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 df2063ed757e492818645aeb24df99ee5cb1b716..0ad42db4f3f925290a9713028e9734cfe1031954 100644
--- a/src/arm/lithium-codegen-arm.cc
+++ b/src/arm/lithium-codegen-arm.cc
@@ -1880,10 +1880,12 @@ 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);
@@ -2438,8 +2440,11 @@ 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;
@@ -2450,8 +2455,11 @@ void LCodeGen::DoIsStringAndBranch(LIsStringAndBranch* instr) {
   Register reg = ToRegister(instr->value());
   Register temp1 = ToRegister(instr->temp());
 
+  SmiCheck check_needed =
+      instr->hydrogen()->value()->IsHeapObject()
+          ? OMIT_SMI_CHECK : INLINE_SMI_CHECK;
   Condition true_cond =
-      EmitIsString(reg, temp1, instr->FalseLabel(chunk_));
+      EmitIsString(reg, temp1, instr->FalseLabel(chunk_), check_needed);
 
   EmitBranch(instr, true_cond);
 }
@@ -2468,7 +2476,9 @@ void LCodeGen::DoIsUndetectableAndBranch(LIsUndetectableAndBranch* instr) {
   Register input = ToRegister(instr->value());
   Register temp = ToRegister(instr->temp());
 
-  __ JumpIfSmi(input, instr->FalseLabel(chunk_));
+  if (!instr->hydrogen()->value()->IsHeapObject()) {
+    __ JumpIfSmi(input, instr->FalseLabel(chunk_));
+  }
   __ ldr(temp, FieldMemOperand(input, HeapObject::kMapOffset));
   __ ldrb(temp, FieldMemOperand(temp, Map::kBitFieldOffset));
   __ tst(temp, Operand(1 << Map::kIsUndetectable));
@@ -2534,7 +2544,9 @@ void LCodeGen::DoHasInstanceTypeAndBranch(LHasInstanceTypeAndBranch* instr) {
   Register scratch = scratch0();
   Register input = ToRegister(instr->value());
 
-  __ JumpIfSmi(input, instr->FalseLabel(chunk_));
+  if (!instr->hydrogen()->value()->IsHeapObject()) {
+    __ JumpIfSmi(input, instr->FalseLabel(chunk_));
+  }
 
   __ CompareObjectType(input, scratch, scratch, TestType(instr->hydrogen()));
   EmitBranch(instr, BranchCondition(instr->hydrogen()));
@@ -2969,9 +2981,9 @@ 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,
@@ -4209,9 +4221,9 @@ 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()
+          ? OMIT_SMI_CHECK : INLINE_SMI_CHECK;
   if (access.IsInobject()) {
     __ str(value, FieldMemOperand(object, offset));
     if (instr->hydrogen()->NeedsWriteBarrier()) {
@@ -4420,9 +4432,9 @@ 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,
@@ -5144,9 +5156,11 @@ void LCodeGen::DoCheckSmi(LCheckSmi* instr) {
 
 
 void LCodeGen::DoCheckNonSmi(LCheckNonSmi* instr) {
-  LOperand* input = instr->value();
-  __ SmiTst(ToRegister(input));
-  DeoptimizeIf(eq, instr->environment());
+  if (!instr->hydrogen()->value()->IsHeapObject()) {
+    LOperand* input = instr->value();
+    __ SmiTst(ToRegister(input));
+    DeoptimizeIf(eq, instr->environment());
+  }
 }