MIPS: Fix Lithium div, mod and floor.

BUG=
R=plind44@gmail.com

Review URL: https://codereview.chromium.org/200423004

Patch from Balazs Kilvady <kilvadyb@homejinni.com>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19949 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

diff --git a/src/mips/lithium-codegen-mips.cc b/src/mips/lithium-codegen-mips.cc
index 0f19ce2..edbc9b5 100644 (file)
--- a/src/mips/lithium-codegen-mips.cc
+++ b/src/mips/lithium-codegen-mips.cc
@@ -1100,6 +1100,34 @@ void LCodeGen::DoModByPowerOf2I(LModByPowerOf2I* instr) {
 }
 
 
+void LCodeGen::DoModByConstI(LModByConstI* instr) {
+  Register dividend = ToRegister(instr->dividend());
+  int32_t divisor = instr->divisor();
+  Register result = ToRegister(instr->result());
+  ASSERT(!dividend.is(result));
+
+  if (divisor == 0) {
+    DeoptimizeIf(al, instr->environment());
+    return;
+  }
+
+  __ FlooringDiv(result, dividend, Abs(divisor));
+  __ srl(at, dividend, 31);
+  __ Addu(result, result, at);
+  __ Mul(result, result, Operand(Abs(divisor)));
+  __ Subu(result, dividend, Operand(result));
+
+  // Check for negative zero.
+  HMod* hmod = instr->hydrogen();
+  if (hmod->CheckFlag(HValue::kBailoutOnMinusZero)) {
+    Label remainder_not_zero;
+    __ Branch(&remainder_not_zero, ne, result, Operand(zero_reg));
+    DeoptimizeIf(lt, instr->environment(), dividend, Operand(zero_reg));
+    __ bind(&remainder_not_zero);
+  }
+}
+
+
 void LCodeGen::DoModI(LModI* instr) {
   HMod* hmod = instr->hydrogen();
   const Register left_reg = ToRegister(instr->left());
@@ -1141,6 +1169,80 @@ void LCodeGen::DoModI(LModI* instr) {
 }
 
 
+void LCodeGen::DoDivByPowerOf2I(LDivByPowerOf2I* instr) {
+  Register dividend = ToRegister(instr->dividend());
+  int32_t divisor = instr->divisor();
+  Register result = ToRegister(instr->result());
+  ASSERT(divisor == kMinInt || (divisor != 0 && IsPowerOf2(Abs(divisor))));
+  ASSERT(!result.is(dividend));
+
+  // Check for (0 / -x) that will produce negative zero.
+  HDiv* hdiv = instr->hydrogen();
+  if (hdiv->CheckFlag(HValue::kBailoutOnMinusZero) && divisor < 0) {
+    DeoptimizeIf(eq, instr->environment(), dividend, Operand(zero_reg));
+  }
+  // Check for (kMinInt / -1).
+  if (hdiv->CheckFlag(HValue::kCanOverflow) && divisor == -1) {
+    DeoptimizeIf(eq, instr->environment(), dividend, Operand(kMinInt));
+  }
+  // Deoptimize if remainder will not be 0.
+  if (!hdiv->CheckFlag(HInstruction::kAllUsesTruncatingToInt32) &&
+      divisor != 1 && divisor != -1) {
+    int32_t mask = divisor < 0 ? -(divisor + 1) : (divisor - 1);
+    __ And(at, dividend, Operand(mask));
+    DeoptimizeIf(ne, instr->environment(), at, Operand(zero_reg));
+  }
+
+  if (divisor == -1) {  // Nice shortcut, not needed for correctness.
+    __ Subu(result, zero_reg, dividend);
+    return;
+  }
+  uint16_t shift = WhichPowerOf2Abs(divisor);
+  if (shift == 0) {
+    __ Move(result, dividend);
+  } else if (shift == 1) {
+    __ srl(result, dividend, 31);
+    __ Addu(result, dividend, Operand(result));
+  } else {
+    __ sra(result, dividend, 31);
+    __ srl(result, result, 32 - shift);
+    __ Addu(result, dividend, Operand(result));
+  }
+  if (shift > 0) __ sra(result, result, shift);
+  if (divisor < 0) __ Subu(result, zero_reg, result);
+}
+
+
+void LCodeGen::DoDivByConstI(LDivByConstI* instr) {
+  Register dividend = ToRegister(instr->dividend());
+  int32_t divisor = instr->divisor();
+  Register result = ToRegister(instr->result());
+  ASSERT(!dividend.is(result));
+
+  if (divisor == 0) {
+    DeoptimizeIf(al, instr->environment());
+    return;
+  }
+
+  // Check for (0 / -x) that will produce negative zero.
+  HDiv* hdiv = instr->hydrogen();
+  if (hdiv->CheckFlag(HValue::kBailoutOnMinusZero) && divisor < 0) {
+    DeoptimizeIf(eq, instr->environment(), dividend, Operand(zero_reg));
+  }
+
+  __ FlooringDiv(result, dividend, Abs(divisor));
+  __ srl(at, dividend, 31);
+  __ Addu(result, result, Operand(at));
+  if (divisor < 0) __ Subu(result, zero_reg, result);
+
+  if (!hdiv->CheckFlag(HInstruction::kAllUsesTruncatingToInt32)) {
+    __ Mul(scratch0(), result, Operand(divisor));
+    __ Subu(scratch0(), scratch0(), dividend);
+    DeoptimizeIf(ne, instr->environment(), scratch0(), Operand(zero_reg));
+  }
+}
+
+
 void LCodeGen::DoDivI(LDivI* instr) {
   HBinaryOperation* hdiv = instr->hydrogen();
   const Register left = ToRegister(instr->left());
@@ -1173,11 +1275,24 @@ void LCodeGen::DoDivI(LDivI* instr) {
     __ bind(&left_not_min_int);
   }
 
