| /* |
| * Copyright (c) 1997, 2015, 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 "classfile/systemDictionary.hpp" |
| #include "memory/allocation.inline.hpp" |
| #include "oops/objArrayKlass.hpp" |
| #include "opto/addnode.hpp" |
| #include "opto/castnode.hpp" |
| #include "opto/cfgnode.hpp" |
| #include "opto/connode.hpp" |
| #include "opto/convertnode.hpp" |
| #include "opto/loopnode.hpp" |
| #include "opto/machnode.hpp" |
| #include "opto/movenode.hpp" |
| #include "opto/narrowptrnode.hpp" |
| #include "opto/mulnode.hpp" |
| #include "opto/phaseX.hpp" |
| #include "opto/regmask.hpp" |
| #include "opto/runtime.hpp" |
| #include "opto/subnode.hpp" |
| |
| // Portions of code courtesy of Clifford Click |
| |
| // Optimization - Graph Style |
| |
| //============================================================================= |
| //------------------------------Value------------------------------------------ |
| // Compute the type of the RegionNode. |
| const Type* RegionNode::Value(PhaseGVN* phase) const { |
| for( uint i=1; i<req(); ++i ) { // For all paths in |
| Node *n = in(i); // Get Control source |
| if( !n ) continue; // Missing inputs are TOP |
| if( phase->type(n) == Type::CONTROL ) |
| return Type::CONTROL; |
| } |
| return Type::TOP; // All paths dead? Then so are we |
| } |
| |
| //------------------------------Identity--------------------------------------- |
| // Check for Region being Identity. |
| Node* RegionNode::Identity(PhaseGVN* phase) { |
| // Cannot have Region be an identity, even if it has only 1 input. |
| // Phi users cannot have their Region input folded away for them, |
| // since they need to select the proper data input |
| return this; |
| } |
| |
| //------------------------------merge_region----------------------------------- |
| // If a Region flows into a Region, merge into one big happy merge. This is |
| // hard to do if there is stuff that has to happen |
| static Node *merge_region(RegionNode *region, PhaseGVN *phase) { |
| if( region->Opcode() != Op_Region ) // Do not do to LoopNodes |
| return NULL; |
| Node *progress = NULL; // Progress flag |
| PhaseIterGVN *igvn = phase->is_IterGVN(); |
| |
| uint rreq = region->req(); |
| for( uint i = 1; i < rreq; i++ ) { |
| Node *r = region->in(i); |
| if( r && r->Opcode() == Op_Region && // Found a region? |
| r->in(0) == r && // Not already collapsed? |
| r != region && // Avoid stupid situations |
| r->outcnt() == 2 ) { // Self user and 'region' user only? |
| assert(!r->as_Region()->has_phi(), "no phi users"); |
| if( !progress ) { // No progress |
| if (region->has_phi()) { |
| return NULL; // Only flatten if no Phi users |
| // igvn->hash_delete( phi ); |
| } |
| igvn->hash_delete( region ); |
| progress = region; // Making progress |
| } |
| igvn->hash_delete( r ); |
| |
| // Append inputs to 'r' onto 'region' |
| for( uint j = 1; j < r->req(); j++ ) { |
| // Move an input from 'r' to 'region' |
| region->add_req(r->in(j)); |
| r->set_req(j, phase->C->top()); |
| // Update phis of 'region' |
| //for( uint k = 0; k < max; k++ ) { |
| // Node *phi = region->out(k); |
| // if( phi->is_Phi() ) { |
| // phi->add_req(phi->in(i)); |
| // } |
| //} |
| |
| rreq++; // One more input to Region |
| } // Found a region to merge into Region |
| igvn->_worklist.push(r); |
| // Clobber pointer to the now dead 'r' |
| region->set_req(i, phase->C->top()); |
| } |
| } |
| |
| return progress; |
| } |
| |
| |
| |
| //--------------------------------has_phi-------------------------------------- |
| // Helper function: Return any PhiNode that uses this region or NULL |
| PhiNode* RegionNode::has_phi() const { |
| for (DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++) { |
| Node* phi = fast_out(i); |
| if (phi->is_Phi()) { // Check for Phi users |
| assert(phi->in(0) == (Node*)this, "phi uses region only via in(0)"); |
| return phi->as_Phi(); // this one is good enough |
| } |
| } |
| |
| return NULL; |
| } |
| |
| |
| //-----------------------------has_unique_phi---------------------------------- |
| // Helper function: Return the only PhiNode that uses this region or NULL |
| PhiNode* RegionNode::has_unique_phi() const { |
| // Check that only one use is a Phi |
| PhiNode* only_phi = NULL; |
| for (DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++) { |
| Node* phi = fast_out(i); |
| if (phi->is_Phi()) { // Check for Phi users |
| assert(phi->in(0) == (Node*)this, "phi uses region only via in(0)"); |
| if (only_phi == NULL) { |
| only_phi = phi->as_Phi(); |
| } else { |
| return NULL; // multiple phis |
| } |
| } |
| } |
| |
| return only_phi; |
| } |
| |
| |
| //------------------------------check_phi_clipping----------------------------- |
| // Helper function for RegionNode's identification of FP clipping |
| // Check inputs to the Phi |
| static bool check_phi_clipping( PhiNode *phi, ConNode * &min, uint &min_idx, ConNode * &max, uint &max_idx, Node * &val, uint &val_idx ) { |
| min = NULL; |
| max = NULL; |
| val = NULL; |
| min_idx = 0; |
| max_idx = 0; |
| val_idx = 0; |
| uint phi_max = phi->req(); |
| if( phi_max == 4 ) { |
| for( uint j = 1; j < phi_max; ++j ) { |
| Node *n = phi->in(j); |
| int opcode = n->Opcode(); |
| switch( opcode ) { |
| case Op_ConI: |
| { |
| if( min == NULL ) { |
| min = n->Opcode() == Op_ConI ? (ConNode*)n : NULL; |
| min_idx = j; |
| } else { |
| max = n->Opcode() == Op_ConI ? (ConNode*)n : NULL; |
| max_idx = j; |
| if( min->get_int() > max->get_int() ) { |
| // Swap min and max |
| ConNode *temp; |
| uint temp_idx; |
| temp = min; min = max; max = temp; |
| temp_idx = min_idx; min_idx = max_idx; max_idx = temp_idx; |
| } |
| } |
| } |
| break; |
| default: |
| { |
| val = n; |
| val_idx = j; |
| } |
| break; |
| } |
| } |
| } |
| return ( min && max && val && (min->get_int() <= 0) && (max->get_int() >=0) ); |
| } |
| |
| |
| //------------------------------check_if_clipping------------------------------ |
| // Helper function for RegionNode's identification of FP clipping |
| // Check that inputs to Region come from two IfNodes, |
| // |
| // If |
| // False True |
| // If | |
| // False True | |
| // | | | |
| // RegionNode_inputs |
| // |
| static bool check_if_clipping( const RegionNode *region, IfNode * &bot_if, IfNode * &top_if ) { |
| top_if = NULL; |
| bot_if = NULL; |
| |
| // Check control structure above RegionNode for (if ( if ) ) |
| Node *in1 = region->in(1); |
| Node *in2 = region->in(2); |
| Node *in3 = region->in(3); |
| // Check that all inputs are projections |
| if( in1->is_Proj() && in2->is_Proj() && in3->is_Proj() ) { |
| Node *in10 = in1->in(0); |
| Node *in20 = in2->in(0); |
| Node *in30 = in3->in(0); |
| // Check that #1 and #2 are ifTrue and ifFalse from same If |
| if( in10 != NULL && in10->is_If() && |
| in20 != NULL && in20->is_If() && |
| in30 != NULL && in30->is_If() && in10 == in20 && |
| (in1->Opcode() != in2->Opcode()) ) { |
| Node *in100 = in10->in(0); |
| Node *in1000 = (in100 != NULL && in100->is_Proj()) ? in100->in(0) : NULL; |
| // Check that control for in10 comes from other branch of IF from in3 |
| if( in1000 != NULL && in1000->is_If() && |
| in30 == in1000 && (in3->Opcode() != in100->Opcode()) ) { |
| // Control pattern checks |
| top_if = (IfNode*)in1000; |
| bot_if = (IfNode*)in10; |
| } |
| } |
| } |
| |
| return (top_if != NULL); |
| } |
| |
| |
| //------------------------------check_convf2i_clipping------------------------- |
| // Helper function for RegionNode's identification of FP clipping |
| // Verify that the value input to the phi comes from "ConvF2I; LShift; RShift" |
| static bool check_convf2i_clipping( PhiNode *phi, uint idx, ConvF2INode * &convf2i, Node *min, Node *max) { |
| convf2i = NULL; |
| |
| // Check for the RShiftNode |
| Node *rshift = phi->in(idx); |
| assert( rshift, "Previous checks ensure phi input is present"); |
| if( rshift->Opcode() != Op_RShiftI ) { return false; } |
| |
| // Check for the LShiftNode |
| Node *lshift = rshift->in(1); |
| assert( lshift, "Previous checks ensure phi input is present"); |
| if( lshift->Opcode() != Op_LShiftI ) { return false; } |
| |
| // Check for the ConvF2INode |
| Node *conv = lshift->in(1); |
| if( conv->Opcode() != Op_ConvF2I ) { return false; } |
| |
| // Check that shift amounts are only to get sign bits set after F2I |
| jint max_cutoff = max->get_int(); |
| jint min_cutoff = min->get_int(); |
| jint left_shift = lshift->in(2)->get_int(); |
| jint right_shift = rshift->in(2)->get_int(); |
| jint max_post_shift = nth_bit(BitsPerJavaInteger - left_shift - 1); |
| if( left_shift != right_shift || |
| 0 > left_shift || left_shift >= BitsPerJavaInteger || |
| max_post_shift < max_cutoff || |
| max_post_shift < -min_cutoff ) { |
| // Shifts are necessary but current transformation eliminates them |
| return false; |
| } |
| |
| // OK to return the result of ConvF2I without shifting |
| convf2i = (ConvF2INode*)conv; |
| return true; |
| } |
| |
| |
| //------------------------------check_compare_clipping------------------------- |
| // Helper function for RegionNode's identification of FP clipping |
| static bool check_compare_clipping( bool less_than, IfNode *iff, ConNode *limit, Node * & input ) { |
| Node *i1 = iff->in(1); |
| if ( !i1->is_Bool() ) { return false; } |
| BoolNode *bool1 = i1->as_Bool(); |
| if( less_than && bool1->_test._test != BoolTest::le ) { return false; } |
| else if( !less_than && bool1->_test._test != BoolTest::lt ) { return false; } |
| const Node *cmpF = bool1->in(1); |
| if( cmpF->Opcode() != Op_CmpF ) { return false; } |
| // Test that the float value being compared against |
| // is equivalent to the int value used as a limit |
| Node *nodef = cmpF->in(2); |
| if( nodef->Opcode() != Op_ConF ) { return false; } |
| jfloat conf = nodef->getf(); |
| jint coni = limit->get_int(); |
| if( ((int)conf) != coni ) { return false; } |
| input = cmpF->in(1); |
| return true; |
| } |
| |
| //------------------------------is_unreachable_region-------------------------- |
| // Find if the Region node is reachable from the root. |
| bool RegionNode::is_unreachable_region(PhaseGVN *phase) const { |
| assert(req() == 2, ""); |
| |
| // First, cut the simple case of fallthrough region when NONE of |
| // region's phis references itself directly or through a data node. |
| uint max = outcnt(); |
| uint i; |
| for (i = 0; i < max; i++) { |
| Node* phi = raw_out(i); |
| if (phi != NULL && phi->is_Phi()) { |
| assert(phase->eqv(phi->in(0), this) && phi->req() == 2, ""); |
| if (phi->outcnt() == 0) |
| continue; // Safe case - no loops |
| if (phi->outcnt() == 1) { |
