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Continuity problemsContinuity problemsPosted Mar 25, 2012 8:49 UTC (Sun) by james_ulrich (guest, #83666)In reply to: Continuity problems by nix Parent article: GCC celebrates 25 years with the 4.7.0 release
Reload has all these "assumptions" because it is such a hughe big convoluted mess. Also, it is a corner stone in the whole compilation process, so you can't just throw it out. And hence, instead of fixing reload when some bug pops out, all the passes around it are fixed just so that reload doesn't need to be touched.
While I had my share of struggling with reload, by far most of the annoying problems with RTL passes was that lot's of them completely ignore some MD feature or other -- it can not even be said that this is old cruft hanging around: even the web construction pass has issues, which is supposed to serve as an example! This is a review problem.
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Continuity problems Posted Mar 26, 2012 19:32 UTC (Mon) by nix (subscriber, #2304) [Link]
Yeah, but part of the problem with reload being a convoluted mess is that for many years earlier in GCC's history, when some target needed something done, half the time it was done in the md file and half the time it was done by hacking reload so that it did *just* the right thing for some shape of RTL that only that target would produce. And, of course, this was often not documented. Hello unstated assumptions and fragility.
(This is not to say that you are wrong in any way. There are other problems too, not least the 'it works on major targets' RTL, it must be complete' problem you mention...)
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