ARM: Improve register allocation and constraints.

Gives ~20% boost for Crypto benchmark on A9.

BUG=none
TEST=none

Review URL: http://codereview.chromium.org//7148018
Patch from Martyn Capewell <m.m.capewell@googlemail.com>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@8381 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/arm/assembler-arm.h

@@ -167,13 +167,14 @@ struct SwVfpRegister {
 
 // Double word VFP register.
 struct DwVfpRegister {
-  // d0 has been excluded from allocation. This is following ia32
-  // where xmm0 is excluded. This should be revisited.
-  // Currently d0 is used as a scratch register.
-  // d1 has also been excluded from allocation to be used as a scratch
-  // register as well.
   static const int kNumRegisters = 16;
-  static const int kNumAllocatableRegisters = 15;
+  // A few double registers are reserved: one as a scratch register and one to
+  // hold 0.0, that does not fit in the immediate field of vmov instructions.
+  //  d14: 0.0
+  //  d15: scratch register.
+  static const int kNumReservedRegisters = 2;
+  static const int kNumAllocatableRegisters = kNumRegisters -
+      kNumReservedRegisters;
 
   static int ToAllocationIndex(DwVfpRegister reg) {
     ASSERT(reg.code() != 0);
@@ -188,6 +189,7 @@ struct DwVfpRegister {
   static const char* AllocationIndexToString(int index) {
     ASSERT(index >= 0 && index < kNumAllocatableRegisters);
     const char* const names[] = {
+      "d0",
       "d1",
       "d2",
       "d3",
@@ -200,9 +202,7 @@ struct DwVfpRegister {
       "d10",
       "d11",
       "d12",
-      "d13",
-      "d14",
-      "d15"
+      "d13"
     };
     return names[index];
   }
@@ -306,6 +306,7 @@ const DwVfpRegister d15 = { 15 };
 // Aliases for double registers.
 const DwVfpRegister kFirstCalleeSavedDoubleReg = d8;
 const DwVfpRegister kLastCalleeSavedDoubleReg = d15;
+const DwVfpRegister kDoubleRegZero = d14;
 
 
 // Coprocessor register

src/arm/code-stubs-arm.cc

@@ -3541,6 +3541,8 @@ void JSEntryStub::GenerateBody(MacroAssembler* masm, bool is_construct) {
     CpuFeatures::Scope scope(VFP3);
     // Save callee-saved vfp registers.
     __ vstm(db_w, sp, kFirstCalleeSavedDoubleReg, kLastCalleeSavedDoubleReg);
+    // Set up the reserved register for 0.0.
+    __ vmov(kDoubleRegZero, 0.0);
   }
 
   // Get address of argv, see stm above.

src/arm/lithium-arm.cc

@@ -823,7 +823,7 @@ LInstruction* LChunkBuilder::DoBit(Token::Value op,
 
     LOperand* left = UseRegisterAtStart(instr->LeastConstantOperand());
     LOperand* right = UseOrConstantAtStart(instr->MostConstantOperand());
-    return DefineSameAsFirst(new LBitI(op, left, right));
+    return DefineAsRegister(new LBitI(op, left, right));
   } else {
     ASSERT(instr->representation().IsTagged());
     ASSERT(instr->left()->representation().IsTagged());
@@ -862,7 +862,7 @@ LInstruction* LChunkBuilder::DoShift(Token::Value op,
     right = chunk_->DefineConstantOperand(constant);
     constant_value = constant->Integer32Value() & 0x1f;
   } else {
-    right = UseRegister(right_value);
+    right = UseRegisterAtStart(right_value);
   }
 
   // Shift operations can only deoptimize if we do a logical shift
@@ -879,7 +879,7 @@ LInstruction* LChunkBuilder::DoShift(Token::Value op,
   }
 
   LInstruction* result =
-      DefineSameAsFirst(new LShiftI(op, left, right, does_deopt));
+      DefineAsRegister(new LShiftI(op, left, right, does_deopt));
   return does_deopt ? AssignEnvironment(result) : result;
 }
 
@@ -893,7 +893,7 @@ LInstruction* LChunkBuilder::DoArithmeticD(Token::Value op,
   LOperand* left = UseRegisterAtStart(instr->left());
   LOperand* right = UseRegisterAtStart(instr->right());
   LArithmeticD* result = new LArithmeticD(op, left, right);
-  return DefineSameAsFirst(result);
+  return DefineAsRegister(result);
 }
 