| Node* u = phi->raw_out(0); |
| // Skip if only one use is an other Phi or Call or Uncommon trap. |
| // It is safe to consider this case as fallthrough. |
| if (u != NULL && (u->is_Phi() || u->is_CFG())) |
| continue; |
| } |
| // Check when phi references itself directly or through an other node. |
| if (phi->as_Phi()->simple_data_loop_check(phi->in(1)) >= PhiNode::Unsafe) |
| break; // Found possible unsafe data loop. |
| } |
| } |
| if (i >= max) |
| return false; // An unsafe case was NOT found - don't need graph walk. |
| |
| // Unsafe case - check if the Region node is reachable from root. |
| ResourceMark rm; |
| |
| Arena *a = Thread::current()->resource_area(); |
| Node_List nstack(a); |
| VectorSet visited(a); |
| |
| // Mark all control nodes reachable from root outputs |
| Node *n = (Node*)phase->C->root(); |
| nstack.push(n); |
| visited.set(n->_idx); |
| while (nstack.size() != 0) { |
| n = nstack.pop(); |
| uint max = n->outcnt(); |
| for (uint i = 0; i < max; i++) { |
| Node* m = n->raw_out(i); |
| if (m != NULL && m->is_CFG()) { |
| if (phase->eqv(m, this)) { |
| return false; // We reached the Region node - it is not dead. |
| } |
| if (!visited.test_set(m->_idx)) |
| nstack.push(m); |
| } |
| } |
| } |
| |
| return true; // The Region node is unreachable - it is dead. |
| } |
| |
| bool RegionNode::try_clean_mem_phi(PhaseGVN *phase) { |
| // Incremental inlining + PhaseStringOpts sometimes produce: |
| // |
| // cmpP with 1 top input |
| // | |
| // If |
| // / \ |
| // IfFalse IfTrue /- Some Node |
| // \ / / / |
| // Region / /-MergeMem |
| // \---Phi |
| // |
| // |
| // It's expected by PhaseStringOpts that the Region goes away and is |
| // replaced by If's control input but because there's still a Phi, |
| // the Region stays in the graph. The top input from the cmpP is |
| // propagated forward and a subgraph that is useful goes away. The |
| // code below replaces the Phi with the MergeMem so that the Region |
| // is simplified. |
| |
| PhiNode* phi = has_unique_phi(); |
| if (phi && phi->type() == Type::MEMORY && req() == 3 && phi->is_diamond_phi(true)) { |
| MergeMemNode* m = NULL; |
| assert(phi->req() == 3, "same as region"); |
| for (uint i = 1; i < 3; ++i) { |
| Node *mem = phi->in(i); |
| if (mem && mem->is_MergeMem() && in(i)->outcnt() == 1) { |
| // Nothing is control-dependent on path #i except the region itself. |
| m = mem->as_MergeMem(); |
| uint j = 3 - i; |
| Node* other = phi->in(j); |
| if (other && other == m->base_memory()) { |
| // m is a successor memory to other, and is not pinned inside the diamond, so push it out. |
| // This will allow the diamond to collapse completely. |
| phase->is_IterGVN()->replace_node(phi, m); |
| return true; |
| } |
| } |
| } |
| } |
| return false; |
| } |
| |
| //------------------------------Ideal------------------------------------------ |
| // Return a node which is more "ideal" than the current node. Must preserve |
| // the CFG, but we can still strip out dead paths. |
| Node *RegionNode::Ideal(PhaseGVN *phase, bool can_reshape) { |
| if( !can_reshape && !in(0) ) return NULL; // Already degraded to a Copy |
| assert(!in(0) || !in(0)->is_Root(), "not a specially hidden merge"); |
| |
| // Check for RegionNode with no Phi users and both inputs come from either |
| // arm of the same IF. If found, then the control-flow split is useless. |
| bool has_phis = false; |
| if (can_reshape) { // Need DU info to check for Phi users |
| has_phis = (has_phi() != NULL); // Cache result |
| if (has_phis && try_clean_mem_phi(phase)) { |
| has_phis = false; |
| } |
| |
| if (!has_phis) { // No Phi users? Nothing merging? |
| for (uint i = 1; i < req()-1; i++) { |
| Node *if1 = in(i); |
| if( !if1 ) continue; |
| Node *iff = if1->in(0); |
| if( !iff || !iff->is_If() ) continue; |
| for( uint j=i+1; j<req(); j++ ) { |
| if( in(j) && in(j)->in(0) == iff && |
| if1->Opcode() != in(j)->Opcode() ) { |
| // Add the IF Projections to the worklist. They (and the IF itself) |
| // will be eliminated if dead. |
| phase->is_IterGVN()->add_users_to_worklist(iff); |
| set_req(i, iff->in(0));// Skip around the useless IF diamond |
| set_req(j, NULL); |
| return this; // Record progress |
| } |
| } |
| } |
| } |
| } |
| |
| // Remove TOP or NULL input paths. If only 1 input path remains, this Region |
| // degrades to a copy. |
| bool add_to_worklist = false; |
| bool modified = false; |
| int cnt = 0; // Count of values merging |
| DEBUG_ONLY( int cnt_orig = req(); ) // Save original inputs count |
| int del_it = 0; // The last input path we delete |
| // For all inputs... |
| for( uint i=1; i<req(); ++i ){// For all paths in |
| Node *n = in(i); // Get the input |
| if( n != NULL ) { |
| // Remove useless control copy inputs |
| if( n->is_Region() && n->as_Region()->is_copy() ) { |
| set_req(i, n->nonnull_req()); |
| modified = true; |
| i--; |
| continue; |
| } |
| if( n->is_Proj() ) { // Remove useless rethrows |
| Node *call = n->in(0); |
| if (call->is_Call() && call->as_Call()->entry_point() == OptoRuntime::rethrow_stub()) { |
| set_req(i, call->in(0)); |
| modified = true; |
| i--; |
| continue; |
| } |
| } |
| if( phase->type(n) == Type::TOP ) { |
| set_req(i, NULL); // Ignore TOP inputs |
| modified = true; |
| i--; |
| continue; |
| } |
| cnt++; // One more value merging |
| |
| } else if (can_reshape) { // Else found dead path with DU info |
| PhaseIterGVN *igvn = phase->is_IterGVN(); |
| del_req(i); // Yank path from self |
| del_it = i; |
| uint max = outcnt(); |
| DUIterator j; |
| bool progress = true; |
| while(progress) { // Need to establish property over all users |
| progress = false; |
| for (j = outs(); has_out(j); j++) { |
| Node *n = out(j); |
| if( n->req() != req() && n->is_Phi() ) { |
| assert( n->in(0) == this, "" ); |
| igvn->hash_delete(n); // Yank from hash before hacking edges |
| n->set_req_X(i,NULL,igvn);// Correct DU info |
| n->del_req(i); // Yank path from Phis |
| if( max != outcnt() ) { |
| progress = true; |
| j = refresh_out_pos(j); |
| max = outcnt(); |
| } |
| } |
| } |
| } |
| add_to_worklist = true; |
| i--; |
| } |
| } |
| |
| if (can_reshape && cnt == 1) { |
| // Is it dead loop? |
| // If it is LoopNopde it had 2 (+1 itself) inputs and |
| // one of them was cut. The loop is dead if it was EntryContol. |
| // Loop node may have only one input because entry path |
| // is removed in PhaseIdealLoop::Dominators(). |
| assert(!this->is_Loop() || cnt_orig <= 3, "Loop node should have 3 or less inputs"); |
| if (this->is_Loop() && (del_it == LoopNode::EntryControl || |
| del_it == 0 && is_unreachable_region(phase)) || |
| !this->is_Loop() && has_phis && is_unreachable_region(phase)) { |
| // Yes, the region will be removed during the next step below. |
| // Cut the backedge input and remove phis since no data paths left. |
| // We don't cut outputs to other nodes here since we need to put them |
| // on the worklist. |
| PhaseIterGVN *igvn = phase->is_IterGVN(); |
| if (in(1)->outcnt() == 1) { |
| igvn->_worklist.push(in(1)); |
| } |
| del_req(1); |
| cnt = 0; |
| assert( req() == 1, "no more inputs expected" ); |
| uint max = outcnt(); |
| bool progress = true; |
| Node *top = phase->C->top(); |
| DUIterator j; |
| while(progress) { |
| progress = false; |
| for (j = outs(); has_out(j); j++) { |
| Node *n = out(j); |
| if( n->is_Phi() ) { |
| assert( igvn->eqv(n->in(0), this), "" ); |
| assert( n->req() == 2 && n->in(1) != NULL, "Only one data input expected" ); |
| // Break dead loop data path. |
| // Eagerly replace phis with top to avoid phis copies generation. |
| igvn->replace_node(n, top); |
| if( max != outcnt() ) { |
| progress = true; |
| j = refresh_out_pos(j); |
| max = outcnt(); |
| } |
| } |
| } |
| } |
| add_to_worklist = true; |
| } |
| } |
| if (add_to_worklist) { |
| phase->is_IterGVN()->add_users_to_worklist(this); // Revisit collapsed Phis |
| } |
| |
| if( cnt <= 1 ) { // Only 1 path in? |
| set_req(0, NULL); // Null control input for region copy |
| if( cnt == 0 && !can_reshape) { // Parse phase - leave the node as it is. |
| // No inputs or all inputs are NULL. |
| return NULL; |
| } else if (can_reshape) { // Optimization phase - remove the node |
| PhaseIterGVN *igvn = phase->is_IterGVN(); |
| Node *parent_ctrl; |
| if( cnt == 0 ) { |
| assert( req() == 1, "no inputs expected" ); |
| // During IGVN phase such region will be subsumed by TOP node |
| // so region's phis will have TOP as control node. |
| // Kill phis here to avoid it. PhiNode::is_copy() will be always false. |
| // Also set other user's input to top. |
| parent_ctrl = phase->C->top(); |
| } else { |
| // The fallthrough case since we already checked dead loops above. |
| parent_ctrl = in(1); |
| assert(parent_ctrl != NULL, "Region is a copy of some non-null control"); |
| assert(!igvn->eqv(parent_ctrl, this), "Close dead loop"); |
| } |
| if (!add_to_worklist) |
| igvn->add_users_to_worklist(this); // Check for further allowed opts |
| for (DUIterator_Last imin, i = last_outs(imin); i >= imin; --i) { |
| Node* n = last_out(i); |
| igvn->hash_delete(n); // Remove from worklist before modifying edges |
| if( n->is_Phi() ) { // Collapse all Phis |
| // Eagerly replace phis to avoid copies generation. |
| Node* in; |
| if( cnt == 0 ) { |
| assert( n->req() == 1, "No data inputs expected" ); |
| in = parent_ctrl; // replaced by top |
| } else { |
| assert( n->req() == 2 && n->in(1) != NULL, "Only one data input expected" ); |
| in = n->in(1); // replaced by unique input |
| if( n->as_Phi()->is_unsafe_data_reference(in) ) |
| in = phase->C->top(); // replaced by top |
| } |
| igvn->replace_node(n, in); |
| } |
| else if( n->is_Region() ) { // Update all incoming edges |
| assert( !igvn->eqv(n, this), "Must be removed from DefUse edges"); |
| uint uses_found = 0; |
| for( uint k=1; k < n->req(); k++ ) { |
| if( n->in(k) == this ) { |
| n->set_req(k, parent_ctrl); |
| uses_found++; |
| } |
| } |
| if( uses_found > 1 ) { // (--i) done at the end of the loop. |
| i -= (uses_found - 1); |
| } |
| } |
| else { |
| assert( igvn->eqv(n->in(0), this), "Expect RegionNode to be control parent"); |
| n->set_req(0, parent_ctrl); |
| } |
| #ifdef ASSERT |
| for( uint k=0; k < n->req(); k++ ) { |
| assert( !igvn->eqv(n->in(k), this), "All uses of RegionNode should be gone"); |
| } |
| #endif |
| } |
| // Remove the RegionNode itself from DefUse info |
| igvn->remove_dead_node(this); |
| return NULL; |
| } |
| return this; // Record progress |
| } |
| |
| |
| // If a Region flows into a Region, merge into one big happy merge. |
| if (can_reshape) { |
| Node *m = merge_region(this, phase); |
| if (m != NULL) return m; |
| } |
| |
| // Check if this region is the root of a clipping idiom on floats |
| if( ConvertFloat2IntClipping && can_reshape && req() == 4 ) { |
| // Check that only one use is a Phi and that it simplifies to two constants + |
| PhiNode* phi = has_unique_phi(); |
| if (phi != NULL) { // One Phi user |
| // Check inputs to the Phi |
| ConNode *min; |
| ConNode *max; |
| Node *val; |
| uint min_idx; |
| uint max_idx; |
| uint val_idx; |
| if( check_phi_clipping( phi, min, min_idx, max, max_idx, val, val_idx ) ) { |
| IfNode *top_if; |
| IfNode *bot_if; |
| if( check_if_clipping( this, bot_if, top_if ) ) { |
| // Control pattern checks, now verify compares |
| Node *top_in = NULL; // value being compared against |
| Node *bot_in = NULL; |
| if( check_compare_clipping( true, bot_if, min, bot_in ) && |
| check_compare_clipping( false, top_if, max, top_in ) ) { |
| if( bot_in == top_in ) { |
| PhaseIterGVN *gvn = phase->is_IterGVN(); |
| assert( gvn != NULL, "Only had DefUse info in IterGVN"); |
| // Only remaining check is that bot_in == top_in == (Phi's val + mods) |
| |
| // Check for the ConvF2INode |
| ConvF2INode *convf2i; |
| if( check_convf2i_clipping( phi, val_idx, convf2i, min, max ) && |
| convf2i->in(1) == bot_in ) { |
| // Matched pattern, including LShiftI; RShiftI, replace with integer compares |
| // max test |
| Node *cmp = gvn->register_new_node_with_optimizer(new CmpINode( convf2i, min )); |
| Node *boo = gvn->register_new_node_with_optimizer(new BoolNode( cmp, BoolTest::lt )); |
| IfNode *iff = (IfNode*)gvn->register_new_node_with_optimizer(new IfNode( top_if->in(0), boo, PROB_UNLIKELY_MAG(5), top_if->_fcnt )); |
| Node *if_min= gvn->register_new_node_with_optimizer(new IfTrueNode (iff)); |
| Node *ifF = gvn->register_new_node_with_optimizer(new IfFalseNode(iff)); |
| // min test |
| cmp = gvn->register_new_node_with_optimizer(new CmpINode( convf2i, max )); |
| boo = gvn->register_new_node_with_optimizer(new BoolNode( cmp, BoolTest::gt )); |
| iff = (IfNode*)gvn->register_new_node_with_optimizer(new IfNode( ifF, boo, PROB_UNLIKELY_MAG(5), bot_if->_fcnt )); |
| Node *if_max= gvn->register_new_node_with_optimizer(new IfTrueNode (iff)); |
| ifF = gvn->register_new_node_with_optimizer(new IfFalseNode(iff)); |
| // update input edges to region node |
| set_req_X( min_idx, if_min, gvn ); |
| set_req_X( max_idx, if_max, gvn ); |
| set_req_X( val_idx, ifF, gvn ); |
| // remove unnecessary 'LShiftI; RShiftI' idiom |
| gvn->hash_delete(phi); |
| phi->set_req_X( val_idx, convf2i, gvn ); |
| gvn->hash_find_insert(phi); |
| // Return transformed region node |
| return this; |
| } |
| } |
| } |
| } |
| } |
| } |
| } |
| |
| return modified ? this : NULL; |
| } |
| |
| |
| |
| const RegMask &RegionNode::out_RegMask() const { |
| return RegMask::Empty; |
| } |
| |
| // Find the one non-null required input. RegionNode only |
| Node *Node::nonnull_req() const { |
| assert( is_Region(), "" ); |
| for( uint i = 1; i < _cnt; i++ ) |
| if( in(i) ) |
| return in(i); |
| ShouldNotReachHere(); |
| return NULL; |
| } |
| |
| |
| //============================================================================= |
| // note that these functions assume that the _adr_type field is flattened |
| uint PhiNode::hash() const { |
| const Type* at = _adr_type; |
| return TypeNode::hash() + (at ? at->hash() : 0); |
| } |
| uint PhiNode::cmp( const Node &n ) const { |
| return TypeNode::cmp(n) && _adr_type == ((PhiNode&)n)._adr_type; |
| } |
| static inline |
| const TypePtr* flatten_phi_adr_type(const TypePtr* at) { |
| if (at == NULL || at == TypePtr::BOTTOM) return at; |
| return Compile::current()->alias_type(at)->adr_type(); |
| } |
| |
| //----------------------------make--------------------------------------------- |
| // create a new phi with edges matching r and set (initially) to x |
| PhiNode* PhiNode::make(Node* r, Node* x, const Type *t, const TypePtr* at) { |
| uint preds = r->req(); // Number of predecessor paths |
| assert(t != Type::MEMORY || at == flatten_phi_adr_type(at), "flatten at"); |
| PhiNode* p = new PhiNode(r, t, at); |
| for (uint j = 1; j < preds; j++) { |
| // Fill in all inputs, except those which the region does not yet have |
| if (r->in(j) != NULL) |
| p->init_req(j, x); |
| } |
| return p; |
| } |
| PhiNode* PhiNode::make(Node* r, Node* x) { |
| const Type* t = x->bottom_type(); |
| const TypePtr* at = NULL; |
| if (t == Type::MEMORY) at = flatten_phi_adr_type(x->adr_type()); |
| return make(r, x, t, at); |
| } |
| PhiNode* PhiNode::make_blank(Node* r, Node* x) { |
| const Type* t = x->bottom_type(); |
| const TypePtr* at = NULL; |
| if (t == Type::MEMORY) at = flatten_phi_adr_type(x->adr_type()); |
| return new PhiNode(r, t, at); |
| } |
| |
| |
| //------------------------slice_memory----------------------------------------- |
| // create a new phi with narrowed memory type |
| PhiNode* PhiNode::slice_memory(const TypePtr* adr_type) const { |
| PhiNode* mem = (PhiNode*) clone(); |
| *(const TypePtr**)&mem->_adr_type = adr_type; |
| // convert self-loops, or else we get a bad graph |
| for (uint i = 1; i < req(); i++) { |
| if ((const Node*)in(i) == this) mem->set_req(i, mem); |
| } |
| mem->verify_adr_type(); |
| return mem; |
| } |
| |
| //------------------------split_out_instance----------------------------------- |
| // Split out an instance type from a bottom phi. |
| PhiNode* PhiNode::split_out_instance(const TypePtr* at, PhaseIterGVN *igvn) const { |
| const TypeOopPtr *t_oop = at->isa_oopptr(); |
| assert(t_oop != NULL && t_oop->is_known_instance(), "expecting instance oopptr"); |
| const TypePtr *t = adr_type(); |
| assert(type() == Type::MEMORY && |
| (t == TypePtr::BOTTOM || t == TypeRawPtr::BOTTOM || |
| t->isa_oopptr() && !t->is_oopptr()->is_known_instance() && |
| t->is_oopptr()->cast_to_exactness(true) |
| ->is_oopptr()->cast_to_ptr_type(t_oop->ptr()) |
| ->is_oopptr()->cast_to_instance_id(t_oop->instance_id()) == t_oop), |
| "bottom or raw memory required"); |
| |
| // Check if an appropriate node already exists. |
| Node *region = in(0); |
| for (DUIterator_Fast kmax, k = region->fast_outs(kmax); k < kmax; k++) { |
| Node* use = region->fast_out(k); |
| if( use->is_Phi()) { |
| PhiNode *phi2 = use->as_Phi(); |
| if (phi2->type() == Type::MEMORY && phi2->adr_type() == at) { |
| return phi2; |
| } |
| } |
| } |
| Compile *C = igvn->C; |
| Arena *a = Thread::current()->resource_area(); |
| Node_Array node_map = new Node_Array(a); |
| Node_Stack stack(a, C->live_nodes() >> 4); |
| PhiNode *nphi = slice_memory(at); |
| igvn->register_new_node_with_optimizer( nphi ); |
| node_map.map(_idx, nphi); |
| stack.push((Node *)this, 1); |
| while(!stack.is_empty()) { |
| PhiNode *ophi = stack.node()->as_Phi(); |
| uint i = stack.index(); |
| assert(i >= 1, "not control edge"); |
| stack.pop(); |
| nphi = node_map[ophi->_idx]->as_Phi(); |
| for (; i < ophi->req(); i++) { |
| Node *in = ophi->in(i); |
| if (in == NULL || igvn->type(in) == Type::TOP) |
| continue; |
| Node *opt = MemNode::optimize_simple_memory_chain(in, t_oop, NULL, igvn); |
| PhiNode *optphi = opt->is_Phi() ? opt->as_Phi() : NULL; |
| if (optphi != NULL && optphi->adr_type() == TypePtr::BOTTOM) { |
| opt = node_map[optphi->_idx]; |
| if (opt == NULL) { |
| stack.push(ophi, i); |
| nphi = optphi->slice_memory(at); |
| igvn->register_new_node_with_optimizer( nphi ); |
| node_map.map(optphi->_idx, nphi); |
| ophi = optphi; |
| i = 0; // will get incremented at top of loop |
| continue; |
| } |
| } |
| nphi->set_req(i, opt); |
| } |
| } |
| return nphi; |
| } |
| |
| //------------------------verify_adr_type-------------------------------------- |
| #ifdef ASSERT |
| void PhiNode::verify_adr_type(VectorSet& visited, const TypePtr* at) const { |
| if (visited.test_set(_idx)) return; //already visited |
| |
| // recheck constructor invariants: |
| verify_adr_type(false); |
| |
| // recheck local phi/phi consistency: |
| assert(_adr_type == at || _adr_type == TypePtr::BOTTOM, |
| "adr_type must be consistent across phi nest"); |
| |
| // walk around |
| for (uint i = 1; i < req(); i++) { |
| Node* n = in(i); |
| if (n == NULL) continue; |
| const Node* np = in(i); |
| if (np->is_Phi()) { |
| np->as_Phi()->verify_adr_type(visited, at); |
| } else if (n->bottom_type() == Type::TOP |
| || (n->is_Mem() && n->in(MemNode::Address)->bottom_type() == Type::TOP)) { |
| // ignore top inputs |
| } else { |
| const TypePtr* nat = flatten_phi_adr_type(n->adr_type()); |
| // recheck phi/non-phi consistency at leaves: |
| assert((nat != NULL) == (at != NULL), ""); |
| assert(nat == at || nat == TypePtr::BOTTOM, |
| "adr_type must be consistent at leaves of phi nest"); |
| } |
| } |
| } |
| |
| // Verify a whole nest of phis rooted at this one. |
| void PhiNode::verify_adr_type(bool recursive) const { |
| if (is_error_reported()) return; // muzzle asserts when debugging an error |
| if (Node::in_dump()) return; // muzzle asserts when printing |
| |
| assert((_type == Type::MEMORY) == (_adr_type != NULL), "adr_type for memory phis only"); |
| |
| if (!VerifyAliases) return; // verify thoroughly only if requested |
| |
| assert(_adr_type == flatten_phi_adr_type(_adr_type), |
| "Phi::adr_type must be pre-normalized"); |
| |
| if (recursive) { |
| VectorSet visited(Thread::current()->resource_area()); |
| verify_adr_type(visited, _adr_type); |
| } |
| } |
| #endif |
| |
| |
| //------------------------------Value------------------------------------------ |
| // Compute the type of the PhiNode |
| const Type* PhiNode::Value(PhaseGVN* phase) const { |
| Node *r = in(0); // RegionNode |
| if( !r ) // Copy or dead |
| return in(1) ? phase->type(in(1)) : Type::TOP; |
| |
| // Note: During parsing, phis are often transformed before their regions. |
| // This means we have to use type_or_null to defend against untyped regions. |
| if( phase->type_or_null(r) == Type::TOP ) // Dead code? |
| return Type::TOP; |
| |
| // Check for trip-counted loop. If so, be smarter. |
| CountedLoopNode* l = r->is_CountedLoop() ? r->as_CountedLoop() : NULL; |
| if (l && ((const Node*)l->phi() == this)) { // Trip counted loop! |
| // protect against init_trip() or limit() returning NULL |
| if (l->can_be_counted_loop(phase)) { |
| const Node *init = l->init_trip(); |
| const Node *limit = l->limit(); |
| const Node* stride = l->stride(); |
| if (init != NULL && limit != NULL && stride != NULL) { |
| const TypeInt* lo = phase->type(init)->isa_int(); |
| const TypeInt* hi = phase->type(limit)->isa_int(); |
| const TypeInt* stride_t = phase->type(stride)->isa_int(); |
