Handle non-power-of-2 divisors in division-like operations

src/a64/lithium-a64.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1351 matching lines @@
   return MarkAsCall(new(zone()) LDeclareGlobals(context), instr);
 }
 
 
 LInstruction* LChunkBuilder::DoDeoptimize(HDeoptimize* instr) {
   return AssignEnvironment(new(zone()) LDeoptimize);
 }
 
 
 LInstruction* LChunkBuilder::DoDivByPowerOf2I(HDiv* instr) {
-  ASSERT(instr->representation().IsSmiOrInteger32());
+  ASSERT(instr->representation().IsInteger32());
   ASSERT(instr->left()->representation().Equals(instr->representation()));
   ASSERT(instr->right()->representation().Equals(instr->representation()));
   LOperand* dividend = UseRegister(instr->left());
   int32_t divisor = instr->right()->GetInteger32Constant();
   LInstruction* result =
       DefineAsRegister(new(zone()) LDivByPowerOf2I(dividend, divisor));
   bool can_deopt =
       (instr->CheckFlag(HValue::kBailoutOnMinusZero) &&
        instr->left()->RangeCanInclude(0) && divisor < 0) ||
       (instr->CheckFlag(HValue::kCanOverflow) &&
        instr->left()->RangeCanInclude(kMinInt) && divisor == -1) ||
       (!instr->CheckFlag(HInstruction::kAllUsesTruncatingToInt32) &&
        divisor != 1 && divisor != -1);
   return can_deopt ? AssignEnvironment(result) : result;
 }
 
 
+LInstruction* LChunkBuilder::DoDivByConstI(HDiv* instr) {
+  ASSERT(instr->representation().IsInteger32());
+  ASSERT(instr->left()->representation().Equals(instr->representation()));
+  ASSERT(instr->right()->representation().Equals(instr->representation()));
+  LOperand* dividend = UseRegister(instr->left());
+  int32_t divisor = instr->right()->GetInteger32Constant();
+  bool truncating = instr->CheckFlag(HInstruction::kAllUsesTruncatingToInt32);
+  LOperand* temp = truncating ? NULL : TempRegister();
+  LInstruction* result =
+      DefineAsRegister(new(zone()) LDivByConstI(dividend, divisor, temp));
+  bool can_deopt =
+      divisor == 0 ||
+      (instr->CheckFlag(HValue::kBailoutOnMinusZero) &&
+       instr->left()->RangeCanInclude(0) && divisor < 0) ||
+      !truncating;
+  return can_deopt ? AssignEnvironment(result) : result;
+}
+
+
 LInstruction* LChunkBuilder::DoDivI(HBinaryOperation* instr) {
   ASSERT(instr->representation().IsSmiOrInteger32());
   ASSERT(instr->left()->representation().Equals(instr->representation()));
   ASSERT(instr->right()->representation().Equals(instr->representation()));
   LOperand* dividend = UseRegister(instr->left());
   LOperand* divisor = UseRegister(instr->right());
   LOperand* temp = instr->CheckFlag(HInstruction::kAllUsesTruncatingToInt32)
       ? NULL : TempRegister();
   LDivI* div = new(zone()) LDivI(dividend, divisor, temp);
   return AssignEnvironment(DefineAsRegister(div));
 }
 
 
 LInstruction* LChunkBuilder::DoDiv(HDiv* instr) {
   if (instr->representation().IsSmiOrInteger32()) {
-    // TODO(all): Add Smi support to DoDivI and turn this into a ternary.
-    if (instr->RightIsPowerOf2()) return DoDivByPowerOf2I(instr);
-    if (instr->representation().IsInteger32()) return DoDivI(instr);
-    return DoArithmeticT(Token::DIV, instr);
+    if (instr->RightIsPowerOf2()) {
+      return DoDivByPowerOf2I(instr);
+    } else if (instr->right()->IsConstant()) {
+      return DoDivByConstI(instr);
+    } else {
+      return DoDivI(instr);
+    }
   } else if (instr->representation().IsDouble()) {
     return DoArithmeticD(Token::DIV, instr);
   } else {
     return DoArithmeticT(Token::DIV, instr);
   }
 }
 
