duke@435: /* xdono@631: * Copyright 1997-2008 Sun Microsystems, Inc. All Rights Reserved. duke@435: * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. duke@435: * duke@435: * This code is free software; you can redistribute it and/or modify it duke@435: * under the terms of the GNU General Public License version 2 only, as duke@435: * published by the Free Software Foundation. duke@435: * duke@435: * This code is distributed in the hope that it will be useful, but WITHOUT duke@435: * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or duke@435: * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License duke@435: * version 2 for more details (a copy is included in the LICENSE file that duke@435: * accompanied this code). duke@435: * duke@435: * You should have received a copy of the GNU General Public License version duke@435: * 2 along with this work; if not, write to the Free Software Foundation, duke@435: * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. duke@435: * duke@435: * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, duke@435: * CA 95054 USA or visit www.sun.com if you need additional information or duke@435: * have any questions. duke@435: * duke@435: */ duke@435: duke@435: // Portions of code courtesy of Clifford Click duke@435: duke@435: // Optimization - Graph Style duke@435: duke@435: #include "incls/_precompiled.incl" duke@435: #include "incls/_cfgnode.cpp.incl" duke@435: duke@435: //============================================================================= duke@435: //------------------------------Value------------------------------------------ duke@435: // Compute the type of the RegionNode. duke@435: const Type *RegionNode::Value( PhaseTransform *phase ) const { duke@435: for( uint i=1; itype(n) == Type::CONTROL ) duke@435: return Type::CONTROL; duke@435: } duke@435: return Type::TOP; // All paths dead? Then so are we duke@435: } duke@435: duke@435: //------------------------------Identity--------------------------------------- duke@435: // Check for Region being Identity. duke@435: Node *RegionNode::Identity( PhaseTransform *phase ) { duke@435: // Cannot have Region be an identity, even if it has only 1 input. duke@435: // Phi users cannot have their Region input folded away for them, duke@435: // since they need to select the proper data input duke@435: return this; duke@435: } duke@435: duke@435: //------------------------------merge_region----------------------------------- duke@435: // If a Region flows into a Region, merge into one big happy merge. This is duke@435: // hard to do if there is stuff that has to happen duke@435: static Node *merge_region(RegionNode *region, PhaseGVN *phase) { duke@435: if( region->Opcode() != Op_Region ) // Do not do to LoopNodes duke@435: return NULL; duke@435: Node *progress = NULL; // Progress flag duke@435: PhaseIterGVN *igvn = phase->is_IterGVN(); duke@435: duke@435: uint rreq = region->req(); duke@435: for( uint i = 1; i < rreq; i++ ) { duke@435: Node *r = region->in(i); duke@435: if( r && r->Opcode() == Op_Region && // Found a region? duke@435: r->in(0) == r && // Not already collapsed? duke@435: r != region && // Avoid stupid situations duke@435: r->outcnt() == 2 ) { // Self user and 'region' user only? duke@435: assert(!r->as_Region()->has_phi(), "no phi users"); duke@435: if( !progress ) { // No progress duke@435: if (region->has_phi()) { duke@435: return NULL; // Only flatten if no Phi users duke@435: // igvn->hash_delete( phi ); duke@435: } duke@435: igvn->hash_delete( region ); duke@435: progress = region; // Making progress duke@435: } duke@435: igvn->hash_delete( r ); duke@435: duke@435: // Append inputs to 'r' onto 'region' duke@435: for( uint j = 1; j < r->req(); j++ ) { duke@435: // Move an input from 'r' to 'region' duke@435: region->add_req(r->in(j)); duke@435: r->set_req(j, phase->C->top()); duke@435: // Update phis of 'region' duke@435: //for( uint k = 0; k < max; k++ ) { duke@435: // Node *phi = region->out(k); duke@435: // if( phi->is_Phi() ) { duke@435: // phi->add_req(phi->in(i)); duke@435: // } duke@435: //} duke@435: duke@435: rreq++; // One more input to Region duke@435: } // Found a region to merge into Region duke@435: // Clobber pointer to the now dead 'r' duke@435: region->set_req(i, phase->C->top()); duke@435: } duke@435: } duke@435: duke@435: return progress; duke@435: } duke@435: duke@435: duke@435: duke@435: //--------------------------------has_phi-------------------------------------- duke@435: // Helper function: Return any PhiNode that uses this region or NULL duke@435: PhiNode* RegionNode::has_phi() const { duke@435: for (DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++) { duke@435: Node* phi = fast_out(i); duke@435: if (phi->is_Phi()) { // Check for Phi users duke@435: assert(phi->in(0) == (Node*)this, "phi uses region only via in(0)"); duke@435: return phi->as_Phi(); // this one is good enough duke@435: } duke@435: } duke@435: duke@435: return NULL; duke@435: } duke@435: duke@435: duke@435: //-----------------------------has_unique_phi---------------------------------- duke@435: // Helper function: Return the only PhiNode that uses this region or NULL duke@435: PhiNode* RegionNode::has_unique_phi() const { duke@435: // Check that only one use is a Phi duke@435: PhiNode* only_phi = NULL; duke@435: for (DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++) { duke@435: Node* phi = fast_out(i); duke@435: if (phi->is_Phi()) { // Check for Phi users duke@435: assert(phi->in(0) == (Node*)this, "phi uses region only via in(0)"); duke@435: if (only_phi == NULL) { duke@435: only_phi = phi->as_Phi(); duke@435: } else { duke@435: return NULL; // multiple phis duke@435: } duke@435: } duke@435: } duke@435: duke@435: return only_phi; duke@435: } duke@435: duke@435: duke@435: //------------------------------check_phi_clipping----------------------------- duke@435: // Helper function for RegionNode's identification of FP clipping duke@435: // Check inputs to the Phi duke@435: static bool check_phi_clipping( PhiNode *phi, ConNode * &min, uint &min_idx, ConNode * &max, uint &max_idx, Node * &val, uint &val_idx ) { duke@435: min = NULL; duke@435: max = NULL; duke@435: val = NULL; duke@435: min_idx = 0; duke@435: max_idx = 0; duke@435: val_idx = 0; duke@435: uint phi_max = phi->req(); duke@435: if( phi_max == 4 ) { duke@435: for( uint j = 1; j < phi_max; ++j ) { duke@435: Node *n = phi->in(j); duke@435: int opcode = n->Opcode(); duke@435: switch( opcode ) { duke@435: case Op_ConI: duke@435: { duke@435: if( min == NULL ) { duke@435: min = n->Opcode() == Op_ConI ? (ConNode*)n : NULL; duke@435: min_idx = j; duke@435: } else { duke@435: max = n->Opcode() == Op_ConI ? (ConNode*)n : NULL; duke@435: max_idx = j; duke@435: if( min->get_int() > max->get_int() ) { duke@435: // Swap min and max duke@435: ConNode *temp; duke@435: uint temp_idx; duke@435: temp = min; min = max; max = temp; duke@435: temp_idx = min_idx; min_idx = max_idx; max_idx = temp_idx; duke@435: } duke@435: } duke@435: } duke@435: break; duke@435: default: duke@435: { duke@435: val = n; duke@435: val_idx = j; duke@435: } duke@435: break; duke@435: } duke@435: } duke@435: } duke@435: return ( min && max && val && (min->get_int() <= 0) && (max->get_int() >=0) ); duke@435: } duke@435: duke@435: duke@435: //------------------------------check_if_clipping------------------------------ duke@435: // Helper function for RegionNode's identification of FP clipping duke@435: // Check that inputs to Region come from two IfNodes, duke@435: // duke@435: // If duke@435: // False True duke@435: // If | duke@435: // False True | duke@435: // | | | duke@435: // RegionNode_inputs duke@435: // duke@435: static bool check_if_clipping( const RegionNode *region, IfNode * &bot_if, IfNode * &top_if ) { duke@435: top_if = NULL; duke@435: bot_if = NULL; duke@435: duke@435: // Check control structure above RegionNode for (if ( if ) ) duke@435: Node *in1 = region->in(1); duke@435: Node *in2 = region->in(2); duke@435: Node *in3 = region->in(3); duke@435: // Check that all inputs are projections duke@435: if( in1->is_Proj() && in2->is_Proj() && in3->is_Proj() ) { duke@435: Node *in10 = in1->in(0); duke@435: Node *in20 = in2->in(0); duke@435: Node *in30 = in3->in(0); duke@435: // Check that #1 and #2 are ifTrue and ifFalse from same If duke@435: if( in10 != NULL && in10->is_If() && duke@435: in20 != NULL && in20->is_If() && duke@435: in30 != NULL && in30->is_If() && in10 == in20 && duke@435: (in1->Opcode() != in2->Opcode()) ) { duke@435: Node *in100 = in10->in(0); duke@435: Node *in1000 = (in100 != NULL && in100->is_Proj()) ? in100->in(0) : NULL; duke@435: // Check that control for in10 comes from other branch of IF from in3 duke@435: if( in1000 != NULL && in1000->is_If() && duke@435: in30 == in1000 && (in3->Opcode() != in100->Opcode()) ) { duke@435: // Control pattern checks duke@435: top_if = (IfNode*)in1000; duke@435: bot_if = (IfNode*)in10; duke@435: } duke@435: } duke@435: } duke@435: duke@435: return (top_if != NULL); duke@435: } duke@435: duke@435: duke@435: //------------------------------check_convf2i_clipping------------------------- duke@435: // Helper function for RegionNode's identification of FP clipping duke@435: // Verify that the value input to the phi comes from "ConvF2I; LShift; RShift" duke@435: static bool check_convf2i_clipping( PhiNode *phi, uint idx, ConvF2INode * &convf2i, Node *min, Node *max) { duke@435: convf2i = NULL; duke@435: duke@435: // Check for the RShiftNode duke@435: Node *rshift = phi->in(idx); duke@435: assert( rshift, "Previous checks ensure phi input is present"); duke@435: if( rshift->Opcode() != Op_RShiftI ) { return false; } duke@435: duke@435: // Check for the LShiftNode duke@435: Node *lshift = rshift->in(1); duke@435: assert( lshift, "Previous checks ensure phi input is present"); duke@435: if( lshift->Opcode() != Op_LShiftI ) { return false; } duke@435: duke@435: // Check for the ConvF2INode duke@435: Node *conv = lshift->in(1); duke@435: if( conv->Opcode() != Op_ConvF2I ) { return false; } duke@435: duke@435: // Check that shift amounts are only to get sign bits set after F2I duke@435: jint max_cutoff = max->get_int(); duke@435: jint min_cutoff = min->get_int(); duke@435: jint left_shift = lshift->in(2)->get_int(); duke@435: jint right_shift = rshift->in(2)->get_int(); duke@435: jint max_post_shift = nth_bit(BitsPerJavaInteger - left_shift - 1); duke@435: if( left_shift != right_shift || duke@435: 0 > left_shift || left_shift >= BitsPerJavaInteger || duke@435: max_post_shift < max_cutoff || duke@435: max_post_shift < -min_cutoff ) { duke@435: // Shifts are