diff --git a/mlir/include/mlir/Dialect/Arithmetic/IR/ArithmeticOps.td b/mlir/include/mlir/Dialect/Arithmetic/IR/ArithmeticOps.td
--- a/mlir/include/mlir/Dialect/Arithmetic/IR/ArithmeticOps.td
+++ b/mlir/include/mlir/Dialect/Arithmetic/IR/ArithmeticOps.td
@@ -1104,6 +1104,7 @@
   }];
 
   let hasFolder = 1;
+  let hasCanonicalizer = 1;
 }
 
 //===----------------------------------------------------------------------===//
diff --git a/mlir/lib/Dialect/Arithmetic/IR/ArithmeticCanonicalization.td b/mlir/lib/Dialect/Arithmetic/IR/ArithmeticCanonicalization.td
--- a/mlir/lib/Dialect/Arithmetic/IR/ArithmeticCanonicalization.td
+++ b/mlir/lib/Dialect/Arithmetic/IR/ArithmeticCanonicalization.td
@@ -106,6 +106,28 @@
           (Arith_ConstantOp ConstantAttr<I1Attr, "1">)),
         (Arith_CmpIOp (InvertPredicate $pred), $a, $b)>;
 
+//===----------------------------------------------------------------------===//
+// CmpIOp
+//===----------------------------------------------------------------------===//
+
+// cmpi(== or !=, a ext iNN, b ext iNN) == cmpi(== or !=, a, b)
+def CmpIExtSI :
+    Pat<(Arith_CmpIOp $pred,
+          (Arith_ExtSIOp $a),
+          (Arith_ExtSIOp $b)),
+        (Arith_CmpIOp $pred, $a, $b),
+        [(Constraint<CPred<"$0.getType() == $1.getType()">> $a, $b),
+         (Constraint<CPred<"$0.getValue() == arith::CmpIPredicate::eq || $0.getValue() == arith::CmpIPredicate::ne">> $pred)]>;
+
+// cmpi(== or !=, a ext iNN, b ext iNN) == cmpi(== or !=, a, b)
+def CmpIExtUI :
+    Pat<(Arith_CmpIOp $pred,
+          (Arith_ExtUIOp $a),
+          (Arith_ExtUIOp $b)),
+        (Arith_CmpIOp $pred, $a, $b),
+        [(Constraint<CPred<"$0.getType() == $1.getType()">> $a, $b),
+         (Constraint<CPred<"$0.getValue() == arith::CmpIPredicate::eq || $0.getValue() == arith::CmpIPredicate::ne">> $pred)]>;
+
 //===----------------------------------------------------------------------===//
 // IndexCastOp
 //===----------------------------------------------------------------------===//
diff --git a/mlir/lib/Dialect/Arithmetic/IR/ArithmeticOps.cpp b/mlir/lib/Dialect/Arithmetic/IR/ArithmeticOps.cpp
--- a/mlir/lib/Dialect/Arithmetic/IR/ArithmeticOps.cpp
+++ b/mlir/lib/Dialect/Arithmetic/IR/ArithmeticOps.cpp
@@ -1322,6 +1322,11 @@
   return BoolAttr::get(getContext(), val);
 }
 
+void arith::CmpIOp::getCanonicalizationPatterns(RewritePatternSet &patterns,
+                                                MLIRContext *context) {
+  patterns.insert<CmpIExtSI, CmpIExtUI>(context);
+}
+
 //===----------------------------------------------------------------------===//
 // CmpFOp
 //===----------------------------------------------------------------------===//
diff --git a/mlir/test/Dialect/Arithmetic/canonicalize.mlir b/mlir/test/Dialect/Arithmetic/canonicalize.mlir
--- a/mlir/test/Dialect/Arithmetic/canonicalize.mlir
+++ b/mlir/test/Dialect/Arithmetic/canonicalize.mlir
@@ -176,6 +176,48 @@
 
 // -----
 
+// CHECK-LABEL: @cmpIExtSINE
+//       CHECK:  %[[comb:.+]] = arith.cmpi ne, %arg0, %arg1 : i8
+//       CHECK:   return %[[comb]]
+func @cmpIExtSINE(%arg0: i8, %arg1: i8) -> i1 {
+  %ext0 = arith.extsi %arg0 : i8 to i64
+  %ext1 = arith.extsi %arg1 : i8 to i64
+  %res = arith.cmpi ne, %ext0, %ext1 : i64
+  return %res : i1
+}
+
+// CHECK-LABEL: @cmpIExtSIEQ
+//       CHECK:  %[[comb:.+]] = arith.cmpi eq, %arg0, %arg1 : i8
+//       CHECK:   return %[[comb]]
+func @cmpIExtSIEQ(%arg0: i8, %arg1: i8) -> i1 {
+  %ext0 = arith.extsi %arg0 : i8 to i64
+  %ext1 = arith.extsi %arg1 : i8 to i64
+  %res = arith.cmpi eq, %ext0, %ext1 : i64
+  return %res : i1
+}
+
+// CHECK-LABEL: @cmpIExtUINE
+//       CHECK:  %[[comb:.+]] = arith.cmpi ne, %arg0, %arg1 : i8
+//       CHECK:   return %[[comb]]
+func @cmpIExtUINE(%arg0: i8, %arg1: i8) -> i1 {
+  %ext0 = arith.extui %arg0 : i8 to i64
+  %ext1 = arith.extui %arg1 : i8 to i64
+  %res = arith.cmpi ne, %ext0, %ext1 : i64
+  return %res : i1
+}
+
+// CHECK-LABEL: @cmpIExtUIEQ
+//       CHECK:  %[[comb:.+]] = arith.cmpi eq, %arg0, %arg1 : i8
+//       CHECK:   return %[[comb]]
+func @cmpIExtUIEQ(%arg0: i8, %arg1: i8) -> i1 {
+  %ext0 = arith.extui %arg0 : i8 to i64
+  %ext1 = arith.extui %arg1 : i8 to i64
+  %res = arith.cmpi eq, %ext0, %ext1 : i64
+  return %res : i1
+}
+
+// -----
+
 // CHECK-LABEL: @andOfExtSI
 //       CHECK:  %[[comb:.+]] = arith.andi %arg0, %arg1 : i8
 //       CHECK:  %[[ext:.+]] = arith.extsi %[[comb]] : i8 to i64