https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99104
--- Comment #6 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:decd8fb0128870d0d768ba53dae626913d6d9c54 commit r11-7274-gdecd8fb0128870d0d768ba53dae626913d6d9c54 Author: Jakub Jelinek <ja...@redhat.com> Date: Thu Feb 18 09:16:28 2021 +0100 i386: Fix up df uses in i386 splitters [PR99104] The following testcase started ICEing with my recent changes to enable split4 after sel-sched, but it seems the bug is more general. Some of the i386 splitter condition functions use and rely on df, but the split passes don't really df_analyze/df_finish_pass, so the DF info may be stale or not computed at all - the particular ICE is because there is a new bb and df_get_live_out (bb) returns NULL on it as the live or lr problem has not been computed yet. This patch fixes it by not calling ix86_ok_to_clobber_flags from ix86_avoid_lea_for_add where it wasn't ever needed because the splitters using that function as condition have (clobber FLAGS) in their pattern. And, changes the ix86_avoid_lea_for_addr using splitter from normal splitter to peephole2 splitter that uses peep2_regno_dead_p infrastructure to determine if FLAGS is dead. Also, it saves and restores recog_data variable around the call to distance_non_agu_define and doesn't call extract_insn_data there, because split_insns or peephole2_insns just clear recog_data.insn and then fill in recog_data.operand array, and so might not match what extract_insn will do on the insn at all. 2021-02-18 Jakub Jelinek <ja...@redhat.com> PR target/99104 * config/i386/i386.c (distance_non_agu_define): Don't call extract_insn_cached here. (ix86_lea_outperforms): Save and restore recog_data around call to distance_non_agu_define and distance_agu_use. (ix86_ok_to_clobber_flags): Remove. (ix86_avoid_lea_for_add): Don't call ix86_ok_to_clobber_flags. (ix86_avoid_lea_for_addr): Likewise. Adjust function comment. * config/i386/i386.md (*lea<mode>): Change from define_insn_and_split into define_insn. Move the splitting to define_peephole2 and check there using peep2_regno_dead_p if FLAGS_REG is dead. * gcc.dg/pr99104.c: New test.
