truffle: src/share/vm/opto/cfgnode.cpp comparison

comparison src/share/vm/opto/cfgnode.cpp @ 0:a61af66fc99e jdk7-b24

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author	duke
date	Sat, 01 Dec 2007 00:00:00 +0000
parents
children	2a9af0b9cb1c

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+:a61af66fc99e
+/*
+* Copyright 1997-2007 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+* CA 95054 USA or visit www.sun.com if you need additional information or
+* have any questions.
+*
+*/
+// Portions of code courtesy of Clifford Click
+// Optimization - Graph Style
+#include "incls/_precompiled.incl"
+#include "incls/_cfgnode.cpp.incl"
+//=============================================================================
+//------------------------------Value------------------------------------------
+// Compute the type of the RegionNode.
+const Type *RegionNode::Value( PhaseTransform *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( PhaseTransform *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
+// 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.
+}
+//------------------------------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) {            // 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;
+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());
+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));
+i--;
+continue;
+}
+}
+if( phase->type(n) == Type::TOP ) {
+set_req(i, NULL);       // Ignore TOP inputs
+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.
+assert(!this->is_Loop() || cnt_orig == 3, "Loop node should have 3 inputs");
+if (this->is_Loop() && del_it == LoopNode::EntryControl ||
+!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.
+del_req(1);
+cnt = 0;
+assert( req() == 1, "no more inputs expected" );
+uint max = outcnt();
+bool progress = true;
+Node *top = phase->C->top();
+PhaseIterGVN *igvn = phase->is_IterGVN();
+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->add_users_to_worklist(n);
+igvn->hash_delete(n); // Yank from hash before hacking edges
+igvn->subsume_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.
+igvn->add_users_to_worklist(n);
+igvn->hash_delete(n); // Yank from hash before hacking edges
+if( cnt == 0 ) {
+assert( n->req() == 1, "No data inputs expected" );
+igvn->subsume_node(n, parent_ctrl); // replaced by top
+} else {
+assert( n->req() == 2 &&  n->in(1) != NULL, "Only one data input expected" );
+Node* in1 = n->in(1);               // replaced by unique input
+if( n->as_Phi()->is_unsafe_data_reference(in1) )
+in1 = phase->C->top();            // replaced by top
+igvn->subsume_node(n, in1);
+}
+}
+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 (phase->C, 3) CmpINode( convf2i, min ));
+Node *boo   = gvn->register_new_node_with_optimizer(new (phase->C, 2) BoolNode( cmp, BoolTest::lt ));
+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 ));
+Node *if_min= gvn->register_new_node_with_optimizer(new (phase->C, 1) IfTrueNode (iff));
+Node *ifF   = gvn->register_new_node_with_optimizer(new (phase->C, 1) IfFalseNode(iff));
+// min test
+cmp         = gvn->register_new_node_with_optimizer(new (phase->C, 3) CmpINode( convf2i, max ));
+boo         = gvn->register_new_node_with_optimizer(new (phase->C, 2) BoolNode( cmp, BoolTest::gt ));
+iff         = (IfNode*)gvn->register_new_node_with_optimizer(new (phase->C, 2) IfNode( ifF, boo, PROB_UNLIKELY_MAG(5), bot_if->_fcnt ));
+Node *if_max= gvn->register_new_node_with_optimizer(new (phase->C, 1) IfTrueNode (iff));
+ifF         = gvn->register_new_node_with_optimizer(new (phase->C, 1) 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 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 (Compile::current(), preds) 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 (Compile::current(), r->req()) 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;
+}
+//------------------------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( PhaseTransform *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 && l->can_be_counted_loop(phase) &&
+((const Node*)l->phi() == this) ) { // Trip counted loop!
+// protect against init_trip() or limit() returning NULL
+const Node *init   = l->init_trip();
+const Node *limit  = l->limit();
+if( init != NULL && limit != NULL && l->stride_is_con() ) {
+const TypeInt *lo = init ->bottom_type()->isa_int();
+const TypeInt *hi = limit->bottom_type()->isa_int();
+if( lo && hi ) {            // Dying loops might have TOP here
+int stride = l->stride_con();
+if( stride < 0 ) {          // Down-counter loop
+const TypeInt *tmp = lo; lo = hi; hi = tmp;
+stride = -stride;
+}
+if( lo->_hi < hi->_lo )     // Reversed endpoints are well defined :-(
+return TypeInt::make(lo->_lo,hi->_hi,3);
+}
+}
+}
+// 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 TypeInstPtr* ttip = _type->isa_instptr();
+bool is_intf = false;
+if (ttip != NULL) {
+ciKlass* k = ttip->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 TypeInstPtr* tiip = ti->isa_instptr();
+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(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(_type);  // Worst case type
+#ifdef ASSERT
+// The following logic has been moved into TypeOopPtr::filter.
+const Type* jt = t->join(_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
+// Otherwise it's something stupid like non-overlapping int ranges
+// found on dying counted loops.
+else
+{ 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 TypeInstPtr *jtip = jt->isa_instptr();
+if( jtip && ttip ) {
+if( jtip->is_loaded() &&  jtip->klass()->is_interface() &&
+ttip->is_loaded() && !ttip->klass()->is_interface() )
+// Happens in a CTW of rt.jar, 320-341, no extra flags
+{ assert(ft == ttip->cast_to_ptr_type(jtip->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.
