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Unified Diff: src/mips/lithium-mips.cc

Issue 213733003: MIPS: Only assign environments when they are actually needed. (Closed) Base URL: https://v8.googlecode.com/svn/branches/bleeding_edge
Patch Set: Created 6 years, 9 months ago
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Index: src/mips/lithium-mips.cc
diff --git a/src/mips/lithium-mips.cc b/src/mips/lithium-mips.cc
index ccdbcdb5db37017d1bab9f593e62fa1182e8d940..5e53e253cfe0e015f1c9de5efbfcbdf7fa17e5ef 100644
--- a/src/mips/lithium-mips.cc
+++ b/src/mips/lithium-mips.cc
@@ -939,18 +939,20 @@ 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;
}
@@ -1162,8 +1164,11 @@ 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;
}
@@ -1296,8 +1301,17 @@ LInstruction* LChunkBuilder::DoDivI(HBinaryOperation* instr) {
ASSERT(instr->right()->representation().Equals(instr->representation()));
LOperand* dividend = UseRegister(instr->left());
LOperand* divisor = UseRegister(instr->right());
- LDivI* div = new(zone()) LDivI(dividend, divisor);
- return AssignEnvironment(DefineAsRegister(div));
+ LInstruction* result =
+ DefineAsRegister(new(zone()) LDivI(dividend, divisor));
+ if (instr->CheckFlag(HValue::kCanBeDivByZero) ||
+ instr->CheckFlag(HValue::kBailoutOnMinusZero) ||
+ (instr->CheckFlag(HValue::kCanOverflow) &&
+ !instr->CheckFlag(HValue::kAllUsesTruncatingToInt32)) ||
+ (!instr->IsMathFloorOfDiv() &&
+ !instr->CheckFlag(HValue::kAllUsesTruncatingToInt32))) {
+ result = AssignEnvironment(result);
+ }
+ return result;
}
@@ -1789,20 +1803,21 @@ 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));
@@ -1810,66 +1825,62 @@ 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(f22);
- 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)) {
@@ -1878,12 +1889,10 @@ 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)));
}
}
}
@@ -1925,6 +1934,7 @@ 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);
}
@@ -2025,7 +2035,10 @@ 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;
}
@@ -2040,7 +2053,10 @@ 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;
}
@@ -2075,7 +2091,7 @@ 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;
@@ -2085,24 +2101,28 @@ 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;
}
@@ -2233,11 +2253,11 @@ 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;
}
@@ -2269,7 +2289,7 @@ 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));
}
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