On Sat, 25 Aug 2012, Uros Bizjak wrote: > Hello! > > v2 patch differences: > - moves hook description text to target.def > - fixes error path to clear clobbers, as expected by recog_for_combine callers > > 2012-08-25 Uros Bizjak <ubiz...@gmail.com> > > * target.def (reject_combined_insn): New target hook. > * doc/tm.texi.in (TARGET_REJECT_COMBINED_INSN): New hook. > * doc/tm.texi: Regenerated. > * combine.c (recog_for_combine): Call targetm.reject_combined_insn > to allow targets to reject combined insn.
Maybe mention that the default is to allow all combinations for which a pattern match? And that the reason to disallow them can be that they're known to result in suboptimal code? Or other reasons. I don't think it should be mentioned that it can be used to stop invalid code to be generated; that'd just be encouraging covering up bugs in reload. (Using it to simplify the port may be valid.) brgds, H-P
