Bias commutative single-use register inputs and support lea adds

src/x64/lithium-codegen-x64.cc

Index: src/x64/lithium-codegen-x64.cc
diff --git a/src/x64/lithium-codegen-x64.cc b/src/x64/lithium-codegen-x64.cc
index 3b873699135edefe1b2b36e417b29962e3b2c22b..c441cdbfbfd4da60e563fdbe1a5eec97636bd472 100644
--- a/src/x64/lithium-codegen-x64.cc
+++ b/src/x64/lithium-codegen-x64.cc
@@ -1674,19 +1674,27 @@ void LCodeGen::DoThrow(LThrow* instr) {
 void LCodeGen::DoAddI(LAddI* instr) {
   LOperand* left = instr->left();
   LOperand* right = instr->right();
-  ASSERT(left->Equals(instr->result()));
 
-  if (right->IsConstantOperand()) {
-    __ addl(ToRegister(left),
-            Immediate(ToInteger32(LConstantOperand::cast(right))));
-  } else if (right->IsRegister()) {
-    __ addl(ToRegister(left), ToRegister(right));
+  if (LAddI::UseLea(instr->hydrogen()) && !left->Equals(instr->result())) {
+    if (right->IsConstantOperand()) {
+      int32_t offset = ToInteger32(LConstantOperand::cast(right));
+      __ lea(ToRegister(instr->result()), MemOperand(ToRegister(left), offset));
+    } else {
+      Operand address(ToRegister(left), ToRegister(right), times_1, 0);
+      __ lea(ToRegister(instr->result()), address);
+    }
   } else {
-    __ addl(ToRegister(left), ToOperand(right));
-  }
-
-  if (instr->hydrogen()->CheckFlag(HValue::kCanOverflow)) {
-    DeoptimizeIf(overflow, instr->environment());
+    if (right->IsConstantOperand()) {
+      __ addl(ToRegister(left),
+              Immediate(ToInteger32(LConstantOperand::cast(right))));
+    } else if (right->IsRegister()) {
+      __ addl(ToRegister(left), ToRegister(right));
+    } else {
+      __ addl(ToRegister(left), ToOperand(right));
+    }
+    if (instr->hydrogen()->CheckFlag(HValue::kCanOverflow)) {
+      DeoptimizeIf(overflow, instr->environment());
+    }
   }
 }