When visiting non-control-flow arguments of a LoopLikeOpInterface op,
IntegerRangeAnalysis assumed that getLoopLowerBounds(),
getLoopUpperBounds(), and getLoopSteps() always return non-null values
when getLoopInductionVars() is non-null. This assumption is incorrect:
for example, AffineForOp returns nullopt from getLoopUpperBounds() when
the upper bound is not a constant affine expression (e.g., a dynamic
index from a tensor.dim).
Fix this by checking whether the bound optionals are engaged before
dereferencing them and falling back to the generic analysis if any bound
is unavailable.
Fixes#180312
14f73345ff