[IRCE][NFC] Add assert that AddRecExpr's step is not zero

We should never return zero steps, ensure this fact by adding
a sanity check when we are analyzing the induction variable.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@309661 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed