diff --git a/mlir/lib/Dialect/StandardOps/IR/Ops.cpp b/mlir/lib/Dialect/StandardOps/IR/Ops.cpp
--- a/mlir/lib/Dialect/StandardOps/IR/Ops.cpp
+++ b/mlir/lib/Dialect/StandardOps/IR/Ops.cpp
@@ -1560,9 +1560,12 @@
   /// or(x, 0) -> x
   if (matchPattern(rhs(), m_Zero()))
     return lhs();
-  /// or(x,x) -> x
+  /// or(x, x) -> x
   if (lhs() == rhs())
     return rhs();
+  /// or(x, 1) -> 1
+  if (matchPattern(rhs(), m_One()))
+    return rhs();
 
   return constFoldBinaryOp<IntegerAttr>(operands,
                                         [](APInt a, APInt b) { return a | b; });
diff --git a/mlir/test/Transforms/canonicalize.mlir b/mlir/test/Transforms/canonicalize.mlir
--- a/mlir/test/Transforms/canonicalize.mlir
+++ b/mlir/test/Transforms/canonicalize.mlir
@@ -287,6 +287,15 @@
   return %1 : tensor<4x5xi32>
 }
 
+// CHECK-LABEL: func @or_one
+func @or_one(%arg0: i32) -> i32 {
+  // CHECK-NEXT: %c1_i32 = constant 1 : i32
+  %c1_i32 = constant 1 : i32
+  // CHECK-NEXT: return %c1_i32
+  %1 = or %arg0, %c1_i32 : i32
+  return %1 : i32
+}
+
 //CHECK-LABEL: func @xor_self
 func @xor_self(%arg0: i32) -> i32 {
   //CHECK-NEXT: %c0_i32 = constant 0