| if (lo != NULL && hi != NULL && stride_t != NULL) { // Dying loops might have TOP here |
| assert(stride_t->_hi >= stride_t->_lo, "bad stride type"); |
| if (stride_t->_hi < 0) { // Down-counter loop |
| swap(lo, hi); |
| return TypeInt::make(MIN2(lo->_lo, hi->_lo) , hi->_hi, 3); |
| } else if (stride_t->_lo >= 0) { |
| return TypeInt::make(lo->_lo, MAX2(lo->_hi, hi->_hi), 3); |
| } |
| } |
| } |
| } else if (l->in(LoopNode::LoopBackControl) != NULL && |
| in(LoopNode::EntryControl) != NULL && |
| phase->type(l->in(LoopNode::LoopBackControl)) == Type::TOP) { |
| // During CCP, if we saturate the type of a counted loop's Phi |
| // before the special code for counted loop above has a chance |
| // to run (that is as long as the type of the backedge's control |
| // is top), we might end up with non monotonic types |
| return phase->type(in(LoopNode::EntryControl)); |
| } |
| } |
| |
| // Until we have harmony between classes and interfaces in the type |
| // lattice, we must tread carefully around phis which implicitly |
| // convert the one to the other. |
| const TypePtr* ttp = _type->make_ptr(); |
| const TypeInstPtr* ttip = (ttp != NULL) ? ttp->isa_instptr() : NULL; |
| const TypeKlassPtr* ttkp = (ttp != NULL) ? ttp->isa_klassptr() : NULL; |
| bool is_intf = false; |
| if (ttip != NULL) { |
| ciKlass* k = ttip->klass(); |
| if (k->is_loaded() && k->is_interface()) |
| is_intf = true; |
| } |
| if (ttkp != NULL) { |
| ciKlass* k = ttkp->klass(); |
| if (k->is_loaded() && k->is_interface()) |
| is_intf = true; |
| } |
| |
| // Default case: merge all inputs |
| const Type *t = Type::TOP; // Merged type starting value |
| for (uint i = 1; i < req(); ++i) {// For all paths in |
| // Reachable control path? |
| if (r->in(i) && phase->type(r->in(i)) == Type::CONTROL) { |
| const Type* ti = phase->type(in(i)); |
| // We assume that each input of an interface-valued Phi is a true |
| // subtype of that interface. This might not be true of the meet |
| // of all the input types. The lattice is not distributive in |
| // such cases. Ward off asserts in type.cpp by refusing to do |
| // meets between interfaces and proper classes. |
| const TypePtr* tip = ti->make_ptr(); |
| const TypeInstPtr* tiip = (tip != NULL) ? tip->isa_instptr() : NULL; |
| if (tiip) { |
| bool ti_is_intf = false; |
| ciKlass* k = tiip->klass(); |
| if (k->is_loaded() && k->is_interface()) |
| ti_is_intf = true; |
| if (is_intf != ti_is_intf) |
| { t = _type; break; } |
| } |
| t = t->meet_speculative(ti); |
| } |
| } |
| |
| // The worst-case type (from ciTypeFlow) should be consistent with "t". |
| // That is, we expect that "t->higher_equal(_type)" holds true. |
| // There are various exceptions: |
| // - Inputs which are phis might in fact be widened unnecessarily. |
| // For example, an input might be a widened int while the phi is a short. |
| // - Inputs might be BotPtrs but this phi is dependent on a null check, |
| // and postCCP has removed the cast which encodes the result of the check. |
| // - The type of this phi is an interface, and the inputs are classes. |
| // - Value calls on inputs might produce fuzzy results. |
| // (Occurrences of this case suggest improvements to Value methods.) |
| // |
| // It is not possible to see Type::BOTTOM values as phi inputs, |
| // because the ciTypeFlow pre-pass produces verifier-quality types. |
| const Type* ft = t->filter_speculative(_type); // Worst case type |
| |
| #ifdef ASSERT |
| // The following logic has been moved into TypeOopPtr::filter. |
| const Type* jt = t->join_speculative(_type); |
| if (jt->empty()) { // Emptied out??? |
| |
| // Check for evil case of 't' being a class and '_type' expecting an |
| // interface. This can happen because the bytecodes do not contain |
| // enough type info to distinguish a Java-level interface variable |
| // from a Java-level object variable. If we meet 2 classes which |
| // both implement interface I, but their meet is at 'j/l/O' which |
| // doesn't implement I, we have no way to tell if the result should |
| // be 'I' or 'j/l/O'. Thus we'll pick 'j/l/O'. If this then flows |
| // into a Phi which "knows" it's an Interface type we'll have to |
| // uplift the type. |
| if (!t->empty() && ttip && ttip->is_loaded() && ttip->klass()->is_interface()) { |
| assert(ft == _type, ""); // Uplift to interface |
| } else if (!t->empty() && ttkp && ttkp->is_loaded() && ttkp->klass()->is_interface()) { |
| assert(ft == _type, ""); // Uplift to interface |
| } else { |
| // We also have to handle 'evil cases' of interface- vs. class-arrays |
| Type::get_arrays_base_elements(jt, _type, NULL, &ttip); |
| if (!t->empty() && ttip != NULL && ttip->is_loaded() && ttip->klass()->is_interface()) { |
| assert(ft == _type, ""); // Uplift to array of interface |
| } else { |
| // Otherwise it's something stupid like non-overlapping int ranges |
| // found on dying counted loops. |
| assert(ft == Type::TOP, ""); // Canonical empty value |
| } |
| } |
| } |
| |
| else { |
| |
| // If we have an interface-typed Phi and we narrow to a class type, the join |
| // should report back the class. However, if we have a J/L/Object |
| // class-typed Phi and an interface flows in, it's possible that the meet & |
| // join report an interface back out. This isn't possible but happens |
| // because the type system doesn't interact well with interfaces. |
| const TypePtr *jtp = jt->make_ptr(); |
| const TypeInstPtr *jtip = (jtp != NULL) ? jtp->isa_instptr() : NULL; |
| const TypeKlassPtr *jtkp = (jtp != NULL) ? jtp->isa_klassptr() : NULL; |
| if( jtip && ttip ) { |
| if( jtip->is_loaded() && jtip->klass()->is_interface() && |
| ttip->is_loaded() && !ttip->klass()->is_interface() ) { |
| assert(ft == ttip->cast_to_ptr_type(jtip->ptr()) || |
| ft->isa_narrowoop() && ft->make_ptr() == ttip->cast_to_ptr_type(jtip->ptr()), ""); |
| jt = ft; |
| } |
| } |
| if( jtkp && ttkp ) { |
| if( jtkp->is_loaded() && jtkp->klass()->is_interface() && |
| !jtkp->klass_is_exact() && // Keep exact interface klass (6894807) |
| ttkp->is_loaded() && !ttkp->klass()->is_interface() ) { |
| assert(ft == ttkp->cast_to_ptr_type(jtkp->ptr()) || |
| ft->isa_narrowklass() && ft->make_ptr() == ttkp->cast_to_ptr_type(jtkp->ptr()), ""); |
| jt = ft; |
| } |
| } |
| if (jt != ft && jt->base() == ft->base()) { |
| if (jt->isa_int() && |
| jt->is_int()->_lo == ft->is_int()->_lo && |
| jt->is_int()->_hi == ft->is_int()->_hi) |
| jt = ft; |
| if (jt->isa_long() && |
| jt->is_long()->_lo == ft->is_long()->_lo && |
| jt->is_long()->_hi == ft->is_long()->_hi) |
| jt = ft; |
| } |
| if (jt != ft) { |
| tty->print("merge type: "); t->dump(); tty->cr(); |
| tty->print("kill type: "); _type->dump(); tty->cr(); |
| tty->print("join type: "); jt->dump(); tty->cr(); |
| tty->print("filter type: "); ft->dump(); tty->cr(); |
| } |
| assert(jt == ft, ""); |
| } |
| #endif //ASSERT |
| |
| // Deal with conversion problems found in data loops. |
| ft = phase->saturate(ft, phase->type_or_null(this), _type); |
| |
| return ft; |
| } |
| |
| |
| //------------------------------is_diamond_phi--------------------------------- |
| // Does this Phi represent a simple well-shaped diamond merge? Return the |
| // index of the true path or 0 otherwise. |
| // If check_control_only is true, do not inspect the If node at the |
| // top, and return -1 (not an edge number) on success. |
| int PhiNode::is_diamond_phi(bool check_control_only) const { |
| // Check for a 2-path merge |
| Node *region = in(0); |
| if( !region ) return 0; |
| if( region->req() != 3 ) return 0; |
| if( req() != 3 ) return 0; |
| // Check that both paths come from the same If |
| Node *ifp1 = region->in(1); |
| Node *ifp2 = region->in(2); |
| if( !ifp1 || !ifp2 ) return 0; |
| Node *iff = ifp1->in(0); |
| if( !iff || !iff->is_If() ) return 0; |
| if( iff != ifp2->in(0) ) return 0; |
| if (check_control_only) return -1; |
| // Check for a proper bool/cmp |
| const Node *b = iff->in(1); |
| if( !b->is_Bool() ) return 0; |
| const Node *cmp = b->in(1); |
| if( !cmp->is_Cmp() ) return 0; |
| |
| // Check for branching opposite expected |
| if( ifp2->Opcode() == Op_IfTrue ) { |
| assert( ifp1->Opcode() == Op_IfFalse, "" ); |
| return 2; |
| } else { |
| assert( ifp1->Opcode() == Op_IfTrue, "" ); |
| return 1; |
| } |
| } |
| |
| //----------------------------check_cmove_id----------------------------------- |
| // Check for CMove'ing a constant after comparing against the constant. |
| // Happens all the time now, since if we compare equality vs a constant in |
| // the parser, we "know" the variable is constant on one path and we force |
| // it. Thus code like "if( x==0 ) {/*EMPTY*/}" ends up inserting a |
| // conditional move: "x = (x==0)?0:x;". Yucko. This fix is slightly more |
| // general in that we don't need constants. Since CMove's are only inserted |
| // in very special circumstances, we do it here on generic Phi's. |
| Node* PhiNode::is_cmove_id(PhaseTransform* phase, int true_path) { |
| assert(true_path !=0, "only diamond shape graph expected"); |
| |
| // is_diamond_phi() has guaranteed the correctness of the nodes sequence: |
| // phi->region->if_proj->ifnode->bool->cmp |
| Node* region = in(0); |
| Node* iff = region->in(1)->in(0); |
| BoolNode* b = iff->in(1)->as_Bool(); |
| Node* cmp = b->in(1); |
| Node* tval = in(true_path); |
| Node* fval = in(3-true_path); |
| Node* id = CMoveNode::is_cmove_id(phase, cmp, tval, fval, b); |
| if (id == NULL) |
| return NULL; |
| |
| // Either value might be a cast that depends on a branch of 'iff'. |
| // Since the 'id' value will float free of the diamond, either |
| // decast or return failure. |
| Node* ctl = id->in(0); |
| if (ctl != NULL && ctl->in(0) == iff) { |
| if (id->is_ConstraintCast()) { |
| return id->in(1); |
| } else { |
| // Don't know how to disentangle this value. |
| return NULL; |
| } |
| } |
| |
| return id; |
| } |
| |
| //------------------------------Identity--------------------------------------- |
| // Check for Region being Identity. |
| Node* PhiNode::Identity(PhaseGVN* phase) { |
| // Check for no merging going on |
| // (There used to be special-case code here when this->region->is_Loop. |
| // It would check for a tributary phi on the backedge that the main phi |
| // trivially, perhaps with a single cast. The unique_input method |
| // does all this and more, by reducing such tributaries to 'this'.) |
| Node* uin = unique_input(phase, false); |
| if (uin != NULL) { |
| return uin; |
| } |
| |
| int true_path = is_diamond_phi(); |
| if (true_path != 0) { |
| Node* id = is_cmove_id(phase, true_path); |
