[MLIR][Affine] Add affine value map difference operator (#127163)

Add affine value map difference operator. NFC otherwise.

Author: bondhugula

mlir/include/mlir/Dialect/Affine/IR/AffineValueMap.h

@@ -84,6 +84,13 @@ class AffineValueMap {
   /// and/or operands have been modified.
   LogicalResult canonicalize();
 
+  /// Checks if the application of this map to its operands is semantically
+  /// equal to `other`'s.
+  bool operator==(const AffineValueMap &other) const;
+  bool operator!=(const AffineValueMap &other) const {
+    return !(*this == other);
+  }
+
 private:
   // A mutable affine map.
   MutableAffineMap map;

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

@@ -2001,9 +2001,7 @@ bool MemRefAccess::operator==(const MemRefAccess &rhs) const {
   AffineValueMap diff, thisMap, rhsMap;
   getAccessMap(&thisMap);
   rhs.getAccessMap(&rhsMap);
-  AffineValueMap::difference(thisMap, rhsMap, &diff);
-  return llvm::all_of(diff.getAffineMap().getResults(),
-                      [](AffineExpr e) { return e == 0; });
+  return thisMap == rhsMap;
 }
 
 void mlir::affine::getAffineIVs(Operation &op, SmallVectorImpl<Value> &ivs) {

mlir/lib/Dialect/Affine/IR/AffineValueMap.cpp

@@ -109,4 +109,12 @@ ArrayRef<Value> AffineValueMap::getOperands() const {
 
 AffineMap AffineValueMap::getAffineMap() const { return map.getAffineMap(); }
 
+bool AffineValueMap::operator==(const AffineValueMap &other) const {
+  AffineValueMap diff;
+  AffineValueMap::difference(*this, other, &diff);
+  return llvm::all_of(diff.getAffineMap().getResults(), [](AffineExpr e) {
+    return e == getAffineConstantExpr(0, e.getContext());
+  });
+}
+
 AffineValueMap::~AffineValueMap() = default;