[turbofan] IA: support better left operand for commutative binops

src/compiler/x64/instruction-selector-x64-unittest.cc

Index: src/compiler/x64/instruction-selector-x64-unittest.cc
diff --git a/src/compiler/x64/instruction-selector-x64-unittest.cc b/src/compiler/x64/instruction-selector-x64-unittest.cc
index 22f0bce6a089033f0a1c3ec8c6cdddb1887aec15..814c2592da9d0dcf522488dabea8c3f5956ad19b 100644
--- a/src/compiler/x64/instruction-selector-x64-unittest.cc
+++ b/src/compiler/x64/instruction-selector-x64-unittest.cc
@@ -40,6 +40,39 @@ TEST_F(InstructionSelectorTest, TruncateInt64ToInt32WithParameter) {
 
 
 // -----------------------------------------------------------------------------
+// Better left operand for commutative binops
+
+TEST_F(InstructionSelectorTest, BetterLeftOperandTestAddBinop) {
+  StreamBuilder m(this, kMachInt32, kMachInt32, kMachInt32);
+  Node* param1 = m.Parameter(0);
+  Node* param2 = m.Parameter(1);
+  Node* add = m.Int32Add(param1, param2);
+  m.Return(m.Int32Add(add, param1));
+  Stream s = m.Build();
+  ASSERT_EQ(2U, s.size());
+  EXPECT_EQ(kX64Add32, s[0]->arch_opcode());
+  ASSERT_EQ(2U, s[0]->InputCount());
+  ASSERT_TRUE(s[0]->InputAt(0)->IsUnallocated());
+  EXPECT_EQ(param2->id(), s.ToVreg(s[0]->InputAt(0)));
+}
+
+
+TEST_F(InstructionSelectorTest, BetterLeftOperandTestMulBinop) {
+  StreamBuilder m(this, kMachInt32, kMachInt32, kMachInt32);
+  Node* param1 = m.Parameter(0);
+  Node* param2 = m.Parameter(1);
+  Node* mul = m.Int32Mul(param1, param2);
+  m.Return(m.Int32Mul(mul, param1));
+  Stream s = m.Build();
+  ASSERT_EQ(2U, s.size());
+  EXPECT_EQ(kX64Imul32, s[0]->arch_opcode());
+  ASSERT_EQ(2U, s[0]->InputCount());
+  ASSERT_TRUE(s[0]->InputAt(0)->IsUnallocated());
+  EXPECT_EQ(param2->id(), s.ToVreg(s[0]->InputAt(0)));
+}
+
+
+// -----------------------------------------------------------------------------
 // Loads and stores
 
 namespace {