Avoid Unnecessary Smi Checks

src/arm/lithium-codegen-arm.cc

Index: src/arm/lithium-codegen-arm.cc
diff --git a/src/arm/lithium-codegen-arm.cc b/src/arm/lithium-codegen-arm.cc
index ef860e0d8774771c00378fc6b7bc8129726d49d6..8a16278023e2445e3884b37fa22dfe0f801f72cc 100644
--- a/src/arm/lithium-codegen-arm.cc
+++ b/src/arm/lithium-codegen-arm.cc
@@ -1906,10 +1906,12 @@ void LCodeGen::DoValueOf(LValueOf* instr) {
   Register map = ToRegister(instr->temp());
   Label done;
 
-  // If the object is a smi return the object.
-  __ SmiTst(input);
-  __ Move(result, input, eq);
-  __ b(eq, &done);
+  if (!instr->hydrogen()->value()->IsHeapObject()) {
+    // If the object is a smi return the object.
+    __ SmiTst(input);
+    __ Move(result, input, eq);
+    __ b(eq, &done);
+  }
 
   // If the object is not a value type, return the object.
   __ CompareObjectType(input, map, map, JS_VALUE_TYPE);
@@ -2461,8 +2463,11 @@ 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);
+  }
   __ CompareObjectType(input, temp1, temp1, FIRST_NONSTRING_TYPE);
 
   return lt;
@@ -2477,8 +2482,11 @@ void LCodeGen::DoIsStringAndBranch(LIsStringAndBranch* instr) {
   int false_block = chunk_->LookupDestination(instr->false_block_id());
   Label* false_label = chunk_->GetAssemblyLabel(false_block);
 
+  SmiCheck check_needed =
+      instr->hydrogen()->value()->IsHeapObject()
+          ? OMIT_SMI_CHECK : INLINE_SMI_CHECK;
   Condition true_cond =
-      EmitIsString(reg, temp1, false_label);
+      EmitIsString(reg, temp1, false_label, check_needed);
 
   EmitBranch(true_block, false_block, true_cond);
 }
@@ -2501,7 +2509,9 @@ void LCodeGen::DoIsUndetectableAndBranch(LIsUndetectableAndBranch* instr) {
   int true_block = chunk_->LookupDestination(instr->true_block_id());
   int false_block = chunk_->LookupDestination(instr->false_block_id());
 
-  __ JumpIfSmi(input, chunk_->GetAssemblyLabel(false_block));
+  if (!instr->hydrogen()->value()->IsHeapObject()) {
+    __ JumpIfSmi(input, chunk_->GetAssemblyLabel(false_block));
+  }
   __ ldr(temp, FieldMemOperand(input, HeapObject::kMapOffset));
   __ ldrb(temp, FieldMemOperand(temp, Map::kBitFieldOffset));
   __ tst(temp, Operand(1 << Map::kIsUndetectable));
@@ -2574,7 +2584,9 @@ 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);
+  }
 
   __ CompareObjectType(input, scratch, scratch, TestType(instr->hydrogen()));
   EmitBranch(true_block, false_block, BranchCondition(instr->hydrogen()));
@@ -3019,9 +3031,9 @@ void LCodeGen::DoStoreContextSlot(LStoreContextSlot* instr) {
 
   __ str(value, target);
   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;
     __ RecordWriteContextSlot(context,
                               target.offset(),
                               value,
@@ -4263,9 +4275,9 @@ void LCodeGen::DoStoreNamedField(LStoreNamedField* instr) {
   // Do the store.
   Register value = ToRegister(instr->value());
   ASSERT(!object.is(value));
-  HType type = instr->hydrogen()->value()->type();
   SmiCheck check_needed =
-      type.IsHeapObject() ? OMIT_SMI_CHECK : INLINE_SMI_CHECK;
+      !instr->hydrogen()->value()->IsHeapObject()

[ulan, 2013/06/20 07:49:11]

Negate the condition to make it consistent with the other similar checks.

+          ? INLINE_SMI_CHECK : OMIT_SMI_CHECK;
   if (access.IsInobject()) {
     __ str(value, FieldMemOperand(object, offset));
     if (instr->hydrogen()->NeedsWriteBarrier()) {
@@ -4474,9 +4486,9 @@ void LCodeGen::DoStoreKeyedFixedArray(LStoreKeyed* instr) {
   __ str(value, FieldMemOperand(store_base, offset));
 
   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;
     // Compute address of modified element and store it into key register.
     __ add(key, store_base, Operand(offset - kHeapObjectTag));
     __ RecordWrite(elements,