LInstruction* instr = current->CompileToLithium(this);
if (instr != NULL) {
+#if DEBUG
+ // Make sure that the lithium instruction has either no fixed register
+ // constraints in temps or the result OR no uses that are only used at
+ // start. If this invariant doesn't hold, the register allocator can decide
+ // to insert a split of a range immediately before the instruction due to an
+ // already allocated register needing to be used for the instruction's fixed
+ // register constraint. In this case, The register allocator won't see an
+ // interference between the split child and the use-at-start (it would if
+ // the it was just a plain use), so it is free to move the split child into
+ // the same register that is used for the use-at-start.
+ // See https://code.google.com/p/chromium/issues/detail?id=201590
+ if (!(instr->ClobbersRegisters() && instr->ClobbersDoubleRegisters())) {
+ int fixed = 0;
+ int used_at_start = 0;
+ for (UseIterator it(instr); !it.Done(); it.Advance()) {
+ LUnallocated* operand = LUnallocated::cast(it.Current());
+ if (operand->IsUsedAtStart()) ++used_at_start;
+ }
+ if (instr->Output() != NULL) {
+ if (LUnallocated::cast(instr->Output())->HasFixedPolicy()) ++fixed;
+ }
+ for (TempIterator it(instr); !it.Done(); it.Advance()) {
+ LUnallocated* operand = LUnallocated::cast(it.Current());
+ if (operand->HasFixedPolicy()) ++fixed;
+ }
+ ASSERT(fixed == 0 || used_at_start == 0);
+ }
+#endif
+
if (FLAG_stress_pointer_maps && !instr->HasPointerMap()) {
instr = AssignPointerMap(instr);
}
LUnaryMathOperation* result = new(zone()) LUnaryMathOperation(input, temp);
return DefineFixedDouble(result, f4);
} else {
- LOperand* input = UseRegisterAtStart(instr->value());
+ LOperand* input = UseRegister(instr->value());
LOperand* temp = (op == kMathRound) ? FixedTemp(f6) :
(op == kMathFloor) ? TempRegister() : NULL;
return AssignEnvironment(DefineAsRegister(res));
} else {
ASSERT(to.IsInteger32());
- LOperand* value = UseRegisterAtStart(instr->value());
+ LOperand* value = NULL;
LInstruction* res = NULL;
if (instr->value()->type().IsSmi()) {
+ value = UseRegisterAtStart(instr->value());
res = DefineAsRegister(new(zone()) LSmiUntag(value, false));
} else {
+ value = UseRegister(instr->value());
LOperand* temp1 = TempRegister();
LOperand* temp2 = instr->CanTruncateToInt32() ? TempRegister()
: NULL;