 
@@ -1237,15 +1237,15 @@ LInstruction* LChunkBuilder::DoUnaryMathOperation(HUnaryMathOperation* instr) {
     LUnaryMathOperation* result = new LUnaryMathOperation(input, temp);
     switch (op) {
       case kMathAbs:
-        return AssignEnvironment(AssignPointerMap(DefineSameAsFirst(result)));
+        return AssignEnvironment(AssignPointerMap(DefineAsRegister(result)));
       case kMathFloor:
         return AssignEnvironment(AssignPointerMap(DefineAsRegister(result)));
       case kMathSqrt:
-        return DefineSameAsFirst(result);
+        return DefineAsRegister(result);
       case kMathRound:
         return AssignEnvironment(DefineAsRegister(result));
       case kMathPowHalf:
-        return DefineSameAsFirst(result);
+        return DefineAsRegister(result);
       default:
         UNREACHABLE();
         return NULL;
@@ -1323,7 +1323,7 @@ LInstruction* LChunkBuilder::DoBitAnd(HBitAnd* instr) {
 LInstruction* LChunkBuilder::DoBitNot(HBitNot* instr) {
   ASSERT(instr->value()->representation().IsInteger32());
   ASSERT(instr->representation().IsInteger32());
-  return DefineSameAsFirst(new LBitNotI(UseRegisterAtStart(instr->value())));
+  return DefineAsRegister(new LBitNotI(UseRegisterAtStart(instr->value())));
 }
 
 
@@ -1372,11 +1372,14 @@ LInstruction* LChunkBuilder::DoMod(HMod* instr) {
       mod = new LModI(dividend,
                       divisor,
                       TempRegister(),
-                      FixedTemp(d1),
-                      FixedTemp(d2));
+                      FixedTemp(d10),
+                      FixedTemp(d11));
     }
 
-    return AssignEnvironment(DefineSameAsFirst(mod));
+    bool needs_env = (instr->CheckFlag(HValue::kBailoutOnMinusZero) ||
+                      instr->CheckFlag(HValue::kCanBeDivByZero));
+    return needs_env ? AssignEnvironment(DefineAsRegister(mod))
+                     : DefineAsRegister(mod);
   } else if (instr->representation().IsTagged()) {
     return DoArithmeticT(Token::MOD, instr);
   } else {
@@ -1396,15 +1399,18 @@ LInstruction* LChunkBuilder::DoMul(HMul* instr) {
   if (instr->representation().IsInteger32()) {
     ASSERT(instr->left()->representation().IsInteger32());
     ASSERT(instr->right()->representation().IsInteger32());
-    LOperand* left = UseRegisterAtStart(instr->LeastConstantOperand());
+    LOperand* left;
     LOperand* right = UseOrConstant(instr->MostConstantOperand());
     LOperand* temp = NULL;
     if (instr->CheckFlag(HValue::kBailoutOnMinusZero) &&
         (instr->CheckFlag(HValue::kCanOverflow) ||
         !right->IsConstantOperand())) {
+      left = UseRegister(instr->LeastConstantOperand());
       temp = TempRegister();
+    } else {
+      left = UseRegisterAtStart(instr->LeastConstantOperand());
     }
-    return AssignEnvironment(DefineSameAsFirst(new LMulI(left, right, temp)));
+    return AssignEnvironment(DefineAsRegister(new LMulI(left, right, temp)));
 
   } else if (instr->representation().IsDouble()) {
     return DoArithmeticD(Token::MUL, instr);
@@ -1422,7 +1428,7 @@ LInstruction* LChunkBuilder::DoSub(HSub* instr) {
     LOperand* left = UseRegisterAtStart(instr->left());
     LOperand* right = UseOrConstantAtStart(instr->right());
     LSubI* sub = new LSubI(left, right);
-    LInstruction* result = DefineSameAsFirst(sub);
+    LInstruction* result = DefineAsRegister(sub);
     if (instr->CheckFlag(HValue::kCanOverflow)) {
       result = AssignEnvironment(result);
     }
@@ -1442,7 +1448,7 @@ LInstruction* LChunkBuilder::DoAdd(HAdd* instr) {
     LOperand* left = UseRegisterAtStart(instr->LeastConstantOperand());
     LOperand* right = UseOrConstantAtStart(instr->MostConstantOperand());
     LAddI* add = new LAddI(left, right);
-    LInstruction* result = DefineSameAsFirst(add);
+    LInstruction* result = DefineAsRegister(add);
     if (instr->CheckFlag(HValue::kCanOverflow)) {
       result = AssignEnvironment(result);
     }
@@ -1608,7 +1614,7 @@ LInstruction* LChunkBuilder::DoElementsKind(HElementsKind* instr) {
 LInstruction* LChunkBuilder::DoValueOf(HValueOf* instr) {
   LOperand* object = UseRegister(instr->value());
   LValueOf* result = new LValueOf(object, TempRegister());
-  return AssignEnvironment(DefineSameAsFirst(result));
+  return AssignEnvironment(DefineAsRegister(result));
 }
 