-  if (!hdiv->CheckFlag(HValue::kAllUsesTruncatingToInt32)) {
+  if (hdiv->IsMathFloorOfDiv()) {
+    // We performed a truncating division. Correct the result if necessary.
+    Label done;
+    Register remainder = scratch0();
+    __ mfhi(remainder);
+    __ mflo(result);
+    __ Branch(&done, eq, remainder, Operand(zero_reg), USE_DELAY_SLOT);
+    __ Xor(remainder, remainder, Operand(right));
+    __ Branch(&done, ge, remainder, Operand(zero_reg));
+    __ Subu(result, result, Operand(1));
+    __ bind(&done);
+  } else if (!hdiv->CheckFlag(HValue::kAllUsesTruncatingToInt32)) {
     __ mfhi(result);
     DeoptimizeIf(ne, instr->environment(), result, Operand(zero_reg));
+    __ mflo(result);
+  } else {
+    __ mflo(result);
   }
-  __ mflo(result);
 }
 
 
@@ -1220,7 +1335,6 @@ void LCodeGen::DoFlooringDivByPowerOf2I(LFlooringDivByPowerOf2I* instr) {
   if (instr->hydrogen()->CheckFlag(HValue::kLeftCanBeMinInt)) {
     // Note that we could emit branch-free code, but that would need one more
     // register.
-
     __ Xor(at, scratch, result);
     if (divisor == -1) {
       DeoptimizeIf(ge, instr->environment(), at, Operand(zero_reg));
@@ -1261,50 +1375,6 @@ void LCodeGen::DoFlooringDivByConstI(LFlooringDivByConstI* instr) {
 }
 
 
-void LCodeGen::DoMathFloorOfDiv(LMathFloorOfDiv* instr) {
-  const Register result = ToRegister(instr->result());
-  const Register left = ToRegister(instr->left());
-  const Register remainder = ToRegister(instr->temp());
-  const Register scratch = scratch0();
-
-  Label done;
-  const Register right = ToRegister(instr->right());
-
-  // On MIPS div is asynchronous - it will run in the background while we
-  // check for special cases.
-  __ div(left, right);
-
-  // Check for x / 0.
-  DeoptimizeIf(eq, instr->environment(), right, Operand(zero_reg));
-
-  // Check for (0 / -x) that will produce negative zero.
-  if (instr->hydrogen()->CheckFlag(HValue::kBailoutOnMinusZero)) {
-    Label left_not_zero;
-    __ Branch(&left_not_zero, ne, left, Operand(zero_reg));
-    DeoptimizeIf(lt, instr->environment(), right, Operand(zero_reg));
-    __ bind(&left_not_zero);
-  }
-
-  // Check for (kMinInt / -1).
-  if (instr->hydrogen()->CheckFlag(HValue::kCanOverflow)) {
-    Label left_not_min_int;
-    __ Branch(&left_not_min_int, ne, left, Operand(kMinInt));
-    DeoptimizeIf(eq, instr->environment(), right, Operand(-1));
-    __ bind(&left_not_min_int);
-  }
-
-  __ mfhi(remainder);
-  __ mflo(result);
-
-  // We performed a truncating division. Correct the result if necessary.
-  __ Branch(&done, eq, remainder, Operand(zero_reg), USE_DELAY_SLOT);
-  __ Xor(scratch , remainder, Operand(right));
-  __ Branch(&done, ge, scratch, Operand(zero_reg));
-  __ Subu(result, result, Operand(1));
-  __ bind(&done);
-}
-
-
 void LCodeGen::DoMulI(LMulI* instr) {
   Register scratch = scratch0();
   Register result = ToRegister(instr->result());

diff --git a/src/mips/lithium-mips.cc b/src/mips/lithium-mips.cc
index ca3c28f..d2473fc 100644 (file)
--- a/src/mips/lithium-mips.cc
+++ b/src/mips/lithium-mips.cc
@@ -1255,6 +1255,41 @@ LInstruction* LChunkBuilder::DoBitwise(HBitwise* instr) {
 }
 
