Change errs() to dbgs().

llvm-svn: 92099

This fixes an in-place update bug where code inserted at the end of basic blocks may not be covered by existing intervals which were live across the entire block. It is also consistent with the way ranges are specified for live intervals.

llvm-svn: 91859

Moved spill weight calculation out of SimpleRegisterCoalescing and into its own pass: CalculateSpillWeights.

llvm-svn: 91273