Only assign environments when they are actually needed. (ARM and ARM64 only)

Twin of https://codereview.chromium.org/210783003/ and https://codereview.chromium.org/211153003/.

Cleaned up DoChange a bit on the way, making things more uniform across platforms, removed useless comments etc.

R=yangguo@chromium.org

Review URL: https://codereview.chromium.org/214613004

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@20376 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

diff --git a/src/arm/lithium-arm.cc b/src/arm/lithium-arm.cc
index ba44b509e1cc9f3d2e81b4131957e8f5ec513c0b..b9f6c33d400e24902139c980d58945bf7db48c65 100644 (file)
--- a/src/arm/lithium-arm.cc
+++ b/src/arm/lithium-arm.cc
@@ -931,18 +931,20 @@ LInstruction* LChunkBuilder::DoBranch(HBranch* instr) {
   if (goto_instr != NULL) return goto_instr;
 
   HValue* value = instr->value();
-  LBranch* result = new(zone()) LBranch(UseRegister(value));
-  // Tagged values that are not known smis or booleans require a
-  // deoptimization environment. If the instruction is generic no
-  // environment is needed since all cases are handled.
-  Representation rep = value->representation();
+  Representation r = value->representation();
   HType type = value->type();
   ToBooleanStub::Types expected = instr->expected_input_types();
-  if (rep.IsTagged() && !type.IsSmi() && !type.IsBoolean() &&
-      !expected.IsGeneric()) {
-    return AssignEnvironment(result);
+  if (expected.IsEmpty()) expected = ToBooleanStub::Types::Generic();
+
+  bool easy_case = !r.IsTagged() || type.IsBoolean() || type.IsSmi() ||
+      type.IsJSArray() || type.IsHeapNumber() || type.IsString();
+  LInstruction* branch = new(zone()) LBranch(UseRegister(value));
+  if (!easy_case &&
+      ((!expected.Contains(ToBooleanStub::SMI) && expected.NeedsMap()) ||
+       !expected.IsGeneric())) {
+    branch = AssignEnvironment(branch);
   }
-  return result;
+  return branch;
 }
 
 
@@ -1138,8 +1140,11 @@ LInstruction* LChunkBuilder::DoMathAbs(HUnaryMathOperation* instr) {
       ? NULL
       : UseFixed(instr->context(), cp);
   LOperand* input = UseRegister(instr->value());
-  LMathAbs* result = new(zone()) LMathAbs(context, input);
-  return AssignEnvironment(AssignPointerMap(DefineAsRegister(result)));
+  LInstruction* result =
+      DefineAsRegister(new(zone()) LMathAbs(context, input));
+  if (!r.IsDouble() && !r.IsSmiOrInteger32()) result = AssignPointerMap(result);
+  if (!r.IsDouble()) result = AssignEnvironment(result);
+  return result;
 }
 
 
@@ -1291,8 +1296,18 @@ LInstruction* LChunkBuilder::DoDivI(HBinaryOperation* instr) {
   LOperand* dividend = UseRegister(instr->left());
   LOperand* divisor = UseRegister(instr->right());
   LOperand* temp = CpuFeatures::IsSupported(SUDIV) ? NULL : FixedTemp(d4);
-  LDivI* div = new(zone()) LDivI(dividend, divisor, temp);
-  return AssignEnvironment(DefineAsRegister(div));
+  LInstruction* result =
+      DefineAsRegister(new(zone()) LDivI(dividend, divisor, temp));
+  if (instr->CheckFlag(HValue::kCanBeDivByZero) ||
+      instr->CheckFlag(HValue::kBailoutOnMinusZero) ||
+      (instr->CheckFlag(HValue::kCanOverflow) &&
+       (!CpuFeatures::IsSupported(SUDIV) ||
+        !instr->CheckFlag(HValue::kAllUsesTruncatingToInt32))) ||
+      (!instr->IsMathFloorOfDiv() &&
+       !instr->CheckFlag(HValue::kAllUsesTruncatingToInt32))) {
+    result = AssignEnvironment(result);
+  }
+  return result;
 }
 
