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From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/104610] New: memcmp () == 0 can be optimized better for avx512f
Date: Mon, 21 Feb 2022 11:00:42 +0000 [thread overview]
Message-ID: <bug-104610-4@http.gcc.gnu.org/bugzilla/> (raw)
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104610
Bug ID: 104610
Summary: memcmp () == 0 can be optimized better for avx512f
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Keywords: missed-optimization
Severity: enhancement
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: pinskia at gcc dot gnu.org
Target Milestone: ---
Target: x86_64-linux-gnu
Take:
bool f(char *a)
{
char t[] = "0123456789012345678901234567890";
return __builtin_memcmp(a, &t[0], sizeof(t)) == 0;
}
----- CUT ----
GCC does this via branches and compares but clang/LLVM does:
vmovdqu (%rdi), %ymm0
vpxor .LCPI0_0(%rip), %ymm0, %ymm0
vptest %ymm0, %ymm0
sete %al
vzeroupper
next reply other threads:[~2022-02-21 11:00 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-21 11:00 pinskia at gcc dot gnu.org [this message]
2022-02-21 11:01 ` [Bug target/104610] " pinskia at gcc dot gnu.org
2022-02-22 4:03 ` crazylht at gmail dot com
2022-02-22 5:54 ` crazylht at gmail dot com
2022-02-22 5:55 ` crazylht at gmail dot com
2022-02-22 6:18 ` crazylht at gmail dot com
2022-02-22 6:32 ` crazylht at gmail dot com
2022-02-23 2:15 ` crazylht at gmail dot com
2022-02-23 6:18 ` crazylht at gmail dot com
2022-02-23 21:04 ` hjl.tools at gmail dot com
2022-02-24 5:33 ` crazylht at gmail dot com
2022-02-24 6:00 ` hjl.tools at gmail dot com
2022-02-26 20:26 ` hjl.tools at gmail dot com
2022-02-27 19:02 ` hjl.tools at gmail dot com
2022-02-27 19:29 ` hjl.tools at gmail dot com
2022-03-04 3:03 ` hjl.tools at gmail dot com
2022-03-28 5:05 ` crazylht at gmail dot com
2022-03-28 5:27 ` crazylht at gmail dot com
2022-05-18 2:47 ` cvs-commit at gcc dot gnu.org
2022-05-18 2:49 ` crazylht at gmail dot com
2022-06-16 7:41 ` crazylht at gmail dot com
2023-06-28 10:12 ` cvs-commit at gcc dot gnu.org
2023-06-28 11:05 ` ubizjak at gmail dot com
2023-10-10 7:37 ` crazylht at gmail dot com
2023-10-30 3:10 ` cvs-commit at gcc dot gnu.org
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