[Bug target/19150] New: [3.3/3.4/4.0 Regression] suboptimal fp division with -ffast-math

[pinskia at gcc dot gnu dot org]

Take the following code:
double test (double x) {
        return 1.1 / x;
}

With -O2 -ffast-math with 2.95.3, we get:
        fldl    .LC0
        pushl   %ebp
        movl    %esp, %ebp
        fdivl   8(%ebp)
        popl    %ebp
        ret

But with 3.3, and 4.0:
        pushl   %ebp
        movl    %esp, %ebp
        fld1
        fdivl   8(%ebp)
        fmull   .LC1
        leave
        ret

-- 
           Summary: [3.3/3.4/4.0 Regression] suboptimal fp division with -
                    ffast-math
           Product: gcc
           Version: 4.0.0
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: normal
          Priority: P2
         Component: target
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: pinskia at gcc dot gnu dot org
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19150