 
@@ -1837,20 +1852,21 @@ LInstruction* LChunkBuilder::DoForceRepresentation(HForceRepresentation* bad) {
 LInstruction* LChunkBuilder::DoChange(HChange* instr) {
   Representation from = instr->from();
   Representation to = instr->to();
+  HValue* val = instr->value();
   if (from.IsSmi()) {
     if (to.IsTagged()) {
-      LOperand* value = UseRegister(instr->value());
+      LOperand* value = UseRegister(val);
       return DefineSameAsFirst(new(zone()) LDummyUse(value));
     }
     from = Representation::Tagged();
   }
   if (from.IsTagged()) {
     if (to.IsDouble()) {
-      LOperand* value = UseRegister(instr->value());
-      LNumberUntagD* res = new(zone()) LNumberUntagD(value);
-      return AssignEnvironment(DefineAsRegister(res));
+      LOperand* value = UseRegister(val);
+      LInstruction* result = DefineAsRegister(new(zone()) LNumberUntagD(value));
+      if (!val->representation().IsSmi()) result = AssignEnvironment(result);
+      return result;
     } else if (to.IsSmi()) {
-      HValue* val = instr->value();
       LOperand* value = UseRegister(val);
       if (val->type().IsSmi()) {
         return DefineSameAsFirst(new(zone()) LDummyUse(value));
@@ -1858,66 +1874,62 @@ LInstruction* LChunkBuilder::DoChange(HChange* instr) {
       return AssignEnvironment(DefineSameAsFirst(new(zone()) LCheckSmi(value)));
     } else {
       ASSERT(to.IsInteger32());
-      LOperand* value = NULL;
-      LInstruction* res = NULL;
-      HValue* val = instr->value();
       if (val->type().IsSmi() || val->representation().IsSmi()) {
-        value = UseRegisterAtStart(val);
-        res = DefineAsRegister(new(zone()) LSmiUntag(value, false));
+        LOperand* value = UseRegisterAtStart(val);
+        return DefineAsRegister(new(zone()) LSmiUntag(value, false));
       } else {
-        value = UseRegister(val);
+        LOperand* value = UseRegister(val);
         LOperand* temp1 = TempRegister();
         LOperand* temp2 = FixedTemp(d11);
-        res = DefineSameAsFirst(new(zone()) LTaggedToI(value,
-                                                       temp1,
-                                                       temp2));
-        res = AssignEnvironment(res);
+        LInstruction* result =
+            DefineSameAsFirst(new(zone()) LTaggedToI(value, temp1, temp2));
+        if (!val->representation().IsSmi()) {
+          // Note: Only deopts in deferred code.
+          result = AssignEnvironment(result);
+        }
+        return result;
       }
-      return res;
     }
   } else if (from.IsDouble()) {
     if (to.IsTagged()) {
       info()->MarkAsDeferredCalling();
-      LOperand* value = UseRegister(instr->value());
+      LOperand* value = UseRegister(val);
       LOperand* temp1 = TempRegister();
       LOperand* temp2 = TempRegister();
-
-      // Make sure that the temp and result_temp registers are
-      // different.
       LUnallocated* result_temp = TempRegister();
       LNumberTagD* result = new(zone()) LNumberTagD(value, temp1, temp2);
-      Define(result, result_temp);
-      return AssignPointerMap(result);
+      return AssignPointerMap(Define(result, result_temp));
     } else if (to.IsSmi()) {
-      LOperand* value = UseRegister(instr->value());
+      LOperand* value = UseRegister(val);
       return AssignEnvironment(
           DefineAsRegister(new(zone()) LDoubleToSmi(value)));
     } else {
       ASSERT(to.IsInteger32());
-      LOperand* value = UseRegister(instr->value());
-      LDoubleToI* res = new(zone()) LDoubleToI(value);
-      return AssignEnvironment(DefineAsRegister(res));
+      LOperand* value = UseRegister(val);
+      LInstruction* result = DefineAsRegister(new(zone()) LDoubleToI(value));
+      if (!instr->CanTruncateToInt32()) result = AssignEnvironment(result);
+      return result;
     }
   } else if (from.IsInteger32()) {
     info()->MarkAsDeferredCalling();
     if (to.IsTagged()) {
-      HValue* val = instr->value();
-      LOperand* value = UseRegisterAtStart(val);
       if (!instr->CheckFlag(HValue::kCanOverflow)) {
+        LOperand* value = UseRegisterAtStart(val);
         return DefineAsRegister(new(zone()) LSmiTag(value));
       } else if (val->CheckFlag(HInstruction::kUint32)) {
+        LOperand* value = UseRegisterAtStart(val);
         LOperand* temp1 = TempRegister();
         LOperand* temp2 = TempRegister();
         LNumberTagU* result = new(zone()) LNumberTagU(value, temp1, temp2);
-        return AssignEnvironment(AssignPointerMap(DefineAsRegister(result)));
+        return AssignPointerMap(DefineAsRegister(result));
       } else {
+        LOperand* value = UseRegisterAtStart(val);
         LOperand* temp1 = TempRegister();
         LOperand* temp2 = TempRegister();
         LNumberTagI* result = new(zone()) LNumberTagI(value, temp1, temp2);
-        return AssignEnvironment(AssignPointerMap(DefineAsRegister(result)));
+        return AssignPointerMap(DefineAsRegister(result));
       }
     } else if (to.IsSmi()) {
-      HValue* val = instr->value();
       LOperand* value = UseRegister(val);
       LInstruction* result = DefineAsRegister(new(zone()) LSmiTag(value));
       if (instr->CheckFlag(HValue::kCanOverflow)) {
@@ -1926,12 +1938,10 @@ LInstruction* LChunkBuilder::DoChange(HChange* instr) {
       return result;
     } else {
       ASSERT(to.IsDouble());
-      if (instr->value()->CheckFlag(HInstruction::kUint32)) {
-        return DefineAsRegister(
-            new(zone()) LUint32ToDouble(UseRegister(instr->value())));
+      if (val->CheckFlag(HInstruction::kUint32)) {
+        return DefineAsRegister(new(zone()) LUint32ToDouble(UseRegister(val)));
       } else {
-        return DefineAsRegister(
-            new(zone()) LInteger32ToDouble(Use(instr->value())));
+        return DefineAsRegister(new(zone()) LInteger32ToDouble(Use(val)));
       }
     }
   }
@@ -1973,6 +1983,7 @@ LInstruction* LChunkBuilder::DoCheckMaps(HCheckMaps* instr) {
   }
   LCheckMaps* result = new(zone()) LCheckMaps(value);
   if (!instr->CanOmitMapChecks()) {
+    // Note: Only deopts in deferred code.
     AssignEnvironment(result);
     if (instr->has_migration_target()) return AssignPointerMap(result);
   }
@@ -2072,7 +2083,10 @@ LInstruction* LChunkBuilder::DoLoadContextSlot(HLoadContextSlot* instr) {
   LOperand* context = UseRegisterAtStart(instr->value());
   LInstruction* result =
       DefineAsRegister(new(zone()) LLoadContextSlot(context));
-  return instr->RequiresHoleCheck() ? AssignEnvironment(result) : result;
+  if (instr->RequiresHoleCheck() && instr->DeoptimizesOnHole()) {
+    result = AssignEnvironment(result);
+  }
+  return result;
 }
 
