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6894779: Loop Predication for Loop Optimizer in C2

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Loop predication implementation

Reviewed-by: never, kvn
This commit is contained in:
Changpeng Fang 2010-01-12 14:37:35 -08:00
parent 96612c6e23
commit 815db4fcba
13 changed files with 838 additions and 30 deletions
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35
hotspot/src/share/vm/opto/parse1.cpp
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@ -1383,6 +1383,10 @@ void Parse::do_one_block() {
set_parse_bci(iter().cur_bci());
if (bci() == block()->limit()) {
// insert a predicate if it falls through to a loop head block
if (should_add_predicate(bci())){
add_predicate();
}
// Do not walk into the next block until directed by do_all_blocks.
merge(bci());
break;
@ -2083,6 +2087,37 @@ void Parse::add_safepoint() {
}
}
//------------------------------should_add_predicate--------------------------
bool Parse::should_add_predicate(int target_bci) {
if (!UseLoopPredicate) return false;
Block* target = successor_for_bci(target_bci);
if (target != NULL &&
target->is_loop_head() &&
block()->rpo() < target->rpo()) {
return true;
}
return false;
}
//------------------------------add_predicate---------------------------------
void Parse::add_predicate() {
assert(UseLoopPredicate,"use only for loop predicate");
Node *cont = _gvn.intcon(1);
Node* opq = _gvn.transform(new (C, 2) Opaque1Node(C, cont));
Node *bol = _gvn.transform(new (C, 2) Conv2BNode(opq));
IfNode* iff = create_and_map_if(control(), bol, PROB_MAX, COUNT_UNKNOWN);
Node* iffalse = _gvn.transform(new (C, 1) IfFalseNode(iff));
C->add_predicate_opaq(opq);
{
PreserveJVMState pjvms(this);
set_control(iffalse);
uncommon_trap(Deoptimization::Reason_predicate,
Deoptimization::Action_maybe_recompile);
}
Node* iftrue = _gvn.transform(new (C, 1) IfTrueNode(iff));
set_control(iftrue);
}
#ifndef PRODUCT
//------------------------show_parse_info--------------------------------------
void Parse::show_parse_info() {