MIPS: Push safepoint registers in deferred number-to-i/u only on-demand.

Port r19649 (49f8c2d)

BUG=
R=plind44@gmail.com

Review URL: https://codereview.chromium.org/186673004

Patch from Balazs Kilvady <kilvadyb@homejinni.com>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19662 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/mips/lithium-codegen-mips.cc

@@ -4553,8 +4553,10 @@ void LCodeGen::DoNumberTagI(LNumberTagI* instr) {
     DeferredNumberTagI(LCodeGen* codegen, LNumberTagI* instr)
         : LDeferredCode(codegen), instr_(instr) { }
     virtual void Generate() V8_OVERRIDE {
-      codegen()->DoDeferredNumberTagI(instr_,
+      codegen()->DoDeferredNumberTagIU(instr_,
                                        instr_->value(),
+                                       instr_->temp1(),
+                                       instr_->temp2(),
                                        SIGNED_INT32);
     }
     virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
@@ -4579,8 +4581,10 @@ void LCodeGen::DoNumberTagU(LNumberTagU* instr) {
     DeferredNumberTagU(LCodeGen* codegen, LNumberTagU* instr)
         : LDeferredCode(codegen), instr_(instr) { }
     virtual void Generate() V8_OVERRIDE {
-      codegen()->DoDeferredNumberTagI(instr_,
+      codegen()->DoDeferredNumberTagIU(instr_,
                                        instr_->value(),
+                                       instr_->temp1(),
+                                       instr_->temp2(),
                                        UNSIGNED_INT32);
     }
     virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
@@ -4598,18 +4602,19 @@ void LCodeGen::DoNumberTagU(LNumberTagU* instr) {
 }
 
 
-void LCodeGen::DoDeferredNumberTagI(LInstruction* instr,
+void LCodeGen::DoDeferredNumberTagIU(LInstruction* instr,
                                      LOperand* value,
+                                     LOperand* temp1,
+                                     LOperand* temp2,
                                      IntegerSignedness signedness) {
-  Label slow;
+  Label done, slow;
   Register src = ToRegister(value);
   Register dst = ToRegister(instr->result());
+  Register tmp1 = scratch0();
+  Register tmp2 = ToRegister(temp1);
+  Register tmp3 = ToRegister(temp2);
   DoubleRegister dbl_scratch = double_scratch0();
 
-  // Preserve the value of all registers.
-  PushSafepointRegistersScope scope(this, Safepoint::kWithRegisters);
-
-  Label done;
   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
@@ -4626,19 +4631,22 @@ void LCodeGen::DoDeferredNumberTagI(LInstruction* instr,
   }
 
   if (FLAG_inline_new) {
-    __ LoadRoot(scratch0(), Heap::kHeapNumberMapRootIndex);
+    __ LoadRoot(tmp3, Heap::kHeapNumberMapRootIndex);
-    __ AllocateHeapNumber(t1, a3, t0, scratch0(), &slow, DONT_TAG_RESULT);
+    __ AllocateHeapNumber(dst, tmp1, tmp2, tmp3, &slow, DONT_TAG_RESULT);
-    __ Move(dst, t1);
     __ Branch(&done);
   }
 
   // Slow case: Call the runtime system to do the number allocation.
   __ bind(&slow);
+  {
+    // TODO(3095996): Put a valid pointer value in the stack slot where the
+    // result register is stored, as this register is in the pointer map, but
+    // contains an integer value.
+    __ mov(dst, zero_reg);
+
+    // Preserve the value of all registers.
+    PushSafepointRegistersScope scope(this, Safepoint::kWithRegisters);
 
-  // TODO(3095996): Put a valid pointer value in the stack slot where the result
-  // register is stored, as this register is in the pointer map, but contains an
-  // integer value.
-  __ StoreToSafepointRegisterSlot(zero_reg, dst);
     // NumberTagI and NumberTagD use the context from the frame, rather than
     // the environment's HContext or HInlinedContext value.
     // They only call Runtime::kAllocateHeapNumber.
@@ -4648,15 +4656,16 @@ void LCodeGen::DoDeferredNumberTagI(LInstruction* instr,
     __ CallRuntimeSaveDoubles(Runtime::kAllocateHeapNumber);
     RecordSafepointWithRegisters(
         instr->pointer_map(), 0, Safepoint::kNoLazyDeopt);
-  __ Move(dst, v0);
+    __ Subu(v0, v0, kHeapObjectTag);
-  __ Subu(dst, dst, kHeapObjectTag);
+    __ StoreToSafepointRegisterSlot(v0, dst);
+  }
+
 
