| /* |
| * Copyright (c) 1999, 2017, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| * |
| */ |
| |
| #include "precompiled.hpp" |
| #include "memory/allocation.inline.hpp" |
| #include "memory/resourceArea.hpp" |
| #include "opto/addnode.hpp" |
| #include "opto/castnode.hpp" |
| #include "opto/connode.hpp" |
| #include "opto/castnode.hpp" |
| #include "opto/divnode.hpp" |
| #include "opto/loopnode.hpp" |
| #include "opto/matcher.hpp" |
| #include "opto/mulnode.hpp" |
| #include "opto/movenode.hpp" |
| #include "opto/opaquenode.hpp" |
| #include "opto/rootnode.hpp" |
| #include "opto/subnode.hpp" |
| |
| //============================================================================= |
| //------------------------------split_thru_phi--------------------------------- |
| // Split Node 'n' through merge point if there is enough win. |
| Node *PhaseIdealLoop::split_thru_phi( Node *n, Node *region, int policy ) { |
| if (n->Opcode() == Op_ConvI2L && n->bottom_type() != TypeLong::LONG) { |
| // ConvI2L may have type information on it which is unsafe to push up |
| // so disable this for now |
| return NULL; |
| } |
| |
| // Splitting range check CastIIs through a loop induction Phi can |
| // cause new Phis to be created that are left unrelated to the loop |
| // induction Phi and prevent optimizations (vectorization) |
| if (n->Opcode() == Op_CastII && n->as_CastII()->has_range_check() && |
| region->is_CountedLoop() && n->in(1) == region->as_CountedLoop()->phi()) { |
| return NULL; |
| } |
| |
| int wins = 0; |
| assert(!n->is_CFG(), ""); |
| assert(region->is_Region(), ""); |
| |
| const Type* type = n->bottom_type(); |
| const TypeOopPtr *t_oop = _igvn.type(n)->isa_oopptr(); |
| Node *phi; |
| if (t_oop != NULL && t_oop->is_known_instance_field()) { |
| int iid = t_oop->instance_id(); |
| int index = C->get_alias_index(t_oop); |
| int offset = t_oop->offset(); |
| phi = new PhiNode(region, type, NULL, iid, index, offset); |
| } else { |
| phi = PhiNode::make_blank(region, n); |
| } |
| uint old_unique = C->unique(); |
| for (uint i = 1; i < region->req(); i++) { |
| Node *x; |
| Node* the_clone = NULL; |
| if (region->in(i) == C->top()) { |
| x = C->top(); // Dead path? Use a dead data op |
| } else { |
| x = n->clone(); // Else clone up the data op |
| the_clone = x; // Remember for possible deletion. |
| // Alter data node to use pre-phi inputs |
| if (n->in(0) == region) |
| x->set_req( 0, region->in(i) ); |
| for (uint j = 1; j < n->req(); j++) { |
| Node *in = n->in(j); |
| if (in->is_Phi() && in->in(0) == region) |
| x->set_req( j, in->in(i) ); // Use pre-Phi input for the clone |
| } |
| } |
| // Check for a 'win' on some paths |
| const Type *t = x->Value(&_igvn); |
| |
| bool singleton = t->singleton(); |
| |
| // A TOP singleton indicates that there are no possible values incoming |
| // along a particular edge. In most cases, this is OK, and the Phi will |
| // be eliminated later in an Ideal call. However, we can't allow this to |
| // happen if the singleton occurs on loop entry, as the elimination of |
| // the PhiNode may cause the resulting node to migrate back to a previous |
| // loop iteration. |
| if (singleton && t == Type::TOP) { |
| // Is_Loop() == false does not confirm the absence of a loop (e.g., an |
| // irreducible loop may not be indicated by an affirmative is_Loop()); |
| // therefore, the only top we can split thru a phi is on a backedge of |
| // a loop. |
| singleton &= region->is_Loop() && (i != LoopNode::EntryControl); |
| } |
| |
| if (singleton) { |
| wins++; |
| x = ((PhaseGVN&)_igvn).makecon(t); |
| } else { |
| // We now call Identity to try to simplify the cloned node. |
| // Note that some Identity methods call phase->type(this). |
| // Make sure that the type array is big enough for |
| // our new node, even though we may throw the node away. |
| // (Note: This tweaking with igvn only works because x is a new node.) |
| _igvn.set_type(x, t); |
| // If x is a TypeNode, capture any more-precise type permanently into Node |
| // otherwise it will be not updated during igvn->transform since |
| // igvn->type(x) is set to x->Value() already. |
| x->raise_bottom_type(t); |
| Node *y = x->Identity(&_igvn); |
| if (y != x) { |
| wins++; |
| x = y; |
| } else { |
| y = _igvn.hash_find(x); |
| if (y) { |
| wins++; |
| x = y; |
| } else { |
| // Else x is a new node we are keeping |
| // We do not need register_new_node_with_optimizer |
| // because set_type has already been called. |
| _igvn._worklist.push(x); |
| } |
| } |
| } |
| if (x != the_clone && the_clone != NULL) |
| _igvn.remove_dead_node(the_clone); |
| phi->set_req( i, x ); |
| } |
| // Too few wins? |
| if (wins <= policy) { |
| _igvn.remove_dead_node(phi); |
| return NULL; |
| } |
| |
| // Record Phi |
| register_new_node( phi, region ); |
| |
| for (uint i2 = 1; i2 < phi->req(); i2++) { |
| Node *x = phi->in(i2); |
| // If we commoned up the cloned 'x' with another existing Node, |
| // the existing Node picks up a new use. We need to make the |
| // existing Node occur higher up so it dominates its uses. |
| Node *old_ctrl; |
| IdealLoopTree *old_loop; |
| |
| if (x->is_Con()) { |
| // Constant's control is always root. |
| set_ctrl(x, C->root()); |
| continue; |
| } |
| // The occasional new node |
| if (x->_idx >= old_unique) { // Found a new, unplaced node? |
| old_ctrl = NULL; |
| old_loop = NULL; // Not in any prior loop |
| } else { |
| old_ctrl = get_ctrl(x); |
| old_loop = get_loop(old_ctrl); // Get prior loop |
| } |
| // New late point must dominate new use |
| Node *new_ctrl = dom_lca(old_ctrl, region->in(i2)); |
| if (new_ctrl == old_ctrl) // Nothing is changed |
| continue; |
| |
| IdealLoopTree *new_loop = get_loop(new_ctrl); |
| |
| // Don't move x into a loop if its uses are |
| // outside of loop. Otherwise x will be cloned |
| // for each use outside of this loop. |
| IdealLoopTree *use_loop = get_loop(region); |
| if (!new_loop->is_member(use_loop) && |
| (old_loop == NULL || !new_loop->is_member(old_loop))) { |
| // Take early control, later control will be recalculated |
| // during next iteration of loop optimizations. |
| new_ctrl = get_early_ctrl(x); |
| new_loop = get_loop(new_ctrl); |
| } |
| // Set new location |
| set_ctrl(x, new_ctrl); |
| // If changing loop bodies, see if we need to collect into new body |
| if (old_loop != new_loop) { |
| if (old_loop && !old_loop->_child) |
| old_loop->_body.yank(x); |
| if (!new_loop->_child) |
| new_loop->_body.push(x); // Collect body info |
| } |
| } |
| |
| return phi; |
| } |
| |
| //------------------------------dominated_by------------------------------------ |
| // Replace the dominated test with an obvious true or false. Place it on the |
| // IGVN worklist for later cleanup. Move control-dependent data Nodes on the |
| // live path up to the dominating control. |
| void PhaseIdealLoop::dominated_by( Node *prevdom, Node *iff, bool flip, bool exclude_loop_predicate ) { |
| if (VerifyLoopOptimizations && PrintOpto) { tty->print_cr("dominating test"); } |
| |
| // prevdom is the dominating projection of the dominating test. |
| assert( iff->is_If(), "" ); |
| assert(iff->Opcode() == Op_If || iff->Opcode() == Op_CountedLoopEnd || iff->Opcode() == Op_RangeCheck, "Check this code when new subtype is added"); |
| int pop = prevdom->Opcode(); |
| assert( pop == Op_IfFalse || pop == Op_IfTrue, "" ); |
| if (flip) { |
| if (pop == Op_IfTrue) |
| pop = Op_IfFalse; |
| else |
| pop = Op_IfTrue; |
| } |
| // 'con' is set to true or false to kill the dominated test. |
| Node *con = _igvn.makecon(pop == Op_IfTrue ? TypeInt::ONE : TypeInt::ZERO); |
| set_ctrl(con, C->root()); // Constant gets a new use |
| // Hack the dominated test |
| _igvn.replace_input_of(iff, 1, con); |
| |
| // If I dont have a reachable TRUE and FALSE path following the IfNode then |
| // I can assume this path reaches an infinite loop. In this case it's not |
| // important to optimize the data Nodes - either the whole compilation will |
| // be tossed or this path (and all data Nodes) will go dead. |
| if (iff->outcnt() != 2) return; |
| |
| // Make control-dependent data Nodes on the live path (path that will remain |
| // once the dominated IF is removed) become control-dependent on the |
| // dominating projection. |
| Node* dp = iff->as_If()->proj_out(pop == Op_IfTrue); |
| |
| // Loop predicates may have depending checks which should not |
| // be skipped. For example, range check predicate has two checks |
| // for lower and upper bounds. |
| if (dp == NULL) |
| return; |
| |
| ProjNode* dp_proj = dp->as_Proj(); |
| ProjNode* unc_proj = iff->as_If()->proj_out(1 - dp_proj->_con)->as_Proj(); |
| if (exclude_loop_predicate && |
| (unc_proj->is_uncommon_trap_proj(Deoptimization::Reason_predicate) != NULL || |
| unc_proj->is_uncommon_trap_proj(Deoptimization::Reason_range_check) != NULL)) { |
| // If this is a range check (IfNode::is_range_check), do not |
| // reorder because Compile::allow_range_check_smearing might have |
| // changed the check. |
| return; // Let IGVN transformation change control dependence. |
| } |
| |
| IdealLoopTree *old_loop = get_loop(dp); |
| |
| for (DUIterator_Fast imax, i = dp->fast_outs(imax); i < imax; i++) { |
| Node* cd = dp->fast_out(i); // Control-dependent node |
| if (cd->depends_only_on_test()) { |
| assert(cd->in(0) == dp, ""); |
| _igvn.replace_input_of(cd, 0, prevdom); |
| set_early_ctrl(cd); |
| IdealLoopTree *new_loop = get_loop(get_ctrl(cd)); |
| if (old_loop != new_loop) { |
| if (!old_loop->_child) old_loop->_body.yank(cd); |
| if (!new_loop->_child) new_loop->_body.push(cd); |
| } |
| --i; |
| --imax; |
| } |
| } |
| } |
| |
| //------------------------------has_local_phi_input---------------------------- |
| // Return TRUE if 'n' has Phi inputs from its local block and no other |
| // block-local inputs (all non-local-phi inputs come from earlier blocks) |
| Node *PhaseIdealLoop::has_local_phi_input( Node *n ) { |
| Node *n_ctrl = get_ctrl(n); |
| // See if some inputs come from a Phi in this block, or from before |
| // this block. |
| uint i; |
| for( i = 1; i < n->req(); i++ ) { |
| Node *phi = n->in(i); |
| if( phi->is_Phi() && phi->in(0) == n_ctrl ) |
| break; |
| } |
| if( i >= n->req() ) |
| return NULL; // No Phi inputs; nowhere to clone thru |
| |
| // Check for inputs created between 'n' and the Phi input. These |
| // must split as well; they have already been given the chance |
| // (courtesy of a post-order visit) and since they did not we must |
| // recover the 'cost' of splitting them by being very profitable |
| // when splitting 'n'. Since this is unlikely we simply give up. |
| for( i = 1; i < n->req(); i++ ) { |
| Node *m = n->in(i); |
| if( get_ctrl(m) == n_ctrl && !m->is_Phi() ) { |
| // We allow the special case of AddP's with no local inputs. |
| // This allows us to split-up address expressions. |
| if (m->is_AddP() && |
| get_ctrl(m->in(2)) != n_ctrl && |
| get_ctrl(m->in(3)) != n_ctrl) { |
| // Move the AddP up to dominating point |
| set_ctrl_and_loop(m, find_non_split_ctrl(idom(n_ctrl))); |
| continue; |
| } |
| return NULL; |
| } |
| } |
| |
| return n_ctrl; |
| } |
| |
| //------------------------------remix_address_expressions---------------------- |
| // Rework addressing expressions to get the most loop-invariant stuff |
| // moved out. We'd like to do all associative operators, but it's especially |
| // important (common) to do address expressions. |
| Node *PhaseIdealLoop::remix_address_expressions( Node *n ) { |
| if (!has_ctrl(n)) return NULL; |
| Node *n_ctrl = get_ctrl(n); |
| IdealLoopTree *n_loop = get_loop(n_ctrl); |
| |
| // See if 'n' mixes loop-varying and loop-invariant inputs and |
| // itself is loop-varying. |
| |
| // Only interested in binary ops (and AddP) |
| if( n->req() < 3 || n->req() > 4 ) return NULL; |
| |
| Node *n1_ctrl = get_ctrl(n->in( 1)); |
| Node *n2_ctrl = get_ctrl(n->in( 2)); |
| Node *n3_ctrl = get_ctrl(n->in(n->req() == 3 ? 2 : 3)); |
| IdealLoopTree *n1_loop = get_loop( n1_ctrl ); |
| IdealLoopTree *n2_loop = get_loop( n2_ctrl ); |
| IdealLoopTree *n3_loop = get_loop( n3_ctrl ); |
| |
| // Does one of my inputs spin in a tighter loop than self? |
| if( (n_loop->is_member( n1_loop ) && n_loop != n1_loop) || |
| (n_loop->is_member( n2_loop ) && n_loop != n2_loop) || |
| (n_loop->is_member( n3_loop ) && n_loop != n3_loop) ) |
| return NULL; // Leave well enough alone |
| |
| // Is at least one of my inputs loop-invariant? |
| if( n1_loop == n_loop && |
| n2_loop == n_loop && |
| n3_loop == n_loop ) |
| return NULL; // No loop-invariant inputs |
| |
| |
| int n_op = n->Opcode(); |
| |
| // Replace expressions like ((V+I) << 2) with (V<<2 + I<<2). |
| if( n_op == Op_LShiftI ) { |
| // Scale is loop invariant |
| Node *scale = n->in(2); |
| Node *scale_ctrl = get_ctrl(scale); |
| IdealLoopTree *scale_loop = get_loop(scale_ctrl ); |
| if( n_loop == scale_loop || !scale_loop->is_member( n_loop ) ) |
| return NULL; |
| const TypeInt *scale_t = scale->bottom_type()->isa_int(); |
| if( scale_t && scale_t->is_con() && scale_t->get_con() >= 16 ) |
| return NULL; // Dont bother with byte/short masking |
| // Add must vary with loop (else shift would be loop-invariant) |
| Node *add = n->in(1); |
| Node *add_ctrl = get_ctrl(add); |
| IdealLoopTree *add_loop = get_loop(add_ctrl); |
| //assert( n_loop == add_loop, "" ); |