| if (id != NULL) return id; |
| } |
| |
| return this; // No identity |
| } |
| |
| //-----------------------------unique_input------------------------------------ |
| // Find the unique value, discounting top, self-loops, and casts. |
| // Return top if there are no inputs, and self if there are multiple. |
| Node* PhiNode::unique_input(PhaseTransform* phase, bool uncast) { |
| // 1) One unique direct input, |
| // or if uncast is true: |
| // 2) some of the inputs have an intervening ConstraintCast |
| // 3) an input is a self loop |
| // |
| // 1) input or 2) input or 3) input __ |
| // / \ / \ \ / \ |
| // \ / | cast phi cast |
| // phi \ / / \ / |
| // phi / -- |
| |
| Node* r = in(0); // RegionNode |
| if (r == NULL) return in(1); // Already degraded to a Copy |
| Node* input = NULL; // The unique direct input (maybe uncasted = ConstraintCasts removed) |
| |
| for (uint i = 1, cnt = req(); i < cnt; ++i) { |
| Node* rc = r->in(i); |
| if (rc == NULL || phase->type(rc) == Type::TOP) |
| continue; // ignore unreachable control path |
| Node* n = in(i); |
| if (n == NULL) |
| continue; |
| Node* un = n; |
| if (uncast) { |
| #ifdef ASSERT |
| Node* m = un->uncast(); |
| #endif |
| while (un != NULL && un->req() == 2 && un->is_ConstraintCast()) { |
| Node* next = un->in(1); |
| if (phase->type(next)->isa_rawptr() && phase->type(un)->isa_oopptr()) { |
| // risk exposing raw ptr at safepoint |
| break; |
| } |
| un = next; |
| } |
| assert(m == un || un->in(1) == m, "Only expected at CheckCastPP from allocation"); |
| } |
| if (un == NULL || un == this || phase->type(un) == Type::TOP) { |
| continue; // ignore if top, or in(i) and "this" are in a data cycle |
| } |
| // Check for a unique input (maybe uncasted) |
| if (input == NULL) { |
| input = un; |
| } else if (input != un) { |
| input = NodeSentinel; // no unique input |
| } |
| } |
| if (input == NULL) { |
| return phase->C->top(); // no inputs |
| } |
| |
| if (input != NodeSentinel) { |
| return input; // one unique direct input |
| } |
| |
| // Nothing. |
| return NULL; |
| } |
| |
| //------------------------------is_x2logic------------------------------------- |
| // Check for simple convert-to-boolean pattern |
| // If:(C Bool) Region:(IfF IfT) Phi:(Region 0 1) |
| // Convert Phi to an ConvIB. |
| static Node *is_x2logic( PhaseGVN *phase, PhiNode *phi, int true_path ) { |
| assert(true_path !=0, "only diamond shape graph expected"); |
| // Convert the true/false index into an expected 0/1 return. |
| // Map 2->0 and 1->1. |
| int flipped = 2-true_path; |
| |
| // is_diamond_phi() has guaranteed the correctness of the nodes sequence: |
| // phi->region->if_proj->ifnode->bool->cmp |
| Node *region = phi->in(0); |
| Node *iff = region->in(1)->in(0); |
| BoolNode *b = (BoolNode*)iff->in(1); |
| const CmpNode *cmp = (CmpNode*)b->in(1); |
| |
| Node *zero = phi->in(1); |
| Node *one = phi->in(2); |
| const Type *tzero = phase->type( zero ); |
| const Type *tone = phase->type( one ); |
| |
| // Check for compare vs 0 |
| const Type *tcmp = phase->type(cmp->in(2)); |
| if( tcmp != TypeInt::ZERO && tcmp != TypePtr::NULL_PTR ) { |
| // Allow cmp-vs-1 if the other input is bounded by 0-1 |
| if( !(tcmp == TypeInt::ONE && phase->type(cmp->in(1)) == TypeInt::BOOL) ) |
| return NULL; |
| flipped = 1-flipped; // Test is vs 1 instead of 0! |
| } |
| |
| // Check for setting zero/one opposite expected |
| if( tzero == TypeInt::ZERO ) { |
| if( tone == TypeInt::ONE ) { |
| } else return NULL; |
| } else if( tzero == TypeInt::ONE ) { |
| if( tone == TypeInt::ZERO ) { |
| flipped = 1-flipped; |
| } else return NULL; |
| } else return NULL; |
| |
| // Check for boolean test backwards |
| if( b->_test._test == BoolTest::ne ) { |
| } else if( b->_test._test == BoolTest::eq ) { |
| flipped = 1-flipped; |
| } else return NULL; |
| |
| // Build int->bool conversion |
| Node *n = new Conv2BNode( cmp->in(1) ); |
| if( flipped ) |
| n = new XorINode( phase->transform(n), phase->intcon(1) ); |
| |
| return n; |
| } |
| |
| //------------------------------is_cond_add------------------------------------ |
| // Check for simple conditional add pattern: "(P < Q) ? X+Y : X;" |
| // To be profitable the control flow has to disappear; there can be no other |
| // values merging here. We replace the test-and-branch with: |
| // "(sgn(P-Q))&Y) + X". Basically, convert "(P < Q)" into 0 or -1 by |
| // moving the carry bit from (P-Q) into a register with 'sbb EAX,EAX'. |
| // Then convert Y to 0-or-Y and finally add. |
| // This is a key transform for SpecJava _201_compress. |
| static Node* is_cond_add(PhaseGVN *phase, PhiNode *phi, int true_path) { |
| assert(true_path !=0, "only diamond shape graph expected"); |
| |
| // is_diamond_phi() has guaranteed the correctness of the nodes sequence: |
| // phi->region->if_proj->ifnode->bool->cmp |
| RegionNode *region = (RegionNode*)phi->in(0); |
| Node *iff = region->in(1)->in(0); |
| BoolNode* b = iff->in(1)->as_Bool(); |
| const CmpNode *cmp = (CmpNode*)b->in(1); |
| |
| // Make sure only merging this one phi here |
| if (region->has_unique_phi() != phi) return NULL; |
| |
| // Make sure each arm of the diamond has exactly one output, which we assume |
| // is the region. Otherwise, the control flow won't disappear. |
| if (region->in(1)->outcnt() != 1) return NULL; |
| if (region->in(2)->outcnt() != 1) return NULL; |
| |
| // Check for "(P < Q)" of type signed int |
| if (b->_test._test != BoolTest::lt) return NULL; |
| if (cmp->Opcode() != Op_CmpI) return NULL; |
| |
| Node *p = cmp->in(1); |
| Node *q = cmp->in(2); |
| Node *n1 = phi->in( true_path); |
| Node *n2 = phi->in(3-true_path); |
| |
| int op = n1->Opcode(); |
| if( op != Op_AddI // Need zero as additive identity |
| /*&&op != Op_SubI && |
| op != Op_AddP && |
| op != Op_XorI && |
| op != Op_OrI*/ ) |
| return NULL; |
| |
| Node *x = n2; |
| Node *y = NULL; |
| if( x == n1->in(1) ) { |
| y = n1->in(2); |
| } else if( x == n1->in(2) ) { |
| y = n1->in(1); |
| } else return NULL; |
| |
| // Not so profitable if compare and add are constants |
| if( q->is_Con() && phase->type(q) != TypeInt::ZERO && y->is_Con() ) |
| return NULL; |
| |
| Node *cmplt = phase->transform( new CmpLTMaskNode(p,q) ); |
| Node *j_and = phase->transform( new AndINode(cmplt,y) ); |
| return new AddINode(j_and,x); |
| } |
| |
| //------------------------------is_absolute------------------------------------ |
| // Check for absolute value. |
| static Node* is_absolute( PhaseGVN *phase, PhiNode *phi_root, int true_path) { |
| assert(true_path !=0, "only diamond shape graph expected"); |
| |
| int cmp_zero_idx = 0; // Index of compare input where to look for zero |
| int phi_x_idx = 0; // Index of phi input where to find naked x |
| |
| // ABS ends with the merge of 2 control flow paths. |
| // Find the false path from the true path. With only 2 inputs, 3 - x works nicely. |
| int false_path = 3 - true_path; |
| |
| // is_diamond_phi() has guaranteed the correctness of the nodes sequence: |
| // phi->region->if_proj->ifnode->bool->cmp |
| BoolNode *bol = phi_root->in(0)->in(1)->in(0)->in(1)->as_Bool(); |
| |
| // Check bool sense |
| switch( bol->_test._test ) { |
| case BoolTest::lt: cmp_zero_idx = 1; phi_x_idx = true_path; break; |
| case BoolTest::le: cmp_zero_idx = 2; phi_x_idx = false_path; break; |
| case BoolTest::gt: cmp_zero_idx = 2; phi_x_idx = true_path; break; |
| case BoolTest::ge: cmp_zero_idx = 1; phi_x_idx = false_path; break; |
| default: return NULL; break; |
| } |
| |
| // Test is next |
| Node *cmp = bol->in(1); |
| const Type *tzero = NULL; |
| switch( cmp->Opcode() ) { |
| case Op_CmpF: tzero = TypeF::ZERO; break; // Float ABS |
| case Op_CmpD: tzero = TypeD::ZERO; break; // Double ABS |
| default: return NULL; |
| } |
| |
| // Find zero input of compare; the other input is being abs'd |
| Node *x = NULL; |
| bool flip = false; |
| if( phase->type(cmp->in(cmp_zero_idx)) == tzero ) { |
| x = cmp->in(3 - cmp_zero_idx); |
| } else if( phase->type(cmp->in(3 - cmp_zero_idx)) == tzero ) { |
| // The test is inverted, we should invert the result... |
| x = cmp->in(cmp_zero_idx); |
| flip = true; |
| } else { |
| return NULL; |
| } |
| |
| // Next get the 2 pieces being selected, one is the original value |
| // and the other is the negated value. |
| if( phi_root->in(phi_x_idx) != x ) return NULL; |
| |
| // Check other phi input for subtract node |
| Node *sub = phi_root->in(3 - phi_x_idx); |
| |
| // Allow only Sub(0,X) and fail out for all others; Neg is not OK |
| if( tzero == TypeF::ZERO ) { |
| if( sub->Opcode() != Op_SubF || |
| sub->in(2) != x || |
| phase->type(sub->in(1)) != tzero ) return NULL; |
| x = new AbsFNode(x); |
| if (flip) { |
| x = new SubFNode(sub->in(1), phase->transform(x)); |
| } |
| } else { |
| if( sub->Opcode() != Op_SubD || |
| sub->in(2) != x || |
| phase->type(sub->in(1)) != tzero ) return NULL; |
| x = new AbsDNode(x); |
| if (flip) { |
| x = new SubDNode(sub->in(1), phase->transform(x)); |
| } |
| } |
| |
| return x; |
| } |
| |
| //------------------------------split_once------------------------------------- |
| // Helper for split_flow_path |
| static void split_once(PhaseIterGVN *igvn, Node *phi, Node *val, Node *n, Node *newn) { |
| igvn->hash_delete(n); // Remove from hash before hacking edges |
| |
| uint j = 1; |
| for (uint i = phi->req()-1; i > 0; i--) { |
| if (phi->in(i) == val) { // Found a path with val? |
| // Add to NEW Region/Phi, no DU info |
| newn->set_req( j++, n->in(i) ); |
| // Remove from OLD Region/Phi |
| n->del_req(i); |
| } |
| } |
| |
| // Register the new node but do not transform it. Cannot transform until the |
| // entire Region/Phi conglomerate has been hacked as a single huge transform. |
| igvn->register_new_node_with_optimizer( newn ); |
| |
| // Now I can point to the new node. |
| n->add_req(newn); |
| igvn->_worklist.push(n); |
| } |
| |
| //------------------------------split_flow_path-------------------------------- |
| // Check for merging identical values and split flow paths |
| static Node* split_flow_path(PhaseGVN *phase, PhiNode *phi) { |
| BasicType bt = phi->type()->basic_type(); |
| if( bt == T_ILLEGAL || type2size[bt] <= 0 ) |
| return NULL; // Bail out on funny non-value stuff |
| if( phi->req() <= 3 ) // Need at least 2 matched inputs and a |
| return NULL; // third unequal input to be worth doing |
| |
| // Scan for a constant |
| uint i; |
| for( i = 1; i < phi->req()-1; i++ ) { |
| Node *n = phi->in(i); |
| if( !n ) return NULL; |
| if( phase->type(n) == Type::TOP ) return NULL; |
