1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/src/share/vm/opto/cfgnode.cpp Sat Dec 01 00:00:00 2007 +0000
1.3 @@ -0,0 +1,1954 @@
1.4 +/*
1.5 + * Copyright 1997-2007 Sun Microsystems, Inc. All Rights Reserved.
1.6 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.7 + *
1.8 + * This code is free software; you can redistribute it and/or modify it
1.9 + * under the terms of the GNU General Public License version 2 only, as
1.10 + * published by the Free Software Foundation.
1.11 + *
1.12 + * This code is distributed in the hope that it will be useful, but WITHOUT
1.13 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
1.14 + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
1.15 + * version 2 for more details (a copy is included in the LICENSE file that
1.16 + * accompanied this code).
1.17 + *
1.18 + * You should have received a copy of the GNU General Public License version
1.19 + * 2 along with this work; if not, write to the Free Software Foundation,
1.20 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1.21 + *
1.22 + * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
1.23 + * CA 95054 USA or visit www.sun.com if you need additional information or
1.24 + * have any questions.
1.25 + *
1.26 + */
1.27 +
1.28 +// Portions of code courtesy of Clifford Click
1.29 +
1.30 +// Optimization - Graph Style
1.31 +
1.32 +#include "incls/_precompiled.incl"
1.33 +#include "incls/_cfgnode.cpp.incl"
1.34 +
1.35 +//=============================================================================
1.36 +//------------------------------Value------------------------------------------
1.37 +// Compute the type of the RegionNode.
1.38 +const Type *RegionNode::Value( PhaseTransform *phase ) const {
1.39 + for( uint i=1; i<req(); ++i ) { // For all paths in
1.40 + Node *n = in(i); // Get Control source
1.41 + if( !n ) continue; // Missing inputs are TOP
1.42 + if( phase->type(n) == Type::CONTROL )
1.43 + return Type::CONTROL;
1.44 + }
1.45 + return Type::TOP; // All paths dead? Then so are we
1.46 +}
1.47 +
1.48 +//------------------------------Identity---------------------------------------
1.49 +// Check for Region being Identity.
1.50 +Node *RegionNode::Identity( PhaseTransform *phase ) {
1.51 + // Cannot have Region be an identity, even if it has only 1 input.
1.52 + // Phi users cannot have their Region input folded away for them,
1.53 + // since they need to select the proper data input
1.54 + return this;
1.55 +}
1.56 +
1.57 +//------------------------------merge_region-----------------------------------
1.58 +// If a Region flows into a Region, merge into one big happy merge. This is
1.59 +// hard to do if there is stuff that has to happen
1.60 +static Node *merge_region(RegionNode *region, PhaseGVN *phase) {
1.61 + if( region->Opcode() != Op_Region ) // Do not do to LoopNodes
1.62 + return NULL;
1.63 + Node *progress = NULL; // Progress flag
1.64 + PhaseIterGVN *igvn = phase->is_IterGVN();
1.65 +
1.66 + uint rreq = region->req();
1.67 + for( uint i = 1; i < rreq; i++ ) {
1.68 + Node *r = region->in(i);
1.69 + if( r && r->Opcode() == Op_Region && // Found a region?
1.70 + r->in(0) == r && // Not already collapsed?
1.71 + r != region && // Avoid stupid situations
1.72 + r->outcnt() == 2 ) { // Self user and 'region' user only?