| if( n_loop != add_loop ) return NULL; // happens w/ evil ZKM loops |
| |
| // Convert I-V into I+ (0-V); same for V-I |
| if( add->Opcode() == Op_SubI && |
| _igvn.type( add->in(1) ) != TypeInt::ZERO ) { |
| Node *zero = _igvn.intcon(0); |
| set_ctrl(zero, C->root()); |
| Node *neg = new SubINode( _igvn.intcon(0), add->in(2) ); |
| register_new_node( neg, get_ctrl(add->in(2) ) ); |
| add = new AddINode( add->in(1), neg ); |
| register_new_node( add, add_ctrl ); |
| } |
| if( add->Opcode() != Op_AddI ) return NULL; |
| // See if one add input is loop invariant |
| Node *add_var = add->in(1); |
| Node *add_var_ctrl = get_ctrl(add_var); |
| IdealLoopTree *add_var_loop = get_loop(add_var_ctrl ); |
| Node *add_invar = add->in(2); |
| Node *add_invar_ctrl = get_ctrl(add_invar); |
| IdealLoopTree *add_invar_loop = get_loop(add_invar_ctrl ); |
| if( add_var_loop == n_loop ) { |
| } else if( add_invar_loop == n_loop ) { |
| // Swap to find the invariant part |
| add_invar = add_var; |
| add_invar_ctrl = add_var_ctrl; |
| add_invar_loop = add_var_loop; |
| add_var = add->in(2); |
| Node *add_var_ctrl = get_ctrl(add_var); |
| IdealLoopTree *add_var_loop = get_loop(add_var_ctrl ); |
| } else // Else neither input is loop invariant |
| return NULL; |
| if( n_loop == add_invar_loop || !add_invar_loop->is_member( n_loop ) ) |
| return NULL; // No invariant part of the add? |
| |
| // Yes! Reshape address expression! |
| Node *inv_scale = new LShiftINode( add_invar, scale ); |
| Node *inv_scale_ctrl = |
| dom_depth(add_invar_ctrl) > dom_depth(scale_ctrl) ? |
| add_invar_ctrl : scale_ctrl; |
| register_new_node( inv_scale, inv_scale_ctrl ); |
| Node *var_scale = new LShiftINode( add_var, scale ); |
| register_new_node( var_scale, n_ctrl ); |
| Node *var_add = new AddINode( var_scale, inv_scale ); |
| register_new_node( var_add, n_ctrl ); |
| _igvn.replace_node( n, var_add ); |
| return var_add; |
| } |
| |
| // Replace (I+V) with (V+I) |
| if( n_op == Op_AddI || |
| n_op == Op_AddL || |
| n_op == Op_AddF || |
| n_op == Op_AddD || |
| n_op == Op_MulI || |
| n_op == Op_MulL || |
| n_op == Op_MulF || |
| n_op == Op_MulD ) { |
| if( n2_loop == n_loop ) { |
| assert( n1_loop != n_loop, "" ); |
| n->swap_edges(1, 2); |
| } |
| } |
| |
| // Replace ((I1 +p V) +p I2) with ((I1 +p I2) +p V), |
| // but not if I2 is a constant. |
| if( n_op == Op_AddP ) { |
| if( n2_loop == n_loop && n3_loop != n_loop ) { |
| if( n->in(2)->Opcode() == Op_AddP && !n->in(3)->is_Con() ) { |
| Node *n22_ctrl = get_ctrl(n->in(2)->in(2)); |
| Node *n23_ctrl = get_ctrl(n->in(2)->in(3)); |
| IdealLoopTree *n22loop = get_loop( n22_ctrl ); |
| IdealLoopTree *n23_loop = get_loop( n23_ctrl ); |
| if( n22loop != n_loop && n22loop->is_member(n_loop) && |
| n23_loop == n_loop ) { |
| Node *add1 = new AddPNode( n->in(1), n->in(2)->in(2), n->in(3) ); |
| // Stuff new AddP in the loop preheader |
| register_new_node( add1, n_loop->_head->in(LoopNode::EntryControl) ); |
| Node *add2 = new AddPNode( n->in(1), add1, n->in(2)->in(3) ); |
| register_new_node( add2, n_ctrl ); |
| _igvn.replace_node( n, add2 ); |
| return add2; |
| } |
| } |
| } |
| |
| // Replace (I1 +p (I2 + V)) with ((I1 +p I2) +p V) |
| if (n2_loop != n_loop && n3_loop == n_loop) { |
| if (n->in(3)->Opcode() == Op_AddX) { |
| Node *V = n->in(3)->in(1); |
| Node *I = n->in(3)->in(2); |
| if (is_member(n_loop,get_ctrl(V))) { |
| } else { |
| Node *tmp = V; V = I; I = tmp; |
| } |
| if (!is_member(n_loop,get_ctrl(I))) { |
| Node *add1 = new AddPNode(n->in(1), n->in(2), I); |
| // Stuff new AddP in the loop preheader |
| register_new_node(add1, n_loop->_head->in(LoopNode::EntryControl)); |
| Node *add2 = new AddPNode(n->in(1), add1, V); |
| register_new_node(add2, n_ctrl); |
| _igvn.replace_node(n, add2); |
| return add2; |
| } |
| } |
| } |
| } |
| |
| return NULL; |
| } |
| |
| //------------------------------conditional_move------------------------------- |
| // Attempt to replace a Phi with a conditional move. We have some pretty |
| // strict profitability requirements. All Phis at the merge point must |
| // be converted, so we can remove the control flow. We need to limit the |
| // number of c-moves to a small handful. All code that was in the side-arms |
| // of the CFG diamond is now speculatively executed. This code has to be |
| // "cheap enough". We are pretty much limited to CFG diamonds that merge |
| // 1 or 2 items with a total of 1 or 2 ops executed speculatively. |
| Node *PhaseIdealLoop::conditional_move( Node *region ) { |
| |
| assert(region->is_Region(), "sanity check"); |
| if (region->req() != 3) return NULL; |
| |
| // Check for CFG diamond |
| Node *lp = region->in(1); |
| Node *rp = region->in(2); |
| if (!lp || !rp) return NULL; |
| Node *lp_c = lp->in(0); |
| if (lp_c == NULL || lp_c != rp->in(0) || !lp_c->is_If()) return NULL; |
| IfNode *iff = lp_c->as_If(); |
| |
| // Check for ops pinned in an arm of the diamond. |
| // Can't remove the control flow in this case |
| if (lp->outcnt() > 1) return NULL; |
| if (rp->outcnt() > 1) return NULL; |
| |
| IdealLoopTree* r_loop = get_loop(region); |
| assert(r_loop == get_loop(iff), "sanity"); |
| // Always convert to CMOVE if all results are used only outside this loop. |
| bool used_inside_loop = (r_loop == _ltree_root); |
| |
| // Check profitability |
| int cost = 0; |
| int phis = 0; |
| for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) { |
| Node *out = region->fast_out(i); |
| if (!out->is_Phi()) continue; // Ignore other control edges, etc |
| phis++; |
| PhiNode* phi = out->as_Phi(); |
| BasicType bt = phi->type()->basic_type(); |
| switch (bt) { |
| case T_DOUBLE: |
| if (C->use_cmove()) { |
| continue; //TODO: maybe we want to add some cost |
| } |
| case T_FLOAT: { |
| cost += Matcher::float_cmove_cost(); // Could be very expensive |
| break; |
| } |
| case T_LONG: { |
| cost += Matcher::long_cmove_cost(); // May encodes as 2 CMOV's |
| } |
| case T_INT: // These all CMOV fine |
| case T_ADDRESS: { // (RawPtr) |
| cost++; |
| break; |
| } |
| case T_NARROWOOP: // Fall through |
| case T_OBJECT: { // Base oops are OK, but not derived oops |
| const TypeOopPtr *tp = phi->type()->make_ptr()->isa_oopptr(); |
| // Derived pointers are Bad (tm): what's the Base (for GC purposes) of a |
| // CMOVE'd derived pointer? It's a CMOVE'd derived base. Thus |
| // CMOVE'ing a derived pointer requires we also CMOVE the base. If we |
| // have a Phi for the base here that we convert to a CMOVE all is well |
| // and good. But if the base is dead, we'll not make a CMOVE. Later |
| // the allocator will have to produce a base by creating a CMOVE of the |
| // relevant bases. This puts the allocator in the business of |
| // manufacturing expensive instructions, generally a bad plan. |
| // Just Say No to Conditionally-Moved Derived Pointers. |
| if (tp && tp->offset() != 0) |
| return NULL; |
| cost++; |
| break; |
| } |
| default: |
| return NULL; // In particular, can't do memory or I/O |
| } |
| // Add in cost any speculative ops |
| for (uint j = 1; j < region->req(); j++) { |
| Node *proj = region->in(j); |
| Node *inp = phi->in(j); |
| if (get_ctrl(inp) == proj) { // Found local op |
| cost++; |
| // Check for a chain of dependent ops; these will all become |
| // speculative in a CMOV. |
| for (uint k = 1; k < inp->req(); k++) |
| if (get_ctrl(inp->in(k)) == proj) |
| cost += ConditionalMoveLimit; // Too much speculative goo |
| } |
| } |
| // See if the Phi is used by a Cmp or Narrow oop Decode/Encode. |
| // This will likely Split-If, a higher-payoff operation. |
| for (DUIterator_Fast kmax, k = phi->fast_outs(kmax); k < kmax; k++) { |
| Node* use = phi->fast_out(k); |
| if (use->is_Cmp() || use->is_DecodeNarrowPtr() || use->is_EncodeNarrowPtr()) |
| cost += ConditionalMoveLimit; |
| // Is there a use inside the loop? |
| // Note: check only basic types since CMoveP is pinned. |
| if (!used_inside_loop && is_java_primitive(bt)) { |
| IdealLoopTree* u_loop = get_loop(has_ctrl(use) ? get_ctrl(use) : use); |
| if (r_loop == u_loop || r_loop->is_member(u_loop)) { |
| used_inside_loop = true; |
| } |
| } |
| } |
| }//for |
| Node* bol = iff->in(1); |
| assert(bol->Opcode() == Op_Bool, ""); |
| int cmp_op = bol->in(1)->Opcode(); |
| // It is expensive to generate flags from a float compare. |
| // Avoid duplicated float compare. |
| if (phis > 1 && (cmp_op == Op_CmpF || cmp_op == Op_CmpD)) return NULL; |
| |
| float infrequent_prob = PROB_UNLIKELY_MAG(3); |
| // Ignore cost and blocks frequency if CMOVE can be moved outside the loop. |
| if (used_inside_loop) { |
| if (cost >= ConditionalMoveLimit) return NULL; // Too much goo |
| |
| // BlockLayoutByFrequency optimization moves infrequent branch |
| // from hot path. No point in CMOV'ing in such case (110 is used |
| // instead of 100 to take into account not exactness of float value). |
| if (BlockLayoutByFrequency) { |
| infrequent_prob = MAX2(infrequent_prob, (float)BlockLayoutMinDiamondPercentage/110.0f); |
| } |
| } |
| // Check for highly predictable branch. No point in CMOV'ing if |
| // we are going to predict accurately all the time. |
| if (C->use_cmove() && cmp_op == Op_CmpD) ;//keep going |
| else if (iff->_prob < infrequent_prob || |
| iff->_prob > (1.0f - infrequent_prob)) |
| return NULL; |
| |
| // -------------- |
| // Now replace all Phis with CMOV's |
| Node *cmov_ctrl = iff->in(0); |
| uint flip = (lp->Opcode() == Op_IfTrue); |
| while (1) { |
| PhiNode* phi = NULL; |
| for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) { |
| Node *out = region->fast_out(i); |
| if (out->is_Phi()) { |
| phi = out->as_Phi(); |
| break; |
| } |
| } |
| if (phi == NULL) break; |
| if (PrintOpto && VerifyLoopOptimizations) { tty->print_cr("CMOV"); } |
| // Move speculative ops |
| for (uint j = 1; j < region->req(); j++) { |
| Node *proj = region->in(j); |
| Node *inp = phi->in(j); |
| if (get_ctrl(inp) == proj) { // Found local op |
| #ifndef PRODUCT |
| if (PrintOpto && VerifyLoopOptimizations) { |
| tty->print(" speculate: "); |
| inp->dump(); |
| } |
| #endif |
| set_ctrl(inp, cmov_ctrl); |
| } |
| } |
| Node *cmov = CMoveNode::make(cmov_ctrl, iff->in(1), phi->in(1+flip), phi->in(2-flip), _igvn.type(phi)); |
| register_new_node( cmov, cmov_ctrl ); |
| _igvn.replace_node( phi, cmov ); |
| #ifndef PRODUCT |
| if (TraceLoopOpts) { |
| tty->print("CMOV "); |
| r_loop->dump_head(); |
| if (Verbose) { |
| bol->in(1)->dump(1); |
| cmov->dump(1); |
| } |
| } |
| if (VerifyLoopOptimizations) verify(); |
| #endif |
| } |
| |
| // The useless CFG diamond will fold up later; see the optimization in |
| // RegionNode::Ideal. |
| _igvn._worklist.push(region); |
| |
| return iff->in(1); |
| } |
| |
| static void enqueue_cfg_uses(Node* m, Unique_Node_List& wq) { |
| for (DUIterator_Fast imax, i = m->fast_outs(imax); i < imax; i++) { |
| Node* u = m->fast_out(i); |
| if (u->is_CFG()) { |
| if (u->Opcode() == Op_NeverBranch) { |
| u = ((NeverBranchNode*)u)->proj_out(0); |
| enqueue_cfg_uses(u, wq); |
| } else { |
| wq.push(u); |
| } |
| } |
| } |
| } |
| |
| // Try moving a store out of a loop, right before the loop |
| Node* PhaseIdealLoop::try_move_store_before_loop(Node* n, Node *n_ctrl) { |
| // Store has to be first in the loop body |
| IdealLoopTree *n_loop = get_loop(n_ctrl); |
| if (n->is_Store() && n_loop != _ltree_root && n_loop->is_loop() && n->in(0) != NULL) { |
| Node* address = n->in(MemNode::Address); |
| Node* value = n->in(MemNode::ValueIn); |
| Node* mem = n->in(MemNode::Memory); |
| IdealLoopTree* address_loop = get_loop(get_ctrl(address)); |
| IdealLoopTree* value_loop = get_loop(get_ctrl(value)); |
| |
| // - address and value must be loop invariant |
| // - memory must be a memory Phi for the loop |
| // - Store must be the only store on this memory slice in the |
| // loop: if there's another store following this one then value |
| // written at iteration i by the second store could be overwritten |
| // at iteration i+n by the first store: it's not safe to move the |
| // first store out of the loop |
| // - nothing must observe the memory Phi: it guarantees no read |
| // before the store, we are also guaranteed the store post |
| // dominates the loop head (ignoring a possible early |
| // exit). Otherwise there would be extra Phi involved between the |
| // loop's Phi and the store. |
| // - there must be no early exit from the loop before the Store |
| // (such an exit most of the time would be an extra use of the |
| // memory Phi but sometimes is a bottom memory Phi that takes the |
| // store as input). |
| |
| if (!n_loop->is_member(address_loop) && |
| !n_loop->is_member(value_loop) && |
| mem->is_Phi() && mem->in(0) == n_loop->_head && |
| mem->outcnt() == 1 && |
| mem->in(LoopNode::LoopBackControl) == n) { |
| |
| assert(n_loop->_tail != NULL, "need a tail"); |
| assert(is_dominator(n_ctrl, n_loop->_tail), "store control must not be in a branch in the loop"); |
| |
| // Verify that there's no early exit of the loop before the store. |
| bool ctrl_ok = false; |
| { |
| // Follow control from loop head until n, we exit the loop or |
| // we reach the tail |
| ResourceMark rm; |
| Unique_Node_List wq; |
| wq.push(n_loop->_head); |
| |
| for (uint next = 0; next < wq.size(); ++next) { |
| Node *m = wq.at(next); |
| if (m == n->in(0)) { |
| ctrl_ok = true; |
| continue; |
| } |
| assert(!has_ctrl(m), "should be CFG"); |
