https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108657
--- Comment #22 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jakub Jelinek <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:866555b170016c49beb869a78cbecdeb07c63135 commit r13-6083-g866555b170016c49beb869a78cbecdeb07c63135 Author: Jakub Jelinek <ja...@redhat.com> Date: Thu Feb 16 15:35:05 2023 +0100 tree-ssa-dse: Fix up handling of lhs of internal calls [PR108657] The r13-1778 PR106378 tree-ssa-dse change didn't just add special support for IFN_LEN_STORE and IFN_MASK_STORE internal function calls as I believe was intended, but given that the function was if (is builtin) { ... } else if (lhs present and non-SSA_NAME) { ... } return false; and it added a new else if (is internal builtin) { ... } in between the two, the last if used to be done before on all stmts with non-SSA_NAME lhs except for calls to builtin functions, but newly isn't done also for calls to internal functions. In the testcase the important internal function is .DEFERRED_INIT, which often has non-SSA_NAME lhs, and the change resulted in them no longer being DSEd, so a block with nothing in it left but var = .DEFERRED_INIT () and var = {CLOBBER} was unrolled several times. The following patch does the lhs handling for all stmts with non-SSA_NAME lhs unless initialize_ao_ref_for_dse handled those specially already and returned (which is the case for various mem* builtins which don't have such lhs, for some cases of calloc which again is fine,and since r13-1778 also for IFN_LEN_STORE call and some IFN_MASK_STORE calls. As IFN_MASK_STORE doesn't have a lhs, the break for the !may_def_ok case doesn't seem to change anything, and because we've handled internal fns that way in the past, I think it is the right thing to do that again. That said, if it is inappropriate for some new ifn, I guess it could be added to the switch and just return false; for it instead of break;. 2023-02-16 Jakub Jelinek <ja...@redhat.com> PR tree-optimization/108657 * tree-ssa-dse.cc (initialize_ao_ref_for_dse): If lhs of stmt exists and is not a SSA_NAME, call ao_ref_init even if the stmt is a call to internal or builtin function. * gcc.dg/pr108657.c: New test.