 
@@ -1663,7 +1669,7 @@ LInstruction* LChunkBuilder::DoChange(HChange* instr) {
         LOperand* temp1 = TempRegister();
         LOperand* temp2 = instr->CanTruncateToInt32() ? TempRegister()
                                                       : NULL;
-        LOperand* temp3 = instr->CanTruncateToInt32() ? FixedTemp(d3)
+        LOperand* temp3 = instr->CanTruncateToInt32() ? FixedTemp(d11)
                                                       : NULL;
         res = DefineSameAsFirst(new LTaggedToI(value, temp1, temp2, temp3));
         res = AssignEnvironment(res);
@@ -1757,14 +1763,14 @@ LInstruction* LChunkBuilder::DoClampToUint8(HClampToUint8* instr) {
   Representation input_rep = value->representation();
   LOperand* reg = UseRegister(value);
   if (input_rep.IsDouble()) {
-    return DefineAsRegister(new LClampDToUint8(reg, FixedTemp(d1)));
+    return DefineAsRegister(new LClampDToUint8(reg, FixedTemp(d11)));
   } else if (input_rep.IsInteger32()) {
     return DefineAsRegister(new LClampIToUint8(reg));
   } else {
     ASSERT(input_rep.IsTagged());
     // Register allocator doesn't (yet) support allocation of double
     // temps. Reserve d1 explicitly.
-    LClampTToUint8* result = new LClampTToUint8(reg, FixedTemp(d1));
+    LClampTToUint8* result = new LClampTToUint8(reg, FixedTemp(d11));
     return AssignEnvironment(DefineAsRegister(result));
   }
 }
@@ -1788,7 +1794,7 @@ LInstruction* LChunkBuilder::DoToInt32(HToInt32* instr) {
     ASSERT(input_rep.IsTagged());
     LOperand* temp1 = TempRegister();
     LOperand* temp2 = TempRegister();
-    LOperand* temp3 = FixedTemp(d3);
+    LOperand* temp3 = FixedTemp(d11);
     LTaggedToI* res = new LTaggedToI(reg, temp1, temp2, temp3);
     return AssignEnvironment(DefineSameAsFirst(res));
   }
@@ -1926,7 +1932,7 @@ LInstruction* LChunkBuilder::DoLoadKeyedFastElement(
   LOperand* obj = UseRegisterAtStart(instr->object());
   LOperand* key = UseRegisterAtStart(instr->key());
   LLoadKeyedFastElement* result = new LLoadKeyedFastElement(obj, key);
-  return AssignEnvironment(DefineSameAsFirst(result));
+  return AssignEnvironment(DefineAsRegister(result));
 }
 
 

src/arm/lithium-codegen-arm.cc

@@ -873,6 +873,7 @@ void LCodeGen::DoUnknownOSRValue(LUnknownOSRValue* instr) {
 void LCodeGen::DoModI(LModI* instr) {
   if (instr->hydrogen()->HasPowerOf2Divisor()) {
     Register dividend = ToRegister(instr->InputAt(0));
+    Register result = ToRegister(instr->result());
 
     int32_t divisor =
         HConstant::cast(instr->hydrogen()->right())->Integer32Value();
@@ -882,17 +883,15 @@ void LCodeGen::DoModI(LModI* instr) {
     Label positive_dividend, done;
     __ cmp(dividend, Operand(0));
     __ b(pl, &positive_dividend);
-    __ rsb(dividend, dividend, Operand(0));
-    __ and_(dividend, dividend, Operand(divisor - 1));
-    __ rsb(dividend, dividend, Operand(0), SetCC);
+    __ rsb(result, dividend, Operand(0));
+    __ and_(dividend, result, Operand(divisor - 1), SetCC);
     if (instr->hydrogen()->CheckFlag(HValue::kBailoutOnMinusZero)) {
-      __ b(ne, &done);
-      DeoptimizeIf(al, instr->environment());
-    } else {
-      __ b(&done);
+      DeoptimizeIf(eq, instr->environment());
     }
+    __ rsb(result, dividend, Operand(0));
+    __ b(&done);
     __ bind(&positive_dividend);
-    __ and_(dividend, dividend, Operand(divisor - 1));
+    __ and_(result, dividend, Operand(divisor - 1));
     __ bind(&done);
     return;
   }
@@ -908,8 +907,6 @@ void LCodeGen::DoModI(LModI* instr) {
   DwVfpRegister divisor = ToDoubleRegister(instr->TempAt(2));
   DwVfpRegister quotient = double_scratch0();
 