| if (!n_loop->is_member(get_loop(m)) || m == n_loop->_tail) { |
| ctrl_ok = false; |
| break; |
| } |
| enqueue_cfg_uses(m, wq); |
| if (wq.size() > 10) { |
| ctrl_ok = false; |
| break; |
| } |
| } |
| } |
| if (ctrl_ok) { |
| // move the Store |
| _igvn.replace_input_of(mem, LoopNode::LoopBackControl, mem); |
| _igvn.replace_input_of(n, 0, n_loop->_head->in(LoopNode::EntryControl)); |
| _igvn.replace_input_of(n, MemNode::Memory, mem->in(LoopNode::EntryControl)); |
| // Disconnect the phi now. An empty phi can confuse other |
| // optimizations in this pass of loop opts. |
| _igvn.replace_node(mem, mem->in(LoopNode::EntryControl)); |
| n_loop->_body.yank(mem); |
| |
| IdealLoopTree* new_loop = get_loop(n->in(0)); |
| set_ctrl_and_loop(n, n->in(0)); |
| |
| return n; |
| } |
| } |
| } |
| return NULL; |
| } |
| |
| // Try moving a store out of a loop, right after the loop |
| void PhaseIdealLoop::try_move_store_after_loop(Node* n) { |
| if (n->is_Store() && n->in(0) != NULL) { |
| Node *n_ctrl = get_ctrl(n); |
| IdealLoopTree *n_loop = get_loop(n_ctrl); |
| // Store must be in a loop |
| if (n_loop != _ltree_root && !n_loop->_irreducible) { |
| Node* address = n->in(MemNode::Address); |
| Node* value = n->in(MemNode::ValueIn); |
| IdealLoopTree* address_loop = get_loop(get_ctrl(address)); |
| // address must be loop invariant |
| if (!n_loop->is_member(address_loop)) { |
| // Store must be last on this memory slice in the loop and |
| // nothing in the loop must observe it |
| Node* phi = NULL; |
| for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) { |
| Node* u = n->fast_out(i); |
| if (has_ctrl(u)) { // control use? |
| IdealLoopTree *u_loop = get_loop(get_ctrl(u)); |
| if (!n_loop->is_member(u_loop)) { |
| continue; |
| } |
| if (u->is_Phi() && u->in(0) == n_loop->_head) { |
| assert(_igvn.type(u) == Type::MEMORY, "bad phi"); |
| // multiple phis on the same slice are possible |
| if (phi != NULL) { |
| return; |
| } |
| phi = u; |
| continue; |
| } |
| } |
| return; |
| } |
| if (phi != NULL) { |
| // Nothing in the loop before the store (next iteration) |
| // must observe the stored value |
| bool mem_ok = true; |
| { |
| ResourceMark rm; |
| Unique_Node_List wq; |
| wq.push(phi); |
| for (uint next = 0; next < wq.size() && mem_ok; ++next) { |
| Node *m = wq.at(next); |
| for (DUIterator_Fast imax, i = m->fast_outs(imax); i < imax && mem_ok; i++) { |
| Node* u = m->fast_out(i); |
| if (u->is_Store() || u->is_Phi()) { |
| if (u != n) { |
| wq.push(u); |
| mem_ok = (wq.size() <= 10); |
| } |
| } else { |
| mem_ok = false; |
| break; |
| } |
| } |
| } |
| } |
| if (mem_ok) { |
| // Move the Store out of the loop creating clones along |
| // all paths out of the loop that observe the stored value |
| _igvn.rehash_node_delayed(phi); |
| int count = phi->replace_edge(n, n->in(MemNode::Memory)); |
| assert(count > 0, "inconsistent phi"); |
| for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) { |
| Node* u = n->fast_out(i); |
| Node* c = get_ctrl(u); |
| |
| if (u->is_Phi()) { |
| c = u->in(0)->in(u->find_edge(n)); |
| } |
| IdealLoopTree *u_loop = get_loop(c); |
| assert (!n_loop->is_member(u_loop), "only the phi should have been a use in the loop"); |
| while(true) { |
| Node* next_c = find_non_split_ctrl(idom(c)); |
| if (n_loop->is_member(get_loop(next_c))) { |
| break; |
| } |
| c = next_c; |
| } |
| |
| Node* st = n->clone(); |
| st->set_req(0, c); |
| _igvn.register_new_node_with_optimizer(st); |
| |
| set_ctrl(st, c); |
| IdealLoopTree* new_loop = get_loop(c); |
| assert(new_loop != n_loop, "should be moved out of loop"); |
| if (new_loop->_child == NULL) new_loop->_body.push(st); |
| |
| _igvn.replace_input_of(u, u->find_edge(n), st); |
| --imax; |
| --i; |
| } |
| |
| |
| assert(n->outcnt() == 0, "all uses should be gone"); |
| _igvn.replace_input_of(n, MemNode::Memory, C->top()); |
| // Disconnect the phi now. An empty phi can confuse other |
| // optimizations in this pass of loop opts.. |
| if (phi->in(LoopNode::LoopBackControl) == phi) { |
| _igvn.replace_node(phi, phi->in(LoopNode::EntryControl)); |
| n_loop->_body.yank(phi); |
| } |
| } |
| } |
| } |
| } |
| } |
| } |
| |
| //------------------------------split_if_with_blocks_pre----------------------- |
| // Do the real work in a non-recursive function. Data nodes want to be |
| // cloned in the pre-order so they can feed each other nicely. |
| Node *PhaseIdealLoop::split_if_with_blocks_pre( Node *n ) { |
| // Cloning these guys is unlikely to win |
| int n_op = n->Opcode(); |
| if( n_op == Op_MergeMem ) return n; |
| if( n->is_Proj() ) return n; |
| // Do not clone-up CmpFXXX variations, as these are always |
| // followed by a CmpI |
| if( n->is_Cmp() ) return n; |
| // Attempt to use a conditional move instead of a phi/branch |
| if( ConditionalMoveLimit > 0 && n_op == Op_Region ) { |
| Node *cmov = conditional_move( n ); |
| if( cmov ) return cmov; |
| } |
| if( n->is_CFG() || n->is_LoadStore() ) |
| return n; |
| if( n_op == Op_Opaque1 || // Opaque nodes cannot be mod'd |
| n_op == Op_Opaque2 ) { |
| if( !C->major_progress() ) // If chance of no more loop opts... |
| _igvn._worklist.push(n); // maybe we'll remove them |
| return n; |
| } |
| |
| if( n->is_Con() ) return n; // No cloning for Con nodes |
| |
| Node *n_ctrl = get_ctrl(n); |
| if( !n_ctrl ) return n; // Dead node |
| |
| Node* res = try_move_store_before_loop(n, n_ctrl); |
| if (res != NULL) { |
| return n; |
| } |
| |
| // Attempt to remix address expressions for loop invariants |
| Node *m = remix_address_expressions( n ); |
| if( m ) return m; |
| |
| if (n->is_ConstraintCast()) { |
| Node* dom_cast = n->as_ConstraintCast()->dominating_cast(&_igvn, this); |
| // ConstraintCastNode::dominating_cast() uses node control input to determine domination. |
| // Node control inputs don't necessarily agree with loop control info (due to |
| // transformations happened in between), thus additional dominance check is needed |
| // to keep loop info valid. |
| if (dom_cast != NULL && is_dominator(get_ctrl(dom_cast), get_ctrl(n))) { |
| _igvn.replace_node(n, dom_cast); |
| return dom_cast; |
| } |
| } |
| |
| // Determine if the Node has inputs from some local Phi. |
| // Returns the block to clone thru. |
| Node *n_blk = has_local_phi_input( n ); |
| if( !n_blk ) return n; |
| |
| // Do not clone the trip counter through on a CountedLoop |
| // (messes up the canonical shape). |
| if( n_blk->is_CountedLoop() && n->Opcode() == Op_AddI ) return n; |
| |
| // Check for having no control input; not pinned. Allow |
| // dominating control. |
| if (n->in(0)) { |
| Node *dom = idom(n_blk); |
| if (dom_lca(n->in(0), dom) != n->in(0)) { |
| return n; |
| } |
| } |
| // Policy: when is it profitable. You must get more wins than |
| // policy before it is considered profitable. Policy is usually 0, |
| // so 1 win is considered profitable. Big merges will require big |
| // cloning, so get a larger policy. |
| int policy = n_blk->req() >> 2; |
| |
| // If the loop is a candidate for range check elimination, |
| // delay splitting through it's phi until a later loop optimization |
| if (n_blk->is_CountedLoop()) { |
| IdealLoopTree *lp = get_loop(n_blk); |
| if (lp && lp->_rce_candidate) { |
| return n; |
| } |
| } |
| |
| // Use same limit as split_if_with_blocks_post |
| if( C->live_nodes() > 35000 ) return n; // Method too big |
| |
| // Split 'n' through the merge point if it is profitable |
| Node *phi = split_thru_phi( n, n_blk, policy ); |
| if (!phi) return n; |
| |
| // Found a Phi to split thru! |
| // Replace 'n' with the new phi |
| _igvn.replace_node( n, phi ); |
| // Moved a load around the loop, 'en-registering' something. |
| if (n_blk->is_Loop() && n->is_Load() && |
| !phi->in(LoopNode::LoopBackControl)->is_Load()) |
| C->set_major_progress(); |
| |
| return phi; |
| } |
| |
| static bool merge_point_too_heavy(Compile* C, Node* region) { |
| // Bail out if the region and its phis have too many users. |
| int weight = 0; |
| for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) { |
| weight += region->fast_out(i)->outcnt(); |
| } |
| int nodes_left = C->max_node_limit() - C->live_nodes(); |
| if (weight * 8 > nodes_left) { |
| if (PrintOpto) { |
| tty->print_cr("*** Split-if bails out: %d nodes, region weight %d", C->unique(), weight); |
| } |
| return true; |
| } else { |
| return false; |
| } |
| } |
| |
| static bool merge_point_safe(Node* region) { |
| // 4799512: Stop split_if_with_blocks from splitting a block with a ConvI2LNode |
| // having a PhiNode input. This sidesteps the dangerous case where the split |
| // ConvI2LNode may become TOP if the input Value() does not |
| // overlap the ConvI2L range, leaving a node which may not dominate its |
| // uses. |
| // A better fix for this problem can be found in the BugTraq entry, but |
| // expediency for Mantis demands this hack. |
| // 6855164: If the merge point has a FastLockNode with a PhiNode input, we stop |
| // split_if_with_blocks from splitting a block because we could not move around |
| // the FastLockNode. |
| for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) { |
| Node* n = region->fast_out(i); |
| if (n->is_Phi()) { |
| for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { |
| Node* m = n->fast_out(j); |
| if (m->is_FastLock()) |
| return false; |
| #ifdef _LP64 |
| if (m->Opcode() == Op_ConvI2L) |
| return false; |
| if (m->is_CastII() && m->isa_CastII()->has_range_check()) { |
| return false; |
| } |
| #endif |
| } |
| } |
| } |
| return true; |
| } |
| |
| |
| //------------------------------place_near_use--------------------------------- |
| // Place some computation next to use but not inside inner loops. |
| // For inner loop uses move it to the preheader area. |
| Node *PhaseIdealLoop::place_near_use( Node *useblock ) const { |
| IdealLoopTree *u_loop = get_loop( useblock ); |
| return (u_loop->_irreducible || u_loop->_child) |
| ? useblock |
| : u_loop->_head->in(LoopNode::EntryControl); |
| } |
| |
| |
| bool PhaseIdealLoop::identical_backtoback_ifs(Node *n) { |
| if (!n->is_If()) { |
| return false; |
| } |
| if (!n->in(0)->is_Region()) { |
| return false; |
| } |
| Node* region = n->in(0); |
| Node* dom = idom(region); |
| if (!dom->is_If() || dom->in(1) != n->in(1)) { |
| return false; |
| } |
| IfNode* dom_if = dom->as_If(); |
| Node* proj_true = dom_if->proj_out(1); |
| Node* proj_false = dom_if->proj_out(0); |
| |
| for (uint i = 1; i < region->req(); i++) { |
| if (is_dominator(proj_true, region->in(i))) { |
| continue; |
| } |
| if (is_dominator(proj_false, region->in(i))) { |
| continue; |
| } |
| return false; |
| } |
| |
| return true; |
| } |
| |
| bool PhaseIdealLoop::can_split_if(Node *n_ctrl) { |
| if (C->live_nodes() > 35000) { |
| return false; // Method too big |
| } |
| |
| // Do not do 'split-if' if irreducible loops are present. |
| if (_has_irreducible_loops) { |
| return false; |
| } |
| |
| if (merge_point_too_heavy(C, n_ctrl)) { |
| return false; |
| } |
| |
| // Do not do 'split-if' if some paths are dead. First do dead code |
| // elimination and then see if its still profitable. |
| for (uint i = 1; i < n_ctrl->req(); i++) { |
| if (n_ctrl->in(i) == C->top()) { |
| return false; |
| } |
| } |
| |
| // If trying to do a 'Split-If' at the loop head, it is only |
| // profitable if the cmp folds up on BOTH paths. Otherwise we |
| // risk peeling a loop forever. |
| |
| // CNC - Disabled for now. Requires careful handling of loop |
| // body selection for the cloned code. Also, make sure we check |
| // for any input path not being in the same loop as n_ctrl. For |
| // irreducible loops we cannot check for 'n_ctrl->is_Loop()' |
| // because the alternative loop entry points won't be converted |
| // into LoopNodes. |
| IdealLoopTree *n_loop = get_loop(n_ctrl); |
| for (uint j = 1; j < n_ctrl->req(); j++) { |
| if (get_loop(n_ctrl->in(j)) != n_loop) { |
| return false; |
| } |
| } |
| |
| // Check for safety of the merge point. |
| if (!merge_point_safe(n_ctrl)) { |
| return false; |
| } |
| |
| return true; |
| } |
| |
| //------------------------------split_if_with_blocks_post---------------------- |
| // Do the real work in a non-recursive function. CFG hackery wants to be |
| // in the post-order, so it can dirty the I-DOM info and not use the dirtied |
| // info. |
| void PhaseIdealLoop::split_if_with_blocks_post(Node *n) { |
| |
| // Cloning Cmp through Phi's involves the split-if transform. |
| // FastLock is not used by an If |
| if (n->is_Cmp() && !n->is_FastLock()) { |
| Node *n_ctrl = get_ctrl(n); |
| // Determine if the Node has inputs from some local Phi. |
| // Returns the block to clone thru. |
| Node *n_blk = has_local_phi_input(n); |
| if (n_blk != n_ctrl) { |
| return; |
| } |
| |
| if (!can_split_if(n_ctrl)) { |
| return; |
| } |
| |
| if (n->outcnt() != 1) { |
| return; // Multiple bool's from 1 compare? |
| } |
| Node *bol = n->unique_out(); |
| assert(bol->is_Bool(), "expect a bool here"); |
| if (bol->outcnt() != 1) { |
| return;// Multiple branches from 1 compare? |
| } |
| Node *iff = bol->unique_out(); |
| |
| // Check some safety conditions |
| if (iff->is_If()) { // Classic split-if? |
| if (iff->in(0) != n_ctrl) { |
| return; // Compare must be in same blk as if |
| } |
| } else if (iff->is_CMove()) { // Trying to split-up a CMOVE |
| // Can't split CMove with different control edge. |
