Allow uint32 value on optimized frames if they are consumed by safe operations.

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 9160f3f3b422e29d800839668a38088c700d1858..cfcb52b3c4c224740d7329557bdc91bfa0e1b612 100644
--- a/src/ia32/lithium-codegen-ia32.cc
+++ b/src/ia32/lithium-codegen-ia32.cc
@@ -449,7 +449,8 @@ void LCodeGen::WriteTranslation(LEnvironment* environment,
         translation->MarkDuplicate();
         AddToTranslation(translation,
                          environment->spilled_registers()[value->index()],
-                         environment->HasTaggedValueAt(i));
+                         environment->HasTaggedValueAt(i),
+                         environment->HasUint32ValueAt(i));
       } else if (
           value->IsDoubleRegister() &&
           environment->spilled_double_registers()[value->index()] != NULL) {
@@ -457,18 +458,23 @@ void LCodeGen::WriteTranslation(LEnvironment* environment,
         AddToTranslation(
             translation,
             environment->spilled_double_registers()[value->index()],
+            false,
             false);
       }
     }
 
-    AddToTranslation(translation, value, environment->HasTaggedValueAt(i));
+    AddToTranslation(translation,
+                     value,
+                     environment->HasTaggedValueAt(i),
+                     environment->HasUint32ValueAt(i));
   }
 }
 
 
 void LCodeGen::AddToTranslation(Translation* translation,
                                 LOperand* op,
-                                bool is_tagged) {
+                                bool is_tagged,
+                                bool is_uint32) {
   if (op == NULL) {
     // TODO(twuerthinger): Introduce marker operands to indicate that this value
     // is not present and must be reconstructed from the deoptimizer. Currently
@@ -477,6 +483,8 @@ void LCodeGen::AddToTranslation(Translation* translation,
   } else if (op->IsStackSlot()) {
     if (is_tagged) {
       translation->StoreStackSlot(op->index());
+    } else if (is_uint32) {
+      translation->StoreUint32StackSlot(op->index());
     } else {
       translation->StoreInt32StackSlot(op->index());
     }
@@ -490,6 +498,8 @@ void LCodeGen::AddToTranslation(Translation* translation,
     Register reg = ToRegister(op);
     if (is_tagged) {
       translation->StoreRegister(reg);
+    } else if (is_uint32) {
+      translation->StoreUint32Register(reg);
     } else {
       translation->StoreInt32Register(reg);
     }
@@ -2835,11 +2845,10 @@ void LCodeGen::DoLoadKeyedSpecializedArrayElement(
         break;
       case EXTERNAL_UNSIGNED_INT_ELEMENTS:
         __ mov(result, operand);
-        __ test(result, Operand(result));
-        // TODO(danno): we could be more clever here, perhaps having a special
-        // version of the stub that detects if the overflow case actually
-        // happens, and generate code that returns a double rather than int.
-        DeoptimizeIf(negative, instr->environment());
+        if (!instr->hydrogen()->CheckFlag(HInstruction::kUint32)) {
+          __ test(result, Operand(result));
+          DeoptimizeIf(negative, instr->environment());
+        }
         break;
       case EXTERNAL_FLOAT_ELEMENTS:
       case EXTERNAL_DOUBLE_ELEMENTS:
@@ -4058,12 +4067,25 @@ void LCodeGen::DoInteger32ToDouble(LInteger32ToDouble* instr) {
 }
 
 
+void LCodeGen::DoUint32ToDouble(LUint32ToDouble* instr) {
+  LOperand* input = instr->InputAt(0);
+  LOperand* output = instr->result();
+  LOperand* temp = instr->TempAt(0);
+
+  __ LoadUint32(ToDoubleRegister(output),
+                ToRegister(input),
+                ToDoubleRegister(temp));
+}
+
+
 void LCodeGen::DoNumberTagI(LNumberTagI* instr) {
   class DeferredNumberTagI: public LDeferredCode {
    public:
     DeferredNumberTagI(LCodeGen* codegen, LNumberTagI* instr)
         : LDeferredCode(codegen), instr_(instr) { }
-    virtual void Generate() { codegen()->DoDeferredNumberTagI(instr_); }
+    virtual void Generate() {
+      codegen()->DoDeferredNumberTagI(instr_, SIGNED_INT32);
+    }
     virtual LInstruction* instr() { return instr_; }
    private:
     LNumberTagI* instr_;
@@ -4080,7 +4102,33 @@ void LCodeGen::DoNumberTagI(LNumberTagI* instr) {
 }
 
 
-void LCodeGen::DoDeferredNumberTagI(LNumberTagI* instr) {
+void LCodeGen::DoNumberTagU(LNumberTagU* instr) {
+  class DeferredNumberTagU: public LDeferredCode {
+   public:
+    DeferredNumberTagU(LCodeGen* codegen, LNumberTagU* instr)
+        : LDeferredCode(codegen), instr_(instr) { }
+    virtual void Generate() {
+      codegen()->DoDeferredNumberTagI(instr_, UNSIGNED_INT32);
+    }
+    virtual LInstruction* instr() { return instr_; }
+   private:
+    LNumberTagU* instr_;
+  };
+
+  LOperand* input = instr->InputAt(0);
+  ASSERT(input->IsRegister() && input->Equals(instr->result()));
+  Register reg = ToRegister(input);
+
+  DeferredNumberTagU* deferred = new(zone()) DeferredNumberTagU(this, instr);
+  __ cmp(reg, Immediate(Smi::kMaxValue));
+  __ j(above, deferred->entry());
+  __ SmiTag(reg);
+  __ bind(deferred->exit());
+}
+
+
+void LCodeGen::DoDeferredNumberTagI(LInstruction* instr,
+                                    IntegerSignedness signedness) {
   Label slow;
   Register reg = ToRegister(instr->InputAt(0));
   Register tmp = reg.is(eax) ? ecx : eax;
@@ -4088,13 +4136,19 @@ void LCodeGen::DoDeferredNumberTagI(LNumberTagI* instr) {
   // Preserve the value of all registers.
   PushSafepointRegistersScope scope(this);
 
-  // There was overflow, so bits 30 and 31 of the original integer
-  // disagree. Try to allocate a heap number in new space and store
-  // the value in there. If that fails, call the runtime system.
   Label done;
-  __ SmiUntag(reg);
-  __ xor_(reg, 0x80000000);
-  __ cvtsi2sd(xmm0, Operand(reg));
+
+  if (signedness == SIGNED_INT32) {
+    // There was overflow, so bits 30 and 31 of the original integer
+    // disagree. Try to allocate a heap number in new space and store
+    // the value in there. If that fails, call the runtime system.
+    __ SmiUntag(reg);
+    __ xor_(reg, 0x80000000);
+    __ cvtsi2sd(xmm0, Operand(reg));
+  } else {
+    __ LoadUint32(xmm0, reg, xmm1);
+  }
+
   if (FLAG_inline_new) {
     __ AllocateHeapNumber(reg, tmp, no_reg, &slow);
     __ jmp(&done, Label::kNear);