[Bug tree-optimization/121405] [13/14/15/16 Regression] Another missed VN via a copy (but via an int copy)

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121405

--- Comment #10 from GCC 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:53f491ccd1e59fad77fb2cb30d1a58b9e5e5f63c

commit r16-3066-g53f491ccd1e59fad77fb2cb30d1a58b9e5e5f63c
Author: Richard Biener <rguenther@suse.de>
Date:   Wed Aug 6 12:31:13 2025 +0200

    tree-optimization/121405 - missed VN with aggregate copy

    The following handles value-numbering of a BIT_FIELD_REF of
    a register that's defined by a load by looking up a subset
    load similar to how we handle bit-and masked loads.  This
    allows the testcase to be simplified by two FRE passes,
    the first one will create the BIT_FIELD_REF.

            PR tree-optimization/121405
            * tree-ssa-sccvn.cc (visit_nary_op): Handle BIT_FIELD_REF
            with reference def by looking up a combination of both.

            * gcc.dg/tree-ssa/ssa-fre-107.c: New testcase.
            * gcc.target/i386/pr90579.c: Adjust.