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

src/x64/lithium-x64.cc

 // Copyright 2012 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 1243 matching lines @@
       (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();
+  LOperand* temp1 = FixedTemp(rax);
+  LOperand* temp2 = FixedTemp(rdx);
+  LInstruction* result =
+      DefineFixed(
+          new(zone()) LDivByConstI(dividend, divisor, temp1, temp2), rdx);
+  bool can_deopt =
+      divisor == 0 ||
+      (instr->CheckFlag(HValue::kBailoutOnMinusZero) &&
+       instr->left()->RangeCanInclude(0) && divisor < 0) ||
+      !instr->CheckFlag(HInstruction::kAllUsesTruncatingToInt32);
+  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 = UseFixed(instr->left(), rax);
   LOperand* divisor = UseRegister(instr->right());
   LOperand* temp = FixedTemp(rdx);
   LInstruction* result =
       DefineFixed(new(zone()) LDivI(dividend, divisor, temp), rax);
   return AssignEnvironment(result);
 }
 
 
 LInstruction* LChunkBuilder::DoDiv(HDiv* instr) {
   if (instr->representation().IsSmiOrInteger32()) {
-    return instr->RightIsPowerOf2() ? DoDivByPowerOf2I(instr) : DoDivI(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::DoFlooringDivByPowerOf2I(HMathFloorOfDiv* instr) {
   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) {
-  LOperand* dividend = UseRegisterAtStart(instr->left());
+  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();
+  LOperand* temp1 = FixedTemp(rax);
+  LOperand* temp2 = FixedTemp(rdx);
   LInstruction* result =
-      DefineAsRegister(
-          new(zone()) LFlooringDivByConstI(dividend, divisor, temp));
-  bool can_deopt = divisor <= 0;
+      DefineFixed(new(zone()) LFlooringDivByConstI(dividend,
+                                                   divisor,
+                                                   temp1,
+                                                   temp2),
+                  rdx);
+  bool can_deopt =
+      divisor == 0 ||
+      (instr->CheckFlag(HValue::kBailoutOnMinusZero) &&
+       instr->left()->RangeCanInclude(0) && divisor < 0);
   return can_deopt ? AssignEnvironment(result) : result;
 }
 
 
 LInstruction* LChunkBuilder::DoMathFloorOfDiv(HMathFloorOfDiv* instr) {
   if (instr->RightIsPowerOf2()) {
     return DoFlooringDivByPowerOf2I(instr);
   } else if (instr->right()->IsConstant()) {
     return DoFlooringDivByConstI(instr);
   } else {
@@ skipping 10 matching lines @@
   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().IsSmiOrInteger32());
+  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* temp1 = FixedTemp(rax);
+  LOperand* temp2 = FixedTemp(rdx);
+  LInstruction* result =
+      DefineFixed(
+          new(zone()) LModByConstI(dividend, divisor, temp1, temp2), rax);
+  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 = UseFixed(instr->left(), rax);
   LOperand* divisor = UseRegister(instr->right());
   LOperand* temp = FixedTemp(rdx);
   LInstruction* result =
       DefineFixed(new(zone()) LModI(dividend, divisor, temp), rdx);
   bool can_deopt = (instr->right()->CanBeZero() ||
                     (instr->CheckFlag(HValue::kBailoutOnMinusZero) &&
                      instr->left()->RangeCanInclude(kMinInt) &&
                      instr->right()->RangeCanInclude(-1)) ||
                     (instr->CheckFlag(HValue::kBailoutOnMinusZero) &&
                      instr->left()->CanBeNegative() &&
                      instr->CanBeZero()));
   return can_deopt ? AssignEnvironment(result) : result;
 }
 
 
 LInstruction* LChunkBuilder::DoMod(HMod* instr) {
   if (instr->representation().IsSmiOrInteger32()) {
-    return  instr->RightIsPowerOf2() ? DoModByPowerOf2I(instr) : DoModI(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 1086 matching lines @@
 LInstruction* LChunkBuilder::DoLoadFieldByIndex(HLoadFieldByIndex* instr) {
   LOperand* object = UseRegister(instr->object());
   LOperand* index = UseTempRegister(instr->index());
   return DefineSameAsFirst(new(zone()) LLoadFieldByIndex(object, index));
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64