Jakob Stoklund Olesen f73b30b329 Simplify RegScavenger::forward a bit more.
Verify that early clobber registers and their aliases are not used.

All changes to RegsAvailable are now done as a transaction so the order of
operands makes no difference.

The included test case is from PR4686. It has behaviour that was dependent on the order of operands.

llvm-svn: 78465
2009-08-08 13:18:47 +00:00
..
2009-08-08 00:21:49 +00:00