--- a/src/hotspot/share/opto/loopTransform.cpp Thu Jun 14 02:01:31 2018 -0400
+++ b/src/hotspot/share/opto/loopTransform.cpp Thu Jun 14 09:04:55 2018 +0200
@@ -1014,125 +1014,143 @@
// loop is never executed). When that happens, range check
// CastII/ConvI2L nodes cause some data paths to die. For consistency,
// the control paths must die too but the range checks were removed by
-// predication. The range checks that we add here guarantee that they
-// do.
+// predication. The range checks that we add here guarantee that they do.
void PhaseIdealLoop::duplicate_predicates(CountedLoopNode* pre_head, Node* min_taken, Node* castii,
IdealLoopTree* outer_loop, LoopNode* outer_main_head,
uint dd_main_head) {
- if (UseLoopPredicate) {
- Node* entry = pre_head->in(LoopNode::EntryControl);
- Node* predicate = NULL;
- predicate = find_predicate_insertion_point(entry, Deoptimization::Reason_loop_limit_check);
- if (predicate != NULL) {
+ assert(UseLoopPredicate, "loop predicates must be enabled");
+ Node* entry = pre_head->in(LoopNode::EntryControl);
+ Node* predicate = NULL;
+ predicate = find_predicate_insertion_point(entry, Deoptimization::Reason_loop_limit_check);
+ if (predicate != NULL) {
+ entry = entry->in(0)->in(0);
+ }
+ predicate = find_predicate_insertion_point(entry, Deoptimization::Reason_predicate);
+ if (predicate != NULL) {
+ IfNode* iff = entry->in(0)->as_If();
+ ProjNode* uncommon_proj = iff->proj_out(1 - entry->as_Proj()->_con);
+ Node* rgn = uncommon_proj->unique_ctrl_out();
+ assert(rgn->is_Region() || rgn->is_Call(), "must be a region or call uct");
+ assert(iff->in(1)->in(1)->Opcode() == Op_Opaque1, "unexpected predicate shape");
+ entry = entry->in(0)->in(0);
+ Node* prev_proj = min_taken;
+ while (entry != NULL && entry->is_Proj() && entry->in(0)->is_If()) {
+ iff = entry->in(0)->as_If();
+ uncommon_proj = iff->proj_out(1 - entry->as_Proj()->_con);
+ if (uncommon_proj->unique_ctrl_out() != rgn)
+ break;
+ if (iff->in(1)->Opcode() == Op_Opaque4) {
+ // Clone the predicate twice and initialize one with the initial
+ // value of the loop induction variable. Leave the other predicate
+ // to be initialized when increasing the stride during loop unrolling.
+ prev_proj = update_skeleton_predicate(iff, castii, entry, uncommon_proj, min_taken, outer_loop, prev_proj);
+ Node* value = new Opaque1Node(C, castii);
+ register_new_node(value, min_taken);
+ prev_proj = update_skeleton_predicate(iff, value, entry, uncommon_proj, min_taken, outer_loop, prev_proj);
+ // Remove the skeleton predicate from the pre-loop
+ _igvn.replace_input_of(iff, 1, _igvn.intcon(1));
+ }
entry = entry->in(0)->in(0);
}
- predicate = find_predicate_insertion_point(entry, Deoptimization::Reason_predicate);
- if (predicate != NULL) {
- IfNode* iff = entry->in(0)->as_If();
- ProjNode* uncommon_proj = iff->proj_out(1 - entry->as_Proj()->_con);
- Node* rgn = uncommon_proj->unique_ctrl_out();
- assert(rgn->is_Region() || rgn->is_Call(), "must be a region or call uct");
- assert(iff->in(1)->in(1)->Opcode() == Op_Opaque1, "unexpected predicate shape");
- entry = entry->in(0)->in(0);
- Node* prev_proj = min_taken;
- while (entry != NULL && entry->is_Proj() && entry->in(0)->is_If()) {
- uncommon_proj = entry->in(0)->as_If()->proj_out(1 - entry->as_Proj()->_con);
- if (uncommon_proj->unique_ctrl_out() != rgn)
- break;
- iff = entry->in(0)->as_If();
- if (iff->in(1)->Opcode() == Op_Opaque4) {
- Node_Stack to_clone(2);
- to_clone.push(iff->in(1), 1);
- uint current = C->unique();
- Node* result = NULL;
- // Look for the opaque node to replace with the init value
- // and clone everything in between. We keep the Opaque4 node
- // so the duplicated predicates are eliminated once loop
- // opts are over: they are here only to keep the IR graph
- // consistent.