 
@@ -2087,7 +2101,10 @@ LInstruction* LChunkBuilder::DoStoreContextSlot(HStoreContextSlot* instr) {
     value = UseRegister(instr->value());
   }
   LInstruction* result = new(zone()) LStoreContextSlot(context, value);
-  return instr->RequiresHoleCheck() ? AssignEnvironment(result) : result;
+  if (instr->RequiresHoleCheck() && instr->DeoptimizesOnHole()) {
+    result = AssignEnvironment(result);
+  }
+  return result;
 }
 
 
@@ -2122,7 +2139,7 @@ LInstruction* LChunkBuilder::DoLoadKeyed(HLoadKeyed* instr) {
   ASSERT(instr->key()->representation().IsSmiOrInteger32());
   ElementsKind elements_kind = instr->elements_kind();
   LOperand* key = UseRegisterOrConstantAtStart(instr->key());
-  LLoadKeyed* result = NULL;
+  LInstruction* result = NULL;
 
   if (!instr->is_typed_elements()) {
     LOperand* obj = NULL;
@@ -2132,24 +2149,28 @@ LInstruction* LChunkBuilder::DoLoadKeyed(HLoadKeyed* instr) {
       ASSERT(instr->representation().IsSmiOrTagged());
       obj = UseRegisterAtStart(instr->elements());
     }
-    result = new(zone()) LLoadKeyed(obj, key);
+    result = DefineAsRegister(new(zone()) LLoadKeyed(obj, key));
   } else {
     ASSERT(
         (instr->representation().IsInteger32() &&
-         !IsDoubleOrFloatElementsKind(instr->elements_kind())) ||
+         !IsDoubleOrFloatElementsKind(elements_kind)) ||
         (instr->representation().IsDouble() &&
-         IsDoubleOrFloatElementsKind(instr->elements_kind())));
+         IsDoubleOrFloatElementsKind(elements_kind)));
     LOperand* backing_store = UseRegister(instr->elements());
-    result = new(zone()) LLoadKeyed(backing_store, key);
+    result = DefineAsRegister(new(zone()) LLoadKeyed(backing_store, key));
   }
 
-  DefineAsRegister(result);
-  // An unsigned int array load might overflow and cause a deopt, make sure it
-  // has an environment.
-  bool can_deoptimize = instr->RequiresHoleCheck() ||
-      elements_kind == EXTERNAL_UINT32_ELEMENTS ||
-      elements_kind == UINT32_ELEMENTS;
-  return can_deoptimize ? AssignEnvironment(result) : result;
+  if ((instr->is_external() || instr->is_fixed_typed_array()) ?
+      // see LCodeGen::DoLoadKeyedExternalArray
+      ((elements_kind == EXTERNAL_UINT32_ELEMENTS ||
+        elements_kind == UINT32_ELEMENTS) &&
+       !instr->CheckFlag(HInstruction::kUint32)) :
+      // see LCodeGen::DoLoadKeyedFixedDoubleArray and
+      // LCodeGen::DoLoadKeyedFixedArray
+      instr->RequiresHoleCheck()) {
+    result = AssignEnvironment(result);
+  }
+  return result;
 }
 
 
@@ -2280,11 +2301,11 @@ LInstruction* LChunkBuilder::DoStoreNamedField(HStoreNamedField* instr) {
   // We need a temporary register for write barrier of the map field.
   LOperand* temp = needs_write_barrier_for_map ? TempRegister() : NULL;
 
-  LStoreNamedField* result = new(zone()) LStoreNamedField(obj, val, temp);
-  if (instr->field_representation().IsHeapObject()) {
-    if (!instr->value()->type().IsHeapObject()) {
-      return AssignEnvironment(result);
-    }
+  LInstruction* result = new(zone()) LStoreNamedField(obj, val, temp);
+  if (!instr->access().IsExternalMemory() &&
+      instr->field_representation().IsHeapObject() &&
+      !instr->value()->type().IsHeapObject()) {
+    result = AssignEnvironment(result);
   }
   return result;
 }
@@ -2316,7 +2337,7 @@ LInstruction* LChunkBuilder::DoStringCharCodeAt(HStringCharCodeAt* instr) {
   LOperand* context = UseAny(instr->context());
   LStringCharCodeAt* result =
       new(zone()) LStringCharCodeAt(context, string, index);
-  return AssignEnvironment(AssignPointerMap(DefineAsRegister(result)));
+  return AssignPointerMap(DefineAsRegister(result));
 }
 
 

