Reload bug & SRA oddness

Alexandre Oliva aoliva@redhat.com
Sun May 6 05:13:00 GMT 2007


On May  5, 2007, Roman Zippel <zippel@linux-m68k.org> wrote:

> This now doesn't even survive stage2.

This one should fare better.  It's completed bootstrap and regression
testing on x86_64-linux-gnu (--enable-languages=all,ada, as usual)

Ok to install?

:ADDPATCH sra:

> In the initial RTL output I also see some rather complex reg:DI 
> operations instead of simple 32bit operations.

I don't see any simple way to avoid this without taking some
machine-specific "preferred access mode" into account.

It might make sense to test whether, instead of a DImode variable, a
pair of SImode variables would do (i.e., no bit-fields crossing the
SImode boundary), as long as registers are known to hold SImode but
not DImode.  But is there a generic way to test for such "efficiency
boundaries"?  And, if not, does it make sense to introduce yet another
machine hook to this end?


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-- 
Alexandre Oliva         http://www.lsd.ic.unicamp.br/~oliva/
FSF Latin America Board Member         http://www.fsfla.org/
Red Hat Compiler Engineer   aoliva@{redhat.com, gcc.gnu.org}
Free Software Evangelist  oliva@{lsd.ic.unicamp.br, gnu.org}


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