Speculating things is generally good. SI+ has instructions for these
for 32-bit values. This is still probably better even with the expansion
for 64-bit values, although it is odd that this callback doesn't have
the size as a parameter.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225822 91177308-0d34-0410-b5e6-96231b3b80d8