1.73 + assert(!r->as_Region()->has_phi(), "no phi users");
1.74 + if( !progress ) { // No progress
1.75 + if (region->has_phi()) {
1.76 + return NULL; // Only flatten if no Phi users
1.77 + // igvn->hash_delete( phi );
1.78 + }
1.79 + igvn->hash_delete( region );
1.80 + progress = region; // Making progress
1.81 + }
1.82 + igvn->hash_delete( r );
1.83 +
1.84 + // Append inputs to 'r' onto 'region'
1.85 + for( uint j = 1; j < r->req(); j++ ) {
1.86 + // Move an input from 'r' to 'region'
1.87 + region->add_req(r->in(j));
1.88 + r->set_req(j, phase->C->top());
1.89 + // Update phis of 'region'
1.90 + //for( uint k = 0; k < max; k++ ) {
1.91 + // Node *phi = region->out(k);
1.92 + // if( phi->is_Phi() ) {
1.93 + // phi->add_req(phi->in(i));
1.94 + // }
1.95 + //}
1.96 +
1.97 + rreq++; // One more input to Region
1.98 + } // Found a region to merge into Region
1.99 + // Clobber pointer to the now dead 'r'
1.100 + region->set_req(i, phase->C->top());
1.101 + }
1.102 + }
1.103 +
1.104 + return progress;
1.105 +}
1.106 +
1.107 +
1.108 +
1.109 +//--------------------------------has_phi--------------------------------------
1.110 +// Helper function: Return any PhiNode that uses this region or NULL
1.111 +PhiNode* RegionNode::has_phi() const {
1.112 + for (DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++) {
1.113 + Node* phi = fast_out(i);
1.114 + if (phi->is_Phi()) { // Check for Phi users
1.115 + assert(phi->in(0) == (Node*)this, "phi uses region only via in(0)");
1.116 + return phi->as_Phi(); // this one is good enough
1.117 + }
1.118 + }
1.119 +
1.120 + return NULL;
1.121 +}
1.122 +
1.123 +
1.124 +//-----------------------------has_unique_phi----------------------------------
1.125 +// Helper function: Return the only PhiNode that uses this region or NULL
1.126 +PhiNode* RegionNode::has_unique_phi() const {
1.127 + // Check that only one use is a Phi
1.128 + PhiNode* only_phi = NULL;
1.129 + for (DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++) {
1.130 + Node* phi = fast_out(i);
1.131 + if (phi->is_Phi()) { // Check for Phi users
1.132 + assert(phi->in(0) == (Node*)this, "phi uses region only via in(0)");
1.133 + if (only_phi == NULL) {
1.134 + only_phi = phi->as_Phi();
1.135 + } else {
1.136 + return NULL; // multiple phis
1.137 + }
1.138 + }
1.139 + }
1.140 +
1.141 + return only_phi;
1.142 +}
1.143 +
1.144 +
1.145 +//------------------------------check_phi_clipping-----------------------------
1.146 +// Helper function for RegionNode's identification of FP clipping
1.147 +// Check inputs to the Phi
1.148 +static bool check_phi_clipping( PhiNode *phi, ConNode * &min, uint &min_idx, ConNode * &max, uint &max_idx, Node * &val, uint &val_idx ) {
1.149 + min = NULL;
1.150 + max = NULL;
1.151 + val = NULL;
1.152 + min_idx = 0;
1.153 + max_idx = 0;
1.154 + val_idx = 0;
1.155 + uint phi_max = phi->req();
1.156 + if( phi_max == 4 ) {
1.157 + for( uint j = 1; j < phi_max; ++j ) {
1.158 + Node *n = phi->in(j);
1.159 + int opcode = n->Opcode();
1.160 + switch( opcode ) {
1.161 + case Op_ConI:
1.162 + {
1.163 + if( min == NULL ) {
1.164 + min = n->Opcode() == Op_ConI ? (ConNode*)n : NULL;
1.165 + min_idx = j;
1.166 + } else {
1.167 + max = n->Opcode() == Op_ConI ? (ConNode*)n : NULL;
1.168 + max_idx = j;
1.169 + if( min->get_int() > max->get_int() ) {
1.170 + // Swap min and max
1.171 + ConNode *temp;
1.172 + uint temp_idx;
1.173 + temp = min; min = max; max = temp;
