Support conversion of clamped double values for pixel arrays in Crankshaft.

src/x64/lithium-codegen-x64.cc

Index: src/x64/lithium-codegen-x64.cc
diff --git a/src/x64/lithium-codegen-x64.cc b/src/x64/lithium-codegen-x64.cc
index 64a6a1d3a0d42b8bf65480a92ba7d89e49e1df55..5af9897dd8bebe1faefa54a9bd392a25ec7624fc 100644
--- a/src/x64/lithium-codegen-x64.cc
+++ b/src/x64/lithium-codegen-x64.cc
@@ -3785,6 +3785,57 @@ void LCodeGen::DoCheckMap(LCheckMap* instr) {
 }
 
 
+void LCodeGen::DoClampDoubleToUint8(LClampDoubleToUint8* instr) {
+  XMMRegister value_reg = ToDoubleRegister(instr->unclamped());
+  Register result_reg = ToRegister(instr->result());
+  Register temp_reg = ToRegister(instr->TempAt(0));
+  __ ClampDoubleToUint8(value_reg, xmm0, result_reg, temp_reg);
+}
+
+
+void LCodeGen::DoClampIToUint8(LClampIToUint8* instr) {
+  ASSERT(instr->unclamped()->Equals(instr->result()));
+  Register value_reg = ToRegister(instr->result());
+  __ ClampUint8(value_reg);
+}
+
+
+void LCodeGen::DoClampTaggedToUint8(LClampTaggedToUint8* instr) {
+  ASSERT(instr->unclamped()->Equals(instr->result()));
+  Register input_reg = ToRegister(instr->unclamped());
+  Register temp_reg = ToRegister(instr->TempAt(0));
+  XMMRegister temp_xmm_reg = ToDoubleRegister(instr->TempAt(1));
+  Label is_smi, done, heap_number;
+
+  __ JumpIfSmi(input_reg, &is_smi);
+
+  // Check for heap number
+  __ Cmp(FieldOperand(input_reg, HeapObject::kMapOffset),
+         factory()->heap_number_map());
+  __ j(equal, &heap_number, Label::kNear);
+
+  // Check for undefined. Undefined is converted to zero for clamping
+  // conversions.
+  __ Cmp(input_reg, factory()->undefined_value());
+  DeoptimizeIf(not_equal, instr->environment());
+  __ movq(input_reg, Immediate(0));
+  __ jmp(&done, Label::kNear);
+
+  // Heap number
+  __ bind(&heap_number);
+  __ movsd(xmm0, FieldOperand(input_reg, HeapNumber::kValueOffset));
+  __ ClampDoubleToUint8(xmm0, temp_xmm_reg, input_reg, temp_reg);
+  __ jmp(&done, Label::kNear);
+
+  // smi
+  __ bind(&is_smi);
+  __ SmiToInteger32(input_reg, input_reg);
+  __ ClampUint8(input_reg);
+
+  __ bind(&done);
+}
+
+
 void LCodeGen::LoadHeapObject(Register result, Handle<HeapObject> object) {
   if (heap()->InNewSpace(*object)) {
     Handle<JSGlobalPropertyCell> cell =