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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug target/105034] [10/11/12 regression]Suboptimal codegen for
 min/max with -Os
Date: Thu, 14 Apr 2022 09:00:08 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D105034

--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
Example that we don't transform but could:

typedef int v4si __attribute__((vector_size(16)));

#define min(a,b) ((a)<(b)?(a):(b))

v4si foo (v4si a, v4si b)
{
  a[0] =3D min (a[0], b[0]);
  return a;
}

here the scalar code is

        movd    %xmm0, %edx
        movd    %xmm1, %eax
        cmpl    %edx, %eax
        cmovg   %edx, %eax
        pinsrd  $0, %eax, %xmm0

where we could use sth like

        movq %xmm0, %xmm2
        minpd %xmm2, %xmm1
        <some pack/unpack/palign or whatever>

a testcase variant could return the scalar minimum.  For both cases it's
likely a win even for -Os.=