1.174 + temp_idx = min_idx; min_idx = max_idx; max_idx = temp_idx;
1.175 + }
1.176 + }
1.177 + }
1.178 + break;
1.179 + default:
1.180 + {
1.181 + val = n;
1.182 + val_idx = j;
1.183 + }
1.184 + break;
1.185 + }
1.186 + }
1.187 + }
1.188 + return ( min && max && val && (min->get_int() <= 0) && (max->get_int() >=0) );
1.189 +}
1.190 +
1.191 +
1.192 +//------------------------------check_if_clipping------------------------------
1.193 +// Helper function for RegionNode's identification of FP clipping
1.194 +// Check that inputs to Region come from two IfNodes,
1.195 +//
1.196 +// If
1.197 +// False True
1.198 +// If |
1.199 +// False True |
1.200 +// | | |
1.201 +// RegionNode_inputs
1.202 +//
1.203 +static bool check_if_clipping( const RegionNode *region, IfNode * &bot_if, IfNode * &top_if ) {
1.204 + top_if = NULL;
1.205 + bot_if = NULL;
1.206 +
1.207 + // Check control structure above RegionNode for (if ( if ) )
1.208 + Node *in1 = region->in(1);
1.209 + Node *in2 = region->in(2);
1.210 + Node *in3 = region->in(3);
1.211 + // Check that all inputs are projections
1.212 + if( in1->is_Proj() && in2->is_Proj() && in3->is_Proj() ) {
1.213 + Node *in10 = in1->in(0);
1.214 + Node *in20 = in2->in(0);
1.215 + Node *in30 = in3->in(0);
1.216 + // Check that #1 and #2 are ifTrue and ifFalse from same If
1.217 + if( in10 != NULL && in10->is_If() &&
1.218 + in20 != NULL && in20->is_If() &&
1.219 + in30 != NULL && in30->is_If() && in10 == in20 &&
1.220 + (in1->Opcode() != in2->Opcode()) ) {
1.221 + Node *in100 = in10->in(0);
1.222 + Node *in1000 = (in100 != NULL && in100->is_Proj()) ? in100->in(0) : NULL;
1.223 + // Check that control for in10 comes from other branch of IF from in3
1.224 + if( in1000 != NULL && in1000->is_If() &&
1.225 + in30 == in1000 && (in3->Opcode() != in100->Opcode()) ) {
1.226 + // Control pattern checks
1.227 + top_if = (IfNode*)in1000;
1.228 + bot_if = (IfNode*)in10;
1.229 + }
1.230 + }
1.231 + }
1.232 +
1.233 + return (top_if != NULL);
1.234 +}
1.235 +
1.236 +
1.237 +//------------------------------check_convf2i_clipping-------------------------
1.238 +// Helper function for RegionNode's identification of FP clipping
1.239 +// Verify that the value input to the phi comes from "ConvF2I; LShift; RShift"
1.240 +static bool check_convf2i_clipping( PhiNode *phi, uint idx, ConvF2INode * &convf2i, Node *min, Node *max) {
1.241 + convf2i = NULL;
1.242 +
1.243 + // Check for the RShiftNode
1.244 + Node *rshift = phi->in(idx);
1.245 + assert( rshift, "Previous checks ensure phi input is present");
1.246 + if( rshift->Opcode() != Op_RShiftI ) { return false; }
1.247 +
1.248 + // Check for the LShiftNode
1.249 + Node *lshift = rshift->in(1);
1.250 + assert( lshift, "Previous checks ensure phi input is present");
1.251 + if( lshift->Opcode() != Op_LShiftI ) { return false; }
1.252 +
1.253 + // Check for the ConvF2INode
1.254 + Node *conv = lshift->in(1);
1.255 + if( conv->Opcode() != Op_ConvF2I ) { return false; }
1.256 +
1.257 + // Check that shift amounts are only to get sign bits set after F2I
1.258 + jint max_cutoff = max->get_int();
1.259 + jint min_cutoff = min->get_int();
1.260 + jint left_shift = lshift->in(2)->get_int();
1.261 + jint right_shift = rshift->in(2)->get_int();
1.262 + jint max_post_shift = nth_bit(BitsPerJavaInteger - left_shift - 1);
1.263 + if( left_shift != right_shift ||
1.264 + 0 > left_shift || left_shift >= BitsPerJavaInteger ||
