Optimize Smi keys for KeyedLoads

src/ia32/lithium-codegen-ia32.cc

Index: src/ia32/lithium-codegen-ia32.cc
diff --git a/src/ia32/lithium-codegen-ia32.cc b/src/ia32/lithium-codegen-ia32.cc
index edc4bc2bf011357b3c987f4533192c4f71477e77..f3bcf1abc3fc1974af2b7bd55a8aeec35aec8269 100644
--- a/src/ia32/lithium-codegen-ia32.cc
+++ b/src/ia32/lithium-codegen-ia32.cc
@@ -2650,6 +2650,7 @@ void LCodeGen::DoLoadKeyedFastElement(LLoadKeyedFastElement* instr) {
   __ mov(result,
          BuildFastArrayOperand(instr->elements(),
                                instr->key(),
+                               instr->hydrogen()->key()->representation(),
                                FAST_ELEMENTS,
                                FixedArray::kHeaderSize - kHeapObjectTag,
                                instr->additional_index()));
@@ -2676,6 +2677,7 @@ void LCodeGen::DoLoadKeyedFastDoubleElement(
         sizeof(kHoleNanLower32);
     Operand hole_check_operand = BuildFastArrayOperand(
         instr->elements(), instr->key(),
+        instr->hydrogen()->key()->representation(),
         FAST_DOUBLE_ELEMENTS,
         offset,
         instr->additional_index());
@@ -2686,6 +2688,7 @@ void LCodeGen::DoLoadKeyedFastDoubleElement(
   Operand double_load_operand = BuildFastArrayOperand(
       instr->elements(),
       instr->key(),
+      instr->hydrogen()->key()->representation(),
       FAST_DOUBLE_ELEMENTS,
       FixedDoubleArray::kHeaderSize - kHeapObjectTag,
       instr->additional_index());
@@ -2696,11 +2699,15 @@ void LCodeGen::DoLoadKeyedFastDoubleElement(
 Operand LCodeGen::BuildFastArrayOperand(
     LOperand* elements_pointer,
     LOperand* key,
+    Representation key_representation,
     ElementsKind elements_kind,
     uint32_t offset,
     uint32_t additional_index) {
   Register elements_pointer_reg = ToRegister(elements_pointer);
   int shift_size = ElementsKindToShiftSize(elements_kind);
+  if (key_representation.IsTagged() && (shift_size >= 1)) {
+    shift_size -= kSmiTagSize;
+  }
   if (key->IsConstantOperand()) {
     int constant_value = ToInteger32(LConstantOperand::cast(key));
     if (constant_value & 0xF0000000) {
@@ -2722,11 +2729,19 @@ Operand LCodeGen::BuildFastArrayOperand(
 void LCodeGen::DoLoadKeyedSpecializedArrayElement(
     LLoadKeyedSpecializedArrayElement* instr) {
   ElementsKind elements_kind = instr->elements_kind();
-  Operand operand(BuildFastArrayOperand(instr->external_pointer(),
-                                        instr->key(),
-                                        elements_kind,
-                                        0,
-                                        instr->additional_index()));
+  LOperand* key = instr->key();
+  if (!key->IsConstantOperand() &&
+      ExternalArrayOpRequiresTemp(instr->hydrogen()->key()->representation(),
+                                  elements_kind)) {
+    __ SmiUntag(ToRegister(key));
+  }
+  Operand operand(BuildFastArrayOperand(
+      instr->external_pointer(),
+      key,
+      instr->hydrogen()->key()->representation(),
+      elements_kind,
+      0,
+      instr->additional_index()));
   if (elements_kind == EXTERNAL_FLOAT_ELEMENTS) {
     XMMRegister result(ToDoubleRegister(instr->result()));
     __ movss(result, operand);
@@ -3679,11 +3694,19 @@ void LCodeGen::DoBoundsCheck(LBoundsCheck* instr) {
 void LCodeGen::DoStoreKeyedSpecializedArrayElement(
     LStoreKeyedSpecializedArrayElement* instr) {
   ElementsKind elements_kind = instr->elements_kind();
-  Operand operand(BuildFastArrayOperand(instr->external_pointer(),
-                                        instr->key(),
-                                        elements_kind,
-                                        0,
-                                        instr->additional_index()));
+  LOperand* key = instr->key();
+  if (!key->IsConstantOperand() &&
+      ExternalArrayOpRequiresTemp(instr->hydrogen()->key()->representation(),
+                                  elements_kind)) {
+    __ SmiUntag(ToRegister(key));
+  }
+  Operand operand(BuildFastArrayOperand(
+      instr->external_pointer(),
+      key,
+      instr->hydrogen()->key()->representation(),
+      elements_kind,
+      0,
+      instr->additional_index()));
   if (elements_kind == EXTERNAL_FLOAT_ELEMENTS) {
     __ cvtsd2ss(xmm0, ToDoubleRegister(instr->value()));
     __ movss(operand, xmm0);
@@ -3730,6 +3753,7 @@ void LCodeGen::DoStoreKeyedFastElement(LStoreKeyedFastElement* instr) {
   Operand operand = BuildFastArrayOperand(
       instr->object(),
       instr->key(),
+      instr->hydrogen()->key()->representation(),
       FAST_ELEMENTS,
       FixedArray::kHeaderSize - kHeapObjectTag,
       instr->additional_index());
@@ -3771,6 +3795,7 @@ void LCodeGen::DoStoreKeyedFastDoubleElement(
   Operand double_store_operand = BuildFastArrayOperand(
       instr->elements(),
       instr->key(),
+      instr->hydrogen()->key()->representation(),
       FAST_DOUBLE_ELEMENTS,
       FixedDoubleArray::kHeaderSize - kHeapObjectTag,
       instr->additional_index());