necessary but current transformation eliminates them duke@435: return false; duke@435: } duke@435: duke@435: // OK to return the result of ConvF2I without shifting duke@435: convf2i = (ConvF2INode*)conv; duke@435: return true; duke@435: } duke@435: duke@435: duke@435: //------------------------------check_compare_clipping------------------------- duke@435: // Helper function for RegionNode's identification of FP clipping duke@435: static bool check_compare_clipping( bool less_than, IfNode *iff, ConNode *limit, Node * & input ) { duke@435: Node *i1 = iff->in(1); duke@435: if ( !i1->is_Bool() ) { return false; } duke@435: BoolNode *bool1 = i1->as_Bool(); duke@435: if( less_than && bool1->_test._test != BoolTest::le ) { return false; } duke@435: else if( !less_than && bool1->_test._test != BoolTest::lt ) { return false; } duke@435: const Node *cmpF = bool1->in(1); duke@435: if( cmpF->Opcode() != Op_CmpF ) { return false; } duke@435: // Test that the float value being compared against duke@435: // is equivalent to the int value used as a limit duke@435: Node *nodef = cmpF->in(2); duke@435: if( nodef->Opcode() != Op_ConF ) { return false; } duke@435: jfloat conf = nodef->getf(); duke@435: jint coni = limit->get_int(); duke@435: if( ((int)conf) != coni ) { return false; } duke@435: input = cmpF->in(1); duke@435: return true; duke@435: } duke@435: duke@435: //------------------------------is_unreachable_region-------------------------- duke@435: // Find if the Region node is reachable from the root. duke@435: bool RegionNode::is_unreachable_region(PhaseGVN *phase) const { duke@435: assert(req() == 2, ""); duke@435: duke@435: // First, cut the simple case of fallthrough region when NONE of duke@435: // region's phis references itself directly or through a data node. duke@435: uint max = outcnt(); duke@435: uint i; duke@435: for (i = 0; i < max; i++) { duke@435: Node* phi = raw_out(i); duke@435: if (phi != NULL && phi->is_Phi()) { duke@435: assert(phase->eqv(phi->in(0), this) && phi->req() == 2, ""); duke@435: if (phi->outcnt() == 0) duke@435: continue; // Safe case - no loops duke@435: if (phi->outcnt() == 1) { duke@435: Node* u = phi->raw_out(0); duke@435: // Skip if only one use is an other Phi or Call or Uncommon trap. duke@435: // It is safe to consider this case as fallthrough. duke@435: if (u != NULL && (u->is_Phi() || u->is_CFG())) duke@435: continue; duke@435: } duke@435: // Check when phi references itself directly or through an other node. duke@435: if (phi->as_Phi()->simple_data_loop_check(phi->in(1)) >= PhiNode::Unsafe) duke@435: break; // Found possible unsafe data loop. duke@435: } duke@435: } duke@435: if (i >= max) duke@435: return false; // An unsafe case was NOT found - don't need graph walk. duke@435: duke@435: // Unsafe case - check if the Region node is reachable from root. duke@435: ResourceMark rm; duke@435: duke@435: Arena *a = Thread::current()->resource_area(); duke@435: Node_List nstack(a); duke@435: VectorSet visited(a); duke@435: duke@435: // Mark all control nodes reachable from root outputs duke@435: Node *n = (Node*)phase->C->root(); duke@435: nstack.push(n); duke@435: visited.set(n->_idx); duke@435: while (nstack.size() != 0) { duke@435: n = nstack.pop(); duke@435: uint max = n->outcnt(); duke@435: for (uint i = 0; i < max; i++) { duke@435: Node* m = n->raw_out(i); duke@435: if (m != NULL && m->is_CFG()) { duke@435: if (phase->eqv(m, this)) { duke@435: return false; // We reached the Region node - it is not dead. duke@435: } duke@435: if (!visited.test_set(m->_idx)) duke@435: nstack.push(m); duke@435: } duke@435: } duke@435: } duke@435: duke@435: return true; // The Region node is unreachable - it is dead. duke@435: } duke@435: duke@435: //------------------------------Ideal------------------------------------------ duke@435: // Return a node which is more "ideal" than the current node. Must preserve duke@435: // the CFG, but we can still strip out dead paths. duke@435: Node *RegionNode::Ideal(PhaseGVN *phase, bool can_reshape) { duke@435: if( !can_reshape && !in(0) ) return NULL; // Already degraded to a Copy duke@435: assert(!in(0) || !in(0)->is_Root(), "not a specially hidden merge"); duke@435: duke@435: // Check for RegionNode with no Phi users and both inputs come from either duke@435: // arm of the same IF. If found, then the control-flow split is useless. duke@435: bool has_phis = false; duke@435: if (can_reshape) { // Need DU info to check for Phi users duke@435: has_phis = (has_phi() != NULL); // Cache result duke@435: if (!has_phis) { // No Phi users? Nothing merging? duke@435: for (uint i = 1; i < req()-1; i++) { duke@435: Node *if1 = in(i); duke@435: if( !if1 ) continue; duke@435: Node *iff = if1->in(0); duke@435: if( !iff || !iff->is_If() ) continue; duke@435: for( uint j=i+1; jin(0) == iff && duke@435: if1->Opcode() != in(j)->Opcode() ) { duke@435: // Add the IF Projections to the worklist. They (and the IF itself) duke@435: // will be eliminated if dead. duke@435: phase->is_IterGVN()->add_users_to_worklist(iff); duke@435: set_req(i, iff->in(0));// Skip around the useless IF diamond duke@435: set_req(j, NULL); duke@435: return this; // Record progress duke@435: } duke@435: } duke@435: } duke@435: } duke@435: } duke@435: duke@435: // Remove TOP or NULL input paths. If only 1 input path remains, this Region duke@435: // degrades to a copy. duke@435: bool add_to_worklist = false; duke@435: int cnt = 0; // Count of values merging duke@435: DEBUG_ONLY( int cnt_orig = req(); ) // Save original inputs count duke@435: int del_it = 0; // The last input path we delete duke@435: // For all inputs... duke@435: for( uint i=1; iis_Region() && n->as_Region()->is_copy() ) { duke@435: set_req(i, n->nonnull_req()); duke@435: i--; duke@435: continue; duke@435: } duke@435: if( n->is_Proj() ) { // Remove useless rethrows duke@435: Node *call = n->in(0); duke@435: if (call->is_Call() && call->as_Call()->entry_point() == OptoRuntime::rethrow_stub()) { duke@435: set_req(i, call->in(0)); duke@435: i--; duke@435: continue; duke@435: } duke@435: } duke@435: if( phase->type(n) == Type::TOP ) { duke@435: set_req(i, NULL); // Ignore TOP inputs duke@435: i--; duke@435: continue; duke@435: } duke@435: cnt++; // One more value merging duke@435: duke@435: } else if (can_reshape) { // Else found dead path with DU info duke@435: PhaseIterGVN *igvn = phase->is_IterGVN(); duke@435: del_req(i); // Yank path from self duke@435: del_it = i; duke@435: uint max = outcnt(); duke@435: DUIterator j; duke@435: bool progress = true; duke@435: while(progress) { // Need to establish property over all users duke@435: progress = false; duke@435: for (j = outs(); has_out(j); j++) { duke@435: Node *n = out(j); duke@435: if( n->req() != req() && n->is_Phi() ) { duke@435: assert( n->in(0) == this, "" ); duke@435: igvn->hash_delete(n); // Yank from hash before hacking edges duke@435: n->set_req_X(i,NULL,igvn);// Correct DU info duke@435: n->del_req(i); // Yank path from Phis duke@435: if( max != outcnt() ) { duke@435: progress = true; duke@435: j = refresh_out_pos(j); duke@435: max = outcnt(); duke@435: } duke@435: } duke@435: } duke@435: } duke@435: add_to_worklist = true; duke@435: i--; duke@435: } duke@435: } duke@435: duke@435: if (can_reshape && cnt == 1) { duke@435: // Is it dead loop? duke@435: // If it is LoopNopde it had 2 (+1 itself) inputs and duke@435: // one of them was cut. The loop is dead if it was EntryContol. duke@435: assert(!this->is_Loop() || cnt_orig == 3, "Loop node should have 3 inputs"); duke@435: if (this->is_Loop() && del_it == LoopNode::EntryControl || duke@435: !this->is_Loop() && has_phis && is_unreachable_region(phase)) { duke@435: // Yes, the region will be removed during the next step below. duke@435: // Cut the backedge input and remove phis since no data paths left. duke@435: // We don't cut outputs to other nodes here since we need to put them duke@435: // on the worklist. duke@435: del_req(1); duke@435: cnt = 0; duke@435: assert( req() == 1, "no more inputs expected" ); duke@435: uint max = outcnt(); duke@435: bool progress = true; duke@435: Node *top = phase->C->top(); duke@435: PhaseIterGVN *igvn = phase->is_IterGVN(); duke@435: DUIterator j; duke@435: while(progress) { duke@435: progress = false; duke@435: for (j = outs(); has_out(j); j++) { duke@435: Node *n = out(j); duke@435: if( n->is_Phi() ) { duke@435: assert( igvn->eqv(n->in(0), this), "" ); duke@435: assert( n->req() == 2 && n->in(1) != NULL, "Only one data input expected" ); duke@435: // Break dead loop data path. duke@435: // Eagerly replace phis with top to avoid phis copies generation. duke@435: igvn->add_users_to_worklist(n); duke@435: igvn->hash_delete(n); // Yank from hash before hacking edges duke@435: igvn->subsume_node(n, top); duke@435: if( max != outcnt() ) { duke@435: progress = true; duke@435: j = refresh_out_pos(j); duke@435: max = outcnt(); duke@435: } duke@435: } duke@435: } duke@435: } duke@435: add_to_worklist = true; duke@435: } duke@435: } duke@435: if (add_to_worklist) { duke@435: phase->is_IterGVN()->add_users_to_worklist(this); // Revisit collapsed Phis duke@435: } duke@435: duke@435: if( cnt <= 1 ) { // Only 1 path in? duke@435: set_req(0, NULL); // Null control input for region copy duke@435: if( cnt == 0 && !can_reshape) { // Parse phase - leave the node as it is. duke@435: // No inputs or all inputs are NULL. duke@435: return NULL; duke@435: } else if (can_reshape) { // Optimization phase - remove the node duke@435: PhaseIterGVN *igvn = phase->is_IterGVN(); duke@435: Node *parent_ctrl; duke@435: if( cnt == 0 ) { duke@435: assert( req() == 1, "no inputs expected" ); duke@435: // During IGVN phase such region will be subsumed by TOP node duke@435: // so region's phis will have TOP as control node. duke@435: // Kill phis here to avoid it. PhiNode::is_copy() will be always false. duke@435: // Also set other user's input to top. duke@435: parent_ctrl = phase->C->top(); duke@435: } else { duke@435: // The fallthrough case since we already checked dead loops above. duke@435: parent_ctrl = in(1); duke@435: assert(parent_ctrl != NULL, "Region is a copy of some non-null control"); duke@435: assert(!igvn->eqv(parent_ctrl, this), "Close dead loop"); duke@435: } duke@435: if (!add_to_worklist) duke@435: igvn->add_users_to_worklist(this); // Check for further allowed opts duke@435: for (DUIterator_Last imin, i = last_outs(imin); i >= imin; --i) { duke@435: Node* n = last_out(i); duke@435: igvn->hash_delete(n); // Remove from worklist before modifying edges duke@435: if( n->is_Phi() ) { // Collapse all Phis duke@435: // Eagerly replace phis to avoid copies