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From: "zhaoweiliew at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug tree-optimization/95424] Failure to optimize division with
 numerator of 1
Date: Thu, 30 Dec 2021 07:12:45 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D95424

--- Comment #1 from Zhao Wei Liew <zhaoweiliew at gmail dot com> ---
Created attachment 52091
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=3D52091&action=3Dedit
Tested patch for the case of unsigned integer X

I tried to tackle the unsigned integer X case by adding an optimization in
match.pd. I suppose it can be done similarly for the signed integer X case =
as
well, but I'll need more time to look into that.

I've attached the proposed patch. With this patch, GCC generates the same
assembly output as Clang.

int f(unsigned int x) {
        return 1 / x;
}


.LFB0:
        .cfi_startproc
        xorl    %eax, %eax
        cmpl    $1, %edi
        sete    %al
        ret=