https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103601
--- Comment #6 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Roger Sayle <sa...@gcc.gnu.org>: https://gcc.gnu.org/g:2a1c3b69c015ea49e4c7c08291efd8f7e28e1193 commit r12-5891-g2a1c3b69c015ea49e4c7c08291efd8f7e28e1193 Author: Roger Sayle <ro...@nextmovesoftware.com> Date: Fri Dec 10 12:02:04 2021 +0000 PR ipa/103601: ICE compiling CSiBE in ipa-modref's insert_kill. This patch fixes PR ipa/103061 which is P1 regression that shows up as an ICE in ipa-modref-tree.c's insert_kill when compiling the CSiBE benchmark. I believe the underlying cause is that the new kill tracking functionality wasn't anticipating memory accesses that are zero bits wide!?. The failing source code (test case) contains the unusual lines: typedef struct { } spinlock_t; and q->lock = (spinlock_t) { }; Making spinlock_t larger, or removing the assignment work around the issue. The one line patch below to useful_for_kill_p teaches IPA that a memory write is only useful as a "kill" if it is more than zero bits wide. In theory, the existing known_size_p (size) test is now redundant, as poly_int64 currently uses the value -1 for unknown size values, but the proposed change makes the semantics clear, and defends against possible future changes in representation. 2021-12-10 Roger Sayle <ro...@nextmovesoftware.com> gcc/ChangeLog PR ipa/103601 * ipa-modref-tree.h (useful_for_kill_p): Zero width accesses aren't useful for kill tracking. gcc/testsuite/ChangeLog PR ipa/103601 * gcc.dg/ipa/pr103601.c: New test case.