1.265 + max_post_shift < max_cutoff ||
1.266 + max_post_shift < -min_cutoff ) {
1.267 + // Shifts are necessary but current transformation eliminates them
1.268 + return false;
1.269 + }
1.270 +
1.271 + // OK to return the result of ConvF2I without shifting
1.272 + convf2i = (ConvF2INode*)conv;
1.273 + return true;
1.274 +}
1.275 +
1.276 +
1.277 +//------------------------------check_compare_clipping-------------------------
1.278 +// Helper function for RegionNode's identification of FP clipping
1.279 +static bool check_compare_clipping( bool less_than, IfNode *iff, ConNode *limit, Node * & input ) {
1.280 + Node *i1 = iff->in(1);
1.281 + if ( !i1->is_Bool() ) { return false; }
1.282 + BoolNode *bool1 = i1->as_Bool();
1.283 + if( less_than && bool1->_test._test != BoolTest::le ) { return false; }
1.284 + else if( !less_than && bool1->_test._test != BoolTest::lt ) { return false; }
1.285 + const Node *cmpF = bool1->in(1);
1.286 + if( cmpF->Opcode() != Op_CmpF ) { return false; }
1.287 + // Test that the float value being compared against
1.288 + // is equivalent to the int value used as a limit
1.289 + Node *nodef = cmpF->in(2);
1.290 + if( nodef->Opcode() != Op_ConF ) { return false; }
1.291 + jfloat conf = nodef->getf();
1.292 + jint coni = limit->get_int();
1.293 + if( ((int)conf) != coni ) { return false; }
1.294 + input = cmpF->in(1);
1.295 + return true;
1.296 +}
1.297 +
1.298 +//------------------------------is_unreachable_region--------------------------
1.299 +// Find if the Region node is reachable from the root.
1.300 +bool RegionNode::is_unreachable_region(PhaseGVN *phase) const {
1.301 + assert(req() == 2, "");
1.302 +
1.303 + // First, cut the simple case of fallthrough region when NONE of
1.304 + // region's phis references itself directly or through a data node.
1.305 + uint max = outcnt();
1.306 + uint i;
1.307 + for (i = 0; i < max; i++) {
1.308 + Node* phi = raw_out(i);
1.309 + if (phi != NULL && phi->is_Phi()) {
1.310 + assert(phase->eqv(phi->in(0), this) && phi->req() == 2, "");
1.311 + if (phi->outcnt() == 0)
1.312 + continue; // Safe case - no loops
1.313 + if (phi->outcnt() == 1) {
1.314 + Node* u = phi->raw_out(0);
1.315 + // Skip if only one use is an other Phi or Call or Uncommon trap.
1.316 + // It is safe to consider this case as fallthrough.
1.317 + if (u != NULL && (u->is_Phi() || u->is_CFG()))
1.318 + continue;
1.319 + }
1.320 + // Check when phi references itself directly or through an other node.
1.321 + if (phi->as_Phi()->simple_data_loop_check(phi->in(1)) >= PhiNode::Unsafe)
1.322 + break; // Found possible unsafe data loop.
1.323 + }
1.324 + }
1.325 + if (i >= max)
1.326 + return false; // An unsafe case was NOT found - don't need graph walk.
1.327 +
1.328 + // Unsafe case - check if the Region node is reachable from root.
1.329 + ResourceMark rm;
1.330 +
1.331 + Arena *a = Thread::current()->resource_area();
1.332 + Node_List nstack(a);
1.333 + VectorSet visited(a);
1.334 +
1.335 + // Mark all control nodes reachable from root outputs
1.336 + Node *n = (Node*)phase->C->root();
1.337 + nstack.push(n);
1.338 + visited.set(n->_idx);
1.339 + while (nstack.size() != 0) {
1.340 + n = nstack.pop();
1.341 + uint max = n->outcnt();
1.342 + for (uint i = 0; i < max; i++) {
1.343 + Node* m = n->raw_out(i);
1.344 + if (m != NULL && m->is_CFG()) {
1.345 + if (phase->eqv(m, this)) {
1.346 + return false; // We reached the Region node - it is not dead.
