva, happy hacker https://FSFLA.org/blogs/lxo/
Free Software Activist GNU Toolchain Engineer
Disinformation flourishes because many people care deeply about injustice
but very few check the facts. Ask me about <https://stallmansupport.org>
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] [PR40457] [arm] expand SI-aligned movdi into pair of movsi
2022-12-02 9:29 [PATCH] [PR40457] [arm] expand SI-aligned movdi into pair of movsi Alexandre Oliva
@ 2023-01-11 18:34 ` Richard Earnshaw
0 siblings, 0 replies; 2+ messages in thread
From: Richard Earnshaw @ 2023-01-11 18:34 UTC (permalink / raw)
To: Alexandre Oliva, gcc-patches
Cc: Nick Clifton, Richard Earnshaw, Ramana Radhakrishnan, Kyrylo Tkachov
On 02/12/2022 09:29, Alexandre Oliva via Gcc-patches wrote:
>
> When expanding a misaligned DImode move, emit aligned SImode moves if
> the parts are sufficiently aligned. This enables neighboring stores
> to be peephole-combined into stm, as expected by the PR40457 testcase,
> even after SLP vectorizes the originally aligned SImode stores into a
> misaligned DImode store.
>
> Regstraped on x86_64-linux-gnu, also tested with crosses to riscv64-elf
> and arm-eabi (tms570). Ok to install?
>
>
> for gcc/ChangeLog
>
> PR target/40457
> * config/arm/arm.md (movmisaligndi): Prefer aligned SImode
> moves.
OK.
R.
> ---
> gcc/config/arm/arm.md | 12 ++++++++++--
> 1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/gcc/config/arm/arm.md b/gcc/config/arm/arm.md
> index 69bf343fb0ed6..a9eb0299aa761 100644
> --- a/gcc/config/arm/arm.md
> +++ b/gcc/config/arm/arm.md
> @@ -12783,8 +12783,16 @@ (define_expand "movmisaligndi"
> rtx hi_op0 = gen_highpart_mode (SImode, DImode, operands[0]);
> rtx hi_op1 = gen_highpart_mode (SImode, DImode, operands[1]);
>
> - emit_insn (gen_movmisalignsi (lo_op0, lo_op1));
> - emit_insn (gen_movmisalignsi (hi_op0, hi_op1));
> + if (aligned_operand (lo_op0, SImode) && aligned_operand (lo_op1, SImode))
> + {
> + emit_move_insn (lo_op0, lo_op1);
> + emit_move_insn (hi_op0, hi_op1);
> + }
> + else
> + {
> + emit_insn (gen_movmisalignsi (lo_op0, lo_op1));
> + emit_insn (gen_movmisalignsi (hi_op0, hi_op1));
> + }
> DONE;
> })
>
>
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