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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/94846] New: Failure to optimize jnc+inc into adc Date: Wed, 29 Apr 2020 12:05:38 +0000 [thread overview] Message-ID: <bug-94846-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94846 Bug ID: 94846 Summary: Failure to optimize jnc+inc into adc 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: --- unsigned f(unsigned *p, unsigned x) { unsigned u = *p; *p += x; if (u > *p) ++*p; return *p; } This is what LLVM outputs with -O3 : f(unsigned int*, unsigned int): # @f(unsigned int*, unsigned int) mov eax, esi add eax, dword ptr [rdi] adc eax, 0 mov dword ptr [rdi], eax ret This is what GCC outputs : f(unsigned int*, unsigned int): mov eax, esi add eax, DWORD PTR [rdi] jnc .L6 add eax, 1 .L6: mov DWORD PTR [rdi], eax ret GCC should most likely be optimizing this to the same thing as LLVM.
next reply other threads:[~2020-04-29 12:05 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-04-29 12:05 gabravier at gmail dot com [this message] 2020-04-29 12:12 ` [Bug rtl-optimization/94846] " gabravier at gmail dot com 2020-04-29 13:03 ` gabravier at gmail dot com 2020-11-25 18:05 ` [Bug tree-optimization/94846] " ubizjak at gmail dot com 2020-11-26 8:42 ` rguenth at gcc dot gnu.org 2021-09-05 0:13 ` pinskia at gcc dot gnu.org
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