diff --git a/mlir/lib/Dialect/Linalg/Transforms/DropUnitDims.cpp b/mlir/lib/Dialect/Linalg/Transforms/DropUnitDims.cpp
--- a/mlir/lib/Dialect/Linalg/Transforms/DropUnitDims.cpp
+++ b/mlir/lib/Dialect/Linalg/Transforms/DropUnitDims.cpp
@@ -242,7 +242,7 @@
 /// - modified index map that can be used to access the replaced result/operand
 /// - the reassociation that converts from the original tensor type to the
 ///   modified tensor type.
-static llvm::Optional<UnitExtentReplacementInfo>
+static std::optional<UnitExtentReplacementInfo>
 replaceUnitExtents(GenericOp genericOp, OpOperand *opOperand,
                    MLIRContext *context) {
   AffineMap indexingMap = genericOp.getMatchingIndexingMap(opOperand);
diff --git a/mlir/lib/Dialect/Linalg/Transforms/Hoisting.cpp b/mlir/lib/Dialect/Linalg/Transforms/Hoisting.cpp
--- a/mlir/lib/Dialect/Linalg/Transforms/Hoisting.cpp
+++ b/mlir/lib/Dialect/Linalg/Transforms/Hoisting.cpp
@@ -57,14 +57,14 @@
 
 /// Return true if op1 and op2 are the same constant or the same SSA value.
 static bool isEqualOffsetSizeOrStride(OpFoldResult op1, OpFoldResult op2) {
-  auto getConstantIntValue = [](OpFoldResult ofr) -> llvm::Optional<int64_t> {
+  auto getConstantIntValue = [](OpFoldResult ofr) -> std::optional<int64_t> {
     Attribute attr = ofr.dyn_cast<Attribute>();
     // Note: isa+cast-like pattern allows writing the condition below as 1 line.
     if (!attr && ofr.get<Value>().getDefiningOp<arith::ConstantOp>())
       attr = ofr.get<Value>().getDefiningOp<arith::ConstantOp>().getValue();
     if (auto intAttr = attr.dyn_cast_or_null<IntegerAttr>())
       return intAttr.getValue().getSExtValue();
-    return llvm::None;
+    return std::nullopt;
   };
   auto cst1 = getConstantIntValue(op1), cst2 = getConstantIntValue(op2);
   if (cst1 && cst2 && *cst1 == *cst2)