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>