| if( n->Opcode() == Op_ConP || n->Opcode() == Op_ConN || n->Opcode() == Op_ConNKlass ) |
| break; |
| } |
| if( i >= phi->req() ) // Only split for constants |
| return NULL; |
| |
| Node *val = phi->in(i); // Constant to split for |
| uint hit = 0; // Number of times it occurs |
| Node *r = phi->region(); |
| |
| for( ; i < phi->req(); i++ ){ // Count occurrences of constant |
| Node *n = phi->in(i); |
| if( !n ) return NULL; |
| if( phase->type(n) == Type::TOP ) return NULL; |
| if( phi->in(i) == val ) { |
| hit++; |
| if (PhaseIdealLoop::find_predicate(r->in(i)) != NULL) { |
| return NULL; // don't split loop entry path |
| } |
| } |
| } |
| |
| if( hit <= 1 || // Make sure we find 2 or more |
| hit == phi->req()-1 ) // and not ALL the same value |
| return NULL; |
| |
| // Now start splitting out the flow paths that merge the same value. |
| // Split first the RegionNode. |
| PhaseIterGVN *igvn = phase->is_IterGVN(); |
| RegionNode *newr = new RegionNode(hit+1); |
| split_once(igvn, phi, val, r, newr); |
| |
| // Now split all other Phis than this one |
| for (DUIterator_Fast kmax, k = r->fast_outs(kmax); k < kmax; k++) { |
| Node* phi2 = r->fast_out(k); |
| if( phi2->is_Phi() && phi2->as_Phi() != phi ) { |
| PhiNode *newphi = PhiNode::make_blank(newr, phi2); |
| split_once(igvn, phi, val, phi2, newphi); |
| } |
| } |
| |
| // Clean up this guy |
| igvn->hash_delete(phi); |
| for( i = phi->req()-1; i > 0; i-- ) { |
| if( phi->in(i) == val ) { |
| phi->del_req(i); |
| } |
| } |
| phi->add_req(val); |
| |
| return phi; |
| } |
| |
| //============================================================================= |
| //------------------------------simple_data_loop_check------------------------- |
| // Try to determining if the phi node in a simple safe/unsafe data loop. |
| // Returns: |
| // enum LoopSafety { Safe = 0, Unsafe, UnsafeLoop }; |
| // Safe - safe case when the phi and it's inputs reference only safe data |
| // nodes; |
| // Unsafe - the phi and it's inputs reference unsafe data nodes but there |
| // is no reference back to the phi - need a graph walk |
| // to determine if it is in a loop; |
| // UnsafeLoop - unsafe case when the phi references itself directly or through |
| // unsafe data node. |
| // Note: a safe data node is a node which could/never reference itself during |
| // GVN transformations. For now it is Con, Proj, Phi, CastPP, CheckCastPP. |
| // I mark Phi nodes as safe node not only because they can reference itself |
| // but also to prevent mistaking the fallthrough case inside an outer loop |
| // as dead loop when the phi references itselfs through an other phi. |
| PhiNode::LoopSafety PhiNode::simple_data_loop_check(Node *in) const { |
| // It is unsafe loop if the phi node references itself directly. |
| if (in == (Node*)this) |
| return UnsafeLoop; // Unsafe loop |
| // Unsafe loop if the phi node references itself through an unsafe data node. |
| // Exclude cases with null inputs or data nodes which could reference |
| // itself (safe for dead loops). |
| if (in != NULL && !in->is_dead_loop_safe()) { |
| // Check inputs of phi's inputs also. |
| // It is much less expensive then full graph walk. |
| uint cnt = in->req(); |
| uint i = (in->is_Proj() && !in->is_CFG()) ? 0 : 1; |
| for (; i < cnt; ++i) { |
| Node* m = in->in(i); |
| if (m == (Node*)this) |
| return UnsafeLoop; // Unsafe loop |
| if (m != NULL && !m->is_dead_loop_safe()) { |
| // Check the most common case (about 30% of all cases): |
| // phi->Load/Store->AddP->(ConP ConP Con)/(Parm Parm Con). |
| Node *m1 = (m->is_AddP() && m->req() > 3) ? m->in(1) : NULL; |
| if (m1 == (Node*)this) |
| return UnsafeLoop; // Unsafe loop |
| if (m1 != NULL && m1 == m->in(2) && |
| m1->is_dead_loop_safe() && m->in(3)->is_Con()) { |
| continue; // Safe case |
| } |
| // The phi references an unsafe node - need full analysis. |
| return Unsafe; |
| } |
| } |
| } |
| return Safe; // Safe case - we can optimize the phi node. |
| } |
| |
| //------------------------------is_unsafe_data_reference----------------------- |
| // If phi can be reached through the data input - it is data loop. |
| bool PhiNode::is_unsafe_data_reference(Node *in) const { |
| assert(req() > 1, ""); |
| // First, check simple cases when phi references itself directly or |
| // through an other node. |
| LoopSafety safety = simple_data_loop_check(in); |
| if (safety == UnsafeLoop) |
| return true; // phi references itself - unsafe loop |
| else if (safety == Safe) |
| return false; // Safe case - phi could be replaced with the unique input. |
| |
| // Unsafe case when we should go through data graph to determine |
| // if the phi references itself. |
| |
| ResourceMark rm; |
| |
| Arena *a = Thread::current()->resource_area(); |
| Node_List nstack(a); |
| VectorSet visited(a); |
| |
| nstack.push(in); // Start with unique input. |
| visited.set(in->_idx); |
| while (nstack.size() != 0) { |
| Node* n = nstack.pop(); |
| uint cnt = n->req(); |
| uint i = (n->is_Proj() && !n->is_CFG()) ? 0 : 1; |
| for (; i < cnt; i++) { |
| Node* m = n->in(i); |
| if (m == (Node*)this) { |
| return true; // Data loop |
| } |
| if (m != NULL && !m->is_dead_loop_safe()) { // Only look for unsafe cases. |
| if (!visited.test_set(m->_idx)) |
| nstack.push(m); |
| } |
| } |
| } |
| return false; // The phi is not reachable from its inputs |
| } |
| |
| |
| //------------------------------Ideal------------------------------------------ |
| // Return a node which is more "ideal" than the current node. Must preserve |
| // the CFG, but we can still strip out dead paths. |
| Node *PhiNode::Ideal(PhaseGVN *phase, bool can_reshape) { |
| // The next should never happen after 6297035 fix. |
| if( is_copy() ) // Already degraded to a Copy ? |
| return NULL; // No change |
| |
| Node *r = in(0); // RegionNode |
| assert(r->in(0) == NULL || !r->in(0)->is_Root(), "not a specially hidden merge"); |
| |
| // Note: During parsing, phis are often transformed before their regions. |
| // This means we have to use type_or_null to defend against untyped regions. |
| if( phase->type_or_null(r) == Type::TOP ) // Dead code? |
| return NULL; // No change |
| |
| Node *top = phase->C->top(); |
| bool new_phi = (outcnt() == 0); // transforming new Phi |
| // No change for igvn if new phi is not hooked |
| if (new_phi && can_reshape) |
| return NULL; |
| |
| // The are 2 situations when only one valid phi's input is left |
| // (in addition to Region input). |
| // One: region is not loop - replace phi with this input. |
| // Two: region is loop - replace phi with top since this data path is dead |
| // and we need to break the dead data loop. |
| Node* progress = NULL; // Record if any progress made |
| for( uint j = 1; j < req(); ++j ){ // For all paths in |
| // Check unreachable control paths |
| Node* rc = r->in(j); |
| Node* n = in(j); // Get the input |
| if (rc == NULL || phase->type(rc) == Type::TOP) { |
| if (n != top) { // Not already top? |
| PhaseIterGVN *igvn = phase->is_IterGVN(); |
| if (can_reshape && igvn != NULL) { |
| igvn->_worklist.push(r); |
| } |
| set_req(j, top); // Nuke it down |
| progress = this; // Record progress |
| } |
| } |
| } |
| |
| if (can_reshape && outcnt() == 0) { |
| // set_req() above may kill outputs if Phi is referenced |
| // only by itself on the dead (top) control path. |
| return top; |
| } |
| |
| bool uncasted = false; |
| Node* uin = unique_input(phase, false); |
| if (uin == NULL && can_reshape) { |
| uncasted = true; |
| uin = unique_input(phase, true); |
| } |
| if (uin == top) { // Simplest case: no alive inputs. |
| if (can_reshape) // IGVN transformation |
| return top; |
| else |
| return NULL; // Identity will return TOP |
| } else if (uin != NULL) { |
| // Only one not-NULL unique input path is left. |
| // Determine if this input is backedge of a loop. |
| // (Skip new phis which have no uses and dead regions). |
| if (outcnt() > 0 && r->in(0) != NULL) { |
| // First, take the short cut when we know it is a loop and |
| // the EntryControl data path is dead. |
| // Loop node may have only one input because entry path |
| // is removed in PhaseIdealLoop::Dominators(). |
| assert(!r->is_Loop() || r->req() <= 3, "Loop node should have 3 or less inputs"); |
| bool is_loop = (r->is_Loop() && r->req() == 3); |
| // Then, check if there is a data loop when phi references itself directly |
| // or through other data nodes. |
| if (is_loop && !uin->eqv_uncast(in(LoopNode::EntryControl)) || |
| !is_loop && is_unsafe_data_reference(uin)) { |
| // Break this data loop to avoid creation of a dead loop. |
| if (can_reshape) { |
| return top; |
| } else { |
| // We can't return top if we are in Parse phase - cut inputs only |
| // let Identity to handle the case. |
| replace_edge(uin, top); |
| return NULL; |
| } |
| } |
| } |
| |
| if (uncasted) { |
| // Wait until after parsing for the type information to propagate from the casts |
| assert(can_reshape, "Invalid during parsing"); |
| const Type* phi_type = bottom_type(); |
| assert(phi_type->isa_int() || phi_type->isa_ptr(), "bad phi type"); |
| int opcode; |
| if (phi_type->isa_int()) { |
| opcode = Op_CastII; |
| } else { |
| const Type* uin_type = phase->type(uin); |
| if (phi_type->join(TypePtr::NOTNULL) == uin_type->join(TypePtr::NOTNULL)) { |
| opcode = Op_CastPP; |
| } else { |
| opcode = Op_CheckCastPP; |
| } |
| } |
| // Add a cast to carry the control dependency of the Phi that is |
| // going away |
| Node* cast = ConstraintCastNode::make_cast(opcode, r, uin, phi_type, true); |
| cast = phase->transform(cast); |
| // set all inputs to the new cast so the Phi is removed by Identity |
| PhaseIterGVN* igvn = phase->is_IterGVN(); |
| for (uint i = 1; i < req(); i++) { |
| set_req_X(i, cast, igvn); |
| } |
| uin = cast; |
| } |
| |
| // One unique input. |
| debug_only(Node* ident = Identity(phase)); |
| // The unique input must eventually be detected by the Identity call. |
| #ifdef ASSERT |
| if (ident != uin && !ident->is_top()) { |
| // print this output before failing assert |
| r->dump(3); |
| this->dump(3); |
| ident->dump(); |
| uin->dump(); |
| } |
| #endif |
| assert(ident == uin || ident->is_top(), "Identity must clean this up"); |
| return NULL; |
| } |
| |
| Node* opt = NULL; |
| int true_path = is_diamond_phi(); |
| if( true_path != 0 ) { |
| // Check for CMove'ing identity. If it would be unsafe, |
| // handle it here. In the safe case, let Identity handle it. |
| Node* unsafe_id = is_cmove_id(phase, true_path); |
| if( unsafe_id != NULL && is_unsafe_data_reference(unsafe_id) ) |
| opt = unsafe_id; |
| |
| // Check for simple convert-to-boolean pattern |
