[Bug tree-optimization/56125] [4.7/4.8 Regression] -O2 -ffast-math generates bad code when dividing a double by the square of another double.

glisse at gcc dot gnu.org gcc-bugzilla@gcc.gnu.org
Mon Jan 28 07:30:00 GMT 2013


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56125

Marc Glisse <glisse at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|-O2 -ffast-math generates   |[4.7/4.8 Regression] -O2
                   |bad code when dividing a    |-ffast-math generates bad
                   |double by the square of     |code when dividing a double
                   |another double.             |by the square of another
                   |                            |double.

--- Comment #2 from Marc Glisse <glisse at gcc dot gnu.org> 2013-01-28 07:30:05 UTC ---
4.6 generated a very suboptimal call to the libm pow function, but it didn't
have the completely wrong result.



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