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8024070: C2 needs some form of type speculation

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Record unused type profile information with type system, propagate and use it.

Reviewed-by: kvn, twisti
This commit is contained in:
Roland Westrelin 2013-10-23 12:40:23 +02:00
parent ceb177b16f
commit 1b5bd82335
22 changed files with 1429 additions and 144 deletions
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51
hotspot/src/share/vm/opto/parse2.cpp
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@ -1366,6 +1366,56 @@ void Parse::sharpen_type_after_if(BoolTest::mask btest,
}
}
/**
* Use speculative type to optimize CmpP node: if comparison is
* against the low level class, cast the object to the speculative
* type if any. CmpP should then go away.
*
* @param c expected CmpP node
* @return result of CmpP on object casted to speculative type
*
*/
Node* Parse::optimize_cmp_with_klass(Node* c) {
// If this is transformed by the _gvn to a comparison with the low
// level klass then we may be able to use speculation
if (c->Opcode() == Op_CmpP &&
(c->in(1)->Opcode() == Op_LoadKlass || c->in(1)->Opcode() == Op_DecodeNKlass) &&
c->in(2)->is_Con()) {
Node* load_klass = NULL;
Node* decode = NULL;
if (c->in(1)->Opcode() == Op_DecodeNKlass) {
decode = c->in(1);
load_klass = c->in(1)->in(1);
} else {
load_klass = c->in(1);
}
if (load_klass->in(2)->is_AddP()) {
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) {
ciKlass* k = obj_type->speculative_type();
inc_sp(2);
obj = maybe_cast_profiled_obj(obj, k);
dec_sp(2);
// Make the CmpP use the casted obj
addp = basic_plus_adr(obj, addp->in(AddPNode::Offset));
load_klass = load_klass->clone();
load_klass->set_req(2, addp);
load_klass = _gvn.transform(load_klass);
if (decode != NULL) {
decode = decode->clone();
decode->set_req(1, load_klass);
load_klass = _gvn.transform(decode);
}
c = c->clone();
c->set_req(1, load_klass);
c = _gvn.transform(c);
}
}
}
return c;
}
//------------------------------do_one_bytecode--------------------------------
// Parse this bytecode, and alter the Parsers JVM->Node mapping
@ -2239,6 +2289,7 @@ void Parse::do_one_bytecode() {
a = pop();
b = pop();
c = _gvn.transform( new (C) CmpPNode(b, a) );
c = optimize_cmp_with_klass(c);
do_if(btest, c);
break;