-  ASSERT(result.is(left));
-
   ASSERT(!dividend.is(divisor));
   ASSERT(!dividend.is(quotient));
   ASSERT(!divisor.is(quotient));
@@ -925,6 +922,8 @@ void LCodeGen::DoModI(LModI* instr) {
     DeoptimizeIf(eq, instr->environment());
   }
 
+  __ Move(result, left);
+
   // (0 % x) must yield 0 (if x is finite, which is the case here).
   __ cmp(left, Operand(0));
   __ b(eq, &done);
@@ -1120,9 +1119,9 @@ void LCodeGen::DoDeferredBinaryOpStub(LTemplateInstruction<1, 2, T>* instr,
 
 
 void LCodeGen::DoMulI(LMulI* instr) {
-  ASSERT(instr->result()->Equals(instr->InputAt(0)));
   Register scratch = scratch0();
   Register result = ToRegister(instr->result());
+  // Note that result may alias left.
   Register left = ToRegister(instr->InputAt(0));
   LOperand* right_op = instr->InputAt(1);
 
@@ -1155,7 +1154,7 @@ void LCodeGen::DoMulI(LMulI* instr) {
         __ mov(result, Operand(0));
         break;
       case 1:
-        // Nothing to do.
+        __ Move(result, left);
         break;
       default:
         // Multiplying by powers of two and powers of two plus or minus
@@ -1217,30 +1216,29 @@ void LCodeGen::DoMulI(LMulI* instr) {
 
 
 void LCodeGen::DoBitI(LBitI* instr) {
-  LOperand* left = instr->InputAt(0);
-  LOperand* right = instr->InputAt(1);
-  ASSERT(left->Equals(instr->result()));
-  ASSERT(left->IsRegister());
-  Register result = ToRegister(left);
-  Operand right_operand(no_reg);
+  LOperand* left_op = instr->InputAt(0);
+  LOperand* right_op = instr->InputAt(1);
+  ASSERT(left_op->IsRegister());
+  Register left = ToRegister(left_op);
+  Register result = ToRegister(instr->result());
+  Operand right(no_reg);
 
-  if (right->IsStackSlot() || right->IsArgument()) {
-    Register right_reg = EmitLoadRegister(right, ip);
-    right_operand = Operand(right_reg);
+  if (right_op->IsStackSlot() || right_op->IsArgument()) {
+    right = Operand(EmitLoadRegister(right_op, ip));
   } else {
-    ASSERT(right->IsRegister() || right->IsConstantOperand());
-    right_operand = ToOperand(right);
+    ASSERT(right_op->IsRegister() || right_op->IsConstantOperand());
+    right = ToOperand(right_op);
   }
 
   switch (instr->op()) {
     case Token::BIT_AND:
-      __ and_(result, ToRegister(left), right_operand);
+      __ and_(result, left, right);
       break;
     case Token::BIT_OR:
-      __ orr(result, ToRegister(left), right_operand);
+      __ orr(result, left, right);
       break;
     case Token::BIT_XOR:
-      __ eor(result, ToRegister(left), right_operand);
+      __ eor(result, left, right);
       break;
     default:
       UNREACHABLE();
@@ -1250,54 +1248,62 @@ void LCodeGen::DoBitI(LBitI* instr) {
 
