diff --git a/mlir/include/mlir/IR/OpImplementation.h b/mlir/include/mlir/IR/OpImplementation.h
--- a/mlir/include/mlir/IR/OpImplementation.h
+++ b/mlir/include/mlir/IR/OpImplementation.h
@@ -1035,7 +1035,7 @@
   /// Parse an affine expr instance into 'expr' using the already computed
   /// mapping from symbols to affine expressions in 'symbolSet'.
   virtual ParseResult
-  parseAffineExpr(SmallVectorImpl<std::pair<StringRef, AffineExpr>> &symbolSet,
+  parseAffineExpr(ArrayRef<std::pair<StringRef, AffineExpr>> symbolSet,
                   AffineExpr &expr) = 0;
 
   /// Parse an integer set instance into 'set'.
diff --git a/mlir/lib/AsmParser/AffineParser.cpp b/mlir/lib/AsmParser/AffineParser.cpp
--- a/mlir/lib/AsmParser/AffineParser.cpp
+++ b/mlir/lib/AsmParser/AffineParser.cpp
@@ -53,9 +53,9 @@
   ParseResult parseAffineMapRange(unsigned numDims, unsigned numSymbols,
                                   AffineMap &result);
   ParseResult parseAffineMapOrIntegerSetInline(AffineMap &map, IntegerSet &set);
-  ParseResult parseAffineExprInline(
-      SmallVectorImpl<std::pair<StringRef, AffineExpr>> &symbolSet,
-      AffineExpr &expr);
+  ParseResult
+  parseAffineExprInline(ArrayRef<std::pair<StringRef, AffineExpr>> symbolSet,
+                        AffineExpr &expr);
   ParseResult parseIntegerSetConstraints(unsigned numDims, unsigned numSymbols,
                                          IntegerSet &result);
   ParseResult parseAffineMapOfSSAIds(AffineMap &map,
@@ -538,9 +538,8 @@
 
 /// Parse an affine expresion definition inline, with given symbols.
 ParseResult AffineParser::parseAffineExprInline(
-    SmallVectorImpl<std::pair<StringRef, AffineExpr>> &symbolSet,
-    AffineExpr &expr) {
-  dimsAndSymbols.assign(symbolSet);
+    ArrayRef<std::pair<StringRef, AffineExpr>> symbolSet, AffineExpr &expr) {
+  dimsAndSymbols.assign(symbolSet.begin(), symbolSet.end());
   expr = parseAffineExpr();
   return success(expr != nullptr);
 }
@@ -716,8 +715,7 @@
   return success();
 }
 ParseResult Parser::parseAffineExprReference(
-    SmallVectorImpl<std::pair<StringRef, AffineExpr>> &symbolSet,
-    AffineExpr &expr) {
+    ArrayRef<std::pair<StringRef, AffineExpr>> symbolSet, AffineExpr &expr) {
   return AffineParser(state).parseAffineExprInline(symbolSet, expr);
 }
 ParseResult Parser::parseIntegerSetReference(IntegerSet &set) {
diff --git a/mlir/lib/AsmParser/AsmParserImpl.h b/mlir/lib/AsmParser/AsmParserImpl.h
--- a/mlir/lib/AsmParser/AsmParserImpl.h
+++ b/mlir/lib/AsmParser/AsmParserImpl.h
@@ -459,7 +459,7 @@
   /// Parse an affine expr instance into 'expr' using the already computed
   /// mapping from symbols to affine expressions in 'symbolSet'.
   ParseResult
-  parseAffineExpr(SmallVectorImpl<std::pair<StringRef, AffineExpr>> &symbolSet,
+  parseAffineExpr(ArrayRef<std::pair<StringRef, AffineExpr>> symbolSet,
                   AffineExpr &expr) override {
     return parser.parseAffineExprReference(symbolSet, expr);
   }
diff --git a/mlir/lib/AsmParser/Parser.h b/mlir/lib/AsmParser/Parser.h
--- a/mlir/lib/AsmParser/Parser.h
+++ b/mlir/lib/AsmParser/Parser.h
@@ -300,9 +300,9 @@
   ParseResult parseAffineMapOrIntegerSetReference(AffineMap &map,
                                                   IntegerSet &set);
   ParseResult parseAffineMapReference(AffineMap &map);
-  ParseResult parseAffineExprReference(
-      SmallVectorImpl<std::pair<StringRef, AffineExpr>> &symbolSet,
-      AffineExpr &expr);
+  ParseResult
+  parseAffineExprReference(ArrayRef<std::pair<StringRef, AffineExpr>> symbolSet,
+                           AffineExpr &expr);
   ParseResult parseIntegerSetReference(IntegerSet &set);
 
   /// Parse an AffineMap where the dim and symbol identifiers are SSA ids.