Use immediates when possible for HBoundsCheck and HLoadKeyedFastElement

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 ce6a9105f23abac7e1edf923ed559227e7692041..3d85022e135fd97c11ad72faef45813e696dc3ea 100644
--- a/src/x64/lithium-codegen-x64.cc
+++ b/src/x64/lithium-codegen-x64.cc
@@ -2305,16 +2305,13 @@ void LCodeGen::DoAccessArgumentsAt(LAccessArgumentsAt* instr) {
 
 
 void LCodeGen::DoLoadKeyedFastElement(LLoadKeyedFastElement* instr) {
-  Register elements = ToRegister(instr->elements());
-  Register key = ToRegister(instr->key());
   Register result = ToRegister(instr->result());
-  ASSERT(result.is(elements));
 
   // Load the result.
-  __ movq(result, FieldOperand(elements,
-                               key,
-                               times_pointer_size,
-                               FixedArray::kHeaderSize));
+  __ movq(result,
+          BuildFastArrayOperand(instr->elements(), instr->key(),
+                                JSObject::FAST_ELEMENTS,
+                                FixedArray::kHeaderSize - kHeapObjectTag));
 
   // Check for the hole value.
   if (instr->hydrogen()->RequiresHoleCheck()) {
@@ -2348,22 +2345,22 @@ void LCodeGen::DoLoadKeyedFastDoubleElement(
 
 
 Operand LCodeGen::BuildFastArrayOperand(
-    LOperand* external_pointer,
+    LOperand* elements_pointer,
     LOperand* key,
     JSObject::ElementsKind elements_kind,
     uint32_t offset) {
-  Register external_pointer_reg = ToRegister(external_pointer);
+  Register elements_pointer_reg = ToRegister(elements_pointer);
   int shift_size = ElementsKindToShiftSize(elements_kind);
   if (key->IsConstantOperand()) {
     int constant_value = ToInteger32(LConstantOperand::cast(key));
     if (constant_value & 0xF0000000) {
       Abort("array index constant value too big");
     }
-    return Operand(external_pointer_reg,
+    return Operand(elements_pointer_reg,
                    constant_value * (1 << shift_size) + offset);
   } else {
     ScaleFactor scale_factor = static_cast<ScaleFactor>(shift_size);
-    return Operand(external_pointer_reg, ToRegister(key),
+    return Operand(elements_pointer_reg, ToRegister(key),
                    scale_factor, offset);
   }
 }
@@ -3137,12 +3134,22 @@ void LCodeGen::DoStoreKeyedSpecializedArrayElement(
 
 
 void LCodeGen::DoBoundsCheck(LBoundsCheck* instr) {
-  if (instr->length()->IsRegister()) {
-    __ cmpq(ToRegister(instr->index()), ToRegister(instr->length()));
+  if (instr->index()->IsConstantOperand()) {
+    if (instr->length()->IsRegister()) {
+      __ cmpq(ToRegister(instr->length()),
+              Immediate(ToInteger32(LConstantOperand::cast(instr->index()))));
+    } else {
+      __ cmpq(ToOperand(instr->length()),
+              Immediate(ToInteger32(LConstantOperand::cast(instr->index()))));
+    }
   } else {
-    __ cmpq(ToRegister(instr->index()), ToOperand(instr->length()));
+    if (instr->length()->IsRegister()) {
+      __ cmpq(ToRegister(instr->length()), ToRegister(instr->index()));
+    } else {
+      __ cmpq(ToOperand(instr->length()), ToRegister(instr->index()));
+    }
   }
-  DeoptimizeIf(above_equal, instr->environment());
+  DeoptimizeIf(below_equal, instr->environment());
 }