https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104704
--- Comment #8 from Hongtao.liu <crazylht at gmail dot com> ---
(In reply to H.J. Lu from comment #4)
> (In reply to Hongtao.liu from comment #3)
> > (In reply to H.J. Lu from comment #1)
> > > ix86_expand_vector_move shouldn't use ix86_gen_scratch_sse_rtx.
> >
> > Is it problematic for TARGET_GEN_MEMSET_SCRATCH_RTX?
>
> It is OK as long as it is used only by memset expander.
Use gen_reg_rtx for TARGET_GEN_MEMSET_SCRATCH_RTX regresses
gcc.target/i386/pieces-memset-21.c scan-assembler-not vzeroupper
gcc.target/i386/pieces-memset-3.c scan-assembler-not %[re]bp
gcc.target/i386/pieces-memset-3.c scan-assembler-not and[^\n\r]*%[re]sp
gcc.target/i386/pieces-memset-37.c scan-assembler-not %[re]bp
gcc.target/i386/pieces-memset-37.c scan-assembler-not and[^\n\r]*%[re]sp
gcc.target/i386/pieces-memset-39.c scan-assembler-not %[re]bp
gcc.target/i386/pieces-memset-39.c scan-assembler-not and[^\n\r]*%[re]sp
gcc.target/i386/pieces-memset-46.c scan-assembler-times vmovw[ \\t]+[^\n]*%xmm
1
gcc.target/i386/pieces-memset-47.c scan-assembler-times vmovw[ \\t]+[^\n]*%xmm
1
gcc.target/i386/pieces-memset-48.c scan-assembler-times vmovw[ \\t]+[^\n]*%xmm
1
gcc.target/i386/pr90773-14.c scan-assembler-times movd[\\t ]+%xmm[0-9]+,
16\\(%[^,]+\\) 1
gcc.target/i386/pr90773-17.c scan-assembler-times vmovd[\\t ]+%xmm[0-9]+,
15\\(%[^,]+\\) 1
gcc.target/i386/pr90773-5.c scan-assembler-times movq[\\t ]+%xmm[0-9]+,
13\\(%[^,]+\\) 1
unix/-m32: gcc.dg/guality/vla-1.c -O2 -DPREVENT_OPTIMIZATION line 24 i == 5
unix/-m32: gcc.dg/guality/vla-1.c -O2 -flto -fno-use-linker-plugin
-flto-partition=none -DPREVENT_OPTIMIZATION line 24 i == 5
unix/-m32: gcc.dg/guality/vla-1.c -O2 -flto -fuse-linker-plugin
-fno-fat-lto-objects -DPREVENT_OPTIMIZATION line 24 i == 5
unix/-m32: gcc.dg/guality/vla-1.c -O2 -flto -fuse-linker-plugin
-fno-fat-lto-objects -DPREVENT_OPTIMIZATION line 24 sizeof (a) == 17 * sizeof
(short)
unix/-m32: gcc.dg/guality/vla-1.c -O3 -g -DPREVENT_OPTIMIZATION line 24 i
== 5
unix/-m32: gcc.target/i386/pieces-memset-3.c scan-assembler-not
and[^\n\r]*%[re]sp
unix/-m32: gcc.target/i386/pieces-memset-37.c scan-assembler-not %[re]bp
unix/-m32: gcc.target/i386/pieces-memset-37.c scan-assembler-not
and[^\n\r]*%[re]sp
unix/-m32: gcc.target/i386/pieces-memset-39.c scan-assembler-not %[re]bp
unix/-m32: gcc.target/i386/pieces-memset-39.c scan-assembler-not
and[^\n\r]*%[re]sp
unix/-m32: gcc.target/i386/pieces-memset-46.c scan-assembler-times vmovw[
\\t]+[^\n]*%xmm 1
unix/-m32: gcc.target/i386/pieces-memset-47.c scan-assembler-times vmovw[
\\t]+[^\n]*%xmm 1
unix/-m32: gcc.target/i386/pieces-memset-48.c scan-assembler-times vmovw[
\\t]+[^\n]*%xmm 1
unix/-m32: gcc.target/i386/pr90773-14.c scan-assembler-times movd[\\t
]+%xmm[0-9]+, 16\\(%[^,]+\\) 1
unix/-m32: gcc.target/i386/pr90773-17.c scan-assembler-times vmovd[\\t
]+%xmm[0-9]+, 15\\(%[^,]+\\) 1
It can be grouped into 4 categories:
1) stack alignment is needed.
2) vzeroupper is needed.
3) rtl optimization rematerial vmovd xmm to movl imm which seems to be more
optimal
vpbroadcastb %eax, %xmm31
- vmovdqu8 %xmm31, (%rdx)
- vmovd %xmm31, 15(%rdx)
+ vpbroadcastb %eax, %xmm0
+ vmovdqu8 %xmm0, (%rdx)
+ movl $202116108, 15(%rdx)
4) Some debug info missing after optimziation(I think it's acceptable, though
we can try to pass down debug info, related testcase gcc.dg/guality/vla-1.c).
I think 1),2) are acceptable since it's the same as GCC11's behavior, 3) is
better than currect trunk, for 4), it's about debuggability, i'll try to handle
this.
