1.1 --- a/src/share/vm/opto/matcher.cpp Fri Jul 26 10:12:15 2013 +0200
1.2 +++ b/src/share/vm/opto/matcher.cpp Thu Aug 01 17:25:10 2013 -0700
1.3 @@ -2308,26 +2308,26 @@
1.4 // atomic instruction acting as a store_load barrier without any
1.5 // intervening volatile load, and thus we don't need a barrier here.
1.6 // We retain the Node to act as a compiler ordering barrier.
1.7 -bool Matcher::post_store_load_barrier(const Node *vmb) {
1.8 - Compile *C = Compile::current();
1.9 - assert( vmb->is_MemBar(), "" );
1.10 - assert( vmb->Opcode() != Op_MemBarAcquire, "" );
1.11 - const MemBarNode *mem = (const MemBarNode*)vmb;
1.12 +bool Matcher::post_store_load_barrier(const Node* vmb) {
1.13 + Compile* C = Compile::current();
1.14 + assert(vmb->is_MemBar(), "");
1.15 + assert(vmb->Opcode() != Op_MemBarAcquire, "");
1.16 + const MemBarNode* membar = vmb->as_MemBar();
1.17
1.18 - // Get the Proj node, ctrl, that can be used to iterate forward
1.19 - Node *ctrl = NULL;
1.20 - DUIterator_Fast imax, i = mem->fast_outs(imax);
1.21 - while( true ) {
1.22 - ctrl = mem->fast_out(i); // Throw out-of-bounds if proj not found
1.23 - assert( ctrl->is_Proj(), "only projections here" );
1.24 - ProjNode *proj = (ProjNode*)ctrl;
1.25 - if( proj->_con == TypeFunc::Control &&
1.26 - !C->node_arena()->contains(ctrl) ) // Unmatched old-space only
1.27 + // Get the Ideal Proj node, ctrl, that can be used to iterate forward
1.28 + Node* ctrl = NULL;
1.29 + for (DUIterator_Fast imax, i = membar->fast_outs(imax); i < imax; i++) {
1.30 + Node* p = membar->fast_out(i);
1.31 + assert(p->is_Proj(), "only projections here");
1.32 + if ((p->as_Proj()->_con == TypeFunc::Control) &&
1.33 + !C->node_arena()->contains(p)) { // Unmatched old-space only
1.34 + ctrl = p;
1.35 break;
1.36 - i++;
1.37 + }
1.38 }
1.39 + assert((ctrl != NULL), "missing control projection");
1.40
1.41 - for( DUIterator_Fast jmax, j = ctrl->fast_outs(jmax); j < jmax; j++ ) {
1.42 + for (DUIterator_Fast jmax, j = ctrl->fast_outs(jmax); j < jmax; j++) {
1.43 Node *x = ctrl->fast_out(j);
1.44 int xop = x->Opcode();
1.45
1.46 @@ -2339,37 +2339,36 @@
1.47 // that a monitor exit operation contains a serializing instruction.
1.48
1.49 if (xop == Op_MemBarVolatile ||
1.50 - xop == Op_FastLock ||
1.51 xop == Op_CompareAndSwapL ||
1.52 xop == Op_CompareAndSwapP ||
1.53 xop == Op_CompareAndSwapN ||
1.54 - xop == Op_CompareAndSwapI)
1.55 + xop == Op_CompareAndSwapI) {
1.56 return true;
1.57 + }
1.58 +
1.59 + // Op_FastLock previously appeared in the Op_* list above.
1.60 + // With biased locking we're no longer guaranteed that a monitor
1.61 + // enter operation contains a serializing instruction.
1.62 + if ((xop == Op_FastLock) && !UseBiasedLocking) {
1.63 + return true;
1.64 + }
1.65
1.66 if (x->is_MemBar()) {
1.67 // We must retain this membar if there is an upcoming volatile
1.68 - // load, which will be preceded by acquire membar.
1.69 - if (xop == Op_MemBarAcquire)
1.70 + // load, which will be followed by acquire membar.
1.71 + if (xop == Op_MemBarAcquire) {
1.72 return false;
1.73 - // For other kinds of barriers, check by pretending we
1.74 - // are them, and seeing if we can be removed.
1.75 - else
1.76 - return post_store_load_barrier((const MemBarNode*)x);
1.77 + } else {
1.78 + // For other kinds of barriers, check by pretending we
1.79 + // are them, and seeing if we can be removed.
1.80 + return post_store_load_barrier(x->as_MemBar());
1.81 + }
1.82 }
1.83
1.84 - // Delicate code to detect case of an upcoming fastlock block
1.85 - if( x->is_If() && x->req() > 1 &&
1.86 - !C->node_arena()->contains(x) ) { // Unmatched old-space only
1.87 - Node *iff = x;
1.88 - Node *bol = iff->in(1);
1.89 - // The iff might be some random subclass of If or bol might be Con-Top
1.90 - if (!bol->is_Bool()) return false;
1.91 - assert( bol->req() > 1, "" );
1.92 - return (bol->in(1)->Opcode() == Op_FastUnlock);
1.93 + // probably not necessary to check for these
1.94 + if (x->is_Call() || x->is_SafePoint() || x->is_block_proj()) {
1.95 + return false;
1.96 }
1.97 - // probably not necessary to check for these
1.98 - if (x->is_Call() || x->is_SafePoint() || x->is_block_proj())
1.99 - return false;
1.100 }
1.101 return false;
1.102 }