| if( opt == NULL ) |
| opt = is_x2logic(phase, this, true_path); |
| |
| // Check for absolute value |
| if( opt == NULL ) |
| opt = is_absolute(phase, this, true_path); |
| |
| // Check for conditional add |
| if( opt == NULL && can_reshape ) |
| opt = is_cond_add(phase, this, true_path); |
| |
| // These 4 optimizations could subsume the phi: |
| // have to check for a dead data loop creation. |
| if( opt != NULL ) { |
| if( opt == unsafe_id || is_unsafe_data_reference(opt) ) { |
| // Found dead loop. |
| if( can_reshape ) |
| return top; |
| // We can't return top if we are in Parse phase - cut inputs only |
| // to stop further optimizations for this phi. Identity will return TOP. |
| assert(req() == 3, "only diamond merge phi here"); |
| set_req(1, top); |
| set_req(2, top); |
| return NULL; |
| } else { |
| return opt; |
| } |
| } |
| } |
| |
| // Check for merging identical values and split flow paths |
| if (can_reshape) { |
| opt = split_flow_path(phase, this); |
| // This optimization only modifies phi - don't need to check for dead loop. |
| assert(opt == NULL || phase->eqv(opt, this), "do not elide phi"); |
| if (opt != NULL) return opt; |
| } |
| |
| if (in(1) != NULL && in(1)->Opcode() == Op_AddP && can_reshape) { |
| // Try to undo Phi of AddP: |
| // (Phi (AddP base base y) (AddP base2 base2 y)) |
| // becomes: |
| // newbase := (Phi base base2) |
| // (AddP newbase newbase y) |
| // |
| // This occurs as a result of unsuccessful split_thru_phi and |
| // interferes with taking advantage of addressing modes. See the |
| // clone_shift_expressions code in matcher.cpp |
| Node* addp = in(1); |
| const Type* type = addp->in(AddPNode::Base)->bottom_type(); |
| Node* y = addp->in(AddPNode::Offset); |
| if (y != NULL && addp->in(AddPNode::Base) == addp->in(AddPNode::Address)) { |
| // make sure that all the inputs are similar to the first one, |
| // i.e. AddP with base == address and same offset as first AddP |
| bool doit = true; |
| for (uint i = 2; i < req(); i++) { |
| if (in(i) == NULL || |
| in(i)->Opcode() != Op_AddP || |
| in(i)->in(AddPNode::Base) != in(i)->in(AddPNode::Address) || |
| in(i)->in(AddPNode::Offset) != y) { |
| doit = false; |
| break; |
| } |
| // Accumulate type for resulting Phi |
| type = type->meet_speculative(in(i)->in(AddPNode::Base)->bottom_type()); |
| } |
| Node* base = NULL; |
| if (doit) { |
| // Check for neighboring AddP nodes in a tree. |
| // If they have a base, use that it. |
| for (DUIterator_Fast kmax, k = this->fast_outs(kmax); k < kmax; k++) { |
| Node* u = this->fast_out(k); |
| if (u->is_AddP()) { |
| Node* base2 = u->in(AddPNode::Base); |
| if (base2 != NULL && !base2->is_top()) { |
| if (base == NULL) |
| base = base2; |
| else if (base != base2) |
| { doit = false; break; } |
| } |
| } |
| } |
| } |
| if (doit) { |
| if (base == NULL) { |
| base = new PhiNode(in(0), type, NULL); |
| for (uint i = 1; i < req(); i++) { |
| base->init_req(i, in(i)->in(AddPNode::Base)); |
| } |
| phase->is_IterGVN()->register_new_node_with_optimizer(base); |
| } |
| return new AddPNode(base, base, y); |
| } |
| } |
| } |
| |
| // Split phis through memory merges, so that the memory merges will go away. |
| // Piggy-back this transformation on the search for a unique input.... |
| // It will be as if the merged memory is the unique value of the phi. |
| // (Do not attempt this optimization unless parsing is complete. |
| // It would make the parser's memory-merge logic sick.) |
| // (MergeMemNode is not dead_loop_safe - need to check for dead loop.) |
| if (progress == NULL && can_reshape && type() == Type::MEMORY) { |
| // see if this phi should be sliced |
| uint merge_width = 0; |
| bool saw_self = false; |
| for( uint i=1; i<req(); ++i ) {// For all paths in |
| Node *ii = in(i); |
| if (ii->is_MergeMem()) { |
| MergeMemNode* n = ii->as_MergeMem(); |
| merge_width = MAX2(merge_width, n->req()); |
| saw_self = saw_self || phase->eqv(n->base_memory(), this); |
| } |
| } |
| |
| // This restriction is temporarily necessary to ensure termination: |
| if (!saw_self && adr_type() == TypePtr::BOTTOM) merge_width = 0; |
| |
| if (merge_width > Compile::AliasIdxRaw) { |
| // found at least one non-empty MergeMem |
| const TypePtr* at = adr_type(); |
| if (at != TypePtr::BOTTOM) { |
| // Patch the existing phi to select an input from the merge: |
| // Phi:AT1(...MergeMem(m0, m1, m2)...) into |
| // Phi:AT1(...m1...) |
| int alias_idx = phase->C->get_alias_index(at); |
| for (uint i=1; i<req(); ++i) { |
| Node *ii = in(i); |
| if (ii->is_MergeMem()) { |
| MergeMemNode* n = ii->as_MergeMem(); |
| // compress paths and change unreachable cycles to TOP |
| // If not, we can update the input infinitely along a MergeMem cycle |
| // Equivalent code is in MemNode::Ideal_common |
| Node *m = phase->transform(n); |
| if (outcnt() == 0) { // Above transform() may kill us! |
| return top; |
| } |
| // If transformed to a MergeMem, get the desired slice |
| // Otherwise the returned node represents memory for every slice |
| Node *new_mem = (m->is_MergeMem()) ? |
| m->as_MergeMem()->memory_at(alias_idx) : m; |
| // Update input if it is progress over what we have now |
| if (new_mem != ii) { |
| set_req(i, new_mem); |
| progress = this; |
| } |
| } |
| } |
| } else { |
| // We know that at least one MergeMem->base_memory() == this |
| // (saw_self == true). If all other inputs also references this phi |
| // (directly or through data nodes) - it is dead loop. |
| bool saw_safe_input = false; |
| for (uint j = 1; j < req(); ++j) { |
| Node *n = in(j); |
| if (n->is_MergeMem() && n->as_MergeMem()->base_memory() == this) |
| continue; // skip known cases |
| if (!is_unsafe_data_reference(n)) { |
| saw_safe_input = true; // found safe input |
| break; |
| } |
| } |
| if (!saw_safe_input) |
| return top; // all inputs reference back to this phi - dead loop |
| |
| // Phi(...MergeMem(m0, m1:AT1, m2:AT2)...) into |
| // MergeMem(Phi(...m0...), Phi:AT1(...m1...), Phi:AT2(...m2...)) |
| PhaseIterGVN *igvn = phase->is_IterGVN(); |
| Node* hook = new Node(1); |
| PhiNode* new_base = (PhiNode*) clone(); |
| // Must eagerly register phis, since they participate in loops. |
| if (igvn) { |
| igvn->register_new_node_with_optimizer(new_base); |
| hook->add_req(new_base); |
| } |
| MergeMemNode* result = MergeMemNode::make(new_base); |
| for (uint i = 1; i < req(); ++i) { |
| Node *ii = in(i); |
| if (ii->is_MergeMem()) { |
| MergeMemNode* n = ii->as_MergeMem(); |
| for (MergeMemStream mms(result, n); mms.next_non_empty2(); ) { |
| // If we have not seen this slice yet, make a phi for it. |
| bool made_new_phi = false; |
| if (mms.is_empty()) { |
| Node* new_phi = new_base->slice_memory(mms.adr_type(phase->C)); |
| made_new_phi = true; |
| if (igvn) { |
| igvn->register_new_node_with_optimizer(new_phi); |
| hook->add_req(new_phi); |
| } |
| mms.set_memory(new_phi); |
| } |
| Node* phi = mms.memory(); |
| assert(made_new_phi || phi->in(i) == n, "replace the i-th merge by a slice"); |
| phi->set_req(i, mms.memory2()); |
| } |
| } |
| } |
| // Distribute all self-loops. |
| { // (Extra braces to hide mms.) |
| for (MergeMemStream mms(result); mms.next_non_empty(); ) { |
| Node* phi = mms.memory(); |
| for (uint i = 1; i < req(); ++i) { |
| if (phi->in(i) == this) phi->set_req(i, phi); |
| } |
| } |
| } |
| // now transform the new nodes, and return the mergemem |
| for (MergeMemStream mms(result); mms.next_non_empty(); ) { |
| Node* phi = mms.memory(); |
| mms.set_memory(phase->transform(phi)); |
| } |
| if (igvn) { // Unhook. |
| igvn->hash_delete(hook); |
| for (uint i = 1; i < hook->req(); i++) { |
| hook->set_req(i, NULL); |
| } |
| } |
| // Replace self with the result. |
| return result; |
| } |
| } |
| // |
| // Other optimizations on the memory chain |
| // |
| const TypePtr* at = adr_type(); |
| for( uint i=1; i<req(); ++i ) {// For all paths in |
| Node *ii = in(i); |
| Node *new_in = MemNode::optimize_memory_chain(ii, at, NULL, phase); |
| if (ii != new_in ) { |
| set_req(i, new_in); |
| progress = this; |
| } |
| } |
| } |
| |
| #ifdef _LP64 |
| // Push DecodeN/DecodeNKlass down through phi. |
| // The rest of phi graph will transform by split EncodeP node though phis up. |
| if ((UseCompressedOops || UseCompressedClassPointers) && can_reshape && progress == NULL) { |
| bool may_push = true; |
| bool has_decodeN = false; |
| bool is_decodeN = false; |
| for (uint i=1; i<req(); ++i) {// For all paths in |
| Node *ii = in(i); |
| if (ii->is_DecodeNarrowPtr() && ii->bottom_type() == bottom_type()) { |
| // Do optimization if a non dead path exist. |
| if (ii->in(1)->bottom_type() != Type::TOP) { |
| has_decodeN = true; |
| is_decodeN = ii->is_DecodeN(); |
| } |
| } else if (!ii->is_Phi()) { |
| may_push = false; |
| } |
| } |
| |
| if (has_decodeN && may_push) { |
| PhaseIterGVN *igvn = phase->is_IterGVN(); |
| // Make narrow type for new phi. |
| const Type* narrow_t; |
| if (is_decodeN) { |
| narrow_t = TypeNarrowOop::make(this->bottom_type()->is_ptr()); |
| } else { |
| narrow_t = TypeNarrowKlass::make(this->bottom_type()->is_ptr()); |
| } |
| PhiNode* new_phi = new PhiNode(r, narrow_t); |
| uint orig_cnt = req(); |
| for (uint i=1; i<req(); ++i) {// For all paths in |
| Node *ii = in(i); |
| Node* new_ii = NULL; |
| if (ii->is_DecodeNarrowPtr()) { |
| assert(ii->bottom_type() == bottom_type(), "sanity"); |
| new_ii = ii->in(1); |
| } else { |
| assert(ii->is_Phi(), "sanity"); |
| if (ii->as_Phi() == this) { |
| new_ii = new_phi; |
| } else { |
| if (is_decodeN) { |
| new_ii = new EncodePNode(ii, narrow_t); |
| } else { |
| new_ii = new EncodePKlassNode(ii, narrow_t); |
| } |
| igvn->register_new_node_with_optimizer(new_ii); |
| } |
| } |
| new_phi->set_req(i, new_ii); |
| } |
| igvn->register_new_node_with_optimizer(new_phi, this); |
| if (is_decodeN) { |
| progress = new DecodeNNode(new_phi, bottom_type()); |
| } else { |
| progress = new DecodeNKlassNode(new_phi, bottom_type()); |
| } |
| } |
| } |
| #endif |
| |
| return progress; // Return any progress |
| } |
| |
| //------------------------------is_tripcount----------------------------------- |
| bool PhiNode::is_tripcount() const { |
| return (in(0) != NULL && in(0)->is_CountedLoop() && |
| in(0)->as_CountedLoop()->phi() == this); |
| } |
| |
| //------------------------------out_RegMask------------------------------------ |
| const RegMask &PhiNode::in_RegMask(uint i) const { |
| return i ? out_RegMask() : RegMask::Empty; |
| } |
| |
| const RegMask &PhiNode::out_RegMask() const { |
| uint ideal_reg = _type->ideal_reg(); |
