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From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/114659] gcc miscompiles a __builtin_memcpy on i386,
 leading to wrong results for SNaN
Date: Tue, 09 Apr 2024 18:18:58 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D114659

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|middle-end                  |target

--- Comment #6 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
I doubt there is not much to be done here. It is a x87 issue where we do the
store of the float register stack register to the stack to get 32bits (or
64bit) version. And then load it into a GPR.




  float t =3D *x;
  float t1 =3D *y;

 __builtin_memcpy (&xu.f, &t, sizeof (float));
 __builtin_memcpy (&xu.f, &t1, sizeof (float));

Produces exactly the same issue.=