 
 LInstruction* LChunkBuilder::DoDummyUse(HDummyUse* instr) {
   return DefineAsRegister(new(zone()) LDummyUse(UseAny(instr->value())));
@@ skipping 288 matching lines @@
 }
 
 
 LInstruction* LChunkBuilder::DoMapEnumLength(HMapEnumLength* instr) {
   LOperand* map = UseRegisterAtStart(instr->value());
   return DefineAsRegister(new(zone()) LMapEnumLength(map));
 }
 
 
 LInstruction* LChunkBuilder::DoFlooringDivByPowerOf2I(HMathFloorOfDiv* instr) {
+  ASSERT(instr->representation().IsInteger32());
+  ASSERT(instr->left()->representation().Equals(instr->representation()));
+  ASSERT(instr->right()->representation().Equals(instr->representation()));
   LOperand* dividend = UseRegisterAtStart(instr->left());
   int32_t divisor = instr->right()->GetInteger32Constant();
   LInstruction* result =
       DefineSameAsFirst(new(zone()) LFlooringDivByPowerOf2I(dividend, divisor));
   bool can_deopt =
       (instr->CheckFlag(HValue::kBailoutOnMinusZero) && divisor < 0) ||
       (instr->left()->RangeCanInclude(kMinInt) && divisor == -1);
   return can_deopt ? AssignEnvironment(result) : result;
 }
 
 
+LInstruction* LChunkBuilder::DoFlooringDivByConstI(HMathFloorOfDiv* instr) {
+  ASSERT(instr->representation().IsInteger32());
+  ASSERT(instr->left()->representation().Equals(instr->representation()));
+  ASSERT(instr->right()->representation().Equals(instr->representation()));
+  LOperand* dividend = UseRegister(instr->left());
+  int32_t divisor = instr->right()->GetInteger32Constant();
+  LInstruction* result =
+      DefineAsRegister(new(zone()) LFlooringDivByConstI(dividend, divisor));
+  bool can_deopt =
+      divisor == 0 ||
+      (instr->CheckFlag(HValue::kBailoutOnMinusZero) &&
+       instr->left()->RangeCanInclude(0) && divisor < 0);
+  return can_deopt ? AssignEnvironment(result) : result;
+}
+
+
 LInstruction* LChunkBuilder::DoFlooringDivI(HMathFloorOfDiv* instr) {
   LOperand* dividend = UseRegister(instr->left());
   LOperand* divisor = UseRegister(instr->right());
   LOperand* remainder = TempRegister();
   LInstruction* result =
       DefineAsRegister(new(zone()) LFlooringDivI(dividend, divisor, remainder));
   return AssignEnvironment(result);
 }
 
 
 LInstruction* LChunkBuilder::DoMathFloorOfDiv(HMathFloorOfDiv* instr) {
   if (instr->RightIsPowerOf2()) {
     return DoFlooringDivByPowerOf2I(instr);
   } else if (instr->right()->IsConstant()) {
-    // TODO(svenpanne) Do something more efficient in this case.
-    return DoFlooringDivI(instr);
+    return DoFlooringDivByConstI(instr);
   } else {
     return DoFlooringDivI(instr);
   }
 }
 
 
 LInstruction* LChunkBuilder::DoMathMinMax(HMathMinMax* instr) {
   LOperand* left = NULL;
   LOperand* right = NULL;
   if (instr->representation().IsSmiOrInteger32()) {
     ASSERT(instr->left()->representation().Equals(instr->representation()));
     ASSERT(instr->right()->representation().Equals(instr->representation()));
     left = UseRegisterAtStart(instr->BetterLeftOperand());
     right = UseRegisterOrConstantAtStart(instr->BetterRightOperand());
   } else {
     ASSERT(instr->representation().IsDouble());
     ASSERT(instr->left()->representation().IsDouble());
     ASSERT(instr->right()->representation().IsDouble());
     left = UseRegisterAtStart(instr->left());
     right = UseRegisterAtStart(instr->right());
   }
   return DefineAsRegister(new(zone()) LMathMinMax(left, right));
 }
 