 
 void LCodeGen::DoShiftI(LShiftI* instr) {
+  // Both 'left' and 'right' are "used at start" (see LCodeGen::DoShift), so
+  // result may alias either of them.
+  LOperand* right_op = instr->InputAt(1);
+  Register left = ToRegister(instr->InputAt(0));
+  Register result = ToRegister(instr->result());
   Register scratch = scratch0();
-  LOperand* left = instr->InputAt(0);
-  LOperand* right = instr->InputAt(1);
-  ASSERT(left->Equals(instr->result()));
-  ASSERT(left->IsRegister());
-  Register result = ToRegister(left);
-  if (right->IsRegister()) {
-    // Mask the right operand.
-    __ and_(scratch, ToRegister(right), Operand(0x1F));
+  if (right_op->IsRegister()) {
+    // Mask the right_op operand.
+    __ and_(scratch, ToRegister(right_op), Operand(0x1F));
     switch (instr->op()) {
       case Token::SAR:
-        __ mov(result, Operand(result, ASR, scratch));
+        __ mov(result, Operand(left, ASR, scratch));
         break;
       case Token::SHR:
         if (instr->can_deopt()) {
-          __ mov(result, Operand(result, LSR, scratch), SetCC);
+          __ mov(result, Operand(left, LSR, scratch), SetCC);
           DeoptimizeIf(mi, instr->environment());
         } else {
-          __ mov(result, Operand(result, LSR, scratch));
+          __ mov(result, Operand(left, LSR, scratch));
         }
         break;
       case Token::SHL:
-        __ mov(result, Operand(result, LSL, scratch));
+        __ mov(result, Operand(left, LSL, scratch));
         break;
       default:
         UNREACHABLE();
         break;
     }
   } else {
-    int value = ToInteger32(LConstantOperand::cast(right));
+    // Mask the right_op operand.
+    int value = ToInteger32(LConstantOperand::cast(right_op));
     uint8_t shift_count = static_cast<uint8_t>(value & 0x1F);
     switch (instr->op()) {
       case Token::SAR:
         if (shift_count != 0) {
-          __ mov(result, Operand(result, ASR, shift_count));
+          __ mov(result, Operand(left, ASR, shift_count));
+        } else {
+          __ Move(result, left);
         }
         break;
       case Token::SHR:
-        if (shift_count == 0 && instr->can_deopt()) {
-          __ tst(result, Operand(0x80000000));
-          DeoptimizeIf(ne, instr->environment());
+        if (shift_count != 0) {
+          __ mov(result, Operand(left, LSR, shift_count));
         } else {
-          __ mov(result, Operand(result, LSR, shift_count));
+          if (instr->can_deopt()) {
+            __ tst(left, Operand(0x80000000));
+            DeoptimizeIf(ne, instr->environment());
+          }
+          __ Move(result, left);
         }
         break;
       case Token::SHL:
         if (shift_count != 0) {
-          __ mov(result, Operand(result, LSL, shift_count));
+          __ mov(result, Operand(left, LSL, shift_count));
+        } else {
+          __ Move(result, left);
         }
         break;
       default:
@@ -1311,16 +1317,16 @@ void LCodeGen::DoShiftI(LShiftI* instr) {
 void LCodeGen::DoSubI(LSubI* instr) {
   LOperand* left = instr->InputAt(0);
   LOperand* right = instr->InputAt(1);
-  ASSERT(left->Equals(instr->result()));
+  LOperand* result = instr->result();
   bool can_overflow = instr->hydrogen()->CheckFlag(HValue::kCanOverflow);
   SBit set_cond = can_overflow ? SetCC : LeaveCC;
 
   if (right->IsStackSlot() || right->IsArgument()) {
     Register right_reg = EmitLoadRegister(right, ip);
-    __ sub(ToRegister(left), ToRegister(left), Operand(right_reg), set_cond);
+    __ sub(ToRegister(result), ToRegister(left), Operand(right_reg), set_cond);
   } else {
     ASSERT(right->IsRegister() || right->IsConstantOperand());
-    __ sub(ToRegister(left), ToRegister(left), ToOperand(right), set_cond);
+    __ sub(ToRegister(result), ToRegister(left), ToOperand(right), set_cond);
   }
 
   if (can_overflow) {
@@ -1339,7 +1345,7 @@ void LCodeGen::DoConstantD(LConstantD* instr) {
   ASSERT(instr->result()->IsDoubleRegister());
   DwVfpRegister result = ToDoubleRegister(instr->result());
   double v = instr->value();
-  __ vmov(result, v);
+  __ Vmov(result, v);
 }
 
 
@@ -1388,14 +1394,16 @@ void LCodeGen::DoValueOf(LValueOf* instr) {
   Register input = ToRegister(instr->InputAt(0));
   Register result = ToRegister(instr->result());
   Register map = ToRegister(instr->TempAt(0));
-  ASSERT(input.is(result));
   Label done;
 
   // If the object is a smi return the object.
-  __ JumpIfSmi(input, &done);
+  __ tst(input, Operand(kSmiTagMask));
+  __ 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);
+  __ Move(result, input, ne);
   __ b(ne, &done);
   __ ldr(result, FieldMemOperand(input, JSValue::kValueOffset));
 
@@ -1404,9 +1412,9 @@ void LCodeGen::DoValueOf(LValueOf* instr) {
 
 
 void LCodeGen::DoBitNotI(LBitNotI* instr) {
-  LOperand* input = instr->InputAt(0);
-  ASSERT(input->Equals(instr->result()));
-  __ mvn(ToRegister(input), Operand(ToRegister(input)));
+  Register input = ToRegister(instr->InputAt(0));
+  Register result = ToRegister(instr->result());
+  __ mvn(result, Operand(input));
 }
 