diff --git a/src/arm64/lithium-arm64.cc b/src/arm64/lithium-arm64.cc
index 4bed135bca576a259a4e137bde030afdfd3d2c0c..1888affd683f74e78ebea1c6f441c0f7585c063d 100644 (file)
--- a/src/arm64/lithium-arm64.cc
+++ b/src/arm64/lithium-arm64.cc
@@ -1074,63 +1074,61 @@ LInstruction* LChunkBuilder::DoCapturedObject(HCapturedObject* instr) {
 LInstruction* LChunkBuilder::DoChange(HChange* instr) {
   Representation from = instr->from();
   Representation to = instr->to();
-
+  HValue* val = instr->value();
   if (from.IsSmi()) {
     if (to.IsTagged()) {
-      LOperand* value = UseRegister(instr->value());
+      LOperand* value = UseRegister(val);
       return DefineSameAsFirst(new(zone()) LDummyUse(value));
     }
     from = Representation::Tagged();
   }
-
   if (from.IsTagged()) {
     if (to.IsDouble()) {
-      LOperand* value = UseRegister(instr->value());
+      LOperand* value = UseRegister(val);
       LOperand* temp = TempRegister();
-      LNumberUntagD* res = new(zone()) LNumberUntagD(value, temp);
-      return AssignEnvironment(DefineAsRegister(res));
+      LInstruction* result =
+          DefineAsRegister(new(zone()) LNumberUntagD(value, temp));
+      if (!val->representation().IsSmi()) result = AssignEnvironment(result);
+      return result;
     } else if (to.IsSmi()) {
-      LOperand* value = UseRegister(instr->value());
-      if (instr->value()->type().IsSmi()) {
+      LOperand* value = UseRegister(val);
+      if (val->type().IsSmi()) {
         return DefineSameAsFirst(new(zone()) LDummyUse(value));
       }
       return AssignEnvironment(DefineSameAsFirst(new(zone()) LCheckSmi(value)));
     } else {
       ASSERT(to.IsInteger32());
-      LInstruction* res = NULL;
-
-      if (instr->value()->type().IsSmi() ||
-          instr->value()->representation().IsSmi()) {
-        LOperand* value = UseRegisterAtStart(instr->value());
-        res = DefineAsRegister(new(zone()) LSmiUntag(value, false));
+      if (val->type().IsSmi() || val->representation().IsSmi()) {
+        LOperand* value = UseRegisterAtStart(val);
+        return DefineAsRegister(new(zone()) LSmiUntag(value, false));
       } else {
-        LOperand* value = UseRegister(instr->value());
+        LOperand* value = UseRegister(val);
         LOperand* temp1 = TempRegister();
         LOperand* temp2 = instr->CanTruncateToInt32() ? NULL : FixedTemp(d24);
-        res = DefineAsRegister(new(zone()) LTaggedToI(value, temp1, temp2));
-        res = AssignEnvironment(res);
+        LInstruction* result =
+            DefineAsRegister(new(zone()) LTaggedToI(value, temp1, temp2));
+        if (!val->representation().IsSmi()) {
+          // Note: Only deopts in deferred code.
+          result = AssignEnvironment(result);
+        }
+        return result;
       }
-
-      return res;
     }
   } else if (from.IsDouble()) {
     if (to.IsTagged()) {
       info()->MarkAsDeferredCalling();
-      LOperand* value = UseRegister(instr->value());
+      LOperand* value = UseRegister(val);
       LOperand* temp1 = TempRegister();
       LOperand* temp2 = TempRegister();
-
       LNumberTagD* result = new(zone()) LNumberTagD(value, temp1, temp2);
       return AssignPointerMap(DefineAsRegister(result));
     } else {
       ASSERT(to.IsSmi() || to.IsInteger32());
-      LOperand* value = UseRegister(instr->value());
-
       if (instr->CanTruncateToInt32()) {
-        LTruncateDoubleToIntOrSmi* result =
-            new(zone()) LTruncateDoubleToIntOrSmi(value);
-        return DefineAsRegister(result);
+        LOperand* value = UseRegister(val);
+        return DefineAsRegister(new(zone()) LTruncateDoubleToIntOrSmi(value));
       } else {
+        LOperand* value = UseRegister(val);
         LDoubleToIntOrSmi* result = new(zone()) LDoubleToIntOrSmi(value);
         return AssignEnvironment(DefineAsRegister(result));
       }
@@ -1138,37 +1136,35 @@ LInstruction* LChunkBuilder::DoChange(HChange* instr) {
   } else if (from.IsInteger32()) {
     info()->MarkAsDeferredCalling();
     if (to.IsTagged()) {
-      if (instr->value()->CheckFlag(HInstruction::kUint32)) {
-        LOperand* value = UseRegister(instr->value());
-        LNumberTagU* result = new(zone()) LNumberTagU(value,
-                                                      TempRegister(),
-                                                      TempRegister());
-        return AssignEnvironment(AssignPointerMap(DefineAsRegister(result)));
+      if (val->CheckFlag(HInstruction::kUint32)) {
+        LOperand* value = UseRegister(val);
+        LNumberTagU* result =
+            new(zone()) LNumberTagU(value, TempRegister(), TempRegister());
+        return AssignPointerMap(DefineAsRegister(result));
       } else {
         STATIC_ASSERT((kMinInt == Smi::kMinValue) &&
                       (kMaxInt == Smi::kMaxValue));
-        LOperand* value = UseRegisterAtStart(instr->value());
+        LOperand* value = UseRegisterAtStart(val);
         return DefineAsRegister(new(zone()) LSmiTag(value));
       }
     } else if (to.IsSmi()) {
-      LOperand* value = UseRegisterAtStart(instr->value());
+      LOperand* value = UseRegisterAtStart(val);
       LInstruction* result = DefineAsRegister(new(zone()) LSmiTag(value));
-      if (instr->value()->CheckFlag(HInstruction::kUint32)) {
+      if (val->CheckFlag(HInstruction::kUint32)) {
         result = AssignEnvironment(result);
       }
       return result;
     } else {
       ASSERT(to.IsDouble());
-      if (instr->value()->CheckFlag(HInstruction::kUint32)) {
+      if (val->CheckFlag(HInstruction::kUint32)) {
         return DefineAsRegister(
-            new(zone()) LUint32ToDouble(UseRegisterAtStart(instr->value())));
+            new(zone()) LUint32ToDouble(UseRegisterAtStart(val)));
       } else {
         return DefineAsRegister(
-            new(zone()) LInteger32ToDouble(UseRegisterAtStart(instr->value())));
+            new(zone()) LInteger32ToDouble(UseRegisterAtStart(val)));
       }
     }
   }
-
   UNREACHABLE();
   return NULL;
 }
@@ -1189,21 +1185,20 @@ LInstruction* LChunkBuilder::DoCheckInstanceType(HCheckInstanceType* instr) {
 
