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From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug c++/61245] #pragma GCC ivdep is ignored with call inside the
 test of a for loop
Date: Sun, 20 Jun 2021 09:38:06 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D61245

--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
The loop is still vectorized though. As it looks like it was versioned.

t6.cc: In function =E2=80=98void doT(SoA<N>&) [with int N =3D 3]=E2=80=99:
t6.cc:34:17: warning: ignoring loop annotation
   34 |   for (auto i=3D0U; i<soa.size(); ++i)
      |                 ^
t6.cc:10:17: optimized: loop vectorized using 16 byte vectors
t6.cc:10:17: optimized: loop vectorized using 8 byte vectors
t6.cc:34:17: optimized: loop vectorized using 16 byte vectors
t6.cc:34:17: optimized:  loop versioned for vectorization because of possib=
le
aliasing
t6.cc:34:17: optimized: loop vectorized using 8 byte vectors

I don't know how useful "#pragma GCC ivdep" is these days really.=