   // Done. Put the value in dbl_scratch into the value of the allocated heap
   // number.
   __ bind(&done);
   __ sdc1(dbl_scratch, MemOperand(dst, HeapNumber::kValueOffset));
   __ Addu(dst, dst, kHeapObjectTag);
-  __ StoreToSafepointRegisterSlot(dst, dst);
 }
 
 

src/mips/lithium-codegen-mips.h

@@ -124,8 +124,10 @@ class LCodeGen: public LCodeGenBase {
   void DoDeferredNumberTagD(LNumberTagD* instr);
 
   enum IntegerSignedness { SIGNED_INT32, UNSIGNED_INT32 };
-  void DoDeferredNumberTagI(LInstruction* instr,
+  void DoDeferredNumberTagIU(LInstruction* instr,
                              LOperand* value,
+                             LOperand* temp1,
+                             LOperand* temp2,
                              IntegerSignedness signedness);
 
   void DoDeferredTaggedToI(LTaggedToI* instr);

src/mips/lithium-mips.cc

@@ -1771,12 +1771,16 @@ LInstruction* LChunkBuilder::DoChange(HChange* instr) {
       HValue* val = instr->value();
       LOperand* value = UseRegisterAtStart(val);
       if (val->CheckFlag(HInstruction::kUint32)) {
-        LNumberTagU* result = new(zone()) LNumberTagU(value);
+        LOperand* temp1 = TempRegister();
+        LOperand* temp2 = TempRegister();
+        LNumberTagU* result = new(zone()) LNumberTagU(value, temp1, temp2);
         return AssignEnvironment(AssignPointerMap(DefineAsRegister(result)));
       } else if (val->HasRange() && val->range()->IsInSmiRange()) {
         return DefineAsRegister(new(zone()) LSmiTag(value));
       } else {
-        LNumberTagI* result = new(zone()) LNumberTagI(value);
+        LOperand* temp1 = TempRegister();
+        LOperand* temp2 = TempRegister();
+        LNumberTagI* result = new(zone()) LNumberTagI(value, temp1, temp2);
         return AssignEnvironment(AssignPointerMap(DefineAsRegister(result)));
       }
     } else if (to.IsSmi()) {

src/mips/lithium-mips.h

@@ -1914,25 +1914,33 @@ class LUint32ToSmi V8_FINAL : public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LNumberTagI V8_FINAL : public LTemplateInstruction<1, 1, 0> {
+class LNumberTagI V8_FINAL : public LTemplateInstruction<1, 1, 2> {
  public:
-  explicit LNumberTagI(LOperand* value) {
+  LNumberTagI(LOperand* value, LOperand* temp1, LOperand* temp2) {
     inputs_[0] = value;
+    temps_[0] = temp1;
+    temps_[1] = temp2;
   }
 
   LOperand* value() { return inputs_[0]; }
+  LOperand* temp1() { return temps_[0]; }
+  LOperand* temp2() { return temps_[1]; }
 
   DECLARE_CONCRETE_INSTRUCTION(NumberTagI, "number-tag-i")
 };
 
 
-class LNumberTagU V8_FINAL : public LTemplateInstruction<1, 1, 0> {
+class LNumberTagU V8_FINAL : public LTemplateInstruction<1, 1, 2> {
  public:
-  explicit LNumberTagU(LOperand* value) {
+  LNumberTagU(LOperand* value, LOperand* temp1, LOperand* temp2) {
     inputs_[0] = value;
+    temps_[0] = temp1;
+    temps_[1] = temp2;
   }
 
   LOperand* value() { return inputs_[0]; }
+  LOperand* temp1() { return temps_[0]; }
+  LOperand* temp2() { return temps_[1]; }
 
   DECLARE_CONCRETE_INSTRUCTION(NumberTagU, "number-tag-u")
 };