 
@@ -1424,16 +1432,16 @@ void LCodeGen::DoThrow(LThrow* instr) {
 void LCodeGen::DoAddI(LAddI* instr) {
   LOperand* left = instr->InputAt(0);
   LOperand* right = instr->InputAt(1);
-  ASSERT(left->Equals(instr->result()));
+  LOperand* result = instr->result();
   bool can_overflow = instr->hydrogen()->CheckFlag(HValue::kCanOverflow);
   SBit set_cond = can_overflow ? SetCC : LeaveCC;
 
   if (right->IsStackSlot() || right->IsArgument()) {
     Register right_reg = EmitLoadRegister(right, ip);
-    __ add(ToRegister(left), ToRegister(left), Operand(right_reg), set_cond);
+    __ add(ToRegister(result), ToRegister(left), Operand(right_reg), set_cond);
   } else {
     ASSERT(right->IsRegister() || right->IsConstantOperand());
-    __ add(ToRegister(left), ToRegister(left), ToOperand(right), set_cond);
+    __ add(ToRegister(result), ToRegister(left), ToOperand(right), set_cond);
   }
 
   if (can_overflow) {
@@ -1445,18 +1453,19 @@ void LCodeGen::DoAddI(LAddI* instr) {
 void LCodeGen::DoArithmeticD(LArithmeticD* instr) {
   DoubleRegister left = ToDoubleRegister(instr->InputAt(0));
   DoubleRegister right = ToDoubleRegister(instr->InputAt(1));
+  DoubleRegister result = ToDoubleRegister(instr->result());
   switch (instr->op()) {
     case Token::ADD:
-      __ vadd(left, left, right);
+      __ vadd(result, left, right);
       break;
     case Token::SUB:
-      __ vsub(left, left, right);
+      __ vsub(result, left, right);
       break;
     case Token::MUL:
-      __ vmul(left, left, right);
+      __ vmul(result, left, right);
       break;
     case Token::DIV:
-      __ vdiv(left, left, right);
+      __ vdiv(result, left, right);
       break;
     case Token::MOD: {
       // Save r0-r3 on the stack.
@@ -1468,7 +1477,7 @@ void LCodeGen::DoArithmeticD(LArithmeticD* instr) {
           ExternalReference::double_fp_operation(Token::MOD, isolate()),
           0, 2);
       // Move the result in the double result register.
-      __ GetCFunctionDoubleResult(ToDoubleRegister(instr->result()));
+      __ GetCFunctionDoubleResult(result);
 
       // Restore r0-r3.
       __ ldm(ia_w, sp, r0.bit() | r1.bit() | r2.bit() | r3.bit());
@@ -1561,7 +1570,7 @@ void LCodeGen::DoBranch(LBranch* instr) {
 
       // Test double values. Zero and NaN are false.
       Label call_stub;
-      DoubleRegister dbl_scratch = d0;
+      DoubleRegister dbl_scratch = double_scratch0();
       Register scratch = scratch0();
       __ ldr(scratch, FieldMemOperand(reg, HeapObject::kMapOffset));
       __ LoadRoot(ip, Heap::kHeapNumberMapRootIndex);
@@ -2607,7 +2616,6 @@ void LCodeGen::DoLoadKeyedFastElement(LLoadKeyedFastElement* instr) {
   Register key = EmitLoadRegister(instr->key(), scratch0());
   Register result = ToRegister(instr->result());
   Register scratch = scratch0();
-  ASSERT(result.is(elements));
 
   // Load the result.
   __ add(scratch, elements, Operand(key, LSL, kPointerSizeLog2));
@@ -2927,8 +2935,8 @@ void LCodeGen::DoCallConstantFunction(LCallConstantFunction* instr) {
 
 
 void LCodeGen::DoDeferredMathAbsTaggedHeapNumber(LUnaryMathOperation* instr) {
-  ASSERT(instr->InputAt(0)->Equals(instr->result()));
   Register input = ToRegister(instr->InputAt(0));
+  Register result = ToRegister(instr->result());
   Register scratch = scratch0();
 
   // Deoptimize if not a heap number.
@@ -2942,10 +2950,10 @@ void LCodeGen::DoDeferredMathAbsTaggedHeapNumber(LUnaryMathOperation* instr) {
   scratch = no_reg;
   __ ldr(exponent, FieldMemOperand(input, HeapNumber::kExponentOffset));
   // Check the sign of the argument. If the argument is positive, just
-  // return it. We do not need to patch the stack since |input| and
-  // |result| are the same register and |input| would be restored
-  // unchanged by popping safepoint registers.
+  // return it.
   __ tst(exponent, Operand(HeapNumber::kSignMask));
+  // Move the input to the result if necessary.
+  __ Move(result, input);
   __ b(eq, &done);
 
