Il 15/10/2012 10:13, Steven Bosscher ha scritto: > > I disagree that it is valid. At least it is risky to consider it valid, > > because a pass that simulates liveness might end up doing something > > wrong because of that note. If simulation is done backwards, it doesn't > > even require any interaction with REG_DEAD notes. > > In any case, if web doesn't properly rename the register in the > REG_EQUAL note (which it doesn't do without my patch) and we declare > such a note invalid, then we should remove the note. You're right that > GCC ends up doing something wrong, that's why Honza's test case fails. > > I think we should come to a conclusion of this discussion: Either we > drop the notes (e.g. by re-computing the DF_NOTE problem after web) or > we update them, like my patch does. I prefer the patch I proposed > because it re-instates the behavior GCC had before.
I prefer to declare the notes invalid and drop the notes. Paolo