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8031755: Type speculation should be used to optimize explicit null checks

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Feed profiling data about reference nullness to type speculation.

Reviewed-by: kvn, iveresov
This commit is contained in:
Roland Westrelin 2014-03-31 09:08:53 +02:00
parent f5d6f0ceb8
commit fa3b0a8f47
16 changed files with 683 additions and 418 deletions
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14
hotspot/src/share/vm/opto/parse2.cpp
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@ -1288,7 +1288,7 @@ void Parse::sharpen_type_after_if(BoolTest::mask btest,
(jvms->is_loc(obj_in_map) || jvms->is_stk(obj_in_map))) {
TypeNode* ccast = new (C) CheckCastPPNode(control(), obj, tboth);
const Type* tcc = ccast->as_Type()->type();
assert(tcc != obj_type && tcc->higher_equal_speculative(obj_type), "must improve");
assert(tcc != obj_type && tcc->higher_equal(obj_type), "must improve");
// Delay transform() call to allow recovery of pre-cast value
// at the control merge.
_gvn.set_type_bottom(ccast);
@ -1352,7 +1352,7 @@ void Parse::sharpen_type_after_if(BoolTest::mask btest,
if (ccast != NULL) {
const Type* tcc = ccast->as_Type()->type();
assert(tcc != tval && tcc->higher_equal_speculative(tval), "must improve");
assert(tcc != tval && tcc->higher_equal(tval), "must improve");
// Delay transform() call to allow recovery of pre-cast value
// at the control merge.
ccast->set_req(0, control());
@ -1393,7 +1393,7 @@ Node* Parse::optimize_cmp_with_klass(Node* c) {
Node* addp = load_klass->in(2);
Node* obj = addp->in(AddPNode::Address);
const TypeOopPtr* obj_type = _gvn.type(obj)->is_oopptr();
if (obj_type->speculative_type() != NULL) {
if (obj_type->speculative_type_not_null() != NULL) {
ciKlass* k = obj_type->speculative_type();
inc_sp(2);
obj = maybe_cast_profiled_obj(obj, k);
@ -2277,6 +2277,14 @@ void Parse::do_one_bytecode() {
maybe_add_safepoint(iter().get_dest());
a = null();
b = pop();
if (!_gvn.type(b)->speculative_maybe_null() &&
!too_many_traps(Deoptimization::Reason_speculate_null_check)) {
inc_sp(1);
Node* null_ctl = top();
b = null_check_oop(b, &null_ctl, true, true, true);
assert(null_ctl->is_top(), "no null control here");
dec_sp(1);
}
c = _gvn.transform( new (C) CmpPNode(b, a) );
do_ifnull(btest, c);
break;