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From: "liuhongt at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/109885] gcc does not generate movmskps and
 testps instructions  (clang does)
Date: Sun, 18 Feb 2024 03:09:49 +0000
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X-Bugzilla-Component: tree-optimization
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D109885

--- Comment #4 from Hongtao Liu <liuhongt at gcc dot gnu.org> ---
int sum() {
   int ret =3D 0;
   for (int i=3D0; i<8; ++i) ret +=3D(0=3D=3Dv[i]);
   return ret;
}

int sum2() {
   int ret =3D 0;
   auto m =3D v=3D=3D0;
   for (int i=3D0; i<8; ++i) ret +=3D m[i];
   return ret;
}

For sum, gcc tries to reduce for an {0/1, 0/1, ...} vector, for sum2, it tr=
ies
to reduce {0/-1,0/-1,...} vector. But LLVM tries to reduce {0/1, 0/1, ... }
vector for both sum and sum2. Not sure which is correct?=