| if (iff->in(0) != NULL && iff->in(0) != n_ctrl ) { |
| return; |
| } |
| if (get_ctrl(iff->in(2)) == n_ctrl || |
| get_ctrl(iff->in(3)) == n_ctrl) { |
| return; // Inputs not yet split-up |
| } |
| if (get_loop(n_ctrl) != get_loop(get_ctrl(iff))) { |
| return; // Loop-invar test gates loop-varying CMOVE |
| } |
| } else { |
| return; // some other kind of node, such as an Allocate |
| } |
| |
| // When is split-if profitable? Every 'win' on means some control flow |
| // goes dead, so it's almost always a win. |
| int policy = 0; |
| // Split compare 'n' through the merge point if it is profitable |
| Node *phi = split_thru_phi( n, n_ctrl, policy); |
| if (!phi) { |
| return; |
| } |
| |
| // Found a Phi to split thru! |
| // Replace 'n' with the new phi |
| _igvn.replace_node(n, phi); |
| |
| // Now split the bool up thru the phi |
| Node *bolphi = split_thru_phi(bol, n_ctrl, -1); |
| guarantee(bolphi != NULL, "null boolean phi node"); |
| |
| _igvn.replace_node(bol, bolphi); |
| assert(iff->in(1) == bolphi, ""); |
| |
| if (bolphi->Value(&_igvn)->singleton()) { |
| return; |
| } |
| |
| // Conditional-move? Must split up now |
| if (!iff->is_If()) { |
| Node *cmovphi = split_thru_phi(iff, n_ctrl, -1); |
| _igvn.replace_node(iff, cmovphi); |
| return; |
| } |
| |
| // Now split the IF |
| do_split_if(iff); |
| return; |
| } |
| |
| // Two identical ifs back to back can be merged |
| if (identical_backtoback_ifs(n) && can_split_if(n->in(0))) { |
| Node *n_ctrl = n->in(0); |
| PhiNode* bolphi = PhiNode::make_blank(n_ctrl, n->in(1)); |
| IfNode* dom_if = idom(n_ctrl)->as_If(); |
| Node* proj_true = dom_if->proj_out(1); |
| Node* proj_false = dom_if->proj_out(0); |
| Node* con_true = _igvn.makecon(TypeInt::ONE); |
| Node* con_false = _igvn.makecon(TypeInt::ZERO); |
| |
| for (uint i = 1; i < n_ctrl->req(); i++) { |
| if (is_dominator(proj_true, n_ctrl->in(i))) { |
| bolphi->init_req(i, con_true); |
| } else { |
| assert(is_dominator(proj_false, n_ctrl->in(i)), "bad if"); |
| bolphi->init_req(i, con_false); |
| } |
| } |
| register_new_node(bolphi, n_ctrl); |
| _igvn.replace_input_of(n, 1, bolphi); |
| |
| // Now split the IF |
| do_split_if(n); |
| return; |
| } |
| |
| // Check for an IF ready to split; one that has its |
| // condition codes input coming from a Phi at the block start. |
| int n_op = n->Opcode(); |
| |
| // Check for an IF being dominated by another IF same test |
| if (n_op == Op_If || |
| n_op == Op_RangeCheck) { |
| Node *bol = n->in(1); |
| uint max = bol->outcnt(); |
| // Check for same test used more than once? |
| if (max > 1 && bol->is_Bool()) { |
| // Search up IDOMs to see if this IF is dominated. |
| Node *cutoff = get_ctrl(bol); |
| |
| // Now search up IDOMs till cutoff, looking for a dominating test |
| Node *prevdom = n; |
| Node *dom = idom(prevdom); |
| while (dom != cutoff) { |
| if (dom->req() > 1 && dom->in(1) == bol && prevdom->in(0) == dom) { |
| // Replace the dominated test with an obvious true or false. |
| // Place it on the IGVN worklist for later cleanup. |
| C->set_major_progress(); |
| dominated_by(prevdom, n, false, true); |
| #ifndef PRODUCT |
| if( VerifyLoopOptimizations ) verify(); |
| #endif |
| return; |
| } |
| prevdom = dom; |
| dom = idom(prevdom); |
| } |
| } |
| } |
| |
| // See if a shared loop-varying computation has no loop-varying uses. |
| // Happens if something is only used for JVM state in uncommon trap exits, |
| // like various versions of induction variable+offset. Clone the |
| // computation per usage to allow it to sink out of the loop. |
| if (has_ctrl(n) && !n->in(0)) {// n not dead and has no control edge (can float about) |
| Node *n_ctrl = get_ctrl(n); |
| IdealLoopTree *n_loop = get_loop(n_ctrl); |
| if( n_loop != _ltree_root ) { |
| DUIterator_Fast imax, i = n->fast_outs(imax); |
| for (; i < imax; i++) { |
| Node* u = n->fast_out(i); |
| if( !has_ctrl(u) ) break; // Found control user |
| IdealLoopTree *u_loop = get_loop(get_ctrl(u)); |
| if( u_loop == n_loop ) break; // Found loop-varying use |
| if( n_loop->is_member( u_loop ) ) break; // Found use in inner loop |
| if( u->Opcode() == Op_Opaque1 ) break; // Found loop limit, bugfix for 4677003 |
| } |
| bool did_break = (i < imax); // Did we break out of the previous loop? |
| if (!did_break && n->outcnt() > 1) { // All uses in outer loops! |
| Node *late_load_ctrl = NULL; |
| if (n->is_Load()) { |
| // If n is a load, get and save the result from get_late_ctrl(), |
| // to be later used in calculating the control for n's clones. |
| clear_dom_lca_tags(); |
| late_load_ctrl = get_late_ctrl(n, n_ctrl); |
| } |
| // If n is a load, and the late control is the same as the current |
| // control, then the cloning of n is a pointless exercise, because |
| // GVN will ensure that we end up where we started. |
| if (!n->is_Load() || late_load_ctrl != n_ctrl) { |
| for (DUIterator_Last jmin, j = n->last_outs(jmin); j >= jmin; ) { |
| Node *u = n->last_out(j); // Clone private computation per use |
| _igvn.rehash_node_delayed(u); |
| Node *x = n->clone(); // Clone computation |
| Node *x_ctrl = NULL; |
| if( u->is_Phi() ) { |
| // Replace all uses of normal nodes. Replace Phi uses |
| // individually, so the separate Nodes can sink down |
| // different paths. |
| uint k = 1; |
| while( u->in(k) != n ) k++; |
| u->set_req( k, x ); |
| // x goes next to Phi input path |
| x_ctrl = u->in(0)->in(k); |
| --j; |
| } else { // Normal use |
| // Replace all uses |
| for( uint k = 0; k < u->req(); k++ ) { |
| if( u->in(k) == n ) { |
| u->set_req( k, x ); |
| --j; |
| } |
| } |
| x_ctrl = get_ctrl(u); |
| } |
| |
| // Find control for 'x' next to use but not inside inner loops. |
| // For inner loop uses get the preheader area. |
| x_ctrl = place_near_use(x_ctrl); |
| |
| if (n->is_Load()) { |
| // For loads, add a control edge to a CFG node outside of the loop |
| // to force them to not combine and return back inside the loop |
| // during GVN optimization (4641526). |
| // |
| // Because we are setting the actual control input, factor in |
| // the result from get_late_ctrl() so we respect any |
| // anti-dependences. (6233005). |
| x_ctrl = dom_lca(late_load_ctrl, x_ctrl); |
| |
| // Don't allow the control input to be a CFG splitting node. |
| // Such nodes should only have ProjNodes as outs, e.g. IfNode |
| // should only have IfTrueNode and IfFalseNode (4985384). |
| x_ctrl = find_non_split_ctrl(x_ctrl); |
| assert(dom_depth(n_ctrl) <= dom_depth(x_ctrl), "n is later than its clone"); |
| |
| x->set_req(0, x_ctrl); |
| } |
| register_new_node(x, x_ctrl); |
| |
| // Some institutional knowledge is needed here: 'x' is |
| // yanked because if the optimizer runs GVN on it all the |
| // cloned x's will common up and undo this optimization and |
| // be forced back in the loop. This is annoying because it |
| // makes +VerifyOpto report false-positives on progress. I |
| // tried setting control edges on the x's to force them to |
| // not combine, but the matching gets worried when it tries |
| // to fold a StoreP and an AddP together (as part of an |
| // address expression) and the AddP and StoreP have |
| // different controls. |
| if (!x->is_Load() && !x->is_DecodeNarrowPtr()) _igvn._worklist.yank(x); |
| } |
| _igvn.remove_dead_node(n); |
| } |
| } |
| } |
| } |
| |
| try_move_store_after_loop(n); |
| |
| // Check for Opaque2's who's loop has disappeared - who's input is in the |
| // same loop nest as their output. Remove 'em, they are no longer useful. |
| if( n_op == Op_Opaque2 && |
| n->in(1) != NULL && |
| get_loop(get_ctrl(n)) == get_loop(get_ctrl(n->in(1))) ) { |
| _igvn.replace_node( n, n->in(1) ); |
| } |
| } |
| |
| //------------------------------split_if_with_blocks--------------------------- |
| // Check for aggressive application of 'split-if' optimization, |
| // using basic block level info. |
| void PhaseIdealLoop::split_if_with_blocks( VectorSet &visited, Node_Stack &nstack ) { |
| Node *n = C->root(); |
| visited.set(n->_idx); // first, mark node as visited |
| // Do pre-visit work for root |
| n = split_if_with_blocks_pre( n ); |
| uint cnt = n->outcnt(); |
| uint i = 0; |
| while (true) { |
| // Visit all children |
| if (i < cnt) { |
| Node* use = n->raw_out(i); |
| ++i; |
| if (use->outcnt() != 0 && !visited.test_set(use->_idx)) { |
| // Now do pre-visit work for this use |
| use = split_if_with_blocks_pre( use ); |
| nstack.push(n, i); // Save parent and next use's index. |
| n = use; // Process all children of current use. |
| cnt = use->outcnt(); |
| i = 0; |
| } |
| } |
| else { |
| // All of n's children have been processed, complete post-processing. |
| if (cnt != 0 && !n->is_Con()) { |
| assert(has_node(n), "no dead nodes"); |
| split_if_with_blocks_post( n ); |
| } |
| if (nstack.is_empty()) { |
| // Finished all nodes on stack. |
| break; |
| } |
| // Get saved parent node and next use's index. Visit the rest of uses. |
| n = nstack.node(); |
| cnt = n->outcnt(); |
| i = nstack.index(); |
| nstack.pop(); |
| } |
| } |
| } |
| |
| |
| //============================================================================= |
| // |
| // C L O N E A L O O P B O D Y |
| // |
| |
| //------------------------------clone_iff-------------------------------------- |
| // Passed in a Phi merging (recursively) some nearly equivalent Bool/Cmps. |
| // "Nearly" because all Nodes have been cloned from the original in the loop, |
| // but the fall-in edges to the Cmp are different. Clone bool/Cmp pairs |
| // through the Phi recursively, and return a Bool. |
| BoolNode *PhaseIdealLoop::clone_iff( PhiNode *phi, IdealLoopTree *loop ) { |
| |
| // Convert this Phi into a Phi merging Bools |
| uint i; |
| for( i = 1; i < phi->req(); i++ ) { |
| Node *b = phi->in(i); |
| if( b->is_Phi() ) { |
| _igvn.replace_input_of(phi, i, clone_iff( b->as_Phi(), loop )); |
| } else { |
| assert( b->is_Bool(), "" ); |
| } |
| } |
| |
| Node *sample_bool = phi->in(1); |
| Node *sample_cmp = sample_bool->in(1); |
| |
| // Make Phis to merge the Cmp's inputs. |
| PhiNode *phi1 = new PhiNode( phi->in(0), Type::TOP ); |
| PhiNode *phi2 = new PhiNode( phi->in(0), Type::TOP ); |
| for( i = 1; i < phi->req(); i++ ) { |
| Node *n1 = phi->in(i)->in(1)->in(1); |
| Node *n2 = phi->in(i)->in(1)->in(2); |
| phi1->set_req( i, n1 ); |
| phi2->set_req( i, n2 ); |
| phi1->set_type( phi1->type()->meet_speculative(n1->bottom_type())); |
| phi2->set_type( phi2->type()->meet_speculative(n2->bottom_type())); |
| } |
| // See if these Phis have been made before. |
| // Register with optimizer |
| Node *hit1 = _igvn.hash_find_insert(phi1); |
| if( hit1 ) { // Hit, toss just made Phi |
| _igvn.remove_dead_node(phi1); // Remove new phi |
| assert( hit1->is_Phi(), "" ); |
| phi1 = (PhiNode*)hit1; // Use existing phi |
| } else { // Miss |
| _igvn.register_new_node_with_optimizer(phi1); |
| } |
| Node *hit2 = _igvn.hash_find_insert(phi2); |
| if( hit2 ) { // Hit, toss just made Phi |
| _igvn.remove_dead_node(phi2); // Remove new phi |
| assert( hit2->is_Phi(), "" ); |
| phi2 = (PhiNode*)hit2; // Use existing phi |
| } else { // Miss |
| _igvn.register_new_node_with_optimizer(phi2); |
| } |
| // Register Phis with loop/block info |
| set_ctrl(phi1, phi->in(0)); |
| set_ctrl(phi2, phi->in(0)); |
| // Make a new Cmp |
| Node *cmp = sample_cmp->clone(); |
| cmp->set_req( 1, phi1 ); |
| cmp->set_req( 2, phi2 ); |
| _igvn.register_new_node_with_optimizer(cmp); |
| set_ctrl(cmp, phi->in(0)); |
| |
| // Make a new Bool |
| Node *b = sample_bool->clone(); |
| b->set_req(1,cmp); |
| _igvn.register_new_node_with_optimizer(b); |
| set_ctrl(b, phi->in(0)); |
| |
| assert( b->is_Bool(), "" ); |
| return (BoolNode*)b; |
| } |
| |
| //------------------------------clone_bool------------------------------------- |
| // Passed in a Phi merging (recursively) some nearly equivalent Bool/Cmps. |
| // "Nearly" because all Nodes have been cloned from the original in the loop, |
| // but the fall-in edges to the Cmp are different. Clone bool/Cmp pairs |
| // through the Phi recursively, and return a Bool. |
| CmpNode *PhaseIdealLoop::clone_bool( PhiNode *phi, IdealLoopTree *loop ) { |
| uint i; |
| // Convert this Phi into a Phi merging Bools |
| for( i = 1; i < phi->req(); i++ ) { |
| Node *b = phi->in(i); |
| if( b->is_Phi() ) { |
| _igvn.replace_input_of(phi, i, clone_bool( b->as_Phi(), loop )); |
| } else { |
| assert( b->is_Cmp() || b->is_top(), "inputs are all Cmp or TOP" ); |
| } |
| } |
| |
| Node *sample_cmp = phi->in(1); |
| |
| // Make Phis to merge the Cmp's inputs. |
| PhiNode *phi1 = new PhiNode( phi->in(0), Type::TOP ); |
| PhiNode *phi2 = new PhiNode( phi->in(0), Type::TOP ); |
| for( uint j = 1; j < phi->req(); j++ ) { |
| Node *cmp_top = phi->in(j); // Inputs are all Cmp or TOP |
| Node *n1, *n2; |
| if( cmp_top->is_Cmp() ) { |
| n1 = cmp_top->in(1); |
| n2 = cmp_top->in(2); |
| } else { |
| n1 = n2 = cmp_top; |
| } |
| phi1->set_req( j, n1 ); |
| phi2->set_req( j, n2 ); |
| phi1->set_type(phi1->type()->meet_speculative(n1->bottom_type())); |
| phi2->set_type(phi2->type()->meet_speculative(n2->bottom_type())); |
| } |
| |
| // See if these Phis have been made before. |
| // Register with optimizer |
| Node *hit1 = _igvn.hash_find_insert(phi1); |
| if( hit1 ) { // Hit, toss just made Phi |
| _igvn.remove_dead_node(phi1); // Remove new phi |
| assert( hit1->is_Phi(), "" ); |
| phi1 = (PhiNode*)hit1; // Use existing phi |
