[Bug target/108922] fmod() 13x slowdown in gcc4.9 dropping "fprem" and calling fmod()

[cvs-commit at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108922

--- Comment #31 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Uros Bizjak <u...@gcc.gnu.org>:

https://gcc.gnu.org/g:8020c9c42349f51f75239b9d35a2be41848a97bd

commit r13-6361-g8020c9c42349f51f75239b9d35a2be41848a97bd
Author: Uros Bizjak <ubiz...@gmail.com>
Date:   Mon Feb 27 22:10:01 2023 +0100

    i386: Do not constrain fmod and remainder patterns with
flag_finite_math_only [PR108922]

    According to Intel ISA manual, fprem and fprem1 return NaN when invalid
    arithmetic exception is generated. This is documented in Table 8-10 of the
    ISA manual and makes these two instructions fully IEEE compatible.

    The reverted patch was based on the data from table 3-30 and 3-31 of the
    Intel ISA manual, where results in case of st(0) being infinity or
    st(1) being 0 are not specified.

    2023-02-27  Uroš Bizjak  <ubiz...@gmail.com>

    gcc/ChangeLog:

            PR target/108922
            Revert:
            * config/i386/i386.md (fmodxf3): Enable for flag_finite_math_only
only.
            (fmod<mode>3): Ditto.
            (fpremxf4_i387): Ditto.
            (reminderxf3): Ditto.
            (reminder<mode>3): Ditto.
            (fprem1xf4_i387): Ditto.