https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92989
--- Comment #12 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Richard Sandiford <rsand...@gcc.gnu.org>: https://gcc.gnu.org/g:e83714f65d1f75fc5af39f9fdc520a909dfc7635 commit r10-7570-ge83714f65d1f75fc5af39f9fdc520a909dfc7635 Author: Richard Sandiford <richard.sandif...@arm.com> Date: Sat Apr 4 17:23:40 2020 +0100 lra: Stop eh_return data regs being incorrectly marked live [PR92989] lra_assign has an assert to make sure that no pseudo is allocated to a conflicting hard register. It used to be restricted to !flag_ipa_ra, but in g:a1e6ee38e708ef2bdef4 I'd enabled it for flag_ipa_ra too. It then tripped a few times while building libstdc++ for mips-mti-linux. Previous patches fixed one of the problems: registers clobbered by the taking of an exception were being treated as live at the beginning of the EH receiver, and this got propagated to predecessor blocks. But it turns out that there was a second problem: eh_return data registers were also being marked live in the same way. These registers are defined by the unwinder and so in reality they are live on entry to the EH receiver. But definitions can only happen in blocks, not on edges, so for liveness purposes we use artificial definitions at the start of the EH receiver. process_bb_lives should therefore model the effect of a definition, not a plain use. 2020-04-06 Richard Sandiford <richard.sandif...@arm.com> gcc/ PR rtl-optimization/92989 * lra-lives.c (process_bb_lives): Do not treat eh_return data registers as being live at the beginning of the EH receiver.
