Use RegisterClassInfo::getOrder in RAFast.

This saves two virtual function calls and an Allocatable BitVector test,
making RAFast run 2% faster.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132471 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed