[Bug tree-optimization/95852] Failure to optimize __builtin_mul_overflow pattern

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95852

--- 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:a2106317cd6673e110b347c70f21e25fbb23379e

commit r11-6579-ga2106317cd6673e110b347c70f21e25fbb23379e
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Mon Jan 11 10:32:07 2021 +0100

    widening_mul: Pattern recognize unsigned multiplication with overflow check
[PR95852]

    The following patch pattern recognizes some forms of multiplication
followed
    by overflow check through division by one of the operands compared to the
    other one, with optional removal of guarding non-zero check for that
operand
    if possible.  The patterns are replaced with effectively
    __builtin_mul_overflow or __builtin_mul_overflow_p.  The testcases cover 64
    different forms of that.

    2021-01-11  Jakub Jelinek  <jakub@redhat.com>

            PR tree-optimization/95852
            * tree-ssa-math-opts.c (maybe_optimize_guarding_check): New
function.
            (uaddsub_overflow_check_p): Renamed to ...
            (arith_overflow_check_p): ... this.  Handle also multiplication
            with overflow check.
            (match_uaddsub_overflow): Renamed to ...
            (match_arith_overflow): ... this.  Add cfg_changed argument. 
Handle
            also multiplication with overflow check.  Adjust function comment.
            (math_opts_dom_walker::after_dom_children): Adjust callers.  Call
            match_arith_overflow also for MULT_EXPR.

            * gcc.target/i386/pr95852-1.c: New test.
            * gcc.target/i386/pr95852-2.c: New test.