| } else { // Miss |
| _igvn.register_new_node_with_optimizer(phi1); |
| } |
| Node *hit2 = _igvn.hash_find_insert(phi2); |
| if( hit2 ) { // Hit, toss just made Phi |
| _igvn.remove_dead_node(phi2); // Remove new phi |
| assert( hit2->is_Phi(), "" ); |
| phi2 = (PhiNode*)hit2; // Use existing phi |
| } else { // Miss |
| _igvn.register_new_node_with_optimizer(phi2); |
| } |
| // Register Phis with loop/block info |
| set_ctrl(phi1, phi->in(0)); |
| set_ctrl(phi2, phi->in(0)); |
| // Make a new Cmp |
| Node *cmp = sample_cmp->clone(); |
| cmp->set_req( 1, phi1 ); |
| cmp->set_req( 2, phi2 ); |
| _igvn.register_new_node_with_optimizer(cmp); |
| set_ctrl(cmp, phi->in(0)); |
| |
| assert( cmp->is_Cmp(), "" ); |
| return (CmpNode*)cmp; |
| } |
| |
| //------------------------------sink_use--------------------------------------- |
| // If 'use' was in the loop-exit block, it now needs to be sunk |
| // below the post-loop merge point. |
| void PhaseIdealLoop::sink_use( Node *use, Node *post_loop ) { |
| if (!use->is_CFG() && get_ctrl(use) == post_loop->in(2)) { |
| set_ctrl(use, post_loop); |
| for (DUIterator j = use->outs(); use->has_out(j); j++) |
| sink_use(use->out(j), post_loop); |
| } |
| } |
| |
| //------------------------------clone_loop------------------------------------- |
| // |
| // C L O N E A L O O P B O D Y |
| // |
| // This is the basic building block of the loop optimizations. It clones an |
| // entire loop body. It makes an old_new loop body mapping; with this mapping |
| // you can find the new-loop equivalent to an old-loop node. All new-loop |
| // nodes are exactly equal to their old-loop counterparts, all edges are the |
| // same. All exits from the old-loop now have a RegionNode that merges the |
| // equivalent new-loop path. This is true even for the normal "loop-exit" |
| // condition. All uses of loop-invariant old-loop values now come from (one |
| // or more) Phis that merge their new-loop equivalents. |
| // |
| // This operation leaves the graph in an illegal state: there are two valid |
| // control edges coming from the loop pre-header to both loop bodies. I'll |
| // definitely have to hack the graph after running this transform. |
| // |
| // From this building block I will further edit edges to perform loop peeling |
| // or loop unrolling or iteration splitting (Range-Check-Elimination), etc. |
| // |
| // Parameter side_by_size_idom: |
| // When side_by_size_idom is NULL, the dominator tree is constructed for |
| // the clone loop to dominate the original. Used in construction of |
| // pre-main-post loop sequence. |
| // When nonnull, the clone and original are side-by-side, both are |
| // dominated by the side_by_side_idom node. Used in construction of |
| // unswitched loops. |
| void PhaseIdealLoop::clone_loop( IdealLoopTree *loop, Node_List &old_new, int dd, |
| Node* side_by_side_idom) { |
| |
| if (C->do_vector_loop() && PrintOpto) { |
| const char* mname = C->method()->name()->as_quoted_ascii(); |
| if (mname != NULL) { |
| tty->print("PhaseIdealLoop::clone_loop: for vectorize method %s\n", mname); |
| } |
| } |
| |
| CloneMap& cm = C->clone_map(); |
| Dict* dict = cm.dict(); |
| if (C->do_vector_loop()) { |
| cm.set_clone_idx(cm.max_gen()+1); |
| #ifndef PRODUCT |
| if (PrintOpto) { |
| tty->print_cr("PhaseIdealLoop::clone_loop: _clone_idx %d", cm.clone_idx()); |
| loop->dump_head(); |
| } |
| #endif |
| } |
| |
| // Step 1: Clone the loop body. Make the old->new mapping. |
| uint i; |
| for( i = 0; i < loop->_body.size(); i++ ) { |
| Node *old = loop->_body.at(i); |
| Node *nnn = old->clone(); |
| old_new.map( old->_idx, nnn ); |
| if (C->do_vector_loop()) { |
| cm.verify_insert_and_clone(old, nnn, cm.clone_idx()); |
| } |
| _igvn.register_new_node_with_optimizer(nnn); |
| } |
| |
| |
| // Step 2: Fix the edges in the new body. If the old input is outside the |
| // loop use it. If the old input is INside the loop, use the corresponding |
| // new node instead. |
| for( i = 0; i < loop->_body.size(); i++ ) { |
| Node *old = loop->_body.at(i); |
| Node *nnn = old_new[old->_idx]; |
| // Fix CFG/Loop controlling the new node |
| if (has_ctrl(old)) { |
| set_ctrl(nnn, old_new[get_ctrl(old)->_idx]); |
| } else { |
| set_loop(nnn, loop->_parent); |
| if (old->outcnt() > 0) { |
| set_idom( nnn, old_new[idom(old)->_idx], dd ); |
| } |
| } |
| // Correct edges to the new node |
| for( uint j = 0; j < nnn->req(); j++ ) { |
| Node *n = nnn->in(j); |
| if( n ) { |
| IdealLoopTree *old_in_loop = get_loop( has_ctrl(n) ? get_ctrl(n) : n ); |
| if( loop->is_member( old_in_loop ) ) |
| nnn->set_req(j, old_new[n->_idx]); |
| } |
| } |
| _igvn.hash_find_insert(nnn); |
| } |
| Node *newhead = old_new[loop->_head->_idx]; |
| set_idom(newhead, newhead->in(LoopNode::EntryControl), dd); |
| |
| |
| // Step 3: Now fix control uses. Loop varying control uses have already |
| // been fixed up (as part of all input edges in Step 2). Loop invariant |
| // control uses must be either an IfFalse or an IfTrue. Make a merge |
| // point to merge the old and new IfFalse/IfTrue nodes; make the use |
| // refer to this. |
| ResourceArea *area = Thread::current()->resource_area(); |
| Node_List worklist(area); |
| uint new_counter = C->unique(); |
| for( i = 0; i < loop->_body.size(); i++ ) { |
| Node* old = loop->_body.at(i); |
| if( !old->is_CFG() ) continue; |
| Node* nnn = old_new[old->_idx]; |
| |
| // Copy uses to a worklist, so I can munge the def-use info |
| // with impunity. |
| for (DUIterator_Fast jmax, j = old->fast_outs(jmax); j < jmax; j++) |
| worklist.push(old->fast_out(j)); |
| |
| while( worklist.size() ) { // Visit all uses |
| Node *use = worklist.pop(); |
| if (!has_node(use)) continue; // Ignore dead nodes |
| IdealLoopTree *use_loop = get_loop( has_ctrl(use) ? get_ctrl(use) : use ); |
| if( !loop->is_member( use_loop ) && use->is_CFG() ) { |
| // Both OLD and USE are CFG nodes here. |
| assert( use->is_Proj(), "" ); |
| |
| // Clone the loop exit control projection |
| Node *newuse = use->clone(); |
| if (C->do_vector_loop()) { |
| cm.verify_insert_and_clone(use, newuse, cm.clone_idx()); |
| } |
| newuse->set_req(0,nnn); |
| _igvn.register_new_node_with_optimizer(newuse); |
| set_loop(newuse, use_loop); |
| set_idom(newuse, nnn, dom_depth(nnn) + 1 ); |
| |
| // We need a Region to merge the exit from the peeled body and the |
| // exit from the old loop body. |
| RegionNode *r = new RegionNode(3); |
| // Map the old use to the new merge point |
| old_new.map( use->_idx, r ); |
| uint dd_r = MIN2(dom_depth(newuse),dom_depth(use)); |
| assert( dd_r >= dom_depth(dom_lca(newuse,use)), "" ); |
| |
| // The original user of 'use' uses 'r' instead. |
| for (DUIterator_Last lmin, l = use->last_outs(lmin); l >= lmin;) { |
| Node* useuse = use->last_out(l); |
| _igvn.rehash_node_delayed(useuse); |
| uint uses_found = 0; |
| if( useuse->in(0) == use ) { |
| useuse->set_req(0, r); |
| uses_found++; |
| if( useuse->is_CFG() ) { |
| assert( dom_depth(useuse) > dd_r, "" ); |
| set_idom(useuse, r, dom_depth(useuse)); |
| } |
| } |
| for( uint k = 1; k < useuse->req(); k++ ) { |
| if( useuse->in(k) == use ) { |
| useuse->set_req(k, r); |
| uses_found++; |
| } |
| } |
| l -= uses_found; // we deleted 1 or more copies of this edge |
| } |
| |
| // Now finish up 'r' |
| r->set_req( 1, newuse ); |
| r->set_req( 2, use ); |
| _igvn.register_new_node_with_optimizer(r); |
| set_loop(r, use_loop); |
| set_idom(r, !side_by_side_idom ? newuse->in(0) : side_by_side_idom, dd_r); |
| } // End of if a loop-exit test |
| } |
| } |
| |
| // Step 4: If loop-invariant use is not control, it must be dominated by a |
| // loop exit IfFalse/IfTrue. Find "proper" loop exit. Make a Region |
| // there if needed. Make a Phi there merging old and new used values. |
| Node_List *split_if_set = NULL; |
| Node_List *split_bool_set = NULL; |
| Node_List *split_cex_set = NULL; |
| for( i = 0; i < loop->_body.size(); i++ ) { |
| Node* old = loop->_body.at(i); |
| Node* nnn = old_new[old->_idx]; |
| // Copy uses to a worklist, so I can munge the def-use info |
| // with impunity. |
| for (DUIterator_Fast jmax, j = old->fast_outs(jmax); j < jmax; j++) |
| worklist.push(old->fast_out(j)); |
| |
| while( worklist.size() ) { |
| Node *use = worklist.pop(); |
| if (!has_node(use)) continue; // Ignore dead nodes |
| if (use->in(0) == C->top()) continue; |
| IdealLoopTree *use_loop = get_loop( has_ctrl(use) ? get_ctrl(use) : use ); |
| // Check for data-use outside of loop - at least one of OLD or USE |
| // must not be a CFG node. |
| if( !loop->is_member( use_loop ) && (!old->is_CFG() || !use->is_CFG())) { |
| |
| // If the Data use is an IF, that means we have an IF outside of the |
| // loop that is switching on a condition that is set inside of the |
| // loop. Happens if people set a loop-exit flag; then test the flag |
| // in the loop to break the loop, then test is again outside of the |
| // loop to determine which way the loop exited. |
| // Loop predicate If node connects to Bool node through Opaque1 node. |
| if (use->is_If() || use->is_CMove() || C->is_predicate_opaq(use)) { |
| // Since this code is highly unlikely, we lazily build the worklist |
| // of such Nodes to go split. |
| if( !split_if_set ) |
| split_if_set = new Node_List(area); |
| split_if_set->push(use); |
| } |
| if( use->is_Bool() ) { |
| if( !split_bool_set ) |
| split_bool_set = new Node_List(area); |
| split_bool_set->push(use); |
| } |
| if( use->Opcode() == Op_CreateEx ) { |
| if( !split_cex_set ) |
| split_cex_set = new Node_List(area); |
| split_cex_set->push(use); |
| } |
| |
| |
| // Get "block" use is in |
| uint idx = 0; |
| while( use->in(idx) != old ) idx++; |
| Node *prev = use->is_CFG() ? use : get_ctrl(use); |
| assert( !loop->is_member( get_loop( prev ) ), "" ); |
| Node *cfg = prev->_idx >= new_counter |
| ? prev->in(2) |
| : idom(prev); |
| if( use->is_Phi() ) // Phi use is in prior block |
| cfg = prev->in(idx); // NOT in block of Phi itself |
| if (cfg->is_top()) { // Use is dead? |
| _igvn.replace_input_of(use, idx, C->top()); |
| continue; |
| } |
| |
| while( !loop->is_member( get_loop( cfg ) ) ) { |
| prev = cfg; |
| cfg = cfg->_idx >= new_counter ? cfg->in(2) : idom(cfg); |
| } |
| // If the use occurs after merging several exits from the loop, then |
| // old value must have dominated all those exits. Since the same old |
| // value was used on all those exits we did not need a Phi at this |
| // merge point. NOW we do need a Phi here. Each loop exit value |
| // is now merged with the peeled body exit; each exit gets its own |
| // private Phi and those Phis need to be merged here. |
| Node *phi; |
| if( prev->is_Region() ) { |
| if( idx == 0 ) { // Updating control edge? |
| phi = prev; // Just use existing control |
| } else { // Else need a new Phi |
| phi = PhiNode::make( prev, old ); |
| // Now recursively fix up the new uses of old! |
| for( uint i = 1; i < prev->req(); i++ ) { |
| worklist.push(phi); // Onto worklist once for each 'old' input |
| } |
| } |
| } else { |
| // Get new RegionNode merging old and new loop exits |
| prev = old_new[prev->_idx]; |
| assert( prev, "just made this in step 7" ); |
| if( idx == 0 ) { // Updating control edge? |
| phi = prev; // Just use existing control |
| } else { // Else need a new Phi |
| // Make a new Phi merging data values properly |
| phi = PhiNode::make( prev, old ); |
| phi->set_req( 1, nnn ); |
| } |
| } |
| // If inserting a new Phi, check for prior hits |
| if( idx != 0 ) { |
| Node *hit = _igvn.hash_find_insert(phi); |
| if( hit == NULL ) { |
| _igvn.register_new_node_with_optimizer(phi); // Register new phi |
| } else { // or |
| // Remove the new phi from the graph and use the hit |
| _igvn.remove_dead_node(phi); |
| phi = hit; // Use existing phi |
| } |
| set_ctrl(phi, prev); |
| } |
| // Make 'use' use the Phi instead of the old loop body exit value |
| _igvn.replace_input_of(use, idx, phi); |
| if( use->_idx >= new_counter ) { // If updating new phis |
| // Not needed for correctness, but prevents a weak assert |
| // in AddPNode from tripping (when we end up with different |
| // base & derived Phis that will become the same after |
| // IGVN does CSE). |
| Node *hit = _igvn.hash_find_insert(use); |
| if( hit ) // Go ahead and re-hash for hits. |
| _igvn.replace_node( use, hit ); |
| } |
| |
| // If 'use' was in the loop-exit block, it now needs to be sunk |
| // below the post-loop merge point. |
| sink_use( use, prev ); |
| } |
| } |
| } |
| |
| // Check for IFs that need splitting/cloning. Happens if an IF outside of |
| // the loop uses a condition set in the loop. The original IF probably |
| // takes control from one or more OLD Regions (which in turn get from NEW |
| // Regions). In any case, there will be a set of Phis for each merge point |
| // from the IF up to where the original BOOL def exists the loop. |
| if( split_if_set ) { |
| while( split_if_set->size() ) { |
| Node *iff = split_if_set->pop(); |
| if( iff->in(1)->is_Phi() ) { |
| BoolNode *b = clone_iff( iff->in(1)->as_Phi(), loop ); |
| _igvn.replace_input_of(iff, 1, b); |
| } |
| } |
| } |
| if( split_bool_set ) { |
| while( split_bool_set->size() ) { |
| Node *b = split_bool_set->pop(); |
| Node *phi = b->in(1); |
| assert( phi->is_Phi(), "" ); |
| CmpNode *cmp = clone_bool( (PhiNode*)phi, loop ); |
| _igvn.replace_input_of(b, 1, cmp); |
