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From: "llvm at rifkin dot dev" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/109044] New: Missed fold for (n - 1) / 2 when n is odd Date: Mon, 06 Mar 2023 18:18:59 +0000 [thread overview] Message-ID: <bug-109044-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109044 Bug ID: 109044 Summary: Missed fold for (n - 1) / 2 when n is odd Product: gcc Version: 12.2.1 Status: UNCONFIRMED Severity: normal Priority: P3 Component: tree-optimization Assignee: unassigned at gcc dot gnu.org Reporter: llvm at rifkin dot dev Target Milestone: --- int foo(unsigned n) { if(n % 2 == 0) __builtin_unreachable(); return (n - 1) / 2; } int bar(unsigned n) { return n >> 1; } foo(unsigned int): lea eax, [rdi-1] shr eax ret bar(unsigned int): mov eax, edi shr eax ret https://godbolt.org/z/3G7enYdnM https://alive2.llvm.org/ce/z/m3qbdN
next reply other threads:[~2023-03-06 18:19 UTC|newest] Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-03-06 18:18 llvm at rifkin dot dev [this message] 2023-03-06 18:20 ` [Bug tree-optimization/109044] " pinskia at gcc dot gnu.org 2023-03-07 9:10 ` rguenth at gcc dot gnu.org
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