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* [Bug rtl-optimization/94796] New: Failure to reuse flags from substraction
@ 2020-04-27 12:32 gabravier at gmail dot com
  2020-04-27 13:06 ` [Bug rtl-optimization/94796] " rguenth at gcc dot gnu.org
  2020-04-27 19:58 ` pinskia at gcc dot gnu.org
  0 siblings, 2 replies; 3+ messages in thread
From: gabravier at gmail dot com @ 2020-04-27 12:32 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94796

            Bug ID: 94796
           Summary: Failure to reuse flags from substraction
           Product: gcc
           Version: 10.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: rtl-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: gabravier at gmail dot com
  Target Milestone: ---

int f(int a, int b)
{
    return ((a == b) & (a - b));
}

The `a == b` is able to use condition flags resulting from `a - b`, and thus
avoid an extra compare. LLVM does this transformation, but GCC does not.

https://godbolt.org/z/SHvTW8

^ permalink raw reply	[flat|nested] 3+ messages in thread
end of thread, other threads:[~2020-04-27 19:58 UTC | newest]

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2020-04-27 12:32 [Bug rtl-optimization/94796] New: Failure to reuse flags from substraction gabravier at gmail dot com
2020-04-27 13:06 ` [Bug rtl-optimization/94796] " rguenth at gcc dot gnu.org
2020-04-27 19:58 ` pinskia at gcc dot gnu.org

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