https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115872
--- Comment #7 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by hongtao Liu <liuho...@gcc.gnu.org>: https://gcc.gnu.org/g:f27bf48e0204524ead795fe618cd8b1224f72fd4 commit r15-2038-gf27bf48e0204524ead795fe618cd8b1224f72fd4 Author: liuhongt <hongtao....@intel.com> Date: Fri Jul 12 09:39:23 2024 +0800 Fix SSA_NAME leak due to def_stmt is removed before use_stmt. - _5 = __atomic_fetch_or_8 (&set_work_pending_p, 1, 0); - # DEBUG old => (long int) _5 + _6 = .ATOMIC_BIT_TEST_AND_SET (&set_work_pending_p, 0, 1, 0, __atomic_fetch_or_8); + # DEBUG old => NULL # DEBUG BEGIN_STMT - # DEBUG D#2 => _5 & 1 + # DEBUG D#2 => NULL ... - _10 = ~_5; - _8 = (_Bool) _10; - # DEBUG ret => _8 + _8 = _6 == 0; + # DEBUG ret => (_Bool) _10 confirmed. convert_atomic_bit_not does this, it checks for single_use and removes the def, failing to release the name (which would fix this up IIRC). Note the function removes stmts in "wrong" order (before uses of LHS are removed), so it requires larger surgery. And it leaks SSA names. gcc/ChangeLog: PR target/115872 * tree-ssa-ccp.cc (convert_atomic_bit_not): Remove use_stmt after use_nop_stmt is removed. (optimize_atomic_bit_test_and): Ditto. gcc/testsuite/ChangeLog: * gcc.target/i386/pr115872.c: New test.
