When recog_for_combine fails to recognize a pattern as-is, it re-tries with the clobbers stripped away. When it eventually fails, and the caller try_combine tries to split the pattern, the clobbers are gone, thus causing combine failures for bridge splitters that need these clobbers.
patch is here: http://gcc.gnu.org/ml/gcc-patches/2005-03/msg00177.html -- Summary: combine throws away clobbers before tying to split Product: gcc Version: 3.3 Status: UNCONFIRMED Keywords: missed-optimization Severity: normal Priority: P2 Component: rtl-optimization AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: amylaar at gcc dot gnu dot org CC: gcc-bugs at gcc dot gnu dot org OtherBugsDependingO 17652 nThis: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20291
