SSATmp* Simplifier::simplifyNot(SSATmp* src) {
// const XORs are handled in simplifyXor()
assert(!src->isConst());
assert(src->getType() == Type::Bool);
IRInstruction* inst = src->getInstruction()->getSrc(0)->getInstruction();
Opcode op = inst->getOpcode();
// TODO: Add more algebraic simplification rules for NOT
switch (op) {
case OpXor: {
// !!X --> bool(X)
if (isNotInst(inst->getSrc(0))) {
return m_tb->genConvToBool(inst->getSrc(0));
}
break;
}
// !(X cmp Y) --> X opposite_cmp Y
case OpLt:
case OpLte:
case OpGt:
case OpGte:
case OpEq:
case OpNeq:
case OpSame:
case OpNSame:
return m_tb->genCmp(negateQueryOp(op), inst->getSrc(0), inst->getSrc(1));
// TODO !(X | non_zero) --> 0
default: (void)op;
}
return NULL;
}
SSATmp* Simplifier::simplifyNot(SSATmp* src) {
IRInstruction* inst = src->getInstruction();
Opcode op = inst->getOpcode();
// TODO: Add more algebraic simplification rules for NOT
switch (op) {
case ConvToBool:
return simplifyNot(inst->getSrc(0));
case OpXor: {
// !!X --> bool(X)
if (isNotInst(inst->getSrc(0))) {
return m_tb->genConvToBool(inst->getSrc(0));
}
break;
}
// !(X cmp Y) --> X opposite_cmp Y
case OpLt:
case OpLte:
case OpGt:
case OpGte:
case OpEq:
case OpNeq:
case OpSame:
case OpNSame:
// XXX: this could technically be losing a ConvToBool, except
// that we kinda know "not" instructions (Xor with 1) are always
// going to be followed by ConvToBool.
//
// TODO(#2058865): This would make more sense with a real Not
// instruction and allowing boolean output types for query ops.
return m_tb->genCmp(negateQueryOp(op),
inst->getSrc(0),
inst->getSrc(1));
case InstanceOf:
case NInstanceOf:
case InstanceOfBitmask:
case NInstanceOfBitmask:
// TODO: combine this with the above check and use isQueryOp or
// add an isNegatable.
return m_tb->gen(negateQueryOp(op),
inst->getNumSrcs(),
inst->getSrcs().begin());
// TODO !(X | non_zero) --> 0
default: (void)op;
}
return nullptr;
}