 
 LInstruction* LChunkBuilder::DoCheckMaps(HCheckMaps* instr) {
-  if (instr->CanOmitMapChecks()) {
-    // LCheckMaps does nothing in this case.
-    return new(zone()) LCheckMaps(NULL);
-  } else {
-    LOperand* value = UseRegisterAtStart(instr->value());
-    LOperand* temp = TempRegister();
-
-    if (instr->has_migration_target()) {
-      info()->MarkAsDeferredCalling();
-      LInstruction* result = new(zone()) LCheckMaps(value, temp);
-      return AssignPointerMap(AssignEnvironment(result));
-    } else {
-      return AssignEnvironment(new(zone()) LCheckMaps(value, temp));
-    }
+  LOperand* value = NULL;
+  LOperand* temp = NULL;
+  if (!instr->CanOmitMapChecks()) {
+    value = UseRegisterAtStart(instr->value());
+    temp = TempRegister();
+    if (instr->has_migration_target()) info()->MarkAsDeferredCalling();
+  }
+  LInstruction* result = new(zone()) LCheckMaps(value, temp);
+  if (!instr->CanOmitMapChecks()) {
+    // Note: Only deopts in deferred code.
+    result = AssignEnvironment(result);
+    if (instr->has_migration_target()) return AssignPointerMap(result);
   }
+  return result;
 }
 
 
@@ -1418,8 +1413,12 @@ LInstruction* LChunkBuilder::DoDivI(HBinaryOperation* instr) {
   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* result =
+      DefineAsRegister(new(zone()) LDivI(dividend, divisor, temp));
+  if (!instr->CheckFlag(HValue::kAllUsesTruncatingToInt32)) {
+    result = AssignEnvironment(result);
+  }
+  return result;
 }
 
 
@@ -1622,7 +1621,10 @@ LInstruction* LChunkBuilder::DoLoadContextSlot(HLoadContextSlot* instr) {
   LOperand* context = UseRegisterAtStart(instr->value());
   LInstruction* result =
       DefineAsRegister(new(zone()) LLoadContextSlot(context));
-  return instr->RequiresHoleCheck() ? AssignEnvironment(result) : result;
+  if (instr->RequiresHoleCheck() && instr->DeoptimizesOnHole()) {
+    result = AssignEnvironment(result);
+  }
+  return result;
 }
 
 
@@ -1687,17 +1689,14 @@ LInstruction* LChunkBuilder::DoLoadKeyed(HLoadKeyed* instr) {
             IsDoubleOrFloatElementsKind(instr->elements_kind())));
 
     LOperand* temp = instr->key()->IsConstant() ? NULL : TempRegister();
-    LLoadKeyedExternal* result =
-        new(zone()) LLoadKeyedExternal(elements, key, temp);
-    // An unsigned int array load might overflow and cause a deopt. Make sure it
-    // has an environment.
-    if (instr->RequiresHoleCheck() ||
-        elements_kind == EXTERNAL_UINT32_ELEMENTS ||
-        elements_kind == UINT32_ELEMENTS) {
-      return AssignEnvironment(DefineAsRegister(result));
-    } else {
-      return DefineAsRegister(result);
+    LInstruction* result = DefineAsRegister(
+        new(zone()) LLoadKeyedExternal(elements, key, temp));
+    if ((elements_kind == EXTERNAL_UINT32_ELEMENTS ||
+         elements_kind == UINT32_ELEMENTS) &&
+        !instr->CheckFlag(HInstruction::kUint32)) {
+      result = AssignEnvironment(result);
     }
+    return result;
   }
 }
 
@@ -1885,13 +1884,10 @@ LInstruction* LChunkBuilder::DoMul(HMul* instr) {
 
     bool can_overflow = instr->CheckFlag(HValue::kCanOverflow);
     bool bailout_on_minus_zero = instr->CheckFlag(HValue::kBailoutOnMinusZero);
-    bool needs_environment = can_overflow || bailout_on_minus_zero;
 
     HValue* least_const = instr->BetterLeftOperand();
     HValue* most_const = instr->BetterRightOperand();
 
-    LOperand* left;
-
     // LMulConstI can handle a subset of constants:
     //  With support for overflow detection:
     //    -1, 0, 1, 2
@@ -1911,26 +1907,27 @@ LInstruction* LChunkBuilder::DoMul(HMul* instr) {
                               IsPowerOf2(constant_abs - 1))))) {
         LConstantOperand* right = UseConstant(most_const);
         bool need_register = IsPowerOf2(constant_abs) && !small_constant;
-        left = need_register ? UseRegister(least_const)
-                             : UseRegisterAtStart(least_const);
-        LMulConstIS* mul = new(zone()) LMulConstIS(left, right);
-        if (needs_environment) AssignEnvironment(mul);
-        return DefineAsRegister(mul);
+        LOperand* left = need_register ? UseRegister(least_const)
+                                       : UseRegisterAtStart(least_const);
+        LInstruction* result =
+            DefineAsRegister(new(zone()) LMulConstIS(left, right));
+        if ((bailout_on_minus_zero && constant <= 0) || can_overflow) {
+          result = AssignEnvironment(result);
+        }
+        return result;
       }
     }
 
