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From: "stefan.kneifel at bluewin dot ch" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/103661] __builtin_cpu_supports returns a negative integer for avx512vbmi2
Date: Sun, 12 Dec 2021 12:50:53 +0000 [thread overview]
Message-ID: <bug-103661-4-CSyMtM73Dk@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-103661-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103661
--- Comment #4 from Stefan Kneifel <stefan.kneifel at bluewin dot ch> ---
Created attachment 51978
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=51978&action=edit
Testcase
Without the proposed patch, it compiles to:
--------
0000000000000000 <has_vbmi>:
0: 50 push %rax
1: e8 00 00 00 00 call 6 <has_vbmi+0x6>
2: R_X86_64_PLT32 __cpu_indicator_init-0x4
6: 31 c0 xor %eax,%eax
8: f6 05 00 00 00 00 04 testb $0x4,0x0(%rip) # f <has_vbmi+0xf>
a: R_X86_64_PC32 __cpu_model+0xa
f: 5a pop %rdx
10: 0f 95 c0 setne %al
13: c3 ret
0000000000000014 <has_vbmi2>:
14: 50 push %rax
15: e8 00 00 00 00 call 1a <has_vbmi2+0x6>
16: R_X86_64_PLT32 __cpu_indicator_init-0x4
1a: 31 c0 xor %eax,%eax
1c: 5a pop %rdx
1d: c3 ret
--------
returning 1 only for avx512vbmi, but not for avx512vbmi2, where it returns
always zero regardless whether the machine has it or not.
With the proposed patch, it compiles to:
--------
0000000000000000 <has_vbmi>:
0: 50 push %rax
1: e8 00 00 00 00 call 6 <has_vbmi+0x6>
2: R_X86_64_PLT32 __cpu_indicator_init-0x4
6: 8b 05 00 00 00 00 mov 0x0(%rip),%eax # c <has_vbmi+0xc>
8: R_X86_64_PC32 __cpu_model+0x8
c: 5a pop %rdx
d: c1 e8 1a shr $0x1a,%eax
10: 83 e0 01 and $0x1,%eax
13: c3 ret
0000000000000014 <has_vbmi2>:
14: 50 push %rax
15: e8 00 00 00 00 call 1a <has_vbmi2+0x6>
16: R_X86_64_PLT32 __cpu_indicator_init-0x4
1a: 8b 05 00 00 00 00 mov 0x0(%rip),%eax # 20
<has_vbmi2+0xc>
1c: R_X86_64_PC32 __cpu_model+0x8
20: 5a pop %rdx
21: c1 e8 1f shr $0x1f,%eax
24: c3 ret
--------
returning correctly 1 if the machine has avx512vbmi2.
next prev parent reply other threads:[~2021-12-12 12:50 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-11 16:56 [Bug target/103661] New: " stefan.kneifel at bluewin dot ch
2021-12-11 18:08 ` [Bug target/103661] " pinskia at gcc dot gnu.org
2021-12-11 18:08 ` pinskia at gcc dot gnu.org
2021-12-11 23:50 ` stefan.kneifel at bluewin dot ch
2021-12-12 12:50 ` stefan.kneifel at bluewin dot ch [this message]
2021-12-13 10:12 ` marxin at gcc dot gnu.org
2021-12-15 9:31 ` cvs-commit at gcc dot gnu.org
2021-12-15 10:52 ` marxin at gcc dot gnu.org
2021-12-15 10:52 ` marxin at gcc dot gnu.org
2021-12-16 11:46 ` cvs-commit at gcc dot gnu.org
2021-12-16 13:03 ` cvs-commit at gcc dot gnu.org
2021-12-16 13:04 ` marxin at gcc dot gnu.org
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