[Bug middle-end/93576] [8/9/10 Regression] internal compiler error: Segmentation fault (in gimplify.c)

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93576

--- Comment #10 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-9 branch has been updated by Jakub Jelinek
<jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:7276dd4c7480dd952f0d4a9322ca04ca29f5126f

commit r9-8227-g7276dd4c7480dd952f0d4a9322ca04ca29f5126f
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Thu Feb 13 21:00:09 2020 +0100

    c: Fix ICE with cast to VLA [93576]

    The following testcase ICEs, because the PR84305 changes try to evaluate
    the size earlier.  If size has side-effects, that is desirable, and the
    side-effects will actually be wrapped in a SAVE_EXPR.  The problem on this
    testcase is that there are no side-effects, and c_fully_fold doesn't fold
    those COMPOUND_EXPRs to constant, and while before gimplification we
unshare
    trees found in the expressions, the unsharing doesn't involve TYPE_SIZE
etc.
    of used types.  Gimplification is destructive though, so when we gimplify
    the two nested COMPOUND_EXPRs and then try to gimplify it the second time
    for the TYPE_SIZEs, we ICE.
    Now, we could use unshare_expr in what we push to *expr, SAVE_EXPRs and
    their operands in there aren't unshared, but I really don't see a point of
    evaluating expressions that don't have side-effects before, so instead
    this just pushes there expressions that do have side-effects.

    2020-02-13  Jakub Jelinek  <jakub@redhat.com>

        PR c/93576
        * c-decl.c (grokdeclarator): If this_size_varies, only push size into
        *expr if it has side effects.

        * gcc.dg/pr93576.c: New test.