generation. duke@435: igvn->add_users_to_worklist(n); duke@435: igvn->hash_delete(n); // Yank from hash before hacking edges duke@435: if( cnt == 0 ) { duke@435: assert( n->req() == 1, "No data inputs expected" ); duke@435: igvn->subsume_node(n, parent_ctrl); // replaced by top duke@435: } else { duke@435: assert( n->req() == 2 && n->in(1) != NULL, "Only one data input expected" ); duke@435: Node* in1 = n->in(1); // replaced by unique input duke@435: if( n->as_Phi()->is_unsafe_data_reference(in1) ) duke@435: in1 = phase->C->top(); // replaced by top duke@435: igvn->subsume_node(n, in1); duke@435: } duke@435: } duke@435: else if( n->is_Region() ) { // Update all incoming edges duke@435: assert( !igvn->eqv(n, this), "Must be removed from DefUse edges"); duke@435: uint uses_found = 0; duke@435: for( uint k=1; k < n->req(); k++ ) { duke@435: if( n->in(k) == this ) { duke@435: n->set_req(k, parent_ctrl); duke@435: uses_found++; duke@435: } duke@435: } duke@435: if( uses_found > 1 ) { // (--i) done at the end of the loop. duke@435: i -= (uses_found - 1); duke@435: } duke@435: } duke@435: else { duke@435: assert( igvn->eqv(n->in(0), this), "Expect RegionNode to be control parent"); duke@435: n->set_req(0, parent_ctrl); duke@435: } duke@435: #ifdef ASSERT duke@435: for( uint k=0; k < n->req(); k++ ) { duke@435: assert( !igvn->eqv(n->in(k), this), "All uses of RegionNode should be gone"); duke@435: } duke@435: #endif duke@435: } duke@435: // Remove the RegionNode itself from DefUse info duke@435: igvn->remove_dead_node(this); duke@435: return NULL; duke@435: } duke@435: return this; // Record progress duke@435: } duke@435: duke@435: duke@435: // If a Region flows into a Region, merge into one big happy merge. duke@435: if (can_reshape) { duke@435: Node *m = merge_region(this, phase); duke@435: if (m != NULL) return m; duke@435: } duke@435: duke@435: // Check if this region is the root of a clipping idiom on floats duke@435: if( ConvertFloat2IntClipping && can_reshape && req() == 4 ) { duke@435: // Check that only one use is a Phi and that it simplifies to two constants + duke@435: PhiNode* phi = has_unique_phi(); duke@435: if (phi != NULL) { // One Phi user duke@435: // Check inputs to the Phi duke@435: ConNode *min; duke@435: ConNode *max; duke@435: Node *val; duke@435: uint min_idx; duke@435: uint max_idx; duke@435: uint val_idx; duke@435: if( check_phi_clipping( phi, min, min_idx, max, max_idx, val, val_idx ) ) { duke@435: IfNode *top_if; duke@435: IfNode *bot_if; duke@435: if( check_if_clipping( this, bot_if, top_if ) ) { duke@435: // Control pattern checks, now verify compares duke@435: Node *top_in = NULL; // value being compared against duke@435: Node *bot_in = NULL; duke@435: if( check_compare_clipping( true, bot_if, min, bot_in ) && duke@435: check_compare_clipping( false, top_if, max, top_in ) ) { duke@435: if( bot_in == top_in ) { duke@435: PhaseIterGVN *gvn = phase->is_IterGVN(); duke@435: assert( gvn != NULL, "Only had DefUse info in IterGVN"); duke@435: // Only remaining check is that bot_in == top_in == (Phi's val + mods) duke@435: duke@435: // Check for the ConvF2INode duke@435: ConvF2INode *convf2i; duke@435: if( check_convf2i_clipping( phi, val_idx, convf2i, min, max ) && duke@435: convf2i->in(1) == bot_in ) { duke@435: // Matched pattern, including LShiftI; RShiftI, replace with integer compares duke@435: // max test duke@435: Node *cmp = gvn->register_new_node_with_optimizer(new (phase->C, 3) CmpINode( convf2i, min )); duke@435: Node *boo = gvn->register_new_node_with_optimizer(new (phase->C, 2) BoolNode( cmp, BoolTest::lt )); duke@435: IfNode *iff = (IfNode*)gvn->register_new_node_with_optimizer(new (phase->C, 2) IfNode( top_if->in(0), boo, PROB_UNLIKELY_MAG(5), top_if->_fcnt )); duke@435: Node *if_min= gvn->register_new_node_with_optimizer(new (phase->C, 1) IfTrueNode (iff)); duke@435: Node *ifF = gvn->register_new_node_with_optimizer(new (phase->C, 1) IfFalseNode(iff)); duke@435: // min test duke@435: cmp = gvn->register_new_node_with_optimizer(new (phase->C, 3) CmpINode( convf2i, max )); duke@435: boo = gvn->register_new_node_with_optimizer(new (phase->C, 2) BoolNode( cmp, BoolTest::gt )); duke@435: iff = (IfNode*)gvn->register_new_node_with_optimizer(new (phase->C, 2) IfNode( ifF, boo, PROB_UNLIKELY_MAG(5), bot_if->_fcnt )); duke@435: Node *if_max= gvn->register_new_node_with_optimizer(new (phase->C, 1) IfTrueNode (iff)); duke@435: ifF = gvn->register_new_node_with_optimizer(new (phase->C, 1) IfFalseNode(iff)); duke@435: // update input edges to region node duke@435: set_req_X( min_idx, if_min, gvn ); duke@435: set_req_X( max_idx, if_max, gvn ); duke@435: set_req_X( val_idx, ifF, gvn ); duke@435: // remove unnecessary 'LShiftI; RShiftI' idiom duke@435: gvn->hash_delete(phi); duke@435: phi->set_req_X( val_idx, convf2i, gvn ); duke@435: gvn->hash_find_insert(phi); duke@435: // Return transformed region node duke@435: return this; duke@435: } duke@435: } duke@435: } duke@435: } duke@435: } duke@435: } duke@435: } duke@435: duke@435: return NULL; duke@435: } duke@435: duke@435: duke@435: duke@435: const RegMask &RegionNode::out_RegMask() const { duke@435: return RegMask::Empty; duke@435: } duke@435: duke@435: // Find the one non-null required input. RegionNode only duke@435: Node *Node::nonnull_req() const { duke@435: assert( is_Region(), "" ); duke@435: for( uint i = 1; i < _cnt; i++ ) duke@435: if( in(i) ) duke@435: return in(i); duke@435: ShouldNotReachHere(); duke@435: return NULL; duke@435: } duke@435: duke@435: duke@435: //============================================================================= duke@435: // note that these functions assume that the _adr_type field is flattened duke@435: uint PhiNode::hash() const { duke@435: const Type* at = _adr_type; duke@435: return TypeNode::hash() + (at ? at->hash() : 0); duke@435: } duke@435: uint PhiNode::cmp( const Node &n ) const { duke@435: return TypeNode::cmp(n) && _adr_type == ((PhiNode&)n)._adr_type; duke@435: } duke@435: static inline duke@435: const TypePtr* flatten_phi_adr_type(const TypePtr* at) { duke@435: if (at == NULL || at == TypePtr::BOTTOM) return at; duke@435: return Compile::current()->alias_type(at)->adr_type(); duke@435: } duke@435: duke@435: //----------------------------make--------------------------------------------- duke@435: // create a new phi with edges matching r and set (initially) to x duke@435: PhiNode* PhiNode::make(Node* r, Node* x, const Type *t, const TypePtr* at) { duke@435: uint preds = r->req(); // Number of predecessor paths duke@435: assert(t != Type::MEMORY || at == flatten_phi_adr_type(at), "flatten at"); duke@435: PhiNode* p = new (Compile::current(), preds) PhiNode(r, t, at); duke@435: for (uint j = 1; j < preds; j++) { duke@435: // Fill in all inputs, except those which the region does not yet have duke@435: if (r->in(j) != NULL) duke@435: p->init_req(j, x); duke@435: } duke@435: return p; duke@435: } duke@435: PhiNode* PhiNode::make(Node* r, Node* x) { duke@435: const Type* t = x->bottom_type(); duke@435: const TypePtr* at = NULL; duke@435: if (t == Type::MEMORY) at = flatten_phi_adr_type(x->adr_type()); duke@435: return make(r, x, t, at); duke@435: } duke@435: PhiNode* PhiNode::make_blank(Node* r, Node* x) { duke@435: const Type* t = x->bottom_type(); duke@435: const TypePtr* at = NULL; duke@435: if (t == Type::MEMORY) at = flatten_phi_adr_type(x->adr_type()); duke@435: return new (Compile::current(), r->req()) PhiNode(r, t, at); duke@435: } duke@435: duke@435: duke@435: //------------------------slice_memory----------------------------------------- duke@435: // create a new phi with narrowed memory type duke@435: PhiNode* PhiNode::slice_memory(const TypePtr* adr_type) const { duke@435: PhiNode* mem = (PhiNode*) clone(); duke@435: *(const TypePtr**)&mem->_adr_type = adr_type; duke@435: // convert self-loops, or else we get a bad graph duke@435: for (uint i = 1; i < req(); i++) { duke@435: if ((const Node*)in(i) == this) mem->set_req(i, mem); duke@435: } duke@435: mem->verify_adr_type(); duke@435: return mem; duke@435: } duke@435: kvn@509: //------------------------split_out_instance----------------------------------- kvn@509: // Split out an instance type from a bottom phi. kvn@509: PhiNode* PhiNode::split_out_instance(const TypePtr* at, PhaseIterGVN *igvn) const { kvn@598: const TypeOopPtr *t_oop = at->isa_oopptr(); kvn@598: assert(t_oop != NULL && t_oop->is_instance(), "expecting instance oopptr"); kvn@598: const TypePtr *t = adr_type(); kvn@598: assert(type() == Type::MEMORY && kvn@598: (t == TypePtr::BOTTOM || t == TypeRawPtr::BOTTOM || kvn@598: t->isa_oopptr() && !t->is_oopptr()->is_instance() && kvn@598: t->is_oopptr()->cast_to_instance(t_oop->instance_id()) == t_oop), kvn@598: "bottom or raw memory required"); kvn@509: kvn@509: // Check if an appropriate node already exists. kvn@509: Node *region = in(0); kvn@509: for (DUIterator_Fast kmax, k = region->fast_outs(kmax); k < kmax; k++) { kvn@509: Node* use = region->fast_out(k); kvn@509: if( use->is_Phi()) { kvn@509: PhiNode *phi2 = use->as_Phi(); kvn@509: if (phi2->type() == Type::MEMORY && phi2->adr_type() == at) { kvn@509: return phi2; kvn@509: } kvn@509: } kvn@509: } kvn@509: Compile *C = igvn->C; kvn@509: Arena *a = Thread::current()->resource_area(); kvn@509: Node_Array node_map = new Node_Array(a); kvn@509: Node_Stack stack(a, C->unique() >> 4); kvn@509: PhiNode *nphi = slice_memory(at); kvn@509: igvn->register_new_node_with_optimizer( nphi ); kvn@509: node_map.map(_idx, nphi); kvn@509: stack.push((Node *)this, 1); kvn@509: while(!stack.is_empty()) { kvn@509: PhiNode *ophi = stack.node()->as_Phi(); kvn@509: uint i = stack.index(); kvn@509: assert(i >= 1, "not control edge"); kvn@509: stack.pop(); kvn@509: nphi = node_map[ophi->_idx]->as_Phi(); kvn@509: for (; i < ophi->req(); i++) { kvn@509: Node *in = ophi->in(i); kvn@509: if (in == NULL || igvn->type(in) == Type::TOP) kvn@509: continue; kvn@509: Node *opt = MemNode::optimize_simple_memory_chain(in, at, igvn); kvn@509: PhiNode *optphi = opt->is_Phi() ? opt->as_Phi() : NULL; kvn@509: if (optphi != NULL && optphi->adr_type() == TypePtr::BOTTOM) { kvn@509: opt = node_map[optphi->_idx]; kvn@509: if (opt == NULL) { kvn@509: stack.push(ophi, i); kvn@509: nphi = optphi->slice_memory(at); kvn@509: igvn->register_new_node_with_optimizer( nphi ); kvn@509: node_map.map(optphi->_idx, nphi); kvn@509: ophi = optphi; kvn@509: i = 0; // will get incremented at top of loop kvn@509: continue; kvn@509: } kvn@509: } kvn@509: nphi->set_req(i, opt); kvn@509: } kvn@509: } kvn@509: return nphi; kvn@509: } kvn@509: duke@435: //------------------------verify_adr_type-------------------------------------- duke@435: #ifdef ASSERT duke@435: void PhiNode::verify_adr_type(VectorSet& visited, const TypePtr* at) const { duke@435: if (visited.test_set(_idx)) return; //already visited duke@435: duke@435: // recheck constructor invariants: duke@435: verify_adr_type(false); duke@435: duke@435: // recheck local phi/phi consistency: duke@435: assert(_adr_type == at || _adr_type == TypePtr::BOTTOM, duke@435: "adr_type must be consistent across phi nest"); duke@435: duke@435: // walk around duke@435: for (uint i = 1; i < req(); i++) { duke@435: Node* n = in(i); duke@435: if (n == NULL) continue; duke@435: const Node* np = in(i); duke@435: if (np->is_Phi()) { duke@435: np->as_Phi()->verify_adr_type(visited, at); duke@435: } else if (n->bottom_type() == Type::TOP duke@435: || (n->is_Mem() && n->in(MemNode::Address)->bottom_type() == Type::TOP)) { duke@435: // ignore top inputs duke@435: } else { duke@435: const TypePtr* nat = flatten_phi_adr_type(n->adr_type()); duke@435: // recheck phi/non-phi consistency at leaves: duke@435: assert((nat != NULL) == (at != NULL), ""); duke@435: assert(nat == at || nat == TypePtr::BOTTOM, duke@435: "adr_type must be consistent at leaves of phi nest"); duke@435: } duke@435: } duke@435: } duke@435: duke@435: // Verify a whole nest of phis rooted at this one. duke@435: void PhiNode::verify_adr_type(bool recursive) const { duke@435: if (is_error_reported()) return; // muzzle asserts when debugging an error duke@435: if (Node::in_dump()) return; // muzzle asserts when printing duke@435: duke@435: assert((_type == Type::MEMORY) == (_adr_type != NULL), "adr_type for memory phis only"); duke@435: duke@435: if (!VerifyAliases) return; // verify thoroughly only if requested duke@435: duke@435: assert(_adr_type == flatten_phi_adr_type(_adr_type), duke@435: "Phi::adr_type must be pre-normalized"); duke@435: duke@435: if (recursive) { duke@435: VectorSet visited(Thread::current()->resource_area()); duke@435: verify_adr_type(visited, _adr_type); duke@435: } duke@435: } duke@435: #endif duke@435: duke@435: duke@435: //------------------------------Value------------------------------------------ duke@435: // Compute the type of the PhiNode duke@435: const Type *PhiNode::Value( PhaseTransform *phase ) const { duke@435: Node *r = in(0); // RegionNode duke@435: if( !r ) // Copy or dead duke@435: return in(1) ? phase->type(in(1)) : Type::TOP; duke@435: duke@435: // Note: During parsing, phis are often transformed before their regions. duke@435: // This means we have to use type_or_null to defend against untyped regions. duke@435: if( phase->type_or_null(r) == Type::TOP ) // Dead code? duke@435: return Type::TOP; duke@435: duke@435: // Check for trip-counted loop. If so, be smarter. duke@435: CountedLoopNode *l = r->is_CountedLoop() ? r->as_CountedLoop() : NULL; duke@435: if( l && l->can_be_counted_loop(phase) && duke@435: ((const Node*)l->phi() == this) ) { // Trip counted loop! duke@435: // protect against init_trip() or limit() returning NULL duke@435: const Node *init = l->init_trip(); duke@435: const Node *limit = l->limit(); duke@435: if( init != NULL && limit != NULL && l->stride_is_con() ) { duke@435: const TypeInt *lo = init ->bottom_type()->isa_int(); duke@435: const TypeInt *hi = limit->bottom_type()->isa_int(); duke@435: if( lo && hi ) { // Dying loops might have TOP here duke@435: int stride = l->stride_con(); duke@435: if( stride < 0 ) { // Down-counter loop duke@435: const TypeInt *tmp = lo; lo = hi; hi = tmp; duke@435: stride = -stride; duke@435: } duke@435: if( lo->_hi < hi->_lo ) // Reversed endpoints are well defined :-( duke@435: return TypeInt::make(lo->_lo,hi->_hi,3); duke@435: } duke@435: } duke@435: } duke@435: duke@435: // Until we have harmony between classes and interfaces in the type duke@435: // lattice, we must tread carefully around phis which implicitly duke@435: // convert the one to the other. coleenp@548: const TypeInstPtr* ttip = _type->isa_narrowoop() ? _type->isa_narrowoop()->make_oopptr()->isa_instptr() :_type->isa_instptr(); duke@435: bool is_intf = false; duke@435: if (ttip != NULL) { duke@435: ciKlass* k = ttip->klass(); duke@435: if (k->is_loaded() && k->is_interface()) duke@435: is_intf = true; duke@435: } duke@435: duke@435: // Default case: merge all inputs duke@435: const Type *t = Type::TOP; // Merged type starting value duke@435: for (uint i = 1; i < req(); ++i) {// For all paths in duke@435: // Reachable control path? duke@435: if (r->in(i) && phase->type(r->in(i)) == Type::CONTROL) { duke@435: const Type* ti = phase->type(in(i)); duke@435: // We assume that each input of an interface-valued Phi is a true duke@435: // subtype of that interface. This might not be true of the meet duke@435: // of all the input types. The lattice is not distributive in duke@435: // such cases. Ward off asserts in type.cpp by refusing to do duke@435: // meets between interfaces and proper classes. coleenp@548: const TypeInstPtr* tiip = ti->isa_narrowoop() ? ti->is_narrowoop()->make_oopptr()->isa_instptr() : ti->isa_instptr(); duke@435: if (tiip) { duke@435: bool ti_is_intf = false; duke@435: ciKlass* k = tiip->klass(); duke@435: if (k->is_loaded() && k->is_interface()) duke@435: ti_is_intf = true; duke@435: if (is_intf != ti_is_intf) duke@435: { t = _type; break; } duke@435: } duke@435: t = t->meet(ti); duke@435: } duke@435: } duke@435: duke@435: // The worst-case type (from ciTypeFlow) should be consistent with "t". duke@435: // That is, we expect that "t->higher_equal(_type)" holds true. duke@435: // There are various exceptions: duke@435: // - Inputs which are phis might in fact be widened unnecessarily. duke@435: // For example, an input might be a widened int while the phi is a short. duke@435: // - Inputs might be BotPtrs but this phi is dependent on a null check, duke@435: // and postCCP has removed the cast which encodes the result of the check. duke@435: // - The type of this phi is an interface, and the inputs are classes. duke@435: // - Value calls on inputs might produce fuzzy results. duke@435: // (Occurrences of this case suggest improvements to Value methods.) duke@435: // duke@435: // It is not possible to see Type::BOTTOM values as phi inputs, duke@435: // because the ciTypeFlow pre-pass produces verifier-quality types. duke@435: const Type* ft = t->filter(_type); // Worst case type duke@435: duke@435: #ifdef ASSERT duke@435: // The following logic has been moved into TypeOopPtr::filter. duke@435: const Type* jt = t->join(_type); duke@435: if( jt->empty() ) { // Emptied out??? duke@435: duke@435: // Check for evil case of 't' being a class and '_type' expecting an duke@435: // interface. This can happen because the bytecodes do not contain duke@435: // enough type info to distinguish a Java-level interface variable duke@435: // from a Java-level object variable. If we meet 2 classes which duke@435: // both implement interface I, but their meet is at 'j/l/O' which duke@435: // doesn't implement I, we have no way to tell if the result should duke@435: // be 'I' or 'j/l/O'. Thus we'll pick 'j/l/O'. If this then flows duke@435: // into a Phi which "knows" it's an Interface type we'll have to duke@435: // uplift the type. duke@435: if( !t->empty() && ttip && ttip->is_loaded() && ttip->klass()->is_interface() ) duke@435: { assert(ft == _type, ""); } // Uplift to interface duke@435: // Otherwise it's something stupid like non-overlapping int ranges duke@435: // found on dying counted loops. duke@435: else duke@435: { assert(ft == Type::TOP, ""); } // Canonical empty value duke@435: } duke@435: duke@435: else { duke@435: duke@435: // If we have an interface-typed Phi and we narrow to a class type, the join duke@435: // should report back the class. However, if we have a J/L/Object duke@435: // class-typed Phi and an interface flows in, it's possible that the meet & duke@435: // join report an interface back out. This isn't possible but happens duke@435: // because the type system doesn't interact well with interfaces. coleenp@548: const TypeInstPtr *jtip = jt->isa_narrowoop() ? jt->isa_narrowoop()->make_oopptr()->isa_instptr() : jt->isa_instptr(); duke@435: if( jtip && ttip ) { duke@435: if( jtip->is_loaded() && jtip->klass()->is_interface() && coleenp@548: ttip->is_loaded() && !ttip->klass()->is_interface() ) { duke@435: // Happens in a CTW of rt.jar, 320-341, no extra flags coleenp@548: assert(ft == ttip->cast_to_ptr_type(jtip->ptr()) || coleenp@548: ft->isa_narrowoop() && ft->isa_narrowoop()->make_oopptr() == ttip->cast_to_ptr_type(jtip->ptr()), ""); coleenp@548: jt = ft; coleenp@548: } duke@435: } duke@435: if (jt != ft && jt->base() == ft->base()) { duke@435: if (jt->isa_int() && duke@435: jt->is_int()->_lo == ft->is_int()->_lo && duke@435: jt->is_int()->_hi == ft->is_int()->_hi) duke@435: jt = ft; duke@435: if (jt->isa_long() && duke@435: jt->is_long()->_lo == ft->is_long()->_lo && duke@435: jt->is_long()->_hi == ft->is_long()->_hi) duke@435: jt = ft; duke@435: } duke@435: if (jt != ft) { duke@435: tty->print("merge type: "); t->dump(); tty->cr(); duke@435: tty->print("kill type: "); _type->dump(); tty->cr(); duke@435: tty->print("join type: "); jt->dump(); tty->cr(); duke@435: tty->print("filter type: "); ft->dump(); tty->cr(); duke@435: } duke@435: assert(jt == ft, ""); duke@435: } duke@435: #endif //ASSERT duke@435: duke@435: // Deal with conversion problems found in data loops. duke@435: ft = phase->saturate(ft, phase->type_or_null(this), _type); duke@435: duke@435: return ft; duke@435: } duke@435: duke@435: duke@435: //------------------------------is_diamond_phi--------------------------------- duke@435: // Does this Phi represent a simple well-shaped diamond merge? Return the duke@435: // index of the true path or 0 otherwise. duke@435: int PhiNode::is_diamond_phi() const { duke@435: // Check for a 2-path merge duke@435: Node *region = in(0); duke@435: if( !region ) return 0; duke@435: if( region->req() != 3 ) return 0; duke@435: if( req() != 3 ) return 0; duke@435: // Check that both paths come from the same If duke@435: Node *ifp1 = region->in(1); duke@435: Node *ifp2 = region->in(2); duke@435: if( !ifp1 || !ifp2 ) return 0; duke@435: Node *iff = ifp1->in(0); duke@435: if( !iff || !iff->is_If() ) return 0; duke@435: if( iff != ifp2->in(0) ) return 0; duke@435: // Check for a proper bool/cmp duke@435: const Node *b = iff->in(1); duke@435: if( !b->is_Bool() ) return 0; duke@435: const Node *cmp = b->in(1); duke@435: if( !cmp->is_Cmp() ) return 0; duke@435: duke@435: // Check for branching opposite expected duke@435: if( ifp2->Opcode() == Op_IfTrue ) { duke@435: assert( ifp1->Opcode() == Op_IfFalse, "" ); duke@435: return 2; duke@435: } else { duke@435: assert( ifp1->Opcode() == Op_IfTrue, "" ); duke@435: return 1; duke@435: } duke@435: } duke@435: duke@435: //----------------------------check_cmove_id----------------------------------- duke@435: // Check for CMove'ing a constant after comparing against the constant. duke@435: // Happens all the time now, since if we compare equality vs a constant in duke@435: // the parser, we "know" the variable is constant on one path and we force duke@435: // it. Thus code like "if( x==0 ) {/*EMPTY*/}" ends up inserting a duke@435: // conditional move: "x = (x==0)?0:x;". Yucko. This fix is slightly more duke@435: // general in that we don't need constants. Since CMove's are only inserted duke@435: // in very special circumstances, we do it here on generic Phi's. duke@435: Node* PhiNode::is_cmove_id(PhaseTransform* phase, int true_path) { duke@435: assert(true_path !