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comparison src/share/vm/opto/ifg.cpp @ 20686:dc763d49b82d

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8065618: C2 RA incorrectly removes kill projections Summary: Don't remove KILL projections if their "defining" nodes have SCMemProj projection (memory side effects). Reviewed-by: iveresov, roland
author kvn
date Tue, 02 Dec 2014 12:08:41 -0800
parents 78bbf4d43a14
children 3f4a5fdca318
comparison
equal deleted inserted replaced
20685:0b86bdf28e07 20686:dc763d49b82d
539 if( !liveout.member(r) && n->Opcode() != Op_SafePoint ) { 539 if( !liveout.member(r) && n->Opcode() != Op_SafePoint ) {
540 Node *def = n->in(0); 540 Node *def = n->in(0);
541 if( !n->is_Proj() || 541 if( !n->is_Proj() ||
542 // Could also be a flags-projection of a dead ADD or such. 542 // Could also be a flags-projection of a dead ADD or such.
543 (_lrg_map.live_range_id(def) && !liveout.member(_lrg_map.live_range_id(def)))) { 543 (_lrg_map.live_range_id(def) && !liveout.member(_lrg_map.live_range_id(def)))) {
544 if (n->is_MachProj()) {
545 // Don't remove KILL projections if their "defining" nodes have
546 // memory effects (have SCMemProj projection node) -
547 // they are not dead even when their result is not used.
548 // For example, compareAndSwapL (and other CAS) and EncodeISOArray nodes.
549 // The method add_input_to_liveout() keeps such nodes alive (put them on liveout list)
550 // when it sees SCMemProj node in a block. Unfortunately SCMemProj node could be placed
551 // in block in such order that KILL MachProj nodes are processed first.
552 uint cnt = def->outcnt();
553 for (uint i = 0; i < cnt; i++) {
554 Node* proj = def->raw_out(i);
555 if (proj->Opcode() == Op_SCMemProj) {
556 return false;
557 }
558 }
559 }
544 block->remove_node(j - 1); 560 block->remove_node(j - 1);
545 if (lrgs(r)._def == n) { 561 if (lrgs(r)._def == n) {
546 lrgs(r)._def = 0; 562 lrgs(r)._def = 0;
547 } 563 }
548 n->disconnect_inputs(NULL, C); 564 n->disconnect_inputs(NULL, C);