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 <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:7276dd4c7480dd952f0d4a9322ca04ca29f5126f commit r9-8227-g7276dd4c7480dd952f0d4a9322ca04ca29f5126f Author: Jakub Jelinek <ja...@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 <ja...@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.
