[MLIR] Fix areIdsUnique in AffineStructures

This patch fixes a bug in areIdsUnique where it ignores the [start, end] range.

No test case is added since there are no use cases through IR from where it
can be tested, and it is hard to create a unittest since we do not currently
have Values in unittests.

Reviewed By: arjunp

Differential Revision: https://reviews.llvm.org/D124735

Author: Groverkss

mlir/lib/Dialect/Affine/Analysis/AffineStructures.cpp

@@ -349,7 +349,8 @@ static bool LLVM_ATTRIBUTE_UNUSED areIdsUnique(
     return true;
 
   SmallPtrSet<Value, 8> uniqueIds;
-  ArrayRef<Optional<Value>> maybeValues = cst.getMaybeValues();
+  ArrayRef<Optional<Value>> maybeValues =
+      cst.getMaybeValues().slice(start, end - start);
   for (Optional<Value> val : maybeValues) {
     if (val.hasValue() && !uniqueIds.insert(val.getValue()).second)
       return false;