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From: "aldyh at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/109154] [13 regression] jump threading
 de-optimizes nested floating point comparisons
Date: Wed, 22 Mar 2023 14:39:59 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D109154

--- Comment #10 from Aldy Hernandez <aldyh at gcc dot gnu.org> ---
(In reply to Andrew Macleod from comment #9)
> (In reply to Richard Biener from comment #7)
> > (In reply to Richard Biener from comment #6)
> > > ah, probably it's the missing CSE there:
> > >=20
> > >     <bb 3> :
> > >     _1 =3D (float) l_10;
> > >     _2 =3D _1 < 0.0;
> > >     zone1_17 =3D (int) _2;
> > >     if (_1 < 0.0)

BTW, I don't think it helps at all here, but casting from l_10 to a float, =
we
know _1 can't be either -0.0 or +-INF or +-NAN.  We could add a range-op en=
try
for NOP_EXPR / CONVERT_EXPR to expose this fact.  Well, at the very least t=
hat
it can't be a NAN...in the current representation for frange's.=