Implement the PPC inline asm "L" modifier. This allows us to compile:

long long test(long long X) {
  __asm__("foo %0 %L0 %1 %L1" : "=r"(X): "r"(X));
  return X;
}

to:
        foo r2 r3 r2 r3

llvm-svn: 26333