https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121619
--- Comment #3 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The trunk branch has been updated by Richard Sandiford <rsand...@gcc.gnu.org>: https://gcc.gnu.org/g:0d34e73b71ce199f52de227c4101256484feaa78 commit r16-3331-g0d34e73b71ce199f52de227c4101256484feaa78 Author: Richard Sandiford <richard.sandif...@arm.com> Date: Thu Aug 21 16:16:02 2025 +0100 rtl-ssa: Add missing live-out uses [PR121619] This PR is another bug in the rtl-ssa code to manage live-out uses. It seems that this didn't get much coverage until recently. In the testcase, late-combine first removed a register-to-register move by substituting into all uses, some of which were in other EBBs. This was done after checking make_uses_available, which (as expected) says that single dominating definitions are available everywhere that the definition dominates. But the update failed to add appropriate live-out uses, so a later parallelisation attempt tried to move the new destination into a later block. gcc/ PR rtl-optimization/121619 * rtl-ssa/functions.h (function_info::commit_make_use_available): Declare. * rtl-ssa/blocks.cc (function_info::commit_make_use_available): New function. * rtl-ssa/changes.cc (function_info::apply_changes_to_insn): Use it. gcc/testsuite/ PR rtl-optimization/121619 * gcc.dg/pr121619.c: New test.
