https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99927
--- Comment #20 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-10 branch has been updated by Segher Boessenkool <seg...@gcc.gnu.org>: https://gcc.gnu.org/g:7ef9f0272258862439348dbaa57a46e9eabdc9ca commit r10-9989-g7ef9f0272258862439348dbaa57a46e9eabdc9ca Author: Segher Boessenkool <seg...@kernel.crashing.org> Date: Sat Apr 17 18:06:17 2021 +0000 combine: Don't create REG_UNUSED notes if the reg already died (PR99927) If the register named in an existing REG_UNUSED note dies somewhere between where the note used to be and I3, we should just drop it. 2021-04-21 Segher Boessenkool <seg...@kernel.crashing.org> PR rtl-optimization/99927 * combine.c (distribute_notes) [REG_UNUSED]: If the register already is dead, just drop it.