| } |
| } |
| if( split_cex_set ) { |
| while( split_cex_set->size() ) { |
| Node *b = split_cex_set->pop(); |
| assert( b->in(0)->is_Region(), "" ); |
| assert( b->in(1)->is_Phi(), "" ); |
| assert( b->in(0)->in(0) == b->in(1)->in(0), "" ); |
| split_up( b, b->in(0), NULL ); |
| } |
| } |
| |
| } |
| |
| |
| //---------------------- stride_of_possible_iv ------------------------------------- |
| // Looks for an iff/bool/comp with one operand of the compare |
| // being a cycle involving an add and a phi, |
| // with an optional truncation (left-shift followed by a right-shift) |
| // of the add. Returns zero if not an iv. |
| int PhaseIdealLoop::stride_of_possible_iv(Node* iff) { |
| Node* trunc1 = NULL; |
| Node* trunc2 = NULL; |
| const TypeInt* ttype = NULL; |
| if (!iff->is_If() || iff->in(1) == NULL || !iff->in(1)->is_Bool()) { |
| return 0; |
| } |
| BoolNode* bl = iff->in(1)->as_Bool(); |
| Node* cmp = bl->in(1); |
| if (!cmp || (cmp->Opcode() != Op_CmpI && cmp->Opcode() != Op_CmpU)) { |
| return 0; |
| } |
| // Must have an invariant operand |
| if (is_member(get_loop(iff), get_ctrl(cmp->in(2)))) { |
| return 0; |
| } |
| Node* add2 = NULL; |
| Node* cmp1 = cmp->in(1); |
| if (cmp1->is_Phi()) { |
| // (If (Bool (CmpX phi:(Phi ...(Optional-trunc(AddI phi add2))) ))) |
| Node* phi = cmp1; |
| for (uint i = 1; i < phi->req(); i++) { |
| Node* in = phi->in(i); |
| Node* add = CountedLoopNode::match_incr_with_optional_truncation(in, |
| &trunc1, &trunc2, &ttype); |
| if (add && add->in(1) == phi) { |
| add2 = add->in(2); |
| break; |
| } |
| } |
| } else { |
| // (If (Bool (CmpX addtrunc:(Optional-trunc((AddI (Phi ...addtrunc...) add2)) ))) |
| Node* addtrunc = cmp1; |
| Node* add = CountedLoopNode::match_incr_with_optional_truncation(addtrunc, |
| &trunc1, &trunc2, &ttype); |
| if (add && add->in(1)->is_Phi()) { |
| Node* phi = add->in(1); |
| for (uint i = 1; i < phi->req(); i++) { |
| if (phi->in(i) == addtrunc) { |
| add2 = add->in(2); |
| break; |
| } |
| } |
| } |
| } |
| if (add2 != NULL) { |
| const TypeInt* add2t = _igvn.type(add2)->is_int(); |
| if (add2t->is_con()) { |
| return add2t->get_con(); |
| } |
| } |
| return 0; |
| } |
| |
| |
| //---------------------- stay_in_loop ------------------------------------- |
| // Return the (unique) control output node that's in the loop (if it exists.) |
| Node* PhaseIdealLoop::stay_in_loop( Node* n, IdealLoopTree *loop) { |
| Node* unique = NULL; |
| if (!n) return NULL; |
| for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) { |
| Node* use = n->fast_out(i); |
| if (!has_ctrl(use) && loop->is_member(get_loop(use))) { |
| if (unique != NULL) { |
| return NULL; |
| } |
| unique = use; |
| } |
| } |
| return unique; |
| } |
| |
| //------------------------------ register_node ------------------------------------- |
| // Utility to register node "n" with PhaseIdealLoop |
| void PhaseIdealLoop::register_node(Node* n, IdealLoopTree *loop, Node* pred, int ddepth) { |
| _igvn.register_new_node_with_optimizer(n); |
| loop->_body.push(n); |
| if (n->is_CFG()) { |
| set_loop(n, loop); |
| set_idom(n, pred, ddepth); |
| } else { |
| set_ctrl(n, pred); |
| } |
| } |
| |
| //------------------------------ proj_clone ------------------------------------- |
| // Utility to create an if-projection |
| ProjNode* PhaseIdealLoop::proj_clone(ProjNode* p, IfNode* iff) { |
| ProjNode* c = p->clone()->as_Proj(); |
| c->set_req(0, iff); |
| return c; |
| } |
| |
| //------------------------------ short_circuit_if ------------------------------------- |
| // Force the iff control output to be the live_proj |
| Node* PhaseIdealLoop::short_circuit_if(IfNode* iff, ProjNode* live_proj) { |
| guarantee(live_proj != NULL, "null projection"); |
| int proj_con = live_proj->_con; |
| assert(proj_con == 0 || proj_con == 1, "false or true projection"); |
| Node *con = _igvn.intcon(proj_con); |
| set_ctrl(con, C->root()); |
| if (iff) { |
| iff->set_req(1, con); |
| } |
| return con; |
| } |
| |
| //------------------------------ insert_if_before_proj ------------------------------------- |
| // Insert a new if before an if projection (* - new node) |
| // |
| // before |
| // if(test) |
| // / \ |
| // v v |
| // other-proj proj (arg) |
| // |
| // after |
| // if(test) |
| // / \ |
| // / v |
| // | * proj-clone |
| // v | |
| // other-proj v |
| // * new_if(relop(cmp[IU](left,right))) |
| // / \ |
| // v v |
| // * new-proj proj |
| // (returned) |
| // |
| ProjNode* PhaseIdealLoop::insert_if_before_proj(Node* left, bool Signed, BoolTest::mask relop, Node* right, ProjNode* proj) { |
| IfNode* iff = proj->in(0)->as_If(); |
| IdealLoopTree *loop = get_loop(proj); |
| ProjNode *other_proj = iff->proj_out(!proj->is_IfTrue())->as_Proj(); |
| int ddepth = dom_depth(proj); |
| |
| _igvn.rehash_node_delayed(iff); |
| _igvn.rehash_node_delayed(proj); |
| |
| proj->set_req(0, NULL); // temporary disconnect |
| ProjNode* proj2 = proj_clone(proj, iff); |
| register_node(proj2, loop, iff, ddepth); |
| |
| Node* cmp = Signed ? (Node*) new CmpINode(left, right) : (Node*) new CmpUNode(left, right); |
| register_node(cmp, loop, proj2, ddepth); |
| |
| BoolNode* bol = new BoolNode(cmp, relop); |
| register_node(bol, loop, proj2, ddepth); |
| |
| int opcode = iff->Opcode(); |
| assert(opcode == Op_If || opcode == Op_RangeCheck, "unexpected opcode"); |
| IfNode* new_if = (opcode == Op_If) ? new IfNode(proj2, bol, iff->_prob, iff->_fcnt): |
| new RangeCheckNode(proj2, bol, iff->_prob, iff->_fcnt); |
| register_node(new_if, loop, proj2, ddepth); |
| |
| proj->set_req(0, new_if); // reattach |
| set_idom(proj, new_if, ddepth); |
| |
| ProjNode* new_exit = proj_clone(other_proj, new_if)->as_Proj(); |
| guarantee(new_exit != NULL, "null exit node"); |
| register_node(new_exit, get_loop(other_proj), new_if, ddepth); |
| |
| return new_exit; |
| } |
| |
| //------------------------------ insert_region_before_proj ------------------------------------- |
| // Insert a region before an if projection (* - new node) |
| // |
| // before |
| // if(test) |
| // / | |
| // v | |
| // proj v |
| // other-proj |
| // |
| // after |
| // if(test) |
| // / | |
| // v | |
| // * proj-clone v |
| // | other-proj |
| // v |
| // * new-region |
| // | |
| // v |
| // * dum_if |
| // / \ |
| // v \ |
| // * dum-proj v |
| // proj |
| // |
| RegionNode* PhaseIdealLoop::insert_region_before_proj(ProjNode* proj) { |
| IfNode* iff = proj->in(0)->as_If(); |
| IdealLoopTree *loop = get_loop(proj); |
| ProjNode *other_proj = iff->proj_out(!proj->is_IfTrue())->as_Proj(); |
| int ddepth = dom_depth(proj); |
| |
| _igvn.rehash_node_delayed(iff); |
| _igvn.rehash_node_delayed(proj); |
| |
| proj->set_req(0, NULL); // temporary disconnect |
| ProjNode* proj2 = proj_clone(proj, iff); |
| register_node(proj2, loop, iff, ddepth); |
| |
| RegionNode* reg = new RegionNode(2); |
| reg->set_req(1, proj2); |
| register_node(reg, loop, iff, ddepth); |
| |
| IfNode* dum_if = new IfNode(reg, short_circuit_if(NULL, proj), iff->_prob, iff->_fcnt); |
| register_node(dum_if, loop, reg, ddepth); |
| |
| proj->set_req(0, dum_if); // reattach |
| set_idom(proj, dum_if, ddepth); |
| |
| ProjNode* dum_proj = proj_clone(other_proj, dum_if); |
| register_node(dum_proj, loop, dum_if, ddepth); |
| |
| return reg; |
| } |
| |
| //------------------------------ insert_cmpi_loop_exit ------------------------------------- |
| // Clone a signed compare loop exit from an unsigned compare and |
| // insert it before the unsigned cmp on the stay-in-loop path. |
| // All new nodes inserted in the dominator tree between the original |
| // if and it's projections. The original if test is replaced with |
| // a constant to force the stay-in-loop path. |
| // |
| // This is done to make sure that the original if and it's projections |
| // still dominate the same set of control nodes, that the ctrl() relation |
| // from data nodes to them is preserved, and that their loop nesting is |
| // preserved. |
| // |
| // before |
| // if(i <u limit) unsigned compare loop exit |
| // / | |
| // v v |
| // exit-proj stay-in-loop-proj |
| // |
| // after |
| // if(stay-in-loop-const) original if |
| // / | |
| // / v |
| // / if(i < limit) new signed test |
| // / / | |
| // / / v |
| // / / if(i <u limit) new cloned unsigned test |
| // / / / | |
| // v v v | |
| // region | |
| // | | |
| // dum-if | |
| // / | | |
| // ether | | |
| // v v |
| // exit-proj stay-in-loop-proj |
| // |
| IfNode* PhaseIdealLoop::insert_cmpi_loop_exit(IfNode* if_cmpu, IdealLoopTree *loop) { |
| const bool Signed = true; |
| const bool Unsigned = false; |
| |
| BoolNode* bol = if_cmpu->in(1)->as_Bool(); |
| if (bol->_test._test != BoolTest::lt) return NULL; |
| CmpNode* cmpu = bol->in(1)->as_Cmp(); |
| if (cmpu->Opcode() != Op_CmpU) return NULL; |
| int stride = stride_of_possible_iv(if_cmpu); |
| if (stride == 0) return NULL; |
| |
| Node* lp_proj = stay_in_loop(if_cmpu, loop); |
| guarantee(lp_proj != NULL, "null loop node"); |
| |
| ProjNode* lp_continue = lp_proj->as_Proj(); |
| ProjNode* lp_exit = if_cmpu->proj_out(!lp_continue->is_IfTrue())->as_Proj(); |
| |
| Node* limit = NULL; |
| if (stride > 0) { |
| limit = cmpu->in(2); |
| } else { |
| limit = _igvn.makecon(TypeInt::ZERO); |
| set_ctrl(limit, C->root()); |
| } |
| // Create a new region on the exit path |
| RegionNode* reg = insert_region_before_proj(lp_exit); |
| guarantee(reg != NULL, "null region node"); |
| |
| // Clone the if-cmpu-true-false using a signed compare |
| BoolTest::mask rel_i = stride > 0 ? bol->_test._test : BoolTest::ge; |
| ProjNode* cmpi_exit = insert_if_before_proj(cmpu->in(1), Signed, rel_i, limit, lp_continue); |
| reg->add_req(cmpi_exit); |
| |
| // Clone the if-cmpu-true-false |
| BoolTest::mask rel_u = bol->_test._test; |
| ProjNode* cmpu_exit = insert_if_before_proj(cmpu->in(1), Unsigned, rel_u, cmpu->in(2), lp_continue); |
| reg->add_req(cmpu_exit); |
| |
| // Force original if to stay in loop. |
| short_circuit_if(if_cmpu, lp_continue); |
| |
| return cmpi_exit->in(0)->as_If(); |
| } |
| |
| //------------------------------ remove_cmpi_loop_exit ------------------------------------- |
| // Remove a previously inserted signed compare loop exit. |
| void PhaseIdealLoop::remove_cmpi_loop_exit(IfNode* if_cmp, IdealLoopTree *loop) { |
| Node* lp_proj = stay_in_loop(if_cmp, loop); |
| assert(if_cmp->in(1)->in(1)->Opcode() == Op_CmpI && |
| stay_in_loop(lp_proj, loop)->is_If() && |
| stay_in_loop(lp_proj, loop)->in(1)->in(1)->Opcode() == Op_CmpU, "inserted cmpi before cmpu"); |
| Node *con = _igvn.makecon(lp_proj->is_IfTrue() ? TypeInt::ONE : TypeInt::ZERO); |
| set_ctrl(con, C->root()); |
| if_cmp->set_req(1, con); |
| } |
| |
| //------------------------------ scheduled_nodelist ------------------------------------- |
| // Create a post order schedule of nodes that are in the |
| // "member" set. The list is returned in "sched". |
| // The first node in "sched" is the loop head, followed by |
| // nodes which have no inputs in the "member" set, and then |
| // followed by the nodes that have an immediate input dependence |
| // on a node in "sched". |
| void PhaseIdealLoop::scheduled_nodelist( IdealLoopTree *loop, VectorSet& member, Node_List &sched ) { |
| |
| assert(member.test(loop->_head->_idx), "loop head must be in member set"); |
| Arena *a = Thread::current()->resource_area(); |
| VectorSet visited(a); |
| Node_Stack nstack(a, loop->_body.size()); |
| |
| Node* n = loop->_head; // top of stack is cached in "n" |
| uint idx = 0; |
| visited.set(n->_idx); |
| |
| // Initially push all with no inputs from within member set |
| for(uint i = 0; i < loop->_body.size(); i++ ) { |
| Node *elt = loop->_body.at(i); |
| if (member.test(elt->_idx)) { |
| bool found = false; |
| for (uint j = 0; j < elt->req(); j++) { |
| Node* def = elt->in(j); |
| if (def && member.test(def->_idx) && def != elt) { |
| found = true; |
| break; |
| } |
| } |
| if (!found && elt != loop->_head) { |
| nstack.push(n, idx); |
| n = elt; |
| assert(!visited.test(n->_idx), "not seen yet"); |
| visited.set(n->_idx); |
| } |
| } |
| } |
| |
| // traverse out's that are in the member set |
| while (true) { |
| if (idx < n->outcnt()) { |
| Node* use = n->raw_out(idx); |
| idx++; |
| if (!visited.test_set(use->_idx)) { |
| if (member.test(use->_idx)) { |
| nstack.push(n, idx); |
| n = use; |
| idx = 0; |
| } |
| } |
| } else { |
| // All outputs processed |
| sched.push(n); |
| if (nstack.is_empty()) break; |
| n = nstack.node(); |
| idx = nstack.index(); |
| nstack.pop(); |
| } |
| } |
| } |
| |
| |
| //------------------------------ has_use_in_set ------------------------------------- |
| // Has a use in the vector set |
| bool PhaseIdealLoop::has_use_in_set( Node* n, VectorSet& vset ) { |
| for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { |
| Node* use = n->fast_out(j); |
| if (vset.test(use->_idx)) { |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| |
| //------------------------------ has_use_internal_to_set ------------------------------------- |
| // Has use internal to the vector set (ie. not in a phi at the loop head) |
| bool PhaseIdealLoop::has_use_internal_to_set( Node* n, VectorSet& vset, IdealLoopTree *loop ) { |
| Node* head = loop->_head; |
| for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { |
| Node* use = n->fast_out(j); |
