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From: "gabravier at gmail dot com" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug target/95535] New: Failure to optimize out cdqe after __bultin_ctz Date: Thu, 04 Jun 2020 14:58:48 +0000 [thread overview] Message-ID: <bug-95535-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95535 Bug ID: 95535 Summary: Failure to optimize out cdqe after __bultin_ctz Product: gcc Version: 11.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: target Assignee: unassigned at gcc dot gnu.org Reporter: gabravier at gmail dot com Target Milestone: --- long long f(int n) { return __builtin_ctz(n); } With -O3, GCC outputs this : f(int): xor eax, eax tzcnt eax, edi cdqe ret LLVM outputs this : f(int): # @f(int) tzcnt eax, edi ret Looks like the cdqe can be omitted.
next reply other threads:[~2020-06-04 14:58 UTC|newest] Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-06-04 14:58 gabravier at gmail dot com [this message] 2020-06-04 16:36 ` [Bug target/95535] " jakub at gcc dot gnu.org 2020-06-04 17:08 ` jakub at gcc dot gnu.org 2020-06-05 8:45 ` cvs-commit at gcc dot gnu.org 2020-09-04 9:08 ` gabravier at gmail dot com
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