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Re: What to do with new-ra for GCC 4.0

Steven Bosscher wrote: 

2) The version on mainline finds itself overruled by reload too
   often.  The fix on the new-regalloc branch is pre-reload, which
   is an excelent idea IMHO, except that pre-reload.c is just a
   stripped version of reload{,1}.c, which is exactly what new-ra
   was supposed to get rid of.  Too fight evil, you have to become
   evil...

I can't say I've really looked at new-ra, but I'm wondering whether this is a sane idea. Reload's purpose is to ensure that every instruction matches its constraints, and its core algorithm is comprehensible enough that you can know that it terminates and guarantees correct register assignments. If it is moved before register allocation, what happens to these guarantees? Or do you follow register allocation with another pass of reload proper?


Bernd

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