| assert( ideal_reg != Node::NotAMachineReg, "invalid type at Phi" ); |
| if( ideal_reg == 0 ) return RegMask::Empty; |
| return *(Compile::current()->matcher()->idealreg2spillmask[ideal_reg]); |
| } |
| |
| #ifndef PRODUCT |
| void PhiNode::related(GrowableArray<Node*> *in_rel, GrowableArray<Node*> *out_rel, bool compact) const { |
| // For a PhiNode, the set of related nodes includes all inputs till level 2, |
| // and all outputs till level 1. In compact mode, inputs till level 1 are |
| // collected. |
| this->collect_nodes(in_rel, compact ? 1 : 2, false, false); |
| this->collect_nodes(out_rel, -1, false, false); |
| } |
| |
| void PhiNode::dump_spec(outputStream *st) const { |
| TypeNode::dump_spec(st); |
| if (is_tripcount()) { |
| st->print(" #tripcount"); |
| } |
| } |
| #endif |
| |
| |
| //============================================================================= |
| const Type* GotoNode::Value(PhaseGVN* phase) const { |
| // If the input is reachable, then we are executed. |
| // If the input is not reachable, then we are not executed. |
| return phase->type(in(0)); |
| } |
| |
| Node* GotoNode::Identity(PhaseGVN* phase) { |
| return in(0); // Simple copy of incoming control |
| } |
| |
| const RegMask &GotoNode::out_RegMask() const { |
| return RegMask::Empty; |
| } |
| |
| #ifndef PRODUCT |
| //-----------------------------related----------------------------------------- |
| // The related nodes of a GotoNode are all inputs at level 1, as well as the |
| // outputs at level 1. This is regardless of compact mode. |
| void GotoNode::related(GrowableArray<Node*> *in_rel, GrowableArray<Node*> *out_rel, bool compact) const { |
| this->collect_nodes(in_rel, 1, false, false); |
| this->collect_nodes(out_rel, -1, false, false); |
| } |
| #endif |
| |
| |
| //============================================================================= |
| const RegMask &JumpNode::out_RegMask() const { |
| return RegMask::Empty; |
| } |
| |
| #ifndef PRODUCT |
| //-----------------------------related----------------------------------------- |
| // The related nodes of a JumpNode are all inputs at level 1, as well as the |
| // outputs at level 2 (to include actual jump targets beyond projection nodes). |
| // This is regardless of compact mode. |
| void JumpNode::related(GrowableArray<Node*> *in_rel, GrowableArray<Node*> *out_rel, bool compact) const { |
| this->collect_nodes(in_rel, 1, false, false); |
| this->collect_nodes(out_rel, -2, false, false); |
| } |
| #endif |
| |
| //============================================================================= |
| const RegMask &JProjNode::out_RegMask() const { |
| return RegMask::Empty; |
| } |
| |
| //============================================================================= |
| const RegMask &CProjNode::out_RegMask() const { |
| return RegMask::Empty; |
| } |
| |
| |
| |
| //============================================================================= |
| |
| uint PCTableNode::hash() const { return Node::hash() + _size; } |
| uint PCTableNode::cmp( const Node &n ) const |
| { return _size == ((PCTableNode&)n)._size; } |
| |
| const Type *PCTableNode::bottom_type() const { |
| const Type** f = TypeTuple::fields(_size); |
| for( uint i = 0; i < _size; i++ ) f[i] = Type::CONTROL; |
| return TypeTuple::make(_size, f); |
| } |
| |
| //------------------------------Value------------------------------------------ |
| // Compute the type of the PCTableNode. If reachable it is a tuple of |
| // Control, otherwise the table targets are not reachable |
| const Type* PCTableNode::Value(PhaseGVN* phase) const { |
| if( phase->type(in(0)) == Type::CONTROL ) |
| return bottom_type(); |
| return Type::TOP; // All paths dead? Then so are we |
| } |
| |
| //------------------------------Ideal------------------------------------------ |
| // Return a node which is more "ideal" than the current node. Strip out |
| // control copies |
| Node *PCTableNode::Ideal(PhaseGVN *phase, bool can_reshape) { |
| return remove_dead_region(phase, can_reshape) ? this : NULL; |
| } |
| |
| //============================================================================= |
| uint JumpProjNode::hash() const { |
| return Node::hash() + _dest_bci; |
| } |
| |
| uint JumpProjNode::cmp( const Node &n ) const { |
| return ProjNode::cmp(n) && |
| _dest_bci == ((JumpProjNode&)n)._dest_bci; |
| } |
| |
| #ifndef PRODUCT |
| void JumpProjNode::dump_spec(outputStream *st) const { |
| ProjNode::dump_spec(st); |
| st->print("@bci %d ",_dest_bci); |
| } |
| |
| void JumpProjNode::dump_compact_spec(outputStream *st) const { |
| ProjNode::dump_compact_spec(st); |
| st->print("(%d)%d@%d", _switch_val, _proj_no, _dest_bci); |
| } |
| |
| void JumpProjNode::related(GrowableArray<Node*> *in_rel, GrowableArray<Node*> *out_rel, bool compact) const { |
| // The related nodes of a JumpProjNode are its inputs and outputs at level 1. |
| this->collect_nodes(in_rel, 1, false, false); |
| this->collect_nodes(out_rel, -1, false, false); |
| } |
| #endif |
| |
| //============================================================================= |
| //------------------------------Value------------------------------------------ |
| // Check for being unreachable, or for coming from a Rethrow. Rethrow's cannot |
| // have the default "fall_through_index" path. |
| const Type* CatchNode::Value(PhaseGVN* phase) const { |
| // Unreachable? Then so are all paths from here. |
| if( phase->type(in(0)) == Type::TOP ) return Type::TOP; |
| // First assume all paths are reachable |
| const Type** f = TypeTuple::fields(_size); |
| for( uint i = 0; i < _size; i++ ) f[i] = Type::CONTROL; |
| // Identify cases that will always throw an exception |
| // () rethrow call |
| // () virtual or interface call with NULL receiver |
| // () call is a check cast with incompatible arguments |
| if( in(1)->is_Proj() ) { |
| Node *i10 = in(1)->in(0); |
| if( i10->is_Call() ) { |
| CallNode *call = i10->as_Call(); |
| // Rethrows always throw exceptions, never return |
| if (call->entry_point() == OptoRuntime::rethrow_stub()) { |
| f[CatchProjNode::fall_through_index] = Type::TOP; |
| } else if( call->req() > TypeFunc::Parms ) { |
| const Type *arg0 = phase->type( call->in(TypeFunc::Parms) ); |
| // Check for null receiver to virtual or interface calls |
| if( call->is_CallDynamicJava() && |
| arg0->higher_equal(TypePtr::NULL_PTR) ) { |
| f[CatchProjNode::fall_through_index] = Type::TOP; |
| } |
| } // End of if not a runtime stub |
| } // End of if have call above me |
| } // End of slot 1 is not a projection |
| return TypeTuple::make(_size, f); |
| } |
| |
| //============================================================================= |
| uint CatchProjNode::hash() const { |
| return Node::hash() + _handler_bci; |
| } |
| |
| |
| uint CatchProjNode::cmp( const Node &n ) const { |
| return ProjNode::cmp(n) && |
| _handler_bci == ((CatchProjNode&)n)._handler_bci; |
| } |
| |
| |
| //------------------------------Identity--------------------------------------- |
| // If only 1 target is possible, choose it if it is the main control |
| Node* CatchProjNode::Identity(PhaseGVN* phase) { |
| // If my value is control and no other value is, then treat as ID |
| const TypeTuple *t = phase->type(in(0))->is_tuple(); |
| if (t->field_at(_con) != Type::CONTROL) return this; |
| // If we remove the last CatchProj and elide the Catch/CatchProj, then we |
| // also remove any exception table entry. Thus we must know the call |
| // feeding the Catch will not really throw an exception. This is ok for |
| // the main fall-thru control (happens when we know a call can never throw |
| // an exception) or for "rethrow", because a further optimization will |
| // yank the rethrow (happens when we inline a function that can throw an |
| // exception and the caller has no handler). Not legal, e.g., for passing |
| // a NULL receiver to a v-call, or passing bad types to a slow-check-cast. |
| // These cases MUST throw an exception via the runtime system, so the VM |
| // will be looking for a table entry. |
| Node *proj = in(0)->in(1); // Expect a proj feeding CatchNode |
| CallNode *call; |
| if (_con != TypeFunc::Control && // Bail out if not the main control. |
| !(proj->is_Proj() && // AND NOT a rethrow |
| proj->in(0)->is_Call() && |
| (call = proj->in(0)->as_Call()) && |
| call->entry_point() == OptoRuntime::rethrow_stub())) |
| return this; |
| |
| // Search for any other path being control |
| for (uint i = 0; i < t->cnt(); i++) { |
| if (i != _con && t->field_at(i) == Type::CONTROL) |
| return this; |
| } |
| // Only my path is possible; I am identity on control to the jump |
| return in(0)->in(0); |
| } |
| |
| |
| #ifndef PRODUCT |
| void CatchProjNode::dump_spec(outputStream *st) const { |
| ProjNode::dump_spec(st); |
| st->print("@bci %d ",_handler_bci); |
| } |
| #endif |
| |
| //============================================================================= |
| //------------------------------Identity--------------------------------------- |
| // Check for CreateEx being Identity. |
| Node* CreateExNode::Identity(PhaseGVN* phase) { |
| if( phase->type(in(1)) == Type::TOP ) return in(1); |
| if( phase->type(in(0)) == Type::TOP ) return in(0); |
| // We only come from CatchProj, unless the CatchProj goes away. |
| // If the CatchProj is optimized away, then we just carry the |
| // exception oop through. |
| CallNode *call = in(1)->in(0)->as_Call(); |
| |
| return ( in(0)->is_CatchProj() && in(0)->in(0)->in(1) == in(1) ) |
| ? this |
| : call->in(TypeFunc::Parms); |
| } |
| |
| //============================================================================= |
| //------------------------------Value------------------------------------------ |
| // Check for being unreachable. |
| const Type* NeverBranchNode::Value(PhaseGVN* phase) const { |
| if (!in(0) || in(0)->is_top()) return Type::TOP; |
| return bottom_type(); |
| } |
| |
| //------------------------------Ideal------------------------------------------ |
| // Check for no longer being part of a loop |
| Node *NeverBranchNode::Ideal(PhaseGVN *phase, bool can_reshape) { |
| if (can_reshape && !in(0)->is_Loop()) { |
| // Dead code elimination can sometimes delete this projection so |
| // if it's not there, there's nothing to do. |
| Node* fallthru = proj_out(0); |
| if (fallthru != NULL) { |
| phase->is_IterGVN()->replace_node(fallthru, in(0)); |
| } |
| return phase->C->top(); |
| } |
| return NULL; |
| } |
| |
| #ifndef PRODUCT |
| void NeverBranchNode::format( PhaseRegAlloc *ra_, outputStream *st) const { |
| st->print("%s", Name()); |
| } |
| #endif |