Avoid Unnecessary Smi Checks

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 ec87a9c72ed88b442efa294297e25d551426a076..8df9d4629765a9e84fbec971b688ab8055a33761 100644
--- a/src/ia32/lithium-codegen-ia32.cc
+++ b/src/ia32/lithium-codegen-ia32.cc
@@ -1836,8 +1836,11 @@ void LCodeGen::DoValueOf(LValueOf* instr) {
   ASSERT(input.is(result));
 
   Label done;
-  // If the object is a smi return the object.
-  __ JumpIfSmi(input, &done, Label::kNear);
+
+  if (!instr->hydrogen()->value()->IsHeapObject()) {
+    // If the object is a smi return the object.
+    __ JumpIfSmi(input, &done, Label::kNear);
+  }
 
   // If the object is not a value type, return the object.
   __ CmpObjectType(input, JS_VALUE_TYPE, map);
@@ -2390,8 +2393,11 @@ void LCodeGen::DoIsObjectAndBranch(LIsObjectAndBranch* instr) {
 
 Condition LCodeGen::EmitIsString(Register input,
                                  Register temp1,
-                                 Label* is_not_string) {
-  __ JumpIfSmi(input, is_not_string);
+                                 Label* is_not_string,
+                                 SmiCheck check_needed = INLINE_SMI_CHECK) {
+  if (check_needed == INLINE_SMI_CHECK) {
+    __ JumpIfSmi(input, is_not_string);
+  }
 
   Condition cond = masm_->IsObjectStringType(input, temp1, temp1);
 
@@ -2407,7 +2413,11 @@ void LCodeGen::DoIsStringAndBranch(LIsStringAndBranch* instr) {
   int false_block = chunk_->LookupDestination(instr->false_block_id());
   Label* false_label = chunk_->GetAssemblyLabel(false_block);
 
-  Condition true_cond = EmitIsString(reg, temp, false_label);
+  SmiCheck check_needed =
+      instr->hydrogen()->value()->IsHeapObject()
+          ? OMIT_SMI_CHECK : INLINE_SMI_CHECK;
+
+  Condition true_cond = EmitIsString(reg, temp, false_label, check_needed);
 
   EmitBranch(true_block, false_block, true_cond);
 }
@@ -2431,8 +2441,10 @@ void LCodeGen::DoIsUndetectableAndBranch(LIsUndetectableAndBranch* instr) {
   int true_block = chunk_->LookupDestination(instr->true_block_id());
   int false_block = chunk_->LookupDestination(instr->false_block_id());
 
-  STATIC_ASSERT(kSmiTag == 0);
-  __ JumpIfSmi(input, chunk_->GetAssemblyLabel(false_block));
+  if (!instr->hydrogen()->value()->IsHeapObject()) {
+    STATIC_ASSERT(kSmiTag == 0);
+    __ JumpIfSmi(input, chunk_->GetAssemblyLabel(false_block));
+  }
   __ mov(temp, FieldOperand(input, HeapObject::kMapOffset));
   __ test_b(FieldOperand(temp, Map::kBitFieldOffset),
             1 << Map::kIsUndetectable);
@@ -2504,7 +2516,9 @@ void LCodeGen::DoHasInstanceTypeAndBranch(LHasInstanceTypeAndBranch* instr) {
 
   Label* false_label = chunk_->GetAssemblyLabel(false_block);
 
-  __ JumpIfSmi(input, false_label);
+  if (!instr->hydrogen()->value()->IsHeapObject()) {
+    __ JumpIfSmi(input, false_label);
+  }
 
   __ CmpObjectType(input, TestType(instr->hydrogen()), temp);
   EmitBranch(true_block, false_block, BranchCondition(instr->hydrogen()));
@@ -2952,9 +2966,9 @@ void LCodeGen::DoStoreContextSlot(LStoreContextSlot* instr) {
 
   __ mov(target, value);
   if (instr->hydrogen()->NeedsWriteBarrier()) {
-    HType type = instr->hydrogen()->value()->type();
     SmiCheck check_needed =
-        type.IsHeapObject() ? OMIT_SMI_CHECK : INLINE_SMI_CHECK;
+        instr->hydrogen()->value()->IsHeapObject()
+            ? OMIT_SMI_CHECK : INLINE_SMI_CHECK;
     Register temp = ToRegister(instr->temp());
     int offset = Context::SlotOffset(instr->slot_index());
     __ RecordWriteContextSlot(context,
@@ -4327,9 +4341,9 @@ void LCodeGen::DoStoreNamedField(LStoreNamedField* instr) {
   }
 
   // Do the store.
-  HType type = instr->hydrogen()->value()->type();
   SmiCheck check_needed =
-      type.IsHeapObject() ? OMIT_SMI_CHECK : INLINE_SMI_CHECK;
+      instr->hydrogen()->value()->IsHeapObject()
+          ? OMIT_SMI_CHECK : INLINE_SMI_CHECK;
 
   Register write_register = object;
   if (!access.IsInobject()) {
@@ -4566,9 +4580,9 @@ void LCodeGen::DoStoreKeyedFixedArray(LStoreKeyed* instr) {
     ASSERT(instr->value()->IsRegister());
     Register value = ToRegister(instr->value());
     ASSERT(!instr->key()->IsConstantOperand());
-    HType type = instr->hydrogen()->value()->type();
     SmiCheck check_needed =
-        type.IsHeapObject() ? OMIT_SMI_CHECK : INLINE_SMI_CHECK;
+        instr->hydrogen()->value()->IsHeapObject()
+          ? OMIT_SMI_CHECK : INLINE_SMI_CHECK;
     // Compute address of modified element and store it into key register.
     __ lea(key, operand);
     __ RecordWrite(elements,
@@ -5709,9 +5723,11 @@ void LCodeGen::DoCheckSmi(LCheckSmi* instr) {
 
 
 void LCodeGen::DoCheckNonSmi(LCheckNonSmi* instr) {
-  LOperand* input = instr->value();
-  __ test(ToOperand(input), Immediate(kSmiTagMask));
-  DeoptimizeIf(zero, instr->environment());
+  if (!instr->hydrogen()->value()->IsHeapObject()) {

[ulan, 2013/06/20 07:53:54]

This check is not present on arm and x64.

+    LOperand* input = instr->value();
+    __ test(ToOperand(input), Immediate(kSmiTagMask));
+    DeoptimizeIf(zero, instr->environment());
+  }
 }