message: [MLIR] Fix uninitialized value found with msan
  The omission of an early exit created opportunities for unitialized memory
  reads. This CL fixes the issue.
diff: @@ -449,7 +449,9 @@ inline bool AffineValueMap::isMultipleOf(unsigned idx, int64_t factor) const {
  /// with the AffineDimExpr in the underlying AffineMap.
  bool AffineValueMap::isFunctionOf(unsigned idx, Value *value) const {
  unsigned index;
  - findIndex(value, operands, /*indexStart=*/0, &index);
  + if (!findIndex(value, operands, /*indexStart=*/0, &index)) {
  + return false;
  + }
  auto expr = const_cast<AffineValueMap *>(this)->getAffineMap().getResult(idx);
  // TODO(ntv): this is better implemented on a flattened representation.
  // At least for now it is conservative.
  