-    left = UseRegisterAtStart(least_const);
     // LMulI/S can handle all cases, but it requires that a register is
     // allocated for the second operand.
-    LInstruction* result;
-    if (instr->representation().IsSmi()) {
-      LOperand* right = UseRegisterAtStart(most_const);
-      result = DefineAsRegister(new(zone()) LMulS(left, right));
-    } else {
-      LOperand* right = UseRegisterAtStart(most_const);
-      result = DefineAsRegister(new(zone()) LMulI(left, right));
+    LOperand* left = UseRegisterAtStart(least_const);
+    LOperand* right = UseRegisterAtStart(most_const);
+    LInstruction* result = instr->representation().IsSmi()
+        ? DefineAsRegister(new(zone()) LMulS(left, right))
+        : DefineAsRegister(new(zone()) LMulI(left, right));
+    if ((bailout_on_minus_zero && least_const != most_const) || can_overflow) {
+      result = AssignEnvironment(result);
     }
-    if (needs_environment) AssignEnvironment(result);
     return result;
   } else if (instr->representation().IsDouble()) {
     return DoArithmeticD(Token::MUL, instr);
@@ -2160,7 +2157,10 @@ LInstruction* LChunkBuilder::DoStoreContextSlot(HStoreContextSlot* instr) {
     value = UseRegister(instr->value());
   }
   LInstruction* result = new(zone()) LStoreContextSlot(context, value, temp);
-  return instr->RequiresHoleCheck() ? AssignEnvironment(result) : result;
+  if (instr->RequiresHoleCheck() && instr->DeoptimizesOnHole()) {
+    result = AssignEnvironment(result);
+  }
+  return result;
 }
 
 
@@ -2294,7 +2294,7 @@ LInstruction* LChunkBuilder::DoStringCharCodeAt(HStringCharCodeAt* instr) {
   LOperand* context = UseAny(instr->context());
   LStringCharCodeAt* result =
       new(zone()) LStringCharCodeAt(context, string, index);
-  return AssignEnvironment(AssignPointerMap(DefineAsRegister(result)));
+  return AssignPointerMap(DefineAsRegister(result));
 }
 
 
@@ -2430,21 +2430,15 @@ LInstruction* LChunkBuilder::DoUnaryMathOperation(HUnaryMathOperation* instr) {
         LOperand* temp1 = TempRegister();
         LOperand* temp2 = TempRegister();
         LOperand* temp3 = TempRegister();
-        LMathAbsTagged* result =
-            new(zone()) LMathAbsTagged(context, input, temp1, temp2, temp3);
-        return AssignEnvironment(AssignPointerMap(DefineAsRegister(result)));
+        LInstruction* result = DefineAsRegister(
+            new(zone()) LMathAbsTagged(context, input, temp1, temp2, temp3));
+        // Note: Only deopts in deferred code.
+        return AssignEnvironment(AssignPointerMap(result));
       } else {
         LOperand* input = UseRegisterAtStart(instr->value());
-        LMathAbs* result = new(zone()) LMathAbs(input);
-        if (r.IsDouble()) {
-          // The Double case can never fail so it doesn't need an environment.
-          return DefineAsRegister(result);
-        } else {
-          ASSERT(r.IsInteger32() || r.IsSmi());
-          // The Integer32 and Smi cases need an environment because they can
-          // deoptimize on minimum representable number.
-          return AssignEnvironment(DefineAsRegister(result));
-        }
+        LInstruction* result = DefineAsRegister(new(zone()) LMathAbs(input));
+        if (!r.IsDouble()) result = AssignEnvironment(result);
+        return result;
       }
     }
     case kMathExp: {

diff --git a/src/arm64/lithium-arm64.h b/src/arm64/lithium-arm64.h
index fcb15526048f0d273dd746ec2ae1a8756019824c..d47a84fffc3638468f87513a3f13a5a1fe11441f 100644 (file)
--- a/src/arm64/lithium-arm64.h
+++ b/src/arm64/lithium-arm64.h
@@ -927,7 +927,7 @@ class LCheckInstanceType V8_FINAL : public LTemplateInstruction<0, 1, 1> {
 
 class LCheckMaps V8_FINAL : public LTemplateInstruction<0, 1, 1> {
  public:
-  explicit LCheckMaps(LOperand* value, LOperand* temp = NULL) {
+  explicit LCheckMaps(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
     temps_[0] = temp;
   }

