Reland "Handle non-power-of-2 divisors in division-like operations".

src/a64/lithium-a64.cc

Index: src/a64/lithium-a64.cc
diff --git a/src/a64/lithium-a64.cc b/src/a64/lithium-a64.cc
index 12812bbf2e4f8b74928d0f56b4ad41b8981b670c..dff700324ff74c9661a97aa71dbfbdd101a9de0a 100644
--- a/src/a64/lithium-a64.cc
+++ b/src/a64/lithium-a64.cc
@@ -1369,7 +1369,7 @@ LInstruction* LChunkBuilder::DoDeoptimize(HDeoptimize* instr) {
 
 
 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());
@@ -1387,6 +1387,25 @@ 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();
+  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()));
@@ -1402,10 +1421,13 @@ LInstruction* LChunkBuilder::DoDivI(HBinaryOperation* instr) {
 
 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 {
@@ -1714,6 +1736,9 @@ LInstruction* LChunkBuilder::DoMapEnumLength(HMapEnumLength* instr) {
 
 
 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 =
@@ -1725,6 +1750,22 @@ LInstruction* LChunkBuilder::DoFlooringDivByPowerOf2I(HMathFloorOfDiv* instr) {
 }
 
 
+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());
@@ -1739,8 +1780,7 @@ 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);
   }
@@ -1767,7 +1807,7 @@ LInstruction* LChunkBuilder::DoMathMinMax(HMathMinMax* instr) {
 
 
 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());
@@ -1781,6 +1821,23 @@ LInstruction* LChunkBuilder::DoModByPowerOf2I(HMod* instr) {
 }
 
 
+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()));
@@ -1798,10 +1855,13 @@ LInstruction* LChunkBuilder::DoModI(HMod* instr) {
 
 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 {