[Bug tree-optimization/108737] [13 Regression] Apparent miscompile of infinite loop on gcc trunk in cddce2 pass since r13-3875

[rguenth at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108737

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |FIXED
             Status|ASSIGNED                    |RESOLVED

--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> ---
I botched the changelog.  Fixed with the following, but latent everywhere.

commit 338739645b8e5bf34636d8d4829d7650001ad08c (origin/master, origin/HEAD)
Author: Richard Biener <rguent...@suse.de>
Date:   Fri Feb 10 10:28:29 2023 +0100

    tree-optimization/106722 - fix CD-DCE edge marking

    The following fixes a latent issue when we mark control edges but
    end up with marking a block with no stmts necessary.  In this case
    we fail to mark dependent control edges of that block.

            PR tree-optimization/106722
            * tree-ssa-dce.cc (mark_last_stmt_necessary): Return
            whether we marked a stmt.
            (mark_control_dependent_edges_necessary): When
            mark_last_stmt_necessary didn't mark any stmt make sure
            to mark its control dependent edges.
            (propagate_necessity): Likewise.

            * gcc.dg/torture/pr108737.c: New testcase.