=0, "only diamond shape graph expected"); duke@435: duke@435: // is_diamond_phi() has guaranteed the correctness of the nodes sequence: duke@435: // phi->region->if_proj->ifnode->bool->cmp duke@435: Node* region = in(0); duke@435: Node* iff = region->in(1)->in(0); duke@435: BoolNode* b = iff->in(1)->as_Bool(); duke@435: Node* cmp = b->in(1); duke@435: Node* tval = in(true_path); duke@435: Node* fval = in(3-true_path); duke@435: Node* id = CMoveNode::is_cmove_id(phase, cmp, tval, fval, b); duke@435: if (id == NULL) duke@435: return NULL; duke@435: duke@435: // Either value might be a cast that depends on a branch of 'iff'. duke@435: // Since the 'id' value will float free of the diamond, either duke@435: // decast or return failure. duke@435: Node* ctl = id->in(0); duke@435: if (ctl != NULL && ctl->in(0) == iff) { duke@435: if (id->is_ConstraintCast()) { duke@435: return id->in(1); duke@435: } else { duke@435: // Don't know how to disentangle this value. duke@435: return NULL; duke@435: } duke@435: } duke@435: duke@435: return id; duke@435: } duke@435: duke@435: //------------------------------Identity--------------------------------------- duke@435: // Check for Region being Identity. duke@435: Node *PhiNode::Identity( PhaseTransform *phase ) { duke@435: // Check for no merging going on duke@435: // (There used to be special-case code here when this->region->is_Loop. duke@435: // It would check for a tributary phi on the backedge that the main phi duke@435: // trivially, perhaps with a single cast. The unique_input method duke@435: // does all this and more, by reducing such tributaries to 'this'.) duke@435: Node* uin = unique_input(phase); duke@435: if (uin != NULL) { duke@435: return uin; duke@435: } duke@435: duke@435: int true_path = is_diamond_phi(); duke@435: if (true_path != 0) { duke@435: Node* id = is_cmove_id(phase, true_path); duke@435: if (id != NULL) return id; duke@435: } duke@435: duke@435: return this; // No identity duke@435: } duke@435: duke@435: //-----------------------------unique_input------------------------------------ duke@435: // Find the unique value, discounting top, self-loops, and casts. duke@435: // Return top if there are no inputs, and self if there are multiple. duke@435: Node* PhiNode::unique_input(PhaseTransform* phase) { duke@435: // 1) One unique direct input, or duke@435: // 2) some of the inputs have an intervening ConstraintCast and duke@435: // the type of input is the same or sharper (more specific) duke@435: // than the phi's type. duke@435: // 3) an input is a self loop duke@435: // duke@435: // 1) input or 2) input or 3) input __ duke@435: // / \ / \ \ / \ duke@435: // \ / | cast phi cast duke@435: // phi \ / / \ / duke@435: // phi / -- duke@435: duke@435: Node* r = in(0); // RegionNode duke@435: if (r == NULL) return in(1); // Already degraded to a Copy duke@435: Node* uncasted_input = NULL; // The unique uncasted input (ConstraintCasts removed) duke@435: Node* direct_input = NULL; // The unique direct input duke@435: duke@435: for (uint i = 1, cnt = req(); i < cnt; ++i) { duke@435: Node* rc = r->in(i); duke@435: if (rc == NULL || phase->type(rc) == Type::TOP) duke@435: continue; // ignore unreachable control path duke@435: Node* n = in(i); duke@435: Node* un = n->uncast(); duke@435: if (un == NULL || un == this || phase->type(un) == Type::TOP) { duke@435: continue; // ignore if top, or in(i) and "this" are in a data cycle duke@435: } duke@435: // Check for a unique uncasted input duke@435: if (uncasted_input == NULL) { duke@435: uncasted_input = un; duke@435: } else if (uncasted_input != un) { duke@435: uncasted_input = NodeSentinel; // no unique uncasted input duke@435: } duke@435: // Check for a unique direct input duke@435: if (direct_input == NULL) { duke@435: direct_input = n; duke@435: } else if (direct_input != n) { duke@435: direct_input = NodeSentinel; // no unique direct input duke@435: } duke@435: } duke@435: if (direct_input == NULL) { duke@435: return phase->C->top(); // no inputs duke@435: } duke@435: assert(uncasted_input != NULL,""); duke@435: duke@435: if (direct_input != NodeSentinel) { duke@435: return direct_input; // one unique direct input duke@435: } duke@435: if (uncasted_input != NodeSentinel && duke@435: phase->type(uncasted_input)->higher_equal(type())) { duke@435: return uncasted_input; // one unique uncasted input duke@435: } duke@435: duke@435: // Nothing. duke@435: return NULL; duke@435: } duke@435: duke@435: //------------------------------is_x2logic------------------------------------- duke@435: // Check for simple convert-to-boolean pattern duke@435: // If:(C Bool) Region:(IfF IfT) Phi:(Region 0 1) duke@435: // Convert Phi to an ConvIB. duke@435: static Node *is_x2logic( PhaseGVN *phase, PhiNode *phi, int true_path ) { duke@435: assert(true_path !=0, "only diamond shape graph expected"); duke@435: // Convert the true/false index into an expected 0/1 return. duke@435: // Map 2->0 and 1->1. duke@435: int flipped = 2-true_path; duke@435: duke@435: // is_diamond_phi() has guaranteed the correctness of the nodes sequence: duke@435: // phi->region->if_proj->ifnode->bool->cmp duke@435: Node *region = phi->in(0); duke@435: Node *iff = region->in(1)->in(0); duke@435: BoolNode *b = (BoolNode*)iff->in(1); duke@435: const CmpNode *cmp = (CmpNode*)b->in(1); duke@435: duke@435: Node *zero = phi->in(1); duke@435: Node *one = phi->in(2); duke@435: const Type *tzero = phase->type( zero ); duke@435: const Type *tone = phase->type( one ); duke@435: duke@435: // Check for compare vs 0 duke@435: const Type *tcmp = phase->type(cmp->in(2)); duke@435: if( tcmp != TypeInt::ZERO && tcmp != TypePtr::NULL_PTR ) { duke@435: // Allow cmp-vs-1 if the other input is bounded by 0-1 duke@435: if( !(tcmp == TypeInt::ONE && phase->type(cmp->in(1)) == TypeInt::BOOL) ) duke@435: return NULL; duke@435: flipped = 1-flipped; // Test is vs 1 instead of 0! duke@435: } duke@435: duke@435: // Check for setting zero/one opposite expected duke@435: if( tzero == TypeInt::ZERO ) { duke@435: if( tone == TypeInt::ONE ) { duke@435: } else return NULL; duke@435: } else if( tzero == TypeInt::ONE ) { duke@435: if( tone == TypeInt::ZERO ) { duke@435: flipped = 1-flipped; duke@435: } else return NULL; duke@435: } else return NULL; duke@435: duke@435: // Check for boolean test backwards duke@435: if( b->_test._test == BoolTest::ne ) { duke@435: } else if( b->_test._test == BoolTest::eq ) { duke@435: flipped = 1-flipped; duke@435: } else return NULL; duke@435: duke@435: // Build int->bool conversion duke@435: Node *n = new (phase->C, 2) Conv2BNode( cmp->in(1) ); duke@435: if( flipped ) duke@435: n = new (phase->C, 3) XorINode( phase->transform(n), phase->intcon(1) ); duke@435: duke@435: return n; duke@435: } duke@435: duke@435: //------------------------------is_cond_add------------------------------------ duke@435: // Check for simple conditional add pattern: "(P < Q) ? X+Y : X;" duke@435: // To be profitable the control flow has to disappear; there can be no other duke@435: // values merging here. We replace the test-and-branch with: duke@435: // "(sgn(P-Q))&Y) + X". Basically, convert "(P < Q)" into 0 or -1 by duke@435: // moving the carry bit from (P-Q) into a register with 'sbb EAX,EAX'. duke@435: // Then convert Y to 0-or-Y and finally add. duke@435: // This is a key transform for SpecJava _201_compress. duke@435: static Node* is_cond_add(PhaseGVN *phase, PhiNode *phi, int true_path) { duke@435: assert(true_path !=0, "only diamond shape graph expected"); duke@435: duke@435: // is_diamond_phi() has guaranteed the correctness of the nodes sequence: duke@435: // phi->region->if_proj->ifnode->bool->cmp duke@435: RegionNode *region = (RegionNode*)phi->in(0); duke@435: Node *iff = region->in(1)->in(0); duke@435: BoolNode* b = iff->in(1)->as_Bool(); duke@435: const CmpNode *cmp = (CmpNode*)b->in(1); duke@435: duke@435: // Make sure only merging this one phi here duke@435: if (region->has_unique_phi() != phi) return NULL; duke@435: duke@435: // Make sure each arm of the diamond has exactly one output, which we assume duke@435: // is the region. Otherwise, the control flow won't disappear. duke@435: if (region->in(1)->outcnt() != 1) return NULL; duke@435: if (region->in(2)->outcnt() != 1) return NULL; duke@435: duke@435: // Check for "(P < Q)" of type signed int duke@435: if (b->_test._test != BoolTest::lt) return NULL; duke@435: if (cmp->Opcode() != Op_CmpI) return NULL; duke@435: duke@435: Node *p = cmp->in(1); duke@435: Node *q = cmp->in(2); duke@435: Node *n1 = phi->in( true_path); duke@435: Node *n2 = phi->in(3-true_path); duke@435: duke@435: int op = n1->Opcode(); duke@435: if( op != Op_AddI // Need zero as additive identity duke@435: /*&&op != Op_SubI && duke@435: op != Op_AddP && duke@435: op != Op_XorI && duke@435: op != Op_OrI*/ ) duke@435: return NULL; duke@435: duke@435: Node *x = n2; duke@435: Node *y = n1->in(1); duke@435: if( n2 == n1->in(1) ) { duke@435: y = n1->in(2); duke@435: } else if( n2 == n1->in(1) ) { duke@435: } else return NULL; duke@435: duke@435: // Not so profitable if compare and add are constants duke@435: if( q->is_Con() && phase->type(q) != TypeInt::ZERO && y->is_Con() ) duke@435: return NULL; duke@435: duke@435: Node *cmplt = phase->transform( new (phase->C, 3) CmpLTMaskNode(p,q) ); duke@435: Node *j_and = phase->transform( new (phase->C, 3) AndINode(cmplt,y) ); duke@435: return new (phase->C, 3) AddINode(j_and,x); duke@435: } duke@435: duke@435: //------------------------------is_absolute------------------------------------ duke@435: // Check for absolute value. duke@435: static Node* is_absolute( PhaseGVN *phase, PhiNode *phi_root, int true_path) { duke@435: assert(true_path !