[Bug tree-optimization/79333] FRE/PRE do not allow folding to look at SSA defs during elimination

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79333

--- Comment #3 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:d846f225c25c5885250c303c8d118caa08c447ab

commit r12-476-gd846f225c25c5885250c303c8d118caa08c447ab
Author: Richard Biener <rguenther@suse.de>
Date:   Tue May 4 15:51:20 2021 +0200

    tree-optimization/79333 - fold stmts following SSA edges in VN

    This makes sure to follow SSA edges when folding eliminated stmts.
    This reaps the same benefit as forwprop folding all stmts, not
    waiting for one to produce copysign in the new testcase.

    2021-05-04  Richard Biener  <rguenther@suse.de>

            PR tree-optimization/79333
            * tree-ssa-sccvn.c (eliminate_dom_walker::eliminate_stmt):
            Fold stmt following SSA edges.

            * gcc.dg/tree-ssa/ssa-fre-94.c: New testcase.
            * gcc.dg/graphite/fuse-1.c: Adjust.
            * gcc.dg/pr43864-4.c: Likewise.