diff --git a/src/ia32/lithium-ia32.cc b/src/ia32/lithium-ia32.cc
index 384a21c6980dc5fce2385de50b2afeb47adb12f5..6eb5343f68666c23142f7b15431876e3a0d8cff4 100644 (file)
--- a/src/ia32/lithium-ia32.cc
+++ b/src/ia32/lithium-ia32.cc
@@ -1882,29 +1882,23 @@ LInstruction* LChunkBuilder::DoForceRepresentation(HForceRepresentation* bad) {
 LInstruction* LChunkBuilder::DoChange(HChange* instr) {
   Representation from = instr->from();
   Representation to = instr->to();
+  HValue* val = instr->value();
   if (from.IsSmi()) {
     if (to.IsTagged()) {
-      LOperand* value = UseRegister(instr->value());
+      LOperand* value = UseRegister(val);
       return DefineSameAsFirst(new(zone()) LDummyUse(value));
     }
     from = Representation::Tagged();
   }
-  // Only mark conversions that might need to allocate as calling rather than
-  // all changes. This makes simple, non-allocating conversion not have to force
-  // building a stack frame.
   if (from.IsTagged()) {
     if (to.IsDouble()) {
-      LOperand* value = UseRegister(instr->value());
-      // Temp register only necessary for minus zero check.
+      LOperand* value = UseRegister(val);
       LOperand* temp = TempRegister();
-      LInstruction* result = DefineAsRegister(
-          new(zone()) LNumberUntagD(value, temp));
-      if (!instr->value()->representation().IsSmi()) {
-        result = AssignEnvironment(result);
-      }
+      LInstruction* result =
+          DefineAsRegister(new(zone()) LNumberUntagD(value, temp));
+      if (!val->representation().IsSmi()) result = AssignEnvironment(result);
       return result;
     } else if (to.IsSmi()) {
-      HValue* val = instr->value();
       LOperand* value = UseRegister(val);
       if (val->type().IsSmi()) {
         return DefineSameAsFirst(new(zone()) LDummyUse(value));
@@ -1912,18 +1906,18 @@ LInstruction* LChunkBuilder::DoChange(HChange* instr) {
       return AssignEnvironment(DefineSameAsFirst(new(zone()) LCheckSmi(value)));
     } else {
       ASSERT(to.IsInteger32());
-      HValue* val = instr->value();
       if (val->type().IsSmi() || val->representation().IsSmi()) {
         LOperand* value = UseRegister(val);
         return DefineSameAsFirst(new(zone()) LSmiUntag(value, false));
       } else {
+        LOperand* value = UseRegister(val);
         bool truncating = instr->CanTruncateToInt32();
         LOperand* xmm_temp =
             (CpuFeatures::IsSafeForSnapshot(SSE2) && !truncating)
                 ? FixedTemp(xmm1) : NULL;
-        LInstruction* result = DefineSameAsFirst(
-            new(zone()) LTaggedToI(UseRegister(val), xmm_temp));
-        if (!instr->value()->representation().IsSmi()) {
+        LInstruction* result =
+            DefineSameAsFirst(new(zone()) LTaggedToI(value, xmm_temp));
+        if (!val->representation().IsSmi()) {
           // Note: Only deopts in deferred code.
           result = AssignEnvironment(result);
         }
@@ -1933,23 +1927,20 @@ LInstruction* LChunkBuilder::DoChange(HChange* instr) {
   } else if (from.IsDouble()) {
     if (to.IsTagged()) {
       info()->MarkAsDeferredCalling();
-      LOperand* value = UseRegisterAtStart(instr->value());
+      LOperand* value = UseRegisterAtStart(val);
       LOperand* temp = FLAG_inline_new ? TempRegister() : NULL;
-
-      // Make sure that temp and result_temp are different registers.
       LUnallocated* result_temp = TempRegister();
       LNumberTagD* result = new(zone()) LNumberTagD(value, temp);
       return AssignPointerMap(Define(result, result_temp));
     } else if (to.IsSmi()) {
-      LOperand* value = UseRegister(instr->value());
+      LOperand* value = UseRegister(val);
       return AssignEnvironment(
           DefineAsRegister(new(zone()) LDoubleToSmi(value)));
     } else {
       ASSERT(to.IsInteger32());
       bool truncating = instr->CanTruncateToInt32();
       bool needs_temp = CpuFeatures::IsSafeForSnapshot(SSE2) && !truncating;
-      LOperand* value = needs_temp ?
-          UseTempRegister(instr->value()) : UseRegister(instr->value());
+      LOperand* value = needs_temp ? UseTempRegister(val) : UseRegister(val);
       LOperand* temp = needs_temp ? TempRegister() : NULL;
       LInstruction* result =
           DefineAsRegister(new(zone()) LDoubleToI(value, temp));
@@ -1959,23 +1950,23 @@ LInstruction* LChunkBuilder::DoChange(HChange* instr) {
   } else if (from.IsInteger32()) {
     info()->MarkAsDeferredCalling();
     if (to.IsTagged()) {
-      HValue* val = instr->value();
-      LOperand* value = UseRegister(val);
       if (!instr->CheckFlag(HValue::kCanOverflow)) {
+        LOperand* value = UseRegister(val);
         return DefineSameAsFirst(new(zone()) LSmiTag(value));
       } else if (val->CheckFlag(HInstruction::kUint32)) {
+        LOperand* value = UseRegister(val);
         LOperand* temp1 = TempRegister();
-        LOperand* temp2 = CpuFeatures::IsSupported(SSE2) ? FixedTemp(xmm1)
-                                                         : NULL;
+        LOperand* temp2 =
+            CpuFeatures::IsSupported(SSE2) ? FixedTemp(xmm1) : NULL;
         LNumberTagU* result = new(zone()) LNumberTagU(value, temp1, temp2);
         return AssignPointerMap(DefineSameAsFirst(result));
       } else {
+        LOperand* value = UseRegister(val);
         LOperand* temp = TempRegister();
         LNumberTagI* result = new(zone()) LNumberTagI(value, temp);
         return AssignPointerMap(DefineSameAsFirst(result));
       }
     } else if (to.IsSmi()) {
-      HValue* val = instr->value();
       LOperand* value = UseRegister(val);
       LInstruction* result = DefineSameAsFirst(new(zone()) LSmiTag(value));
       if (instr->CheckFlag(HValue::kCanOverflow)) {
@@ -1984,13 +1975,12 @@ LInstruction* LChunkBuilder::DoChange(HChange* instr) {
       return result;
     } else {
       ASSERT(to.IsDouble());
-      if (instr->value()->CheckFlag(HInstruction::kUint32)) {
+      if (val->CheckFlag(HInstruction::kUint32)) {
         LOperand* temp = FixedTemp(xmm1);
         return DefineAsRegister(
-            new(zone()) LUint32ToDouble(UseRegister(instr->value()), temp));
+            new(zone()) LUint32ToDouble(UseRegister(val), temp));
       } else {
-        return DefineAsRegister(
-            new(zone()) LInteger32ToDouble(Use(instr->value())));
+        return DefineAsRegister(new(zone()) LInteger32ToDouble(Use(val)));
       }
     }
   }