+int PhiNode::is_diamond_phi() 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;
+// 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( PhaseTransform *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);
+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) {
+//  1) One unique direct input, or
+//  2) some of the inputs have an intervening ConstraintCast and
+//     the type of input is the same or sharper (more specific)
+//     than the phi's type.
+//  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* uncasted_input = NULL; // The unique uncasted input (ConstraintCasts removed)
+Node* direct_input   = NULL; // The unique direct input
+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);
+Node* un = n->uncast();
+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 uncasted input
+if (uncasted_input == NULL) {
+uncasted_input = un;
+} else if (uncasted_input != un) {
+uncasted_input = NodeSentinel; // no unique uncasted input
+}
+// Check for a unique direct input
+if (direct_input == NULL) {
+direct_input = n;
+} else if (direct_input != n) {
+direct_input = NodeSentinel; // no unique direct input
+}
+}
+if (direct_input == NULL) {
+return phase->C->top();        // no inputs
+}
+assert(uncasted_input != NULL,"");
+if (direct_input != NodeSentinel) {
+return direct_input;           // one unique direct input
+}
+if (uncasted_input != NodeSentinel &&
+phase->type(uncasted_input)->higher_equal(type())) {
+return uncasted_input;         // one unique uncasted 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 (phase->C, 2) Conv2BNode( cmp->in(1) );
+if( flipped )
+n = new (phase->C, 3) 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 = n1->in(1);
+if( n2 == n1->in(1) ) {
+y = n1->in(2);
+} else if( n2 == 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 (phase->C, 3) CmpLTMaskNode(p,q) );
+Node *j_and   = phase->transform( new (phase->C, 3) AndINode(cmplt,y) );
+return new (phase->C, 3) 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 (phase->C, 2) AbsFNode(x);
+if (flip) {
+x = new (phase->C, 3) 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 (phase->C, 2) AbsDNode(x);
+if (flip) {
+x = new (phase->C, 3) 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 conglerate 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 )
+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
+for( ; i < phi->req(); i++ ){ // Count occurances 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( 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();
+Node *r = phi->region();
+RegionNode *newr = new (phase->C, hit+1) 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 determing 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();
+for (uint i = 1; 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();
+for (uint i = 1; i < cnt; i++) { // Only data paths
+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();
+// 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?
+set_req(j, top);        // Nuke it down
+progress = this;        // Record progress
+}
+}
+}
+Node* uin = unique_input(phase);
+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.
+assert(!r->is_Loop() || r->req() == 3, "Loop node should have 3 inputs");
+// Then, check if there is a data loop when phi references itself directly
+// or through other data nodes.
+if( r->is_Loop() && !phase->eqv_uncast(uin, in(LoopNode::EntryControl)) ||
+!r->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;
+}
+}
+}
+// 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(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 (phase->C, in(0)->req()) 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 (phase->C, 4) 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 tranformed 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 (phase->C, 1) 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(phase->C, 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;
+}
+}
+}
+return progress;              // Return any progress
+}
+//------------------------------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 = Matcher::base2reg[_type->base()];
+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::dump_spec(outputStream *st) const {
+TypeNode::dump_spec(st);
+if (in(0) != NULL &&
+in(0)->is_CountedLoop() &&
+in(0)->as_CountedLoop()->phi() == this) {
+st->print(" #tripcount");
+}
+}
+#endif
+//=============================================================================
+const Type *GotoNode::Value( PhaseTransform *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( PhaseTransform *phase ) {
+return in(0);                // Simple copy of incoming control
+}
+const RegMask &GotoNode::out_RegMask() const {
+return RegMask::Empty;
+}
+//=============================================================================
+const RegMask &JumpNode::out_RegMask() const {
+return RegMask::Empty;
+}
+//=============================================================================
+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( PhaseTransform *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);
+}
+#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( PhaseTransform *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 reciever 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( PhaseTransform *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 optimnization 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( PhaseTransform *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);
+}
+//=============================================================================
+#ifndef PRODUCT
+void NeverBranchNode::format( PhaseRegAlloc *ra_, outputStream *st) const {
+st->print("%s", Name());
+}
+#endif

Mercurial > hg > truffle

comparison src/share/vm/opto/cfgnode.cpp @ 0:a61af66fc99e jdk7-b24