- do {
- Node* n = to_clone.node();
- uint i = to_clone.index();
- Node* m = n->in(i);
- int op = m->Opcode();
- if (m->is_Bool() ||
- m->is_Cmp() ||
- op == Op_AndL ||
- op == Op_OrL ||
- op == Op_RShiftL ||
- op == Op_LShiftL ||
- op == Op_AddL ||
- op == Op_AddI ||
- op == Op_MulL ||
- op == Op_MulI ||
- op == Op_SubL ||
- op == Op_SubI ||
- op == Op_ConvI2L) {
- to_clone.push(m, 1);
- continue;
- }
- if (op == Op_Opaque1) {
- if (n->_idx < current) {
- n = n->clone();
- }
- n->set_req(i, castii);
- register_new_node(n, min_taken);
- to_clone.set_node(n);
- }
- for (;;) {
- Node* cur = to_clone.node();
- uint j = to_clone.index();
- if (j+1 < cur->req()) {
- to_clone.set_index(j+1);
- break;
- }
- to_clone.pop();
- if (to_clone.size() == 0) {
- result = cur;
- break;
- }
- Node* next = to_clone.node();
- j = to_clone.index();
- if (cur->_idx >= current) {
- if (next->_idx < current) {
- next = next->clone();
- register_new_node(next, min_taken);
- to_clone.set_node(next);
- }
- assert(next->in(j) != cur, "input should have been cloned");
- next->set_req(j, cur);
- }
- }
- } while (result == NULL);
- assert(result->_idx >= current, "new node expected");
-
- Node* proj = entry->clone();
- Node* other_proj = uncommon_proj->clone();
- Node* new_iff = iff->clone();
- new_iff->set_req(1, result);
- proj->set_req(0, new_iff);
- other_proj->set_req(0, new_iff);
- Node *frame = new ParmNode(C->start(), TypeFunc::FramePtr);
- register_new_node(frame, C->start());
- // It's impossible for the predicate to fail at runtime. Use
- // an Halt node.
- Node* halt = new HaltNode(other_proj, frame);
- C->root()->add_req(halt);
- new_iff->set_req(0, prev_proj);
-
- register_control(new_iff, outer_loop->_parent, prev_proj);
- register_control(proj, outer_loop->_parent, new_iff);
- register_control(other_proj, _ltree_root, new_iff);
- register_control(halt, _ltree_root, other_proj);
-
- prev_proj = proj;
+ _igvn.replace_input_of(outer_main_head, LoopNode::EntryControl, prev_proj);
+ set_idom(outer_main_head, prev_proj, dd_main_head);
+ }
+}
+
+Node* PhaseIdealLoop::update_skeleton_predicate(Node* iff, Node* value, Node* entry, Node* uncommon_proj,
+ Node* min_taken, IdealLoopTree* outer_loop, Node* prev_proj) {
+ bool clone = (outer_loop != NULL); // Clone the predicate?
+ Node_Stack to_clone(2);
+ to_clone.push(iff->in(1), 1);
+ uint current = C->unique();
+ Node* result = NULL;
+ // Look for the opaque node to replace with the new value
+ // and clone everything in between. We keep the Opaque4 node
+ // so the duplicated predicates are eliminated once loop
+ // opts are over: they are here only to keep the IR graph
+ // consistent.
