[ConstantRange] Rewrite shl to avoid repeated calls to getUnsignedMax and avoid creating the min APInt until we're sure we need it. Use inplace shift operations.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@302510 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed