Hi Richard, On 21/09/22 1:03 pm, Richard Biener wrote: > On Tue, Sep 20, 2022 at 9:18 AM Surya Kumari Jangala via Gcc-patches > <gcc-patches@gcc.gnu.org> wrote: >> >> Hi Jeff, Richard, >> Thank you for reviewing the patch! >> I have committed the patch to the gcc repo. >> Can I backport this patch to prior versions of gcc, as this is an easy patch >> to backport and the issue exists in prior versions too? > > It doesn't seem to be a regression so I'd error on the safe side here.
Can you please clarify, should this patch be backported? It is not very clear what "safe side" means here. Thanks! Surya > > Richard. > >> Regards, >> Surya >> >> >> On 31/08/22 9:09 pm, Jeff Law via Gcc-patches wrote: >>> >>> >>> On 8/23/2022 5:49 AM, Surya Kumari Jangala via Gcc-patches wrote: >>>> sched1: Fix -fcompare-debug issue in schedule_region [PR105586] >>>> >>>> In schedule_region(), a basic block that does not contain any real insns >>>> is not scheduled and the dfa state at the entry of the bb is not copied >>>> to the fallthru basic block. However a DEBUG insn is treated as a real >>>> insn, and if a bb contains non-real insns and a DEBUG insn, it's dfa >>>> state is copied to the fallthru bb. This was resulting in >>>> -fcompare-debug failure as the incoming dfa state of the fallthru block >>>> is different with -g. We should always copy the dfa state of a bb to >>>> it's fallthru bb even if the bb does not contain real insns. >>>> >>>> 2022-08-22 Surya Kumari Jangala <jskum...@linux.ibm.com> >>>> >>>> gcc/ >>>> PR rtl-optimization/105586 >>>> * sched-rgn.cc (schedule_region): Always copy dfa state to >>>> fallthru block. >>>> >>>> gcc/testsuite/ >>>> PR rtl-optimization/105586 >>>> * gcc.target/powerpc/pr105586.c: New test. >>> Interesting. We may have stumbled over this bug internally a little >>> while ago -- not from a compare-debug standpoint, but from a "why isn't the >>> processor state copied to the fallthru block" point of view. I had it on >>> my to investigate list, but hadn't gotten around to it yet. >>> >>> I think there were requests for ChangeLog updates and a function comment >>> for save_state_for_fallthru_edge. OK with those updates. >>> >>> jeff >>>
