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From: "ubizjak at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug target/103905] [12 Regression] Miscompiled i386-expand.c with
 -march=bdver1 and -O3 since r12-1789-g836328b2c99f5b8d
Date: Tue, 04 Jan 2022 21:03:44 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D103905

--- Comment #3 from Uro=C5=A1 Bizjak <ubizjak at gmail dot com> ---
(In reply to Martin Li=C5=A1ka from comment #1)
> Created attachment 52120 [details]
> Isolated test-case
>=20
> Isolated test-case where only the miscompiled function
> ix86_expand_vec_extract_even_odd uses -O3.
>=20
> @Uros: Can you please compare -fdump-tree-optimized before and after the
> revision?

When compiled with -O2 -march=3Dbdver1, there are indeed a bunch of suspici=
ous
XOP vpperm instructions in the function:

        vmovd   12(%rsp), %xmm6 # 303   [c=3D9 l=3D6]  *movsi_internal/10
        vpperm  %xmm3, %xmm0, %xmm1, %xmm0      # 124   [c=3D4 l=3D5]  mmx_=
ppermv64
        vpaddd  %xmm4, %xmm1, %xmm1     # 129   [c=3D8 l=3D4]  *mmx_addv2si=
3/2
        vpperm  %xmm3, %xmm1, %xmm2, %xmm1      # 131   [c=3D4 l=3D5]  mmx_=
ppermv64
        vpperm  .LC165(%rip), %xmm1, %xmm0, %xmm0       # 134   [c=3D13 l=
=3D9]=20
mmx_ppermv64
        vpaddb  %xmm0, %xmm0, %xmm0     # 137   [c=3D8 l=3D4]  *mmx_addv8qi=
3/2
        vpshuflw        $0, %xmm6, %xmm1        # 140   [c=3D8 l=3D5]=20
*vec_dupv4hi/1
        vpaddb  %xmm1, %xmm0, %xmm0     # 142   [c=3D8 l=3D4]  *mmx_addv8qi=
3/2
        vmovq   %xmm0, 32(%rsp,%rdi)    # 143   [c=3D4 l=3D6]  *movv8qi_int=
ernal/14
        je      .L4198  # 150   [c=3D12 l=3D2]  *jcc

I was not able to test them on my target, so I bet these are the problem.=