[Bug tree-optimization/94269] widening_mul should consider block frequency

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94269

--- Comment #2 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Richard Biener <rguenth@gcc.gnu.org>:

https://gcc.gnu.org/g:d21dff5b4fee51ae432143065bededfc763dc344

commit r10-7391-gd21dff5b4fee51ae432143065bededfc763dc344
Author: Richard Biener <rguenther@suse.de>
Date:   Thu Mar 26 08:33:57 2020 +0100

    widening_mul: restrict ops to be defined in the same basic-block when
convert plusminus to widen

    In the testcase for PR94269, widening_mul moves two multiply
    instructions from outside the loop to inside
    the loop, merging with two add instructions separately.  This
    increases the cost of the loop.  Like FMA detection
    in the same pass, simply restrict ops to be defined in the same
    basic-block to avoid possibly moving multiply
    to a different block with a higher execution frequency.

    2020-03-26  Felix Yang  <felix.yang@huawei.com>

            PR tree-optimization/94269
            * tree-ssa-math-opts.c (convert_plusminus_to_widen): Restrict
            this
            operation to single basic block.

            * gcc.dg/pr94269.c: New test.