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From: "gabravier at gmail dot com" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/94877] New: Failure to simplify ~(x + 1) to -2 - x Date: Thu, 30 Apr 2020 12:02:00 +0000 [thread overview] Message-ID: <bug-94877-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94877 Bug ID: 94877 Summary: Failure to simplify ~(x + 1) to -2 - x Product: gcc Version: 10.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: tree-optimization Assignee: unassigned at gcc dot gnu.org Reporter: gabravier at gmail dot com Target Milestone: --- int f(int x) { return ~(x + 1); } With -O3, LLVM outputs this : f(int): # @f(int) mov eax, -2 sub eax, edi ret GCC outputs this : f(int): lea eax, [rdi+1] not eax ret `~x - 1` is already simplified to `-2 - x`, so optimizing this looks like it would make sense too.
next reply other threads:[~2020-04-30 12:02 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-04-30 12:02 gabravier at gmail dot com [this message] 2020-04-30 12:50 ` [Bug tree-optimization/94877] " rguenth at gcc dot gnu.org 2020-04-30 19:08 ` pinskia at gcc dot gnu.org 2020-05-06 14:55 ` jakub at gcc dot gnu.org 2020-05-06 15:56 ` ubizjak at gmail dot com 2021-08-14 23:47 ` pinskia at gcc dot gnu.org
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