| if (vset.test(use->_idx) && !(use->is_Phi() && use->in(0) == head)) { |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| |
| //------------------------------ clone_for_use_outside_loop ------------------------------------- |
| // clone "n" for uses that are outside of loop |
| int PhaseIdealLoop::clone_for_use_outside_loop( IdealLoopTree *loop, Node* n, Node_List& worklist ) { |
| int cloned = 0; |
| assert(worklist.size() == 0, "should be empty"); |
| for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { |
| Node* use = n->fast_out(j); |
| if( !loop->is_member(get_loop(has_ctrl(use) ? get_ctrl(use) : use)) ) { |
| worklist.push(use); |
| } |
| } |
| while( worklist.size() ) { |
| Node *use = worklist.pop(); |
| if (!has_node(use) || use->in(0) == C->top()) continue; |
| uint j; |
| for (j = 0; j < use->req(); j++) { |
| if (use->in(j) == n) break; |
| } |
| assert(j < use->req(), "must be there"); |
| |
| // clone "n" and insert it between the inputs of "n" and the use outside the loop |
| Node* n_clone = n->clone(); |
| _igvn.replace_input_of(use, j, n_clone); |
| cloned++; |
| Node* use_c; |
| if (!use->is_Phi()) { |
| use_c = has_ctrl(use) ? get_ctrl(use) : use->in(0); |
| } else { |
| // Use in a phi is considered a use in the associated predecessor block |
| use_c = use->in(0)->in(j); |
| } |
| set_ctrl(n_clone, use_c); |
| assert(!loop->is_member(get_loop(use_c)), "should be outside loop"); |
| get_loop(use_c)->_body.push(n_clone); |
| _igvn.register_new_node_with_optimizer(n_clone); |
| #if !defined(PRODUCT) |
| if (TracePartialPeeling) { |
| tty->print_cr("loop exit cloning old: %d new: %d newbb: %d", n->_idx, n_clone->_idx, get_ctrl(n_clone)->_idx); |
| } |
| #endif |
| } |
| return cloned; |
| } |
| |
| |
| //------------------------------ clone_for_special_use_inside_loop ------------------------------------- |
| // clone "n" for special uses that are in the not_peeled region. |
| // If these def-uses occur in separate blocks, the code generator |
| // marks the method as not compilable. For example, if a "BoolNode" |
| // is in a different basic block than the "IfNode" that uses it, then |
| // the compilation is aborted in the code generator. |
| void PhaseIdealLoop::clone_for_special_use_inside_loop( IdealLoopTree *loop, Node* n, |
| VectorSet& not_peel, Node_List& sink_list, Node_List& worklist ) { |
| if (n->is_Phi() || n->is_Load()) { |
| return; |
| } |
| assert(worklist.size() == 0, "should be empty"); |
| for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { |
| Node* use = n->fast_out(j); |
| if ( not_peel.test(use->_idx) && |
| (use->is_If() || use->is_CMove() || use->is_Bool()) && |
| use->in(1) == n) { |
| worklist.push(use); |
| } |
| } |
| if (worklist.size() > 0) { |
| // clone "n" and insert it between inputs of "n" and the use |
| Node* n_clone = n->clone(); |
| loop->_body.push(n_clone); |
| _igvn.register_new_node_with_optimizer(n_clone); |
| set_ctrl(n_clone, get_ctrl(n)); |
| sink_list.push(n_clone); |
| not_peel <<= n_clone->_idx; // add n_clone to not_peel set. |
| #if !defined(PRODUCT) |
| if (TracePartialPeeling) { |
| tty->print_cr("special not_peeled cloning old: %d new: %d", n->_idx, n_clone->_idx); |
| } |
| #endif |
| while( worklist.size() ) { |
| Node *use = worklist.pop(); |
| _igvn.rehash_node_delayed(use); |
| for (uint j = 1; j < use->req(); j++) { |
| if (use->in(j) == n) { |
| use->set_req(j, n_clone); |
| } |
| } |
| } |
| } |
| } |
| |
| |
| //------------------------------ insert_phi_for_loop ------------------------------------- |
| // Insert phi(lp_entry_val, back_edge_val) at use->in(idx) for loop lp if phi does not already exist |
| void PhaseIdealLoop::insert_phi_for_loop( Node* use, uint idx, Node* lp_entry_val, Node* back_edge_val, LoopNode* lp ) { |
| Node *phi = PhiNode::make(lp, back_edge_val); |
| phi->set_req(LoopNode::EntryControl, lp_entry_val); |
| // Use existing phi if it already exists |
| Node *hit = _igvn.hash_find_insert(phi); |
| if( hit == NULL ) { |
| _igvn.register_new_node_with_optimizer(phi); |
| set_ctrl(phi, lp); |
| } else { |
| // Remove the new phi from the graph and use the hit |
| _igvn.remove_dead_node(phi); |
| phi = hit; |
| } |
| _igvn.replace_input_of(use, idx, phi); |
| } |
| |
| #ifdef ASSERT |
| //------------------------------ is_valid_loop_partition ------------------------------------- |
| // Validate the loop partition sets: peel and not_peel |
| bool PhaseIdealLoop::is_valid_loop_partition( IdealLoopTree *loop, VectorSet& peel, Node_List& peel_list, |
| VectorSet& not_peel ) { |
| uint i; |
| // Check that peel_list entries are in the peel set |
| for (i = 0; i < peel_list.size(); i++) { |
| if (!peel.test(peel_list.at(i)->_idx)) { |
| return false; |
| } |
| } |
| // Check at loop members are in one of peel set or not_peel set |
| for (i = 0; i < loop->_body.size(); i++ ) { |
| Node *def = loop->_body.at(i); |
| uint di = def->_idx; |
| // Check that peel set elements are in peel_list |
| if (peel.test(di)) { |
| if (not_peel.test(di)) { |
| return false; |
| } |
| // Must be in peel_list also |
| bool found = false; |
| for (uint j = 0; j < peel_list.size(); j++) { |
| if (peel_list.at(j)->_idx == di) { |
| found = true; |
| break; |
| } |
| } |
| if (!found) { |
| return false; |
| } |
| } else if (not_peel.test(di)) { |
| if (peel.test(di)) { |
| return false; |
| } |
| } else { |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| //------------------------------ is_valid_clone_loop_exit_use ------------------------------------- |
| // Ensure a use outside of loop is of the right form |
| bool PhaseIdealLoop::is_valid_clone_loop_exit_use( IdealLoopTree *loop, Node* use, uint exit_idx) { |
| Node *use_c = has_ctrl(use) ? get_ctrl(use) : use; |
| return (use->is_Phi() && |
| use_c->is_Region() && use_c->req() == 3 && |
| (use_c->in(exit_idx)->Opcode() == Op_IfTrue || |
| use_c->in(exit_idx)->Opcode() == Op_IfFalse || |
| use_c->in(exit_idx)->Opcode() == Op_JumpProj) && |
| loop->is_member( get_loop( use_c->in(exit_idx)->in(0) ) ) ); |
| } |
| |
| //------------------------------ is_valid_clone_loop_form ------------------------------------- |
| // Ensure that all uses outside of loop are of the right form |
| bool PhaseIdealLoop::is_valid_clone_loop_form( IdealLoopTree *loop, Node_List& peel_list, |
| uint orig_exit_idx, uint clone_exit_idx) { |
| uint len = peel_list.size(); |
| for (uint i = 0; i < len; i++) { |
| Node *def = peel_list.at(i); |
| |
| for (DUIterator_Fast jmax, j = def->fast_outs(jmax); j < jmax; j++) { |
| Node *use = def->fast_out(j); |
| Node *use_c = has_ctrl(use) ? get_ctrl(use) : use; |
| if (!loop->is_member(get_loop(use_c))) { |
| // use is not in the loop, check for correct structure |
| if (use->in(0) == def) { |
| // Okay |
| } else if (!is_valid_clone_loop_exit_use(loop, use, orig_exit_idx)) { |
| return false; |
| } |
| } |
| } |
| } |
| return true; |
| } |
| #endif |
| |
| //------------------------------ partial_peel ------------------------------------- |
| // Partially peel (aka loop rotation) the top portion of a loop (called |
| // the peel section below) by cloning it and placing one copy just before |
| // the new loop head and the other copy at the bottom of the new loop. |
| // |
| // before after where it came from |
| // |
| // stmt1 stmt1 |
| // loop: stmt2 clone |
| // stmt2 if condA goto exitA clone |
| // if condA goto exitA new_loop: new |
| // stmt3 stmt3 clone |
| // if !condB goto loop if condB goto exitB clone |
| // exitB: stmt2 orig |
| // stmt4 if !condA goto new_loop orig |
| // exitA: goto exitA |
| // exitB: |
| // stmt4 |
| // exitA: |
| // |
| // Step 1: find the cut point: an exit test on probable |
| // induction variable. |
| // Step 2: schedule (with cloning) operations in the peel |
| // section that can be executed after the cut into |
| // the section that is not peeled. This may need |
| // to clone operations into exit blocks. For |
| // instance, a reference to A[i] in the not-peel |
| // section and a reference to B[i] in an exit block |
| // may cause a left-shift of i by 2 to be placed |
| // in the peel block. This step will clone the left |
| // shift into the exit block and sink the left shift |
| // from the peel to the not-peel section. |
| // Step 3: clone the loop, retarget the control, and insert |
| // phis for values that are live across the new loop |
| // head. This is very dependent on the graph structure |
| // from clone_loop. It creates region nodes for |
| // exit control and associated phi nodes for values |
| // flow out of the loop through that exit. The region |
| // node is dominated by the clone's control projection. |
| // So the clone's peel section is placed before the |
| // new loop head, and the clone's not-peel section is |
| // forms the top part of the new loop. The original |
| // peel section forms the tail of the new loop. |
| // Step 4: update the dominator tree and recompute the |
| // dominator depth. |
| // |
| // orig |
| // |
| // stmt1 |
| // | |
| // v |
| // loop predicate |
| // | |
| // v |
| // loop<----+ |
| // | | |
| // stmt2 | |
| // | | |
| // v | |
| // ifA | |
| // / | | |
| // v v | |
| // false true ^ <-- last_peel |
| // / | | |
| // / ===|==cut | |
| // / stmt3 | <-- first_not_peel |
| // / | | |
| // | v | |
| // v ifB | |
| // exitA: / \ | |
| // / \ | |
| // v v | |
| // false true | |
| // / \ | |
| // / ----+ |
| // | |
| // v |
| // exitB: |
| // stmt4 |
| // |
| // |
| // after clone loop |
| // |
| // stmt1 |
| // | |
| // v |
| // loop predicate |
| // / \ |
| // clone / \ orig |
| // / \ |
| // / \ |
| // v v |
| // +---->loop loop<----+ |
| // | | | | |
| // | stmt2 stmt2 | |
| // | | | | |
| // | v v | |
| // | ifA ifA | |
| // | | \ / | | |
| // | v v v v | |
| // ^ true false false true ^ <-- last_peel |
| // | | ^ \ / | | |
| // | cut==|== \ \ / ===|==cut | |
| // | stmt3 \ \ / stmt3 | <-- first_not_peel |
| // | | dom | | | | |
| // | v \ 1v v2 v | |
| // | ifB regionA ifB | |
| // | / \ | / \ | |
| // | / \ v / \ | |
| // | v v exitA: v v | |
| // | true false false true | |
| // | / ^ \ / \ | |
| // +---- \ \ / ----+ |
| // dom \ / |
| // \ 1v v2 |
| // regionB |
| // | |
| // v |
| // exitB: |
| // stmt4 |
| // |
| // |
| // after partial peel |
| // |
| // stmt1 |
| // | |
| // v |
| // loop predicate |
| // / |
| // clone / orig |
| // / TOP |
| // / \ |
| // v v |
| // TOP->loop loop----+ |
| // | | | |
| // stmt2 stmt2 | |
| // | | | |
| // v v | |
| // ifA ifA | |
| // | \ / | | |
| // v v v v | |
| // true false false true | <-- last_peel |
| // | ^ \ / +------|---+ |
| // +->newloop \ \ / === ==cut | | |
| // | stmt3 \ \ / TOP | | |
| // | | dom | | stmt3 | | <-- first_not_peel |
| // | v \ 1v v2 v | | |
| // | ifB regionA ifB ^ v |
| // | / \ | / \ | | |
| // | / \ v / \ | | |
| // | v v exitA: v v | | |
| // | true false false true | | |
| // | / ^ \ / \ | | |
| // | | \ \ / v | | |
| // | | dom \ / TOP | | |
| // | | \ 1v v2 | | |
| // ^ v regionB | | |
| // | | | | | |
| // | | v ^ v |
| // | | exitB: | | |
| // | | stmt4 | | |
| // | +------------>-----------------+ | |
| // | | |
| // +-----------------<---------------------+ |
| // |
| // |
| // final graph |
| // |
| // stmt1 |
| // | |
| // v |
| // loop predicate |
| // | |
| // v |
| // stmt2 clone |
| // | |
| // v |
| // ........> ifA clone |
| // : / | |
| // dom / | |
| // : v v |
| // : false true |
| // : | | |
| // : | v |
| // : | newloop<-----+ |
| // : | | | |
| // : | stmt3 clone | |
| // : | | | |
| // : | v | |
| // : | ifB | |
| // : | / \ | |
| // : | v v | |
| // : | false true | |
| // : | | | | |
| // : | v stmt2 | |
| // : | exitB: | | |
| // : | stmt4 v | |
| // : | ifA orig | |
| // : | / \ | |
| // : | / \ | |
| // : | v v | |
| // : | false true | |
| // : | / \ | |
| // : v v -----+ |
| // RegionA |
| // | |
| // v |
| // exitA |
| // |
| bool PhaseIdealLoop::partial_peel( IdealLoopTree *loop, Node_List &old_new ) { |
| |
| assert(!loop->_head->is_CountedLoop(), "Non-counted loop only"); |
| if (!loop->_head->is_Loop()) { |
| return false; } |
| |
| LoopNode *head = loop->_head->as_Loop(); |
| |
| if (head->is_partial_peel_loop() || head->partial_peel_has_failed()) { |
| return false; |
| } |
| |
| // Check for complex exit control |
| for(uint ii = 0; ii < loop->_body.size(); ii++ ) { |
| Node *n = loop->_body.at(ii); |
| int opc = n->Opcode(); |
| if (n->is_Call() || |
| opc == Op_Catch || |
| opc == Op_CatchProj || |
| opc == Op_Jump || |
| opc == Op_JumpProj) { |
| #if !defined(PRODUCT) |
| if (TracePartialPeeling) { |
| tty->print_cr("\nExit control too complex: lp: %d", head->_idx); |
| } |
| #endif |
| return false; |
| } |
| } |
| |
| int dd = dom_depth(head); |
| |
| // Step 1: find cut point |
| |
| // Walk up dominators to loop head looking for first loop exit |
| // which is executed on every path thru loop. |
| IfNode *peel_if = NULL; |
| IfNode *peel_if_cmpu = NULL; |
| |
| Node *iff = loop->tail(); |
| while( iff != head ) { |
| if( iff->is_If() ) { |
| Node *ctrl = get_ctrl(iff->in(1)); |
| if (ctrl->is_top()) return false; // Dead test on live IF. |
| // If loop-varying exit-test, check for induction variable |
| if( loop->is_member(get_loop(ctrl)) && |
| loop->is_loop_exit(iff) && |
| is_possible_iv_test(iff)) { |
| Node* cmp = iff->in(1)->in(1); |
| if (cmp->Opcode() == Op_CmpI) { |
| peel_if = iff->as_If(); |
| } else { |
