Codegen

bool %test(int %X) {
  %Y = seteq int %X, 13
  ret bool %Y
}

as

_test:
        addi r2, r3, -13
        cntlzw r2, r2
        srwi r3, r2, 5
        blr

rather than

_test:
        cmpwi cr7, r3, 13
        mfcr r2
        rlwinm r3, r2, 31, 31, 31
        blr

This has very little effect on most code, but speeds up analyzer 23% and
mason 11%

llvm-svn: 25848