void Canonicalizer::do_Op2(Op2* x) {
if (x->x() == x->y()) {
switch (x->op()) {
case Bytecodes::_isub: set_constant(0); return;
case Bytecodes::_lsub: set_constant(jlong_cast(0)); return;
case Bytecodes::_iand: // fall through
case Bytecodes::_land: // fall through
case Bytecodes::_ior: // fall through
case Bytecodes::_lor : set_canonical(x->x()); return;
case Bytecodes::_ixor: set_constant(0); return;
case Bytecodes::_lxor: set_constant(jlong_cast(0)); return;
}
}
if (x->x()->type()->is_constant() && x->y()->type()->is_constant()) {
// do constant folding for selected operations
switch (x->type()->tag()) {
case intTag:
{ jint a = x->x()->type()->as_IntConstant()->value();
jint b = x->y()->type()->as_IntConstant()->value();
switch (x->op()) {
case Bytecodes::_iadd: set_constant(a + b); return;
case Bytecodes::_isub: set_constant(a - b); return;
case Bytecodes::_imul: set_constant(a * b); return;
case Bytecodes::_idiv:
if (b != 0) {
if (a == min_jint && b == -1) {
set_constant(min_jint);
} else {
set_constant(a / b);
}
return;
}
break;
case Bytecodes::_irem:
if (b != 0) {
if (a == min_jint && b == -1) {
set_constant(0);
} else {
set_constant(a % b);
}
return;
}
break;
case Bytecodes::_iand: set_constant(a & b); return;
case Bytecodes::_ior : set_constant(a | b); return;
case Bytecodes::_ixor: set_constant(a ^ b); return;
}
}
break;
case longTag:
{ jlong a = x->x()->type()->as_LongConstant()->value();
jlong b = x->y()->type()->as_LongConstant()->value();
switch (x->op()) {
case Bytecodes::_ladd: set_constant(a + b); return;
case Bytecodes::_lsub: set_constant(a - b); return;
case Bytecodes::_lmul: set_constant(a * b); return;
case Bytecodes::_ldiv:
if (b != 0) {
set_constant(SharedRuntime::ldiv(b, a));
return;
}
break;
case Bytecodes::_lrem:
if (b != 0) {
set_constant(SharedRuntime::lrem(b, a));
return;
}
break;
case Bytecodes::_land: set_constant(a & b); return;
case Bytecodes::_lor : set_constant(a | b); return;
case Bytecodes::_lxor: set_constant(a ^ b); return;
}
}
break;
// other cases not implemented (must be extremely careful with floats & doubles!)
}
}
// make sure constant is on the right side, if any
move_const_to_right(x);
if (x->y()->type()->is_constant()) {
// do constant folding for selected operations
switch (x->type()->tag()) {
case intTag:
if (x->y()->type()->as_IntConstant()->value() == 0) {
switch (x->op()) {
case Bytecodes::_iadd: set_canonical(x->x()); return;
case Bytecodes::_isub: set_canonical(x->x()); return;
case Bytecodes::_imul: set_constant(0); return;
// Note: for div and rem, make sure that C semantics
// corresponds to Java semantics!
case Bytecodes::_iand: set_constant(0); return;
case Bytecodes::_ior : set_canonical(x->x()); return;
}
}
break;
case longTag:
if (x->y()->type()->as_LongConstant()->value() == (jlong)0) {
switch (x->op()) {
case Bytecodes::_ladd: set_canonical(x->x()); return;
case Bytecodes::_lsub: set_canonical(x->x()); return;
case Bytecodes::_lmul: set_constant((jlong)0); return;
// Note: for div and rem, make sure that C semantics
// corresponds to Java semantics!
case Bytecodes::_land: set_constant((jlong)0); return;
case Bytecodes::_lor : set_canonical(x->x()); return;
}
}
break;
}
}
}
void Canonicalizer::do_IfOp(IfOp* x) {
// Caution: do not use do_Op2(x) here for now since
// we map the condition to the op for now!
move_const_to_right(x);
}