diff --git a/src/x64/lithium-x64.cc b/src/x64/lithium-x64.cc
index 9d99e91d721b54832f90315072d3f8cd8033ba6b..f766ba47624518537ba3dba11f2d58ee16f9123b 100644 (file)
--- a/src/x64/lithium-x64.cc
+++ b/src/x64/lithium-x64.cc
@@ -1804,26 +1804,21 @@ LInstruction* LChunkBuilder::DoForceRepresentation(HForceRepresentation* bad) {
 LInstruction* LChunkBuilder::DoChange(HChange* instr) {
   Representation from = instr->from();
   Representation to = instr->to();
+  HValue* val = instr->value();
   if (from.IsSmi()) {
     if (to.IsTagged()) {
-      LOperand* value = UseRegister(instr->value());
+      LOperand* value = UseRegister(val);
       return DefineSameAsFirst(new(zone()) LDummyUse(value));
     }
     from = Representation::Tagged();
   }
-  // Only mark conversions that might need to allocate as calling rather than
-  // all changes. This makes simple, non-allocating conversion not have to force
-  // building a stack frame.
   if (from.IsTagged()) {
     if (to.IsDouble()) {
-      LOperand* value = UseRegister(instr->value());
-      LInstruction* res = DefineAsRegister(new(zone()) LNumberUntagD(value));
-      if (!instr->value()->representation().IsSmi()) {
-        res = AssignEnvironment(res);
-      }
-      return res;
+      LOperand* value = UseRegister(val);
+      LInstruction* result = DefineAsRegister(new(zone()) LNumberUntagD(value));
+      if (!val->representation().IsSmi()) result = AssignEnvironment(result);
+      return result;
     } else if (to.IsSmi()) {
-      HValue* val = instr->value();
       LOperand* value = UseRegister(val);
       if (val->type().IsSmi()) {
         return DefineSameAsFirst(new(zone()) LDummyUse(value));
@@ -1831,78 +1826,73 @@ LInstruction* LChunkBuilder::DoChange(HChange* instr) {
       return AssignEnvironment(DefineSameAsFirst(new(zone()) LCheckSmi(value)));
     } else {
       ASSERT(to.IsInteger32());
-      HValue* val = instr->value();
-      LOperand* value = UseRegister(val);
       if (val->type().IsSmi() || val->representation().IsSmi()) {
+        LOperand* value = UseRegister(val);
         return DefineSameAsFirst(new(zone()) LSmiUntag(value, false));
       } else {
+        LOperand* value = UseRegister(val);
         bool truncating = instr->CanTruncateToInt32();
         LOperand* xmm_temp = truncating ? NULL : FixedTemp(xmm1);
-        LInstruction* res =
+        LInstruction* result =
             DefineSameAsFirst(new(zone()) LTaggedToI(value, xmm_temp));
-        if (!instr->value()->representation().IsSmi()) {
+        if (!val->representation().IsSmi()) {
           // Note: Only deopts in deferred code.
-          res = AssignEnvironment(res);
+          result = AssignEnvironment(result);
         }
-        return res;
+        return result;
       }
     }
   } else if (from.IsDouble()) {
     if (to.IsTagged()) {
       info()->MarkAsDeferredCalling();
-      LOperand* value = UseRegister(instr->value());
+      LOperand* value = UseRegister(val);
       LOperand* temp = TempRegister();
-
-      // Make sure that temp and result_temp are different registers.
       LUnallocated* result_temp = TempRegister();
       LNumberTagD* result = new(zone()) LNumberTagD(value, temp);
       return AssignPointerMap(Define(result, result_temp));
     } else if (to.IsSmi()) {
-      LOperand* value = UseRegister(instr->value());
+      LOperand* value = UseRegister(val);
       return AssignEnvironment(
           DefineAsRegister(new(zone()) LDoubleToSmi(value)));
     } else {
       ASSERT(to.IsInteger32());
-      LOperand* value = UseRegister(instr->value());
+      LOperand* value = UseRegister(val);
       LInstruction* result = DefineAsRegister(new(zone()) LDoubleToI(value));
-      if (!instr->CanTruncateToInt32()) {
-        result = AssignEnvironment(result);
-      }
+      if (!instr->CanTruncateToInt32()) result = AssignEnvironment(result);
       return result;
     }
   } else if (from.IsInteger32()) {
     info()->MarkAsDeferredCalling();
     if (to.IsTagged()) {
-      HValue* val = instr->value();
-      LOperand* value = UseRegister(val);
       if (!instr->CheckFlag(HValue::kCanOverflow)) {
+        LOperand* value = UseRegister(val);
         return DefineAsRegister(new(zone()) LSmiTag(value));
       } else if (val->CheckFlag(HInstruction::kUint32)) {
+        LOperand* value = UseRegister(val);
         LOperand* temp1 = TempRegister();
         LOperand* temp2 = FixedTemp(xmm1);
         LNumberTagU* result = new(zone()) LNumberTagU(value, temp1, temp2);
         return AssignPointerMap(DefineSameAsFirst(result));
       } else {
+        LOperand* value = UseRegister(val);
         LNumberTagI* result = new(zone()) LNumberTagI(value);
         return AssignPointerMap(DefineSameAsFirst(result));
       }
     } else if (to.IsSmi()) {
-      HValue* val = instr->value();
       LOperand* value = UseRegister(val);
       LInstruction* result = DefineAsRegister(new(zone()) LSmiTag(value));
       if (instr->CheckFlag(HValue::kCanOverflow)) {
-        ASSERT(val->CheckFlag(HValue::kUint32));
         result = AssignEnvironment(result);
       }
       return result;
     } else {
-      if (instr->value()->CheckFlag(HInstruction::kUint32)) {
+      ASSERT(to.IsDouble());
+      if (val->CheckFlag(HInstruction::kUint32)) {
         LOperand* temp = FixedTemp(xmm1);
         return DefineAsRegister(
-            new(zone()) LUint32ToDouble(UseRegister(instr->value()), temp));
+            new(zone()) LUint32ToDouble(UseRegister(val), temp));
       } else {
-        ASSERT(to.IsDouble());
-        LOperand* value = Use(instr->value());
+        LOperand* value = Use(val);
         return DefineAsRegister(new(zone()) LInteger32ToDouble(value));
       }
     }