[Bug c++/110477] New: -fexcess-precision=standard not applied consistently

["pdimov at gmail dot com" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110477

            Bug ID: 110477
           Summary: -fexcess-precision=standard not applied consistently
           Product: gcc
           Version: 13.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: pdimov at gmail dot com
  Target Milestone: ---

The following program

float f( float x, int y )
{
    return x + y;
}

int main()
{
    return f( 3.14f, 1 ) == 3.14f + 1;
}

returns different values with -std=c++XX (https://godbolt.org/z/8dK98ondM) and
-std=gnu++XX (https://godbolt.org/z/4Y4qfsKzM) under GCC 13/14 -m32, because
-fexcess-precision=standard is not consistently applied to both sides of the
comparison. Under -fexcess-precision=fast (and hence under previous GCC
versions), the comparison always succeeds because both sides use excess
precision (https://godbolt.org/z/dzdoxdnM9).

This is the runtime equivalent of
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110476.