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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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30
hotspot/src/share/vm/opto/compile.cpp
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@ -932,6 +932,7 @@ void Compile::Init(int aliaslevel) {
_intrinsics = NULL;
_macro_nodes = new GrowableArray<Node*>(comp_arena(), 8, 0, NULL);
_predicate_opaqs = new GrowableArray<Node*>(comp_arena(), 8, 0, NULL);
register_library_intrinsics();
}
@ -1553,6 +1554,19 @@ void Compile::Finish_Warm() {
}
}
//---------------------cleanup_loop_predicates-----------------------
// Remove the opaque nodes that protect the predicates so that all unused
// checks and uncommon_traps will be eliminated from the ideal graph
void Compile::cleanup_loop_predicates(PhaseIterGVN &igvn) {
if (predicate_count()==0) return;
for (int i = predicate_count(); i > 0; i--) {
Node * n = predicate_opaque1_node(i-1);
assert(n->Opcode() == Op_Opaque1, "must be");
igvn.replace_node(n, n->in(1));
}
assert(predicate_count()==0, "should be clean!");
igvn.optimize();
}
//------------------------------Optimize---------------------------------------
// Given a graph, optimize it.
@ -1594,7 +1608,7 @@ void Compile::Optimize() {
if((loop_opts_cnt > 0) && (has_loops() || has_split_ifs())) {
{
TracePhase t2("idealLoop", &_t_idealLoop, true);
PhaseIdealLoop ideal_loop( igvn, true );
PhaseIdealLoop ideal_loop( igvn, true, UseLoopPredicate);
loop_opts_cnt--;
if (major_progress()) print_method("PhaseIdealLoop 1", 2);
if (failing()) return;
@ -1602,7 +1616,7 @@ void Compile::Optimize() {
// Loop opts pass if partial peeling occurred in previous pass
if(PartialPeelLoop && major_progress() && (loop_opts_cnt > 0)) {
TracePhase t3("idealLoop", &_t_idealLoop, true);
PhaseIdealLoop ideal_loop( igvn, false );
PhaseIdealLoop ideal_loop( igvn, false, UseLoopPredicate);
loop_opts_cnt--;
if (major_progress()) print_method("PhaseIdealLoop 2", 2);
if (failing()) return;
@ -1610,7 +1624,7 @@ void Compile::Optimize() {
// Loop opts pass for loop-unrolling before CCP
if(major_progress() && (loop_opts_cnt > 0)) {
TracePhase t4("idealLoop", &_t_idealLoop, true);
PhaseIdealLoop ideal_loop( igvn, false );
PhaseIdealLoop ideal_loop( igvn, false, UseLoopPredicate);
loop_opts_cnt--;
if (major_progress()) print_method("PhaseIdealLoop 3", 2);
}
@ -1648,13 +1662,21 @@ void Compile::Optimize() {
// peeling, unrolling, etc.
if(loop_opts_cnt > 0) {
debug_only( int cnt = 0; );
bool loop_predication = UseLoopPredicate;
while(major_progress() && (loop_opts_cnt > 0)) {
TracePhase t2("idealLoop", &_t_idealLoop, true);
assert( cnt++ < 40, "infinite cycle in loop optimization" );
PhaseIdealLoop ideal_loop( igvn, true );
PhaseIdealLoop ideal_loop( igvn, true, loop_predication);
loop_opts_cnt--;
if (major_progress()) print_method("PhaseIdealLoop iterations", 2);
if (failing()) return;
// Perform loop predication optimization during first iteration after CCP.
// After that switch it off and cleanup unused loop predicates.
if (loop_predication) {
loop_predication = false;
cleanup_loop_predicates(igvn);
if (failing()) return;
}
}
}