 
 LInstruction* LChunkBuilder::DoModByPowerOf2I(HMod* instr) {
-  ASSERT(instr->representation().IsSmiOrInteger32());
+  ASSERT(instr->representation().IsInteger32());
   ASSERT(instr->left()->representation().Equals(instr->representation()));
   ASSERT(instr->right()->representation().Equals(instr->representation()));
   LOperand* dividend = UseRegisterAtStart(instr->left());
   int32_t divisor = instr->right()->GetInteger32Constant();
   LInstruction* result =
       DefineSameAsFirst(new(zone()) LModByPowerOf2I(dividend, divisor));
   bool can_deopt =
       instr->CheckFlag(HValue::kBailoutOnMinusZero) &&
       instr->left()->CanBeNegative();
   return can_deopt ? AssignEnvironment(result) : result;
 }
 
 
+LInstruction* LChunkBuilder::DoModByConstI(HMod* instr) {
+  ASSERT(instr->representation().IsInteger32());
+  ASSERT(instr->left()->representation().Equals(instr->representation()));
+  ASSERT(instr->right()->representation().Equals(instr->representation()));
+  LOperand* dividend = UseRegister(instr->left());
+  int32_t divisor = instr->right()->GetInteger32Constant();
+  LOperand* temp = TempRegister();
+  LInstruction* result =
+      DefineAsRegister(new(zone()) LModByConstI(dividend, divisor, temp));
+  bool can_deopt =
+      divisor == 0 ||
+      (instr->CheckFlag(HValue::kBailoutOnMinusZero) &&
+       instr->left()->CanBeNegative());
+  return can_deopt ? AssignEnvironment(result) : result;
+}
+
+
 LInstruction* LChunkBuilder::DoModI(HMod* instr) {
   ASSERT(instr->representation().IsSmiOrInteger32());
   ASSERT(instr->left()->representation().Equals(instr->representation()));
   ASSERT(instr->right()->representation().Equals(instr->representation()));
   LOperand* dividend = UseRegister(instr->left());
   LOperand* divisor = UseRegister(instr->right());
   LInstruction* result =
       DefineAsRegister(new(zone()) LModI(dividend, divisor));
   bool can_deopt = (instr->right()->CanBeZero() ||
                     (instr->CheckFlag(HValue::kBailoutOnMinusZero) &&
                      instr->left()->CanBeNegative() && instr->CanBeZero()));
   return can_deopt ? AssignEnvironment(result) : result;
 }
 
 
 LInstruction* LChunkBuilder::DoMod(HMod* instr) {
   if (instr->representation().IsSmiOrInteger32()) {
-    // TODO(all): Add Smi support to DoDivI and turn this into a ternary.
-    if (instr->RightIsPowerOf2()) return DoModByPowerOf2I(instr);
-    if (instr->representation().IsInteger32()) return DoModI(instr);
-    return DoArithmeticT(Token::MOD, instr);
+    if (instr->RightIsPowerOf2()) {
+      return DoModByPowerOf2I(instr);
+    } else if (instr->right()->IsConstant()) {
+      return DoModByConstI(instr);
+    } else {
+      return DoModI(instr);
+    }
   } else if (instr->representation().IsDouble()) {
     return DoArithmeticD(Token::MOD, instr);
   } else {
     return DoArithmeticT(Token::MOD, instr);
   }
 }
 
 
 LInstruction* LChunkBuilder::DoMul(HMul* instr) {
   if (instr->representation().IsSmiOrInteger32()) {
@@ skipping 677 matching lines @@
 
 LInstruction* LChunkBuilder::DoWrapReceiver(HWrapReceiver* instr) {
   LOperand* receiver = UseRegister(instr->receiver());
   LOperand* function = UseRegister(instr->function());
   LWrapReceiver* result = new(zone()) LWrapReceiver(receiver, function);
   return AssignEnvironment(DefineAsRegister(result));
 }
 
 
 } }  // namespace v8::internal