+ do {
+ Node* n = to_clone.node();
+ uint i = to_clone.index();
+ Node* m = n->in(i);
+ int op = m->Opcode();
+ if (m->is_Bool() ||
+ m->is_Cmp() ||
+ op == Op_AndL ||
+ op == Op_OrL ||
+ op == Op_RShiftL ||
+ op == Op_LShiftL ||
+ op == Op_AddL ||
+ op == Op_AddI ||
+ op == Op_MulL ||
+ op == Op_MulI ||
+ op == Op_SubL ||
+ op == Op_SubI ||
+ op == Op_ConvI2L) {
+ to_clone.push(m, 1);
+ continue;
+ }
+ if (op == Op_Opaque1) {
+ if (!clone) {
+ // Update the input of the Opaque1Node and exit
+ _igvn.replace_input_of(m, 1, value);
+ return prev_proj;
+ }
+ if (n->_idx < current) {
+ n = n->clone();
+ }
+ n->set_req(i, value);
+ register_new_node(n, min_taken);
+ to_clone.set_node(n);
+ }
+ for (;;) {
+ Node* cur = to_clone.node();
+ uint j = to_clone.index();
+ if (j+1 < cur->req()) {
+ to_clone.set_index(j+1);
+ break;
+ }
+ to_clone.pop();
+ if (to_clone.size() == 0) {
+ result = cur;
+ break;
+ }
+ Node* next = to_clone.node();
+ j = to_clone.index();
+ if (clone && cur->_idx >= current) {
+ if (next->_idx < current) {
+ next = next->clone();
+ register_new_node(next, min_taken);
+ to_clone.set_node(next);
}
- entry = entry->in(0)->in(0);
+ assert(next->in(j) != cur, "input should have been cloned");
+ next->set_req(j, cur);
}
- _igvn.replace_input_of(outer_main_head, LoopNode::EntryControl, prev_proj);
- set_idom(outer_main_head, prev_proj, dd_main_head);
}
+ } while (result == NULL);
+ if (!clone) {
+ return NULL;
}
+ assert(result->_idx >= current, "new node expected");
+
+ Node* proj = entry->clone();
+ Node* other_proj = uncommon_proj->clone();
+ Node* new_iff = iff->clone();
+ new_iff->set_req(1, result);
+ proj->set_req(0, new_iff);
+ other_proj->set_req(0, new_iff);
+ Node *frame = new ParmNode(C->start(), TypeFunc::FramePtr);
+ register_new_node(frame, C->start());
+ // It's impossible for the predicate to fail at runtime. Use an Halt node.
+ Node* halt = new HaltNode(other_proj, frame);
+ C->root()->add_req(halt);
+ new_iff->set_req(0, prev_proj);
+
+ register_control(new_iff, outer_loop->_parent, prev_proj);
+ register_control(proj, outer_loop->_parent, new_iff);
+ register_control(other_proj, _ltree_root, new_iff);
+ register_control(halt, _ltree_root, other_proj);
+ return proj;
}
//------------------------------insert_pre_post_loops--------------------------
@@ -1278,7 +1296,9 @@
// CastII for the main loop:
Node* castii = cast_incr_before_loop( pre_incr, min_taken, main_head );
assert(castii != NULL, "no castII inserted");
- duplicate_predicates(pre_head, min_taken, castii, outer_loop, outer_main_head, dd_main_head);
+ if (UseLoopPredicate) {
+ duplicate_predicates(pre_head, min_taken, castii, outer_loop, outer_main_head, dd_main_head);
+ }
// Step B4: Shorten the pre-loop to run only 1 iteration (for now).
// RCE and alignment may change this later.
@@ -1622,6 +1642,26 @@
assert(old_trip_count > 1 &&
(!adjust_min_trip || stride_p <= (1<<3)*loop_head->unrolled_count()), "sanity");
+ if (UseLoopPredicate) {
+ // Search for skeleton predicates and update them according to the new stride
+ Node* entry = ctrl;
+ while (entry != NULL && entry->is_Proj() && entry->in(0)->is_If()) {
+ IfNode* iff = entry->in(0)->as_If();
+ ProjNode* proj = iff->proj_out(1 - entry->as_Proj()->_con);
+ if (proj->unique_ctrl_out()->Opcode() != Op_Halt) {
+ break;
+ }
+ if (iff->in(1)->Opcode() == Op_Opaque4) {
+ // Compute value of loop induction variable at the end of the first iteration
+ Node* max_value = _igvn.intcon(2 * stride_con - (stride_con > 0 ? 1 : -1));
+ max_value = new AddINode(init, max_value);
+ register_new_node(max_value, get_ctrl(iff->in(1)));
+ update_skeleton_predicate(iff, max_value);
+ }
+ entry = entry->in(0)->in(0);
+ }
+ }
+
// Adjust loop limit to keep valid iterations number after unroll.
// Use (limit - stride) instead of (((limit - init)/stride) & (-2))*stride
// which may overflow.