| assert(cmp->Opcode() == Op_CmpU, "must be CmpI or CmpU"); |
| peel_if_cmpu = iff->as_If(); |
| } |
| } |
| } |
| iff = idom(iff); |
| } |
| // Prefer signed compare over unsigned compare. |
| IfNode* new_peel_if = NULL; |
| if (peel_if == NULL) { |
| if (!PartialPeelAtUnsignedTests || peel_if_cmpu == NULL) { |
| return false; // No peel point found |
| } |
| new_peel_if = insert_cmpi_loop_exit(peel_if_cmpu, loop); |
| if (new_peel_if == NULL) { |
| return false; // No peel point found |
| } |
| peel_if = new_peel_if; |
| } |
| Node* last_peel = stay_in_loop(peel_if, loop); |
| Node* first_not_peeled = stay_in_loop(last_peel, loop); |
| if (first_not_peeled == NULL || first_not_peeled == head) { |
| return false; |
| } |
| |
| #if !defined(PRODUCT) |
| if (TraceLoopOpts) { |
| tty->print("PartialPeel "); |
| loop->dump_head(); |
| } |
| |
| if (TracePartialPeeling) { |
| tty->print_cr("before partial peel one iteration"); |
| Node_List wl; |
| Node* t = head->in(2); |
| while (true) { |
| wl.push(t); |
| if (t == head) break; |
| t = idom(t); |
| } |
| while (wl.size() > 0) { |
| Node* tt = wl.pop(); |
| tt->dump(); |
| if (tt == last_peel) tty->print_cr("-- cut --"); |
| } |
| } |
| #endif |
| ResourceArea *area = Thread::current()->resource_area(); |
| VectorSet peel(area); |
| VectorSet not_peel(area); |
| Node_List peel_list(area); |
| Node_List worklist(area); |
| Node_List sink_list(area); |
| |
| // Set of cfg nodes to peel are those that are executable from |
| // the head through last_peel. |
| assert(worklist.size() == 0, "should be empty"); |
| worklist.push(head); |
| peel.set(head->_idx); |
| while (worklist.size() > 0) { |
| Node *n = worklist.pop(); |
| if (n != last_peel) { |
| for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { |
| Node* use = n->fast_out(j); |
| if (use->is_CFG() && |
| loop->is_member(get_loop(use)) && |
| !peel.test_set(use->_idx)) { |
| worklist.push(use); |
| } |
| } |
| } |
| } |
| |
| // Set of non-cfg nodes to peel are those that are control |
| // dependent on the cfg nodes. |
| uint i; |
| for(i = 0; i < loop->_body.size(); i++ ) { |
| Node *n = loop->_body.at(i); |
| Node *n_c = has_ctrl(n) ? get_ctrl(n) : n; |
| if (peel.test(n_c->_idx)) { |
| peel.set(n->_idx); |
| } else { |
| not_peel.set(n->_idx); |
| } |
| } |
| |
| // Step 2: move operations from the peeled section down into the |
| // not-peeled section |
| |
| // Get a post order schedule of nodes in the peel region |
| // Result in right-most operand. |
| scheduled_nodelist(loop, peel, peel_list ); |
| |
| assert(is_valid_loop_partition(loop, peel, peel_list, not_peel), "bad partition"); |
| |
| // For future check for too many new phis |
| uint old_phi_cnt = 0; |
| for (DUIterator_Fast jmax, j = head->fast_outs(jmax); j < jmax; j++) { |
| Node* use = head->fast_out(j); |
| if (use->is_Phi()) old_phi_cnt++; |
| } |
| |
| #if !defined(PRODUCT) |
| if (TracePartialPeeling) { |
| tty->print_cr("\npeeled list"); |
| } |
| #endif |
| |
| // Evacuate nodes in peel region into the not_peeled region if possible |
| uint new_phi_cnt = 0; |
| uint cloned_for_outside_use = 0; |
| for (i = 0; i < peel_list.size();) { |
| Node* n = peel_list.at(i); |
| #if !defined(PRODUCT) |
| if (TracePartialPeeling) n->dump(); |
| #endif |
| bool incr = true; |
| if ( !n->is_CFG() ) { |
| |
| if ( has_use_in_set(n, not_peel) ) { |
| |
| // If not used internal to the peeled region, |
| // move "n" from peeled to not_peeled region. |
| |
| if ( !has_use_internal_to_set(n, peel, loop) ) { |
| |
| // if not pinned and not a load (which maybe anti-dependent on a store) |
| // and not a CMove (Matcher expects only bool->cmove). |
| if ( n->in(0) == NULL && !n->is_Load() && !n->is_CMove() ) { |
| cloned_for_outside_use += clone_for_use_outside_loop( loop, n, worklist ); |
| sink_list.push(n); |
| peel >>= n->_idx; // delete n from peel set. |
| not_peel <<= n->_idx; // add n to not_peel set. |
| peel_list.remove(i); |
| incr = false; |
| #if !defined(PRODUCT) |
| if (TracePartialPeeling) { |
| tty->print_cr("sink to not_peeled region: %d newbb: %d", |
| n->_idx, get_ctrl(n)->_idx); |
| } |
| #endif |
| } |
| } else { |
| // Otherwise check for special def-use cases that span |
| // the peel/not_peel boundary such as bool->if |
| clone_for_special_use_inside_loop( loop, n, not_peel, sink_list, worklist ); |
| new_phi_cnt++; |
| } |
| } |
| } |
| if (incr) i++; |
| } |
| |
| if (new_phi_cnt > old_phi_cnt + PartialPeelNewPhiDelta) { |
| #if !defined(PRODUCT) |
| if (TracePartialPeeling) { |
| tty->print_cr("\nToo many new phis: %d old %d new cmpi: %c", |
| new_phi_cnt, old_phi_cnt, new_peel_if != NULL?'T':'F'); |
| } |
| #endif |
| if (new_peel_if != NULL) { |
| remove_cmpi_loop_exit(new_peel_if, loop); |
| } |
| // Inhibit more partial peeling on this loop |
| assert(!head->is_partial_peel_loop(), "not partial peeled"); |
| head->mark_partial_peel_failed(); |
| if (cloned_for_outside_use > 0) { |
| // Terminate this round of loop opts because |
| // the graph outside this loop was changed. |
| C->set_major_progress(); |
| return true; |
| } |
| return false; |
| } |
| |
| // Step 3: clone loop, retarget control, and insert new phis |
| |
| // Create new loop head for new phis and to hang |
| // the nodes being moved (sinked) from the peel region. |
| LoopNode* new_head = new LoopNode(last_peel, last_peel); |
| new_head->set_unswitch_count(head->unswitch_count()); // Preserve |
| _igvn.register_new_node_with_optimizer(new_head); |
| assert(first_not_peeled->in(0) == last_peel, "last_peel <- first_not_peeled"); |
| _igvn.replace_input_of(first_not_peeled, 0, new_head); |
| set_loop(new_head, loop); |
| loop->_body.push(new_head); |
| not_peel.set(new_head->_idx); |
| set_idom(new_head, last_peel, dom_depth(first_not_peeled)); |
| set_idom(first_not_peeled, new_head, dom_depth(first_not_peeled)); |
| |
| while (sink_list.size() > 0) { |
| Node* n = sink_list.pop(); |
| set_ctrl(n, new_head); |
| } |
| |
| assert(is_valid_loop_partition(loop, peel, peel_list, not_peel), "bad partition"); |
| |
| clone_loop( loop, old_new, dd ); |
| |
| const uint clone_exit_idx = 1; |
| const uint orig_exit_idx = 2; |
| assert(is_valid_clone_loop_form( loop, peel_list, orig_exit_idx, clone_exit_idx ), "bad clone loop"); |
| |
| Node* head_clone = old_new[head->_idx]; |
| LoopNode* new_head_clone = old_new[new_head->_idx]->as_Loop(); |
| Node* orig_tail_clone = head_clone->in(2); |
| |
| // Add phi if "def" node is in peel set and "use" is not |
| |
| for(i = 0; i < peel_list.size(); i++ ) { |
| Node *def = peel_list.at(i); |
| if (!def->is_CFG()) { |
| for (DUIterator_Fast jmax, j = def->fast_outs(jmax); j < jmax; j++) { |
| Node *use = def->fast_out(j); |
| if (has_node(use) && use->in(0) != C->top() && |
| (!peel.test(use->_idx) || |
| (use->is_Phi() && use->in(0) == head)) ) { |
| worklist.push(use); |
| } |
| } |
| while( worklist.size() ) { |
| Node *use = worklist.pop(); |
| for (uint j = 1; j < use->req(); j++) { |
| Node* n = use->in(j); |
| if (n == def) { |
| |
| // "def" is in peel set, "use" is not in peel set |
| // or "use" is in the entry boundary (a phi) of the peel set |
| |
| Node* use_c = has_ctrl(use) ? get_ctrl(use) : use; |
| |
| if ( loop->is_member(get_loop( use_c )) ) { |
| // use is in loop |
| if (old_new[use->_idx] != NULL) { // null for dead code |
| Node* use_clone = old_new[use->_idx]; |
| _igvn.replace_input_of(use, j, C->top()); |
| insert_phi_for_loop( use_clone, j, old_new[def->_idx], def, new_head_clone ); |
| } |
| } else { |
| assert(is_valid_clone_loop_exit_use(loop, use, orig_exit_idx), "clone loop format"); |
| // use is not in the loop, check if the live range includes the cut |
| Node* lp_if = use_c->in(orig_exit_idx)->in(0); |
| if (not_peel.test(lp_if->_idx)) { |
| assert(j == orig_exit_idx, "use from original loop"); |
| insert_phi_for_loop( use, clone_exit_idx, old_new[def->_idx], def, new_head_clone ); |
| } |
| } |
| } |
| } |
| } |
| } |
| } |
| |
| // Step 3b: retarget control |
| |
| // Redirect control to the new loop head if a cloned node in |
| // the not_peeled region has control that points into the peeled region. |
| // This necessary because the cloned peeled region will be outside |
| // the loop. |
| // from to |
| // cloned-peeled <---+ |
| // new_head_clone: | <--+ |
| // cloned-not_peeled in(0) in(0) |
| // orig-peeled |
| |
| for(i = 0; i < loop->_body.size(); i++ ) { |
| Node *n = loop->_body.at(i); |
| if (!n->is_CFG() && n->in(0) != NULL && |
| not_peel.test(n->_idx) && peel.test(n->in(0)->_idx)) { |
| Node* n_clone = old_new[n->_idx]; |
| _igvn.replace_input_of(n_clone, 0, new_head_clone); |
| } |
| } |
| |
| // Backedge of the surviving new_head (the clone) is original last_peel |
| _igvn.replace_input_of(new_head_clone, LoopNode::LoopBackControl, last_peel); |
| |
| // Cut first node in original not_peel set |
| _igvn.rehash_node_delayed(new_head); // Multiple edge updates: |
| new_head->set_req(LoopNode::EntryControl, C->top()); // use rehash_node_delayed / set_req instead of |
| new_head->set_req(LoopNode::LoopBackControl, C->top()); // multiple replace_input_of calls |
| |
| // Copy head_clone back-branch info to original head |
| // and remove original head's loop entry and |
| // clone head's back-branch |
| _igvn.rehash_node_delayed(head); // Multiple edge updates |
| head->set_req(LoopNode::EntryControl, head_clone->in(LoopNode::LoopBackControl)); |
| head->set_req(LoopNode::LoopBackControl, C->top()); |
| _igvn.replace_input_of(head_clone, LoopNode::LoopBackControl, C->top()); |
| |
| // Similarly modify the phis |
| for (DUIterator_Fast kmax, k = head->fast_outs(kmax); k < kmax; k++) { |
| Node* use = head->fast_out(k); |
| if (use->is_Phi() && use->outcnt() > 0) { |
| Node* use_clone = old_new[use->_idx]; |
| _igvn.rehash_node_delayed(use); // Multiple edge updates |
| use->set_req(LoopNode::EntryControl, use_clone->in(LoopNode::LoopBackControl)); |
| use->set_req(LoopNode::LoopBackControl, C->top()); |
| _igvn.replace_input_of(use_clone, LoopNode::LoopBackControl, C->top()); |
| } |
| } |
| |
| // Step 4: update dominator tree and dominator depth |
| |
| set_idom(head, orig_tail_clone, dd); |
| recompute_dom_depth(); |
| |
| // Inhibit more partial peeling on this loop |
| new_head_clone->set_partial_peel_loop(); |
| C->set_major_progress(); |
| loop->record_for_igvn(); |
| |
| #if !defined(PRODUCT) |
| if (TracePartialPeeling) { |
| tty->print_cr("\nafter partial peel one iteration"); |
| Node_List wl(area); |
| Node* t = last_peel; |
| while (true) { |
| wl.push(t); |
| if (t == head_clone) break; |
| t = idom(t); |
| } |
| while (wl.size() > 0) { |
| Node* tt = wl.pop(); |
| if (tt == head) tty->print_cr("orig head"); |
| else if (tt == new_head_clone) tty->print_cr("new head"); |
| else if (tt == head_clone) tty->print_cr("clone head"); |
| tt->dump(); |
| } |
| } |
| #endif |
| return true; |
| } |
| |
| //------------------------------reorg_offsets---------------------------------- |
| // Reorganize offset computations to lower register pressure. Mostly |
| // prevent loop-fallout uses of the pre-incremented trip counter (which are |
| // then alive with the post-incremented trip counter forcing an extra |
| // register move) |
| void PhaseIdealLoop::reorg_offsets(IdealLoopTree *loop) { |
| // Perform it only for canonical counted loops. |
| // Loop's shape could be messed up by iteration_split_impl. |
| if (!loop->_head->is_CountedLoop()) |
| return; |
| if (!loop->_head->as_Loop()->is_valid_counted_loop()) |
| return; |
| |
| CountedLoopNode *cl = loop->_head->as_CountedLoop(); |
| CountedLoopEndNode *cle = cl->loopexit(); |
| Node *exit = cle->proj_out(false); |
| Node *phi = cl->phi(); |
| |
| // Check for the special case of folks using the pre-incremented |
| // trip-counter on the fall-out path (forces the pre-incremented |
| // and post-incremented trip counter to be live at the same time). |
| // Fix this by adjusting to use the post-increment trip counter. |
| |
| bool progress = true; |
| while (progress) { |
| progress = false; |
| for (DUIterator_Fast imax, i = phi->fast_outs(imax); i < imax; i++) { |
| Node* use = phi->fast_out(i); // User of trip-counter |
| if (!has_ctrl(use)) continue; |
| Node *u_ctrl = get_ctrl(use); |
| if (use->is_Phi()) { |
| u_ctrl = NULL; |
| for (uint j = 1; j < use->req(); j++) |
| if (use->in(j) == phi) |
| u_ctrl = dom_lca(u_ctrl, use->in(0)->in(j)); |
| } |
| IdealLoopTree *u_loop = get_loop(u_ctrl); |
| // Look for loop-invariant use |
| if (u_loop == loop) continue; |
| if (loop->is_member(u_loop)) continue; |
| // Check that use is live out the bottom. Assuming the trip-counter |
| // update is right at the bottom, uses of of the loop middle are ok. |
| if (dom_lca(exit, u_ctrl) != exit) continue; |
| // Hit! Refactor use to use the post-incremented tripcounter. |
| // Compute a post-increment tripcounter. |
| Node *opaq = new Opaque2Node( C, cle->incr() ); |
| register_new_node(opaq, exit); |
| Node *neg_stride = _igvn.intcon(-cle->stride_con()); |
| set_ctrl(neg_stride, C->root()); |
| Node *post = new AddINode( opaq, neg_stride); |
| register_new_node(post, exit); |
| _igvn.rehash_node_delayed(use); |
| for (uint j = 1; j < use->req(); j++) { |
| if (use->in(j) == phi) |
| use->set_req(j, post); |
| } |
| // Since DU info changed, rerun loop |
| progress = true; |
| break; |
| } |
| } |
| |
| } |