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From: "liuhongt at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug target/113729] Missing APX NDD optimization Date: Sun, 04 Feb 2024 07:29:38 +0000 [thread overview] Message-ID: <bug-113729-4-0weaV2chM6@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-113729-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113729 --- Comment #2 from Hongtao Liu <liuhongt at gcc dot gnu.org> --- extern unsigned char b; int foo (void) { return (unsigned char)(200 + b); } gcc -O2 -mapxf foo(): subb $56, b(%rip), %al movzbl %al, %eax ret And this can be optimzied to foo(): subb $56, b(%rip), %al ret Note, if we want to optimize it in pass_combine, the pattern need to generate explicit APX NDD instructions, since APX non-NDD will not clear upper bits.
prev parent reply other threads:[~2024-02-04 7:29 UTC|newest] Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top 2024-02-02 21:44 [Bug target/113729] New: " hjl.tools at gmail dot com 2024-02-04 2:04 ` [Bug target/113729] " liuhongt at gcc dot gnu.org 2024-02-04 7:29 ` liuhongt at gcc dot gnu.org [this message]
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