   // Input is negative. Reverse its sign.
@@ -2985,7 +2993,7 @@ void LCodeGen::DoDeferredMathAbsTaggedHeapNumber(LUnaryMathOperation* instr) {
     __ ldr(tmp2, FieldMemOperand(input, HeapNumber::kMantissaOffset));
     __ str(tmp2, FieldMemOperand(tmp1, HeapNumber::kMantissaOffset));
 
-    __ StoreToSafepointRegisterSlot(tmp1, input);
+    __ StoreToSafepointRegisterSlot(tmp1, result);
   }
 
   __ bind(&done);
@@ -2994,11 +3002,13 @@ void LCodeGen::DoDeferredMathAbsTaggedHeapNumber(LUnaryMathOperation* instr) {
 
 void LCodeGen::EmitIntegerMathAbs(LUnaryMathOperation* instr) {
   Register input = ToRegister(instr->InputAt(0));
+  Register result = ToRegister(instr->result());
   __ cmp(input, Operand(0));
+  __ Move(result, input, pl);
   // We can make rsb conditional because the previous cmp instruction
   // will clear the V (overflow) flag and rsb won't set this flag
   // if input is positive.
-  __ rsb(input, input, Operand(0), SetCC, mi);
+  __ rsb(result, input, Operand(0), SetCC, mi);
   // Deoptimize on overflow.
   DeoptimizeIf(vs, instr->environment());
 }
@@ -3018,11 +3028,11 @@ void LCodeGen::DoMathAbs(LUnaryMathOperation* instr) {
     LUnaryMathOperation* instr_;
   };
 
-  ASSERT(instr->InputAt(0)->Equals(instr->result()));
   Representation r = instr->hydrogen()->value()->representation();
   if (r.IsDouble()) {
     DwVfpRegister input = ToDoubleRegister(instr->InputAt(0));
-    __ vabs(input, input);
+    DwVfpRegister result = ToDoubleRegister(instr->result());
+    __ vabs(result, input);
   } else if (r.IsInteger32()) {
     EmitIntegerMathAbs(instr);
   } else {
@@ -3100,7 +3110,7 @@ void LCodeGen::DoMathRound(LUnaryMathOperation* instr) {
   // Save the original sign for later comparison.
   __ and_(scratch2, scratch1, Operand(HeapNumber::kSignMask));
 
-  __ vmov(double_scratch0(), 0.5);
+  __ Vmov(double_scratch0(), 0.5);
   __ vadd(input, input, double_scratch0());
 
   // Check sign of the result: if the sign changed, the input
@@ -3137,24 +3147,17 @@ void LCodeGen::DoMathRound(LUnaryMathOperation* instr) {
 
 void LCodeGen::DoMathSqrt(LUnaryMathOperation* instr) {
   DoubleRegister input = ToDoubleRegister(instr->InputAt(0));
-  ASSERT(ToDoubleRegister(instr->result()).is(input));
-  __ vsqrt(input, input);
+  DoubleRegister result = ToDoubleRegister(instr->result());
+  __ vsqrt(result, input);
 }
 
 
 void LCodeGen::DoMathPowHalf(LUnaryMathOperation* instr) {
   DoubleRegister input = ToDoubleRegister(instr->InputAt(0));
-  Register scratch = scratch0();
-  SwVfpRegister single_scratch = double_scratch0().low();
-  DoubleRegister double_scratch = double_scratch0();
-  ASSERT(ToDoubleRegister(instr->result()).is(input));
-
+  DoubleRegister result = ToDoubleRegister(instr->result());
   // Add +0 to convert -0 to +0.
-  __ mov(scratch, Operand(0));
-  __ vmov(single_scratch, scratch);
-  __ vcvt_f64_s32(double_scratch, single_scratch);
-  __ vadd(input, input, double_scratch);
-  __ vsqrt(input, input);
+  __ vadd(result, input, kDoubleRegZero);
+  __ vsqrt(result, result);
 }
 
 
@@ -3753,8 +3756,8 @@ void LCodeGen::DoNumberTagI(LNumberTagI* instr) {
 void LCodeGen::DoDeferredNumberTagI(LNumberTagI* instr) {
   Label slow;
   Register reg = ToRegister(instr->InputAt(0));
-  DoubleRegister dbl_scratch = d0;
-  SwVfpRegister flt_scratch = s0;
+  DoubleRegister dbl_scratch = double_scratch0();
+  SwVfpRegister flt_scratch = dbl_scratch.low();
 