1.347 + }
1.348 + if (!visited.test_set(m->_idx))
1.349 + nstack.push(m);
1.350 + }
1.351 + }
1.352 + }
1.353 +
1.354 + return true; // The Region node is unreachable - it is dead.
1.355 +}
1.356 +
1.357 +//------------------------------Ideal------------------------------------------
1.358 +// Return a node which is more "ideal" than the current node. Must preserve
1.359 +// the CFG, but we can still strip out dead paths.
1.360 +Node *RegionNode::Ideal(PhaseGVN *phase, bool can_reshape) {
1.361 + if( !can_reshape && !in(0) ) return NULL; // Already degraded to a Copy
1.362 + assert(!in(0) || !in(0)->is_Root(), "not a specially hidden merge");
1.363 +
1.364 + // Check for RegionNode with no Phi users and both inputs come from either
1.365 + // arm of the same IF. If found, then the control-flow split is useless.
1.366 + bool has_phis = false;
1.367 + if (can_reshape) { // Need DU info to check for Phi users
1.368 + has_phis = (has_phi() != NULL); // Cache result
1.369 + if (!has_phis) { // No Phi users? Nothing merging?
1.370 + for (uint i = 1; i < req()-1; i++) {
1.371 + Node *if1 = in(i);
1.372 + if( !if1 ) continue;
1.373 + Node *iff = if1->in(0);
1.374 + if( !iff || !iff->is_If() ) continue;
1.375 + for( uint j=i+1; j<req(); j++ ) {
1.376 + if( in(j) && in(j)->in(0) == iff &&
1.377 + if1->Opcode() != in(j)->Opcode() ) {
1.378 + // Add the IF Projections to the worklist. They (and the IF itself)
1.379 + // will be eliminated if dead.
1.380 + phase->is_IterGVN()->add_users_to_worklist(iff);
1.381 + set_req(i, iff->in(0));// Skip around the useless IF diamond
1.382 + set_req(j, NULL);
1.383 + return this; // Record progress
1.384 + }
1.385 + }
1.386 + }
1.387 + }
1.388 + }
1.389 +
1.390 + // Remove TOP or NULL input paths. If only 1 input path remains, this Region
1.391 + // degrades to a copy.
1.392 + bool add_to_worklist = false;
1.393 + int cnt = 0; // Count of values merging
1.394 + DEBUG_ONLY( int cnt_orig = req(); ) // Save original inputs count
1.395 + int del_it = 0; // The last input path we delete
1.396 + // For all inputs...
1.397 + for( uint i=1; i<req(); ++i ){// For all paths in
1.398 + Node *n = in(i); // Get the input
1.399 + if( n != NULL ) {
1.400 + // Remove useless control copy inputs
1.401 + if( n->is_Region() && n->as_Region()->is_copy() ) {
1.402 + set_req(i, n->nonnull_req());
1.403 + i--;
1.404 + continue;
1.405 + }
1.406 + if( n->is_Proj() ) { // Remove useless rethrows
1.407 + Node *call = n->in(0);
1.408 + if (call->is_Call() && call->as_Call()->entry_point() == OptoRuntime::rethrow_stub()) {
1.409 + set_req(i, call->in(0));
1.410 + i--;
1.411 + continue;
1.412 + }
1.413 + }
1.414 + if( phase->type(n) == Type::TOP ) {
1.415 + set_req(i, NULL); // Ignore TOP inputs
1.416 + i--;
1.417 + continue;
1.418 + }
1.419 + cnt++; // One more value merging
1.420 +
1.421 + } else if (can_reshape) { // Else found dead path with DU info
1.422 + PhaseIterGVN *igvn = phase->is_IterGVN();
1.423 + del_req(i); // Yank path from self
1.424 + del_it = i;
1.425 + uint max = outcnt();
1.426 + DUIterator j;
1.427 + bool progress = true;
1.428 + while(progress) { // Need to establish property over all users
1.429 + progress = false;
1.430 + for (j = outs(); has_out(j); j++) {
1.431 + Node *n = out(j);
1.432 + if( n->req() != req() && n->is_Phi() ) {
1.433 + assert( n->in(0) == this, "" );
1.434 + igvn->hash_delete(n); // Yank from hash before hacking edges
1.435 + n->set_req_X(i,NULL,igvn);// Correct DU info
1.436 + n->del_req(i); // Yank path from Phis
1.437 + if( max != outcnt() ) {
1.438 + progress = true;
1.439 + j = refresh_out_pos(j);
1.440 + max = outcnt();
1.441 + }
1.442 + }
1.443 + }
1.444 + }
1.445 + add_to_worklist = true;
1.446 + i--;
1.447 + }
1.448 + }
1.449 +
1.450 + if (can_reshape && cnt == 1) {
1.451 + // Is it dead loop?
