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

src/ia32/lithium-ia32.cc

Index: src/ia32/lithium-ia32.cc
diff --git a/src/ia32/lithium-ia32.cc b/src/ia32/lithium-ia32.cc
index 4ff765b87bb83cca9cd703fe3f6d60731c2c2621..3153584553c250fb1d4e7f9f0732a99e610c547d 100644
--- a/src/ia32/lithium-ia32.cc
+++ b/src/ia32/lithium-ia32.cc
@@ -1340,6 +1340,26 @@ LInstruction* LChunkBuilder::DoDivByPowerOf2I(HDiv* instr) {
 }
 
 
+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(eax);
+  LOperand* temp2 = FixedTemp(edx);
+  LInstruction* result =
+      DefineFixed(
+          new(zone()) LDivByConstI(dividend, divisor, temp1, temp2), edx);
+  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()));
@@ -1347,14 +1367,21 @@ LInstruction* LChunkBuilder::DoDivI(HBinaryOperation* instr) {
   LOperand* dividend = UseFixed(instr->left(), eax);
   LOperand* divisor = UseRegister(instr->right());
   LOperand* temp = FixedTemp(edx);
-  LDivI* result = new(zone()) LDivI(dividend, divisor, temp);
-  return AssignEnvironment(DefineFixed(result, eax));
+  LInstruction* result =
+      DefineFixed(new(zone()) LDivI(dividend, divisor, temp), eax);
+  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 {
@@ -1376,13 +1403,23 @@ LInstruction* LChunkBuilder::DoFlooringDivByPowerOf2I(HMathFloorOfDiv* instr) {
 
 
 LInstruction* LChunkBuilder::DoFlooringDivByConstI(HMathFloorOfDiv* instr) {
-  LOperand* dividend = UseFixed(instr->left(), eax);
+  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(eax);
+  LOperand* temp2 = FixedTemp(edx);
   LInstruction* result =
-      DefineFixed(
-          new(zone()) LFlooringDivByConstI(dividend, divisor, temp), edx);
-  bool can_deopt = divisor <= 0;
+      DefineFixed(new(zone()) LFlooringDivByConstI(dividend,
+                                                   divisor,
+                                                   temp1,
+                                                   temp2),
+                  edx);
+  bool can_deopt =
+      divisor == 0 ||
+      (instr->CheckFlag(HValue::kBailoutOnMinusZero) &&
+       instr->left()->RangeCanInclude(0) && divisor < 0);
   return can_deopt ? AssignEnvironment(result) : result;
 }
 
@@ -1413,6 +1450,25 @@ LInstruction* LChunkBuilder::DoModByPowerOf2I(HMod* instr) {
 }
 
 
+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(eax);
+  LOperand* temp2 = FixedTemp(edx);
+  LInstruction* result =
+      DefineFixed(
+          new(zone()) LModByConstI(dividend, divisor, temp1, temp2), eax);
+  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()));
@@ -1435,7 +1491,13 @@ LInstruction* LChunkBuilder::DoModI(HMod* instr) {
 
 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 {