=0, "only diamond shape graph expected"); duke@435: duke@435: int cmp_zero_idx = 0; // Index of compare input where to look for zero duke@435: int phi_x_idx = 0; // Index of phi input where to find naked x duke@435: duke@435: // ABS ends with the merge of 2 control flow paths. duke@435: // Find the false path from the true path. With only 2 inputs, 3 - x works nicely. duke@435: int false_path = 3 - true_path; duke@435: duke@435: // is_diamond_phi() has guaranteed the correctness of the nodes sequence: duke@435: // phi->region->if_proj->ifnode->bool->cmp duke@435: BoolNode *bol = phi_root->in(0)->in(1)->in(0)->in(1)->as_Bool(); duke@435: duke@435: // Check bool sense duke@435: switch( bol->_test._test ) { duke@435: case BoolTest::lt: cmp_zero_idx = 1; phi_x_idx = true_path; break; duke@435: case BoolTest::le: cmp_zero_idx = 2; phi_x_idx = false_path; break; duke@435: case BoolTest::gt: cmp_zero_idx = 2; phi_x_idx = true_path; break; duke@435: case BoolTest::ge: cmp_zero_idx = 1; phi_x_idx = false_path; break; duke@435: default: return NULL; break; duke@435: } duke@435: duke@435: // Test is next duke@435: Node *cmp = bol->in(1); duke@435: const Type *tzero = NULL; duke@435: switch( cmp->Opcode() ) { duke@435: case Op_CmpF: tzero = TypeF::ZERO; break; // Float ABS duke@435: case Op_CmpD: tzero = TypeD::ZERO; break; // Double ABS duke@435: default: return NULL; duke@435: } duke@435: duke@435: // Find zero input of compare; the other input is being abs'd duke@435: Node *x = NULL; duke@435: bool flip = false; duke@435: if( phase->type(cmp->in(cmp_zero_idx)) == tzero ) { duke@435: x = cmp->in(3 - cmp_zero_idx); duke@435: } else if( phase->type(cmp->in(3 - cmp_zero_idx)) == tzero ) { duke@435: // The test is inverted, we should invert the result... duke@435: x = cmp->in(cmp_zero_idx); duke@435: flip = true; duke@435: } else { duke@435: return NULL; duke@435: } duke@435: duke@435: // Next get the 2 pieces being selected, one is the original value duke@435: // and the other is the negated value. duke@435: if( phi_root->in(phi_x_idx) != x ) return NULL; duke@435: duke@435: // Check other phi input for subtract node duke@435: Node *sub = phi_root->in(3 - phi_x_idx); duke@435: duke@435: // Allow only Sub(0,X) and fail out for all others; Neg is not OK duke@435: if( tzero == TypeF::ZERO ) { duke@435: if( sub->Opcode() != Op_SubF || duke@435: sub->in(2) != x || duke@435: phase->type(sub->in(1)) != tzero ) return NULL; duke@435: x = new (phase->C, 2) AbsFNode(x); duke@435: if (flip) { duke@435: x = new (phase->C, 3) SubFNode(sub->in(1), phase->transform(x)); duke@435: } duke@435: } else { duke@435: if( sub->Opcode() != Op_SubD || duke@435: sub->in(2) != x || duke@435: phase->type(sub->in(1)) != tzero ) return NULL; duke@435: x = new (phase->C, 2) AbsDNode(x); duke@435: if (flip) { duke@435: x = new (phase->C, 3) SubDNode(sub->in(1), phase->transform(x)); duke@435: } duke@435: } duke@435: duke@435: return x; duke@435: } duke@435: duke@435: //------------------------------split_once------------------------------------- duke@435: // Helper for split_flow_path duke@435: static void split_once(PhaseIterGVN *igvn, Node *phi, Node *val, Node *n, Node *newn) { duke@435: igvn->hash_delete(n); // Remove from hash before hacking edges duke@435: duke@435: uint j = 1; duke@435: for( uint i = phi->req()-1; i > 0; i-- ) { duke@435: if( phi->in(i) == val ) { // Found a path with val? duke@435: // Add to NEW Region/Phi, no DU info duke@435: newn->set_req( j++, n->in(i) ); duke@435: // Remove from OLD Region/Phi duke@435: n->del_req(i); duke@435: } duke@435: } duke@435: duke@435: // Register the new node but do not transform it. Cannot transform until the duke@435: // entire Region/Phi conglerate has been hacked as a single huge transform. duke@435: igvn->register_new_node_with_optimizer( newn ); duke@435: // Now I can point to the new node. duke@435: n->add_req(newn); duke@435: igvn->_worklist.push(n); duke@435: } duke@435: duke@435: //------------------------------split_flow_path-------------------------------- duke@435: // Check for merging identical values and split flow paths duke@435: static Node* split_flow_path(PhaseGVN *phase, PhiNode *phi) { duke@435: BasicType bt = phi->type()->basic_type(); duke@435: if( bt == T_ILLEGAL || type2size[bt] <= 0 ) duke@435: return NULL; // Bail out on funny non-value stuff duke@435: if( phi->req() <= 3 ) // Need at least 2 matched inputs and a duke@435: return NULL; // third unequal input to be worth doing duke@435: duke@435: // Scan for a constant duke@435: uint i; duke@435: for( i = 1; i < phi->req()-1; i++ ) { duke@435: Node *n = phi->in(i); duke@435: if( !n ) return NULL; duke@435: if( phase->type(n) == Type::TOP ) return NULL; kvn@598: if( n->Opcode() == Op_ConP || n->Opcode() == Op_ConN ) duke@435: break; duke@435: } duke@435: if( i >= phi->req() ) // Only split for constants duke@435: return NULL; duke@435: duke@435: Node *val = phi->in(i); // Constant to split for duke@435: uint hit = 0; // Number of times it occurs duke@435: duke@435: for( ; i < phi->req(); i++ ){ // Count occurances of constant duke@435: Node *n = phi->in(i); duke@435: if( !n ) return NULL; duke@435: if( phase->type(n) == Type::TOP ) return NULL; duke@435: if( phi->in(i) == val ) duke@435: hit++; duke@435: } duke@435: duke@435: if( hit <= 1 || // Make sure we find 2 or more duke@435: hit == phi->req()-1 ) // and not ALL the same value duke@435: return NULL; duke@435: duke@435: // Now start splitting out the flow paths that merge the same value. duke@435: // Split first the RegionNode. duke@435: PhaseIterGVN *igvn = phase->is_IterGVN(); duke@435: Node *r = phi->region(); duke@435: RegionNode *newr = new (phase->C, hit+1) RegionNode(hit+1); duke@435: split_once(igvn, phi, val, r, newr); duke@435: duke@435: // Now split all other Phis than this one duke@435: for (DUIterator_Fast kmax, k = r->fast_outs(kmax); k < kmax; k++) { duke@435: Node* phi2 = r->fast_out(k); duke@435: if( phi2->is_Phi() && phi2->as_Phi() != phi ) { duke@435: PhiNode *newphi = PhiNode::make_blank(newr, phi2); duke@435: split_once(igvn, phi, val, phi2, newphi); duke@435: } duke@435: } duke@435: duke@435: // Clean up this guy duke@435: igvn->hash_delete(phi); duke@435: for( i = phi->req()-1; i > 0; i-- ) { duke@435: if( phi->in(i) == val ) { duke@435: phi->del_req(i); duke@435: } duke@435: } duke@435: phi->add_req(val); duke@435: duke@435: return phi; duke@435: } duke@435: duke@435: //============================================================================= duke@435: //------------------------------simple_data_loop_check------------------------- duke@435: // Try to determing if the phi node in a simple safe/unsafe data loop. duke@435: // Returns: duke@435: // enum LoopSafety { Safe = 0, Unsafe, UnsafeLoop }; duke@435: // Safe - safe case when the phi and it's inputs reference only safe data duke@435: // nodes; duke@435: // Unsafe - the phi and it's inputs reference unsafe data nodes but there duke@435: // is no reference back to the phi - need a graph walk duke@435: // to determine if it is in a loop; duke@435: // UnsafeLoop - unsafe case when the phi references itself directly or through duke@435: // unsafe data node. duke@435: // Note: a safe data node is a node which could/never reference itself during duke@435: // GVN transformations. For now it is Con, Proj, Phi, CastPP, CheckCastPP. duke@435: // I mark Phi nodes as safe node not only because they can reference itself duke@435: // but also to prevent mistaking the fallthrough case inside an outer loop duke@435: // as dead loop when the phi references itselfs through an other phi. duke@435: PhiNode::LoopSafety PhiNode::simple_data_loop_check(Node *in) const { duke@435: // It is unsafe loop if the phi node references itself directly. duke@435: if (in == (Node*)this) duke@435: return UnsafeLoop; // Unsafe loop duke@435: // Unsafe loop if the phi node references itself through an unsafe data node. duke@435: // Exclude cases with null inputs or data nodes which could reference duke@435: // itself (safe for dead loops). duke@435: if (in != NULL && !in->is_dead_loop_safe()) { duke@435: // Check inputs of phi's inputs also. duke@435: // It is much less expensive then full graph walk. duke@435: uint cnt = in->req(); kvn@561: uint i = (in->is_Proj() && !in->is_CFG()) ? 0 : 1; kvn@561: for (; i < cnt; ++i) { duke@435: Node* m = in->in(i); duke@435: if (m == (Node*)this) duke@435: return UnsafeLoop; // Unsafe loop duke@435: if (m != NULL && !m->is_dead_loop_safe()) { duke@435: // Check the most common case (about 30% of all cases): duke@435: // phi->Load/Store->AddP->(ConP ConP Con)/(Parm Parm Con). duke@435: Node *m1 = (m->is_AddP() && m->req() > 3) ? m->in(1) : NULL; duke@435: if (m1 == (Node*)this) duke@435: return UnsafeLoop; // Unsafe loop duke@435: if (m1 != NULL && m1 == m->in(2) && duke@435: m1->is_dead_loop_safe() && m->in(3)->is_Con()) { duke@435: continue; // Safe case duke@435: } duke@435: // The phi references an unsafe node - need full analysis. duke@435: return Unsafe; duke@435: } duke@435: } duke@435: } duke@435: return Safe; // Safe case - we can optimize the phi node. duke@435: } duke@435: duke@435: //------------------------------is_unsafe_data_reference----------------------- duke@435: // If phi can be reached through the data input - it is data loop. duke@435: bool PhiNode::is_unsafe_data_reference(Node *in) const { duke@435: assert(req() > 1, ""); duke@435: // First, check simple cases when phi references itself directly or duke@435: // through an other node. duke@435: LoopSafety safety = simple_data_loop_check(in); duke@435: if (safety == UnsafeLoop) duke@435: return true; // phi references itself - unsafe loop duke@435: else if (safety == Safe) duke@435: return false; // Safe case - phi could be replaced with the unique input. duke@435: duke@435: // Unsafe case when we should go through data graph to determine duke@435: // if the phi references itself. duke@435: duke@435: ResourceMark rm; duke@435: duke@435: Arena *a = Thread::current()->resource_area(); duke@435: Node_List nstack(a); duke@435: VectorSet visited(a); duke@435: duke@435: nstack.push(in); // Start with unique input. duke@435: visited.set(in->_idx); duke@435: while (nstack.size() != 0) { duke@435: Node* n = nstack.pop(); duke@435: uint cnt = n->req(); kvn@561: uint i = (n->is_Proj() && !n->is_CFG()) ? 