[Bug target/95535] Failure to optimize out cdqe after __bultin_ctz

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95535

--- Comment #3 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jakub Jelinek <jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:892b51cb73f24157391cd18c2215e8d703af97e7

commit r11-965-g892b51cb73f24157391cd18c2215e8d703af97e7
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Fri Jun 5 10:44:23 2020 +0200

    ix86: Improve __builtin_c[lt]z followed by extension [PR95535]

    In January I've added patterns to optimize SImode -> DImode sign or zero
    extension of __builtin_popcount, this patch does the same for
    __builtin_c[lt]z.  Like most other instructions, the [tl]zcntl instructions
    clear the upper 32 bits of the destination register and as the instructions
    only result in values 0 to 32 inclusive, both sign and zero extensions
    behave the same.

    2020-06-05  Jakub Jelinek  <jakub@redhat.com>

            PR target/95535
            * config/i386/i386.md (*ctzsi2_zext, *clzsi2_lzcnt_zext): New
            define_insn_and_split patterns.
            (*ctzsi2_zext_falsedep, *clzsi2_lzcnt_zext_falsedep): New
            define_insn patterns.

            * gcc.target/i386/pr95535-1.c: New test.
            * gcc.target/i386/pr95535-2.c: New test.