   // Preserve the value of all registers.
   PushSafepointRegistersScope scope(this, Safepoint::kWithRegisters);
@@ -3863,8 +3866,8 @@ void LCodeGen::EmitNumberUntagD(Register input_reg,
                                 bool deoptimize_on_undefined,
                                 LEnvironment* env) {
   Register scratch = scratch0();
-  SwVfpRegister flt_scratch = s0;
-  ASSERT(!result_reg.is(d0));
+  SwVfpRegister flt_scratch = double_scratch0().low();
+  ASSERT(!result_reg.is(double_scratch0()));
 
   Label load_smi, heap_number, done;
 

src/arm/lithium-codegen-arm.h

@@ -148,7 +148,7 @@ class LCodeGen BASE_EMBEDDED {
   HGraph* graph() const { return chunk_->graph(); }
 
   Register scratch0() { return r9; }
-  DwVfpRegister double_scratch0() { return d0; }
+  DwVfpRegister double_scratch0() { return d15; }
 
   int GetNextEmittedBlock(int block);
   LInstruction* GetNextInstruction();

src/arm/macro-assembler-arm.cc

@@ -309,9 +309,9 @@ void MacroAssembler::Move(Register dst, Handle<Object> value) {
 }
 
 
-void MacroAssembler::Move(Register dst, Register src) {
+void MacroAssembler::Move(Register dst, Register src, Condition cond) {
   if (!dst.is(src)) {
-    mov(dst, src);
+    mov(dst, src, LeaveCC, cond);
   }
 }
 
@@ -755,6 +755,23 @@ void MacroAssembler::VFPCompareAndLoadFlags(const DwVfpRegister src1,
   vmrs(fpscr_flags, cond);
 }
 
+void MacroAssembler::Vmov(const DwVfpRegister dst,
+                          const double imm,
+                          const Condition cond) {
+  ASSERT(CpuFeatures::IsEnabled(VFP3));
+  static const DoubleRepresentation minus_zero(-0.0);
+  static const DoubleRepresentation zero(0.0);
+  DoubleRepresentation value(imm);
+  // Handle special values first.
+  if (value.bits == zero.bits) {
+    vmov(dst, kDoubleRegZero, cond);
+  } else if (value.bits == minus_zero.bits) {
+    vneg(dst, kDoubleRegZero, cond);
+  } else {
+    vmov(dst, imm, cond);
+  }
+}
+
 
 void MacroAssembler::EnterFrame(StackFrame::Type type) {
   // r0-r3: preserved
@@ -3112,7 +3129,7 @@ void MacroAssembler::ClampDoubleToUint8(Register result_reg,
   Label done;
   Label in_bounds;
 
-  vmov(temp_double_reg, 0.0);
+  Vmov(temp_double_reg, 0.0);
   VFPCompareAndSetFlags(input_reg, temp_double_reg);
   b(gt, &above_zero);
 
@@ -3122,7 +3139,7 @@ void MacroAssembler::ClampDoubleToUint8(Register result_reg,
 
   // Double value is >= 255, return 255.
   bind(&above_zero);
-  vmov(temp_double_reg, 255.0);
+  Vmov(temp_double_reg, 255.0);
   VFPCompareAndSetFlags(input_reg, temp_double_reg);
   b(le, &in_bounds);
   mov(result_reg, Operand(255));
@@ -3130,7 +3147,7 @@ void MacroAssembler::ClampDoubleToUint8(Register result_reg,
 
   // In 0-255 range, round and truncate.
   bind(&in_bounds);
-  vmov(temp_double_reg, 0.5);
+  Vmov(temp_double_reg, 0.5);
   vadd(temp_double_reg, input_reg, temp_double_reg);
   vcvt_u32_f64(s0, temp_double_reg);
   vmov(result_reg, s0);

src/arm/macro-assembler-arm.h

@@ -143,7 +143,7 @@ class MacroAssembler: public Assembler {
 
   // Register move. May do nothing if the registers are identical.
   void Move(Register dst, Handle<Object> value);
-  void Move(Register dst, Register src);
+  void Move(Register dst, Register src, Condition cond = al);
   void Move(DoubleRegister dst, DoubleRegister src);
 
   // Load an object from the root table.
@@ -312,6 +312,10 @@ class MacroAssembler: public Assembler {
                               const Register fpscr_flags,
                               const Condition cond = al);
 
+  void Vmov(const DwVfpRegister dst,
+            const double imm,
+            const Condition cond = al);
+
 
   // ---------------------------------------------------------------------------
   // Activation frames