 
+LInstruction* LChunkBuilder::DoDivByPowerOf2I(HDiv* 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();
+  LInstruction* result = DefineAsRegister(new(zone()) LDivByPowerOf2I(
+          dividend, divisor));
+  if ((instr->CheckFlag(HValue::kBailoutOnMinusZero) && divisor < 0) ||
+      (instr->CheckFlag(HValue::kCanOverflow) && divisor == -1) ||
+      (!instr->CheckFlag(HInstruction::kAllUsesTruncatingToInt32) &&
+       divisor != 1 && divisor != -1)) {
+    result = AssignEnvironment(result);
+  }
+  return 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();
+  LInstruction* result = DefineAsRegister(new(zone()) LDivByConstI(
+          dividend, divisor));
+  if (divisor == 0 ||
+      (instr->CheckFlag(HValue::kBailoutOnMinusZero) && divisor < 0) ||
+      !instr->CheckFlag(HInstruction::kAllUsesTruncatingToInt32)) {
+    result = AssignEnvironment(result);
+  }
+  return result;
+}
+
+
 LInstruction* LChunkBuilder::DoDivI(HBinaryOperation* instr) {
   ASSERT(instr->representation().IsSmiOrInteger32());
   ASSERT(instr->left()->representation().Equals(instr->representation()));
@@ -1268,7 +1303,13 @@ LInstruction* LChunkBuilder::DoDivI(HBinaryOperation* instr) {
 
 LInstruction* LChunkBuilder::DoDiv(HDiv* instr) {
   if (instr->representation().IsSmiOrInteger32()) {
-    return 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 {
@@ -1308,15 +1349,10 @@ LInstruction* LChunkBuilder::DoFlooringDivByConstI(HMathFloorOfDiv* instr) {
 LInstruction* LChunkBuilder::DoMathFloorOfDiv(HMathFloorOfDiv* instr) {
   if (instr->RightIsPowerOf2()) {
     return DoFlooringDivByPowerOf2I(instr);
-  } else if (instr->right()->IsConstant()) {
-    return DoFlooringDivByConstI(instr);
+  } else if (false && instr->right()->IsConstant()) {
+    return DoFlooringDivByConstI(instr);  // TODO(svenpanne) Fix and re-enable.
   } else {
-    HValue* right = instr->right();
-    LOperand* dividend = UseRegister(instr->left());
-    LOperand* divisor = UseRegisterOrConstant(right);
-    LOperand* remainder = TempRegister();
-    return AssignEnvironment(DefineAsRegister(
-        new(zone()) LMathFloorOfDiv(dividend, divisor, remainder)));
+    return DoDivI(instr);
   }
 }
 
@@ -1336,6 +1372,21 @@ 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();
+  LInstruction* result = DefineAsRegister(new(zone()) LModByConstI(
+          dividend, divisor));
+  if (divisor == 0 || instr->CheckFlag(HValue::kBailoutOnMinusZero)) {
+    result = AssignEnvironment(result);
+  }
+  return result;
+}
+
+
 LInstruction* LChunkBuilder::DoModI(HMod* instr) {
   ASSERT(instr->representation().IsSmiOrInteger32());
   ASSERT(instr->left()->representation().Equals(instr->representation()));

diff --git a/src/mips/lithium-mips.h b/src/mips/lithium-mips.h
index 1cfcbc8..81f7fb6 100644 (file)
--- a/src/mips/lithium-mips.h
+++ b/src/mips/lithium-mips.h
@@ -86,6 +86,8 @@ class LCodeGen;
   V(DebugBreak)                                 \
   V(DeclareGlobals)                             \
   V(Deoptimize)                                 \
+  V(DivByConstI)                                \
+  V(DivByPowerOf2I)                             \
   V(DivI)                                       \
   V(DoubleToI)                                  \
   V(DoubleBits)                                 \
@@ -130,12 +132,12 @@ class LCodeGen;
   V(MathExp)                                    \
   V(MathClz32)                                  \
   V(MathFloor)                                  \
-  V(MathFloorOfDiv)                             \
   V(MathLog)                                    \
   V(MathMinMax)                                 \
   V(MathPowHalf)                                \
   V(MathRound)                                  \
   V(MathSqrt)                                   \
+  V(ModByConstI)                                \
   V(ModByPowerOf2I)                             \
   V(ModI)                                       \
   V(MulI)                                       \
@@ -635,6 +637,24 @@ class LModByPowerOf2I V8_FINAL : public LTemplateInstruction<1, 1, 0> {
 };
 
