Index: lib/Transforms/Utils/FunctionComparator.cpp
===================================================================
--- lib/Transforms/Utils/FunctionComparator.cpp
+++ lib/Transforms/Utils/FunctionComparator.cpp
@@ -758,13 +758,35 @@
     if (needToCmpOperands) {
       assert(InstL->getNumOperands() == InstR->getNumOperands());
 
-      for (unsigned i = 0, e = InstL->getNumOperands(); i != e; ++i) {
-        Value *OpL = InstL->getOperand(i);
-        Value *OpR = InstR->getOperand(i);
-        if (int Res = cmpValues(OpL, OpR))
-          return Res;
-        // cmpValues should ensure this is true.
-        assert(cmpTypes(OpL->getType(), OpR->getType()) == 0);
+      const BinaryOperator *BOL = dyn_cast<BinaryOperator>(InstL);
+      const BinaryOperator *BOR = dyn_cast<BinaryOperator>(InstR);
+      if (BOL && BOR && BOL->isCommutative()) {
+        assert(BOR->isCommutative());
+
+        Value *Op0L = BOL->getOperand(0);
+        Value *Op0R = BOR->getOperand(0);
+        Value *Op1L = BOL->getOperand(1);
+        Value *Op1R = BOR->getOperand(1);
+        int Res00 = cmpValues(Op0L, Op0R);
+        int Res01 = cmpValues(Op0L, Op1R);
+        int Res10 = cmpValues(Op1L, Op0R);
+        int Res11 = cmpValues(Op1L, Op1R);
+        int FinalRes;
+        //get the final result to return
+        if (Res00==0 && Res11==0) FinalRes = 0; //validate operands in the original order
+        else if (Res01==0 && Res10==0) FinalRes = 0; //validate reodered operands
+        else if (Res00) FinalRes = Res00; //assume original order
+        else FinalRes = Res11;
+        if (FinalRes) return FinalRes;
+      } else {
+        for (unsigned i = 0, e = InstL->getNumOperands(); i != e; ++i) {
+          Value *OpL = InstL->getOperand(i);
+          Value *OpR = InstR->getOperand(i);
+          if (int Res = cmpValues(OpL, OpR))
+            return Res;
+          // cmpValues should ensure this is true.
+          assert(cmpTypes(OpL->getType(), OpR->getType()) == 0);
+        }
       }
     }
 
Index: unittests/Transforms/Utils/FunctionComparatorTest.cpp
===================================================================
--- unittests/Transforms/Utils/FunctionComparatorTest.cpp
+++ unittests/Transforms/Utils/FunctionComparatorTest.cpp
@@ -11,10 +11,21 @@
 #include "llvm/IR/Instructions.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Module.h"
+#include "llvm/AsmParser/Parser.h"
+#include "llvm/Support/SourceMgr.h"
 #include "gtest/gtest.h"
 
 using namespace llvm;
 
+
+static std::unique_ptr<Module> parseIR(LLVMContext &C, const char *IR) {
+  SMDiagnostic Err;
+  std::unique_ptr<Module> Mod = parseAssemblyString(IR, Err, C);
+  if (!Mod)
+    Err.print("FunctionComparatorTest", errs());
+  return Mod;
+}
+
 /// Generates a simple test function.
 struct TestFunction {
   Function *F;
@@ -127,3 +138,35 @@
   EXPECT_EQ(Cmp.testCmpTypes(F1.T, F2.T), 0);
   EXPECT_EQ(Cmp.testCmpPrimitives(), -4);
 }
+
+
+TEST(FunctionComparatorTest, TestOperandReordering) {
+  LLVMContext C;
+
+  std::unique_ptr<Module> M = parseIR(
+    C,
+    R"(
+define dso_local i32 @foo(i32 %a, i32 %b, i32 %c) local_unnamed_addr {
+entry:
+  %mul1 = mul nsw i32 %b, %c
+  %mul = mul nsw i32 3, %a
+  %add = add nsw i32 %mul1, %mul
+  ret i32 %add
+}
+
+define dso_local i32 @bar(i32 %a, i32 %b, i32 %c) local_unnamed_addr {
+entry:
+  %mul = mul nsw i32 %c, %b
+  %mul1 = mul nsw i32 %a, 3
+  %add = add nsw i32 %mul1, %mul
+  ret i32 %add
+}
+  )");
+
+  auto *F1 = M->getFunction("foo");
+  auto *F2 = M->getFunction("bar");
+  GlobalNumberState GlobalNumbers;
+  FunctionComparator FCmp(F1,F2,&GlobalNumbers);
+  bool AreEqual = FCmp.compare()==0;
+  EXPECT_TRUE(AreEqual);
+}