1.452 + // If it is LoopNopde it had 2 (+1 itself) inputs and
1.453 + // one of them was cut. The loop is dead if it was EntryContol.
1.454 + assert(!this->is_Loop() || cnt_orig == 3, "Loop node should have 3 inputs");
1.455 + if (this->is_Loop() && del_it == LoopNode::EntryControl ||
1.456 + !this->is_Loop() && has_phis && is_unreachable_region(phase)) {
1.457 + // Yes, the region will be removed during the next step below.
1.458 + // Cut the backedge input and remove phis since no data paths left.
1.459 + // We don't cut outputs to other nodes here since we need to put them
1.460 + // on the worklist.
1.461 + del_req(1);
1.462 + cnt = 0;
1.463 + assert( req() == 1, "no more inputs expected" );
1.464 + uint max = outcnt();
1.465 + bool progress = true;
1.466 + Node *top = phase->C->top();
1.467 + PhaseIterGVN *igvn = phase->is_IterGVN();
1.468 + DUIterator j;
1.469 + while(progress) {
1.470 + progress = false;
1.471 + for (j = outs(); has_out(j); j++) {
1.472 + Node *n = out(j);
1.473 + if( n->is_Phi() ) {
1.474 + assert( igvn->eqv(n->in(0), this), "" );
1.475 + assert( n->req() == 2 && n->in(1) != NULL, "Only one data input expected" );
1.476 + // Break dead loop data path.
1.477 + // Eagerly replace phis with top to avoid phis copies generation.
1.478 + igvn->add_users_to_worklist(n);
1.479 + igvn->hash_delete(n); // Yank from hash before hacking edges
1.480 + igvn->subsume_node(n, top);
1.481 + if( max != outcnt() ) {
1.482 + progress = true;
1.483 + j = refresh_out_pos(j);
1.484 + max = outcnt();
1.485 + }
1.486 + }
1.487 + }
1.488 + }
1.489 + add_to_worklist = true;
1.490 + }
1.491 + }
1.492 + if (add_to_worklist) {
1.493 + phase->is_IterGVN()->add_users_to_worklist(this); // Revisit collapsed Phis
1.494 + }
1.495 +
1.496 + if( cnt <= 1 ) { // Only 1 path in?
1.497 + set_req(0, NULL); // Null control input for region copy
1.498 + if( cnt == 0 && !can_reshape) { // Parse phase - leave the node as it is.
1.499 + // No inputs or all inputs are NULL.
1.500 + return NULL;
1.501 + } else if (can_reshape) { // Optimization phase - remove the node
1.502 + PhaseIterGVN *igvn = phase->is_IterGVN();
1.503 + Node *parent_ctrl;
1.504 + if( cnt == 0 ) {
1.505 + assert( req() == 1, "no inputs expected" );
1.506 + // During IGVN phase such region will be subsumed by TOP node
1.507 + // so region's phis will have TOP as control node.
1.508 + // Kill phis here to avoid it. PhiNode::is_copy() will be always false.
1.509 + // Also set other user's input to top.
1.510 + parent_ctrl = phase->C->top();
1.511 + } else {
1.512 + // The fallthrough case since we already checked dead loops above.
1.513 + parent_ctrl = in(1);
1.514 + assert(parent_ctrl != NULL, