[EMAIL PROTECTED] wrote:
Jeff,
thanks again for suggestions.
As I understand it (perhaps wrongly), actual splitting only occurs after
combine pass (by split1 pass).
Combine has some limited splitting capabilities. For example it can
try to combine 3 insns, which might not match a pattern, but can match
a splitter which generates 2 insns. I don't recall the other cases
where combine splits, nor do I offhand recall if the split insns are
ever simplified. Search for "split" in combine.c
If your description is correct, you may have answered the question -
combine is before split1 so there are no further optimisation perfromed
on any split - since simplfy-rtx is never called.
I could use expand - but I know that will cause a world of hurt by
missing optimisations at the "word" level. So new psuedos seems my only
way forward (at the target level)
Which optimiser/pass would benefit from handling subregs better?
Well, if you get it into simplify-rtx, then it can be used by multiple
passes. Look for something like simplify_binary. A well placed
conditional breakpoint can be invaluable.
jeff