 
+class LModByConstI V8_FINAL : public LTemplateInstruction<1, 1, 0> {
+ public:
+  LModByConstI(LOperand* dividend, int32_t divisor) {
+    inputs_[0] = dividend;
+    divisor_ = divisor;
+  }
+
+  LOperand* dividend() { return inputs_[0]; }
+  int32_t divisor() const { return divisor_; }
+
+  DECLARE_CONCRETE_INSTRUCTION(ModByConstI, "mod-by-const-i")
+  DECLARE_HYDROGEN_ACCESSOR(Mod)
+
+ private:
+  int32_t divisor_;
+};
+
+
 class LModI V8_FINAL : public LTemplateInstruction<1, 2, 3> {
  public:
   LModI(LOperand* left,
@@ -651,6 +671,42 @@ class LModI V8_FINAL : public LTemplateInstruction<1, 2, 3> {
 };
 
 
+class LDivByPowerOf2I V8_FINAL : public LTemplateInstruction<1, 1, 0> {
+ public:
+  LDivByPowerOf2I(LOperand* dividend, int32_t divisor) {
+    inputs_[0] = dividend;
+    divisor_ = divisor;
+  }
+
+  LOperand* dividend() { return inputs_[0]; }
+  int32_t divisor() const { return divisor_; }
+
+  DECLARE_CONCRETE_INSTRUCTION(DivByPowerOf2I, "div-by-power-of-2-i")
+  DECLARE_HYDROGEN_ACCESSOR(Div)
+
+ private:
+  int32_t divisor_;
+};
+
+
+class LDivByConstI V8_FINAL : public LTemplateInstruction<1, 1, 0> {
+ public:
+  LDivByConstI(LOperand* dividend, int32_t divisor) {
+    inputs_[0] = dividend;
+    divisor_ = divisor;
+  }
+
+  LOperand* dividend() { return inputs_[0]; }
+  int32_t divisor() const { return divisor_; }
+
+  DECLARE_CONCRETE_INSTRUCTION(DivByConstI, "div-by-const-i")
+  DECLARE_HYDROGEN_ACCESSOR(Div)
+
+ private:
+  int32_t divisor_;
+};
+
+
 class LDivI V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LDivI(LOperand* left, LOperand* right) {
@@ -704,25 +760,6 @@ class LFlooringDivByConstI V8_FINAL : public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LMathFloorOfDiv V8_FINAL : public LTemplateInstruction<1, 2, 1> {
- public:
-  LMathFloorOfDiv(LOperand* left,
-                  LOperand* right,
-                  LOperand* temp = NULL) {
-    inputs_[0] = left;
-    inputs_[1] = right;
-    temps_[0] = temp;
-  }
-
-  LOperand* left() { return inputs_[0]; }
-  LOperand* right() { return inputs_[1]; }
-  LOperand* temp() { return temps_[0]; }
-
-  DECLARE_CONCRETE_INSTRUCTION(MathFloorOfDiv, "math-floor-of-div")
-  DECLARE_HYDROGEN_ACCESSOR(MathFloorOfDiv)
-};
-
-
 class LMulI V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LMulI(LOperand* left, LOperand* right) {
@@ -2639,8 +2676,11 @@ class LChunkBuilder V8_FINAL : public LChunkBuilderBase {
   LInstruction* DoMathSqrt(HUnaryMathOperation* instr);
   LInstruction* DoMathPowHalf(HUnaryMathOperation* instr);
   LInstruction* DoMathClz32(HUnaryMathOperation* instr);
+  LInstruction* DoDivByPowerOf2I(HDiv* instr);
+  LInstruction* DoDivByConstI(HDiv* instr);
   LInstruction* DoDivI(HBinaryOperation* instr);
   LInstruction* DoModByPowerOf2I(HMod* instr);
+  LInstruction* DoModByConstI(HMod* instr);
   LInstruction* DoModI(HMod* instr);
   LInstruction* DoFlooringDivByPowerOf2I(HMathFloorOfDiv* instr);
   LInstruction* DoFlooringDivByConstI(HMathFloorOfDiv* instr);