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From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/107591] range-op{,-float}.cc for x * x
Date: Wed, 09 Nov 2022 16:40:07 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D107591

--- Comment #8 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
(In reply to Aldy Hernandez from comment #6)
> FYI, the range operators have a relation field, so it should be able to t=
ell
> you that both operands are equal with VREL_EQ (?).  You could use that to
> optimize things.

You're right, at least for irange trio.op1_op2 () in the mult fold_range is
VREL_EQ and we could just go from that.
For frange perhaps it isn't as perfect because of signed zeros, so in
float
foo (float x, float y)
{
  if (x =3D=3D y)
    return x * y;
  return 42.0f;
}
trio.op1_op2 () could be VREL_EQ even if one is signed and the other unsign=
ed
zero, and in that case -0.0 would need to be in the range too.  But maybe t=
hat
is good enough for now.=