0 : 1; kvn@561: for (; i < cnt; i++) { duke@435: Node* m = n->in(i); duke@435: if (m == (Node*)this) { duke@435: return true; // Data loop duke@435: } duke@435: if (m != NULL && !m->is_dead_loop_safe()) { // Only look for unsafe cases. duke@435: if (!visited.test_set(m->_idx)) duke@435: nstack.push(m); duke@435: } duke@435: } duke@435: } duke@435: return false; // The phi is not reachable from its inputs duke@435: } duke@435: duke@435: duke@435: //------------------------------Ideal------------------------------------------ duke@435: // Return a node which is more "ideal" than the current node. Must preserve duke@435: // the CFG, but we can still strip out dead paths. duke@435: Node *PhiNode::Ideal(PhaseGVN *phase, bool can_reshape) { duke@435: // The next should never happen after 6297035 fix. duke@435: if( is_copy() ) // Already degraded to a Copy ? duke@435: return NULL; // No change duke@435: duke@435: Node *r = in(0); // RegionNode duke@435: assert(r->in(0) == NULL || !r->in(0)->is_Root(), "not a specially hidden merge"); duke@435: duke@435: // Note: During parsing, phis are often transformed before their regions. duke@435: // This means we have to use type_or_null to defend against untyped regions. duke@435: if( phase->type_or_null(r) == Type::TOP ) // Dead code? duke@435: return NULL; // No change duke@435: duke@435: Node *top = phase->C->top(); duke@435: duke@435: // The are 2 situations when only one valid phi's input is left duke@435: // (in addition to Region input). duke@435: // One: region is not loop - replace phi with this input. duke@435: // Two: region is loop - replace phi with top since this data path is dead duke@435: // and we need to break the dead data loop. duke@435: Node* progress = NULL; // Record if any progress made duke@435: for( uint j = 1; j < req(); ++j ){ // For all paths in duke@435: // Check unreachable control paths duke@435: Node* rc = r->in(j); duke@435: Node* n = in(j); // Get the input duke@435: if (rc == NULL || phase->type(rc) == Type::TOP) { duke@435: if (n != top) { // Not already top? duke@435: set_req(j, top); // Nuke it down duke@435: progress = this; // Record progress duke@435: } duke@435: } duke@435: } duke@435: duke@435: Node* uin = unique_input(phase); duke@435: if (uin == top) { // Simplest case: no alive inputs. duke@435: if (can_reshape) // IGVN transformation duke@435: return top; duke@435: else duke@435: return NULL; // Identity will return TOP duke@435: } else if (uin != NULL) { duke@435: // Only one not-NULL unique input path is left. duke@435: // Determine if this input is backedge of a loop. duke@435: // (Skip new phis which have no uses and dead regions). duke@435: if( outcnt() > 0 && r->in(0) != NULL ) { duke@435: // First, take the short cut when we know it is a loop and duke@435: // the EntryControl data path is dead. duke@435: assert(!r->is_Loop() || r->req() == 3, "Loop node should have 3 inputs"); duke@435: // Then, check if there is a data loop when phi references itself directly duke@435: // or through other data nodes. duke@435: if( r->is_Loop() && !phase->eqv_uncast(uin, in(LoopNode::EntryControl)) || duke@435: !r->is_Loop() && is_unsafe_data_reference(uin) ) { duke@435: // Break this data loop to avoid creation of a dead loop. duke@435: if (can_reshape) { duke@435: return top; duke@435: } else { duke@435: // We can't return top if we are in Parse phase - cut inputs only duke@435: // let Identity to handle the case. duke@435: replace_edge(uin, top); duke@435: return NULL; duke@435: } duke@435: } duke@435: } duke@435: duke@435: // One unique input. duke@435: debug_only(Node* ident = Identity(phase)); duke@435: // The unique input must eventually be detected by the Identity call. duke@435: #ifdef ASSERT duke@435: if (ident != uin && !ident->is_top()) { duke@435: // print this output before failing assert duke@435: r->dump(3); duke@435: this->dump(3); duke@435: ident->dump(); duke@435: uin->dump(); duke@435: } duke@435: #endif duke@435: assert(ident == uin || ident->is_top(), "Identity must clean this up"); duke@435: return NULL; duke@435: } duke@435: duke@435: duke@435: Node* opt = NULL; duke@435: int true_path = is_diamond_phi(); duke@435: if( true_path != 0 ) { duke@435: // Check for CMove'ing identity. If it would be unsafe, duke@435: // handle it here. In the safe case, let Identity handle it. duke@435: Node* unsafe_id = is_cmove_id(phase, true_path); duke@435: if( unsafe_id != NULL && is_unsafe_data_reference(unsafe_id) ) duke@435: opt = unsafe_id; duke@435: duke@435: // Check for simple convert-to-boolean pattern duke@435: if( opt == NULL ) duke@435: opt = is_x2logic(phase, this, true_path); duke@435: duke@435: // Check for absolute value duke@435: if( opt == NULL ) duke@435: opt = is_absolute(phase, this, true_path); duke@435: duke@435: // Check for conditional add duke@435: if( opt == NULL && can_reshape ) duke@435: opt = is_cond_add(phase, this, true_path); duke@435: duke@435: // These 4 optimizations could subsume the phi: duke@435: // have to check for a dead data loop creation. duke@435: if( opt != NULL ) { duke@435: if( opt == unsafe_id || is_unsafe_data_reference(opt) ) { duke@435: // Found dead loop. duke@435: if( can_reshape ) duke@435: return top; duke@435: // We can't return top if we are in Parse phase - cut inputs only duke@435: // to stop further optimizations for this phi. Identity will return TOP. duke@435: assert(req() == 3, "only diamond merge phi here"); duke@435: set_req(1, top); duke@435: set_req(2, top); duke@435: return NULL; duke@435: } else { duke@435: return opt; duke@435: } duke@435: } duke@435: } duke@435: duke@435: // Check for merging identical values and split flow paths duke@435: if (can_reshape) { duke@435: opt = split_flow_path(phase, this); duke@435: // This optimization only modifies phi - don't need to check for dead loop. duke@435: assert(opt == NULL || phase->eqv(opt, this), "do not elide phi"); duke@435: if (opt != NULL) return opt; duke@435: } duke@435: duke@435: // Split phis through memory merges, so that the memory merges will go away. duke@435: // Piggy-back this transformation on the search for a unique input.... duke@435: // It will be as if the merged memory is the unique value of the phi. duke@435: // (Do not attempt this optimization unless parsing is complete. duke@435: // It would make the parser's memory-merge logic sick.) duke@435: // (MergeMemNode is not dead_loop_safe - need to check for dead loop.) duke@435: if (progress == NULL && can_reshape && type() == Type::MEMORY) { duke@435: // see if this phi should be sliced duke@435: uint merge_width = 0; duke@435: bool saw_self = false; duke@435: for( uint i=1; iis_MergeMem()) { duke@435: MergeMemNode* n = ii->as_MergeMem(); duke@435: merge_width = MAX2(merge_width, n->req()); duke@435: saw_self = saw_self || phase->eqv(n->base_memory(), this); duke@435: } duke@435: } duke@435: duke@435: // This restriction is temporarily necessary to ensure termination: duke@435: if (!saw_self && adr_type() == TypePtr::BOTTOM) merge_width = 0; duke@435: duke@435: if (merge_width > Compile::AliasIdxRaw) { duke@435: // found at least one non-empty MergeMem duke@435: const TypePtr* at = adr_type(); duke@435: if (at != TypePtr::BOTTOM) { duke@435: // Patch the existing phi to select an input from the merge: duke@435: // Phi:AT1(...MergeMem(m0, m1, m2)...) into duke@435: // Phi:AT1(...m1...) duke@435: int alias_idx = phase->C->get_alias_index(at); duke@435: for (uint i=1; iis_MergeMem()) { duke@435: MergeMemNode* n = ii->as_MergeMem(); duke@435: // compress paths and change unreachable cycles to TOP duke@435: // If not, we can update the input infinitely along a MergeMem cycle duke@435: // Equivalent code is in MemNode::Ideal_common duke@435: Node *m = phase->transform(n); duke@435: // If tranformed to a MergeMem, get the desired slice duke@435: // Otherwise the returned node represents memory for every slice duke@435: Node *new_mem = (m->is_MergeMem()) ? duke@435: m->as_MergeMem()->memory_at(alias_idx) : m; duke@435: // Update input if it is progress over what we have now duke@435: if (new_mem != ii) { duke@435: set_req(i, new_mem); duke@435: progress = this; duke@435: } duke@435: } duke@435: } duke@435: } else { duke@435: // We know that at least one MergeMem->base_memory() == this duke@435: // (saw_self == true). If all other inputs also references this phi duke@435: // (directly or through data nodes) - it is dead loop. duke@435: bool saw_safe_input = false; duke@435: for (uint j = 1; j < req(); ++j) { duke@435: Node *n = in(j); duke@435: if (n->is_MergeMem() && n->as_MergeMem()->base_memory() == this) duke@435: continue; // skip known cases duke@435: if (!is_unsafe_data_reference(n)) { duke@435: saw_safe_input = true; // found safe input duke@435: break; duke@435: } duke@435: } duke@435: if (!saw_safe_input) duke@435: return top; // all inputs reference back to this phi - dead loop duke@435: duke@435: // Phi(...MergeMem(m0, m1:AT1, m2:AT2)...) into duke@435: // MergeMem(Phi(...m0...), Phi:AT1(...m1...), Phi:AT2(...m2...)) duke@435: PhaseIterGVN *igvn = phase->is_IterGVN(); duke@435: Node* hook = new (phase->C, 1) Node(1); duke@435: PhiNode* new_base = (PhiNode*) clone(); duke@435: // Must eagerly register phis, since they participate in loops. duke@435: if (igvn) { duke@435: igvn->register_new_node_with_optimizer(new_base); duke@435: hook->add_req(new_base); duke@435: } duke@435: MergeMemNode* result = MergeMemNode::make(phase->C, new_base); duke@435: for (uint i = 1; i < req(); ++i) { duke@435: Node *ii = in(i); duke@435: if (ii->is_MergeMem()) { duke@435: MergeMemNode* n = ii->as_MergeMem(); duke@435: for (MergeMemStream mms(result, n); mms.next_non_empty2(); ) { duke@435: // If we have not seen this slice yet, make a phi for it. duke@435: bool made_new_phi = false; duke@435: if (mms.is_empty()) { duke@435: Node* new_phi = new_base->slice_memory(mms.adr_type(phase->C)); duke@435: made_new_phi = true; duke@435: if (igvn) { duke@435: igvn->register_new_node_with_optimizer(new_phi); duke@435: hook->add_req(new_phi); duke@435: } duke@435: mms.set_memory(new_phi); duke@435: } duke@435: Node* phi = mms.memory(); duke@435: assert(made_new_phi || phi->in(i) == n, "replace the i-th merge by a slice"); duke@435: phi->set_req(i, mms.memory2()); duke@435: } duke@435: } duke@435: } duke@435: // Distribute all self-loops. duke@435: { // (Extra braces to hide mms.) duke@435: for (MergeMemStream mms(result); mms.next_non_empty(); ) { duke@435: Node* phi = mms.memory(); duke@435: for (uint i = 1; i < req(); ++i) { duke@435: if (phi->in(i) == this) phi->set_req(i, phi); duke@435: } duke@435: } duke@435: } duke@435: // now transform the new nodes, and return the mergemem duke@435: for (MergeMemStream mms(result); mms.next_non_empty(); ) { duke@435: Node* phi = mms.memory(); duke@435: mms.set_memory(phase->transform(phi)); duke@435: } duke@435: if (igvn) { // Unhook. duke@435: igvn->hash_delete(hook); duke@435: for (uint i = 1; i < hook->req(); i++) { duke@435: hook->set_req(i, NULL); duke@435: } duke@435: } duke@435: // Replace self with the result. duke@435: return result; duke@435: } duke@435: } kvn@509: // kvn@509: // Other optimizations on the memory chain kvn@509: // kvn@509: const TypePtr* at = adr_type(); kvn@509: for( uint i=1; ibase()]; duke@435: assert( ideal_reg != Node::NotAMachineReg, "invalid type at Phi" ); duke@435: if( ideal_reg == 0 ) return RegMask::Empty; duke@435: return *(Compile::current()->matcher()->idealreg2spillmask[ideal_reg]); duke@435: } duke@435: duke@435: #ifndef PRODUCT duke@435: void PhiNode::dump_spec(outputStream *st) const { duke@435: TypeNode::dump_spec(st); duke@435: if (in(0) != NULL && duke@435: in(0)->is_CountedLoop() && duke@435: in(0)->as_CountedLoop()->phi() == this) { duke@435: st->print(" #tripcount"); duke@435: } duke@435: } duke@435: #endif duke@435: duke@435: duke@435: //============================================================================= duke@435: const Type *GotoNode::Value( PhaseTransform *phase ) const { duke@435: // If the input is reachable, then we are executed. duke@435: // If the input is not reachable, then we are not executed. duke@435: return phase->type(in(0)); duke@435: } duke@435: duke@435: Node *GotoNode::Identity( PhaseTransform *phase ) { duke@435: return in(0); // Simple copy of incoming control duke@435: } duke@435: duke@435: const RegMask &GotoNode::out_RegMask() const { duke@435: return RegMask::Empty; duke@435: } duke@435: duke@435: //============================================================================= duke@435: const RegMask &JumpNode::out_RegMask() const { duke@435: return RegMask::Empty; duke@435: } duke@435: duke@435: //============================================================================= duke@435: const RegMask &JProjNode::out_RegMask() const { duke@435: return RegMask::Empty; duke@435: } duke@435: duke@435: //============================================================================= duke@435: const RegMask &CProjNode::out_RegMask() const { duke@435: return RegMask::Empty; duke@435: } duke@435: duke@435: duke@435: duke@435: //============================================================================= duke@435: duke@435: uint PCTableNode::hash() const { return Node::hash() + _size; } duke@435: uint PCTableNode::cmp( const Node &n ) const duke@435: { return _size == ((PCTableNode&)n)._size; } duke@435: duke@435: const Type *PCTableNode::bottom_type() const { duke@435: const Type** f = TypeTuple::fields(_size); duke@435: for( uint i = 0; i < _size; i++ ) f[i] = Type::CONTROL; duke@435: return TypeTuple::make(_size, f); duke@435: } duke@435: duke@435: //------------------------------Value------------------------------------------ duke@435: // Compute the type of the PCTableNode. If reachable it is a tuple of duke@435: // Control, otherwise the table targets are not reachable duke@435: const Type *PCTableNode::Value( PhaseTransform *phase ) const { duke@435: if( phase->type(in(0)) == Type::CONTROL ) duke@435: return bottom_type(); duke@435: return Type::TOP; // All paths dead? Then so are we duke@435: } duke@435: duke@435: //------------------------------Ideal------------------------------------------ duke@435: // Return a node which is more "ideal" than the current node. Strip out duke@435: // control copies duke@435: Node *PCTableNode::Ideal(PhaseGVN *phase, bool can_reshape) { duke@435: return remove_dead_region(phase, can_reshape) ? this : NULL; duke@435: } duke@435: duke@435: //============================================================================= duke@435: uint JumpProjNode::hash() const { duke@435: return Node::hash() + _dest_bci; duke@435: } duke@435: duke@435: uint JumpProjNode::cmp( const Node &n ) const { duke@435: return ProjNode::cmp(n) && duke@435: _dest_bci == ((JumpProjNode&)n)._dest_bci; duke@435: } duke@435: duke@435: #ifndef PRODUCT duke@435: void JumpProjNode::dump_spec(outputStream *st) const { duke@435: ProjNode::dump_spec(st); duke@435: st->print("@bci %d ",_dest_bci); duke@435: } duke@435: #endif duke@435: duke@435: //============================================================================= duke@435: //------------------------------Value------------------------------------------ duke@435: // Check for being unreachable, or for coming from a Rethrow. Rethrow's cannot duke@435: // have the default "fall_through_index" path. duke@435: const Type *CatchNode::Value( PhaseTransform *phase ) const { duke@435: // Unreachable? Then so are all paths from here. duke@435: if( phase->type(in(0)) == Type::TOP ) return Type::TOP; duke@435: // First assume all paths are reachable duke@435: const Type** f = TypeTuple::fields(_size); duke@435: for( uint i = 0; i < _size; i++ ) f[i] = Type::CONTROL; duke@435: // Identify cases that will always throw an exception duke@435: // () rethrow call duke@435: // () virtual or interface call with NULL receiver duke@435: // () call is a check cast with incompatible arguments duke@435: if( in(1)->is_Proj() ) { duke@435: Node *i10 = in(1)->in(0); duke@435: if( i10->is_Call() ) { duke@435: CallNode *call = i10->as_Call(); duke@435: // Rethrows always throw exceptions, never return duke@435: if (call->entry_point() == OptoRuntime::rethrow_stub()) { duke@435: f[CatchProjNode::fall_through_index] = Type::TOP; duke@435: } else if( call->req() > TypeFunc::Parms ) { duke@435: const Type *arg0 = phase->type( call->in(TypeFunc::Parms) ); duke@435: // Check for null reciever to virtual or interface calls duke@435: if( call->is_CallDynamicJava() && duke@435: arg0->higher_equal(TypePtr::NULL_PTR) ) { duke@435: f[CatchProjNode::fall_through_index] = Type::TOP; duke@435: } duke@435: } // End of if not a runtime stub duke@435: } // End of if have call above me duke@435: } // End of slot 1 is not a projection duke@435: return TypeTuple::make(_size, f); duke@435: } duke@435: duke@435: //============================================================================= duke@435: uint CatchProjNode::hash() const { duke@435: return Node::hash() + _handler_bci; duke@435: } duke@435: duke@435: duke@435: uint CatchProjNode::cmp( const Node &n ) const { duke@435: return ProjNode::cmp(n) && duke@435: _handler_bci == ((CatchProjNode&)n)._handler_bci; duke@435: } duke@435: duke@435: duke@435: //------------------------------Identity--------------------------------------- duke@435: // If only 1 target is possible, choose it if it is the main control duke@435: Node *CatchProjNode::Identity( PhaseTransform *phase ) { duke@435: // If my value is control and no other value is, then treat as ID duke@435: const TypeTuple *t = phase->type(in(0))->is_tuple(); duke@435: if (t->field_at(_con) != Type::CONTROL) return this; duke@435: // If we remove the last CatchProj and elide the Catch/CatchProj, then we duke@435: // also remove any exception table entry. Thus we must know the call duke@435: // feeding the Catch will not really throw an exception. This is ok for duke@435: // the main fall-thru control (happens when we know a call can never throw duke@435: // an exception) or for "rethrow", because a further optimnization will duke@435: // yank the rethrow (happens when we inline a function that can throw an duke@435: // exception and the caller has no handler). Not legal, e.g., for passing duke@435: // a NULL receiver to a v-call, or passing bad types to a slow-check-cast. duke@435: // These cases MUST throw an exception via the runtime system, so the VM duke@435: // will be looking for a table entry. duke@435: Node *proj = in(0)->in(1); // Expect a proj feeding CatchNode duke@435: CallNode *call; duke@435: if (_con != TypeFunc::Control && // Bail out if not the main control. duke@435: !(proj->is_Proj() && // AND NOT a rethrow duke@435: proj->in(0)->is_Call() && duke@435: (call = proj->in(0)->as_Call()) && duke@435: call->entry_point() == OptoRuntime::rethrow_stub())) duke@435: return this; duke@435: duke@435: // Search for any other path being control duke@435: for (uint i = 0; i < t->cnt(); i++) { duke@435: if (i != _con && t->field_at(i) == Type::CONTROL) duke@435: return this; duke@435: } duke@435: // Only my path is possible; I am identity on control to the jump duke@435: return in(0)->in(0); duke@435: } duke@435: duke@435: duke@435: #ifndef PRODUCT duke@435: void CatchProjNode::dump_spec(outputStream *st) const { duke@435: ProjNode::dump_spec(st); duke@435: st->print("@bci %d ",_handler_bci); duke@435: } duke@435: #endif duke@435: duke@435: //============================================================================= duke@435: //------------------------------Identity--------------------------------------- duke@435: // Check for CreateEx being Identity. duke@435: Node *CreateExNode::Identity( PhaseTransform *phase ) { duke@435: if( phase->type(in(1)) == Type::TOP ) return in(1); duke@435: if( phase->type(in(0)) == Type::TOP ) return in(0); duke@435: // We only come from CatchProj, unless the CatchProj goes away. duke@435: // If the CatchProj is optimized away, then we just carry the duke@435: // exception oop through. duke@435: CallNode *call = in(1)->in(0)->as_Call(); duke@435: duke@435: return ( in(0)->is_CatchProj() && in(0)->in(0)->in(1) == in(1) ) duke@435: ? this duke@435: : call->in(TypeFunc::Parms); duke@435: } duke@435: duke@435: //============================================================================= never@562: //------------------------------Value------------------------------------------ never@562: // Check for being unreachable. never@562: const Type *NeverBranchNode::Value( PhaseTransform *phase ) const { never@562: if (!in(0) || in(0)->is_top()) return Type::TOP; never@562: return bottom_type(); never@562: } never@562: never@562: //------------------------------Ideal------------------------------------------ never@562: // Check for no longer being part of a loop never@562: Node *NeverBranchNode::Ideal(PhaseGVN *phase, bool can_reshape) { never@562: if (can_reshape && !in(0)->is_Loop()) { never@562: // Dead code elimination can sometimes delete this projection so never@562: // if it's not there, there's nothing to do. never@562: Node* fallthru = proj_out(0); never@562: if (fallthru != NULL) { never@562: phase->is_IterGVN()->subsume_node(fallthru, in(0)); never@562: } never@562: return phase->C->top(); never@562: } never@562: return NULL; never@562: } never@562: duke@435: #ifndef PRODUCT duke@435: void NeverBranchNode::format( PhaseRegAlloc *ra_, outputStream *st) const { duke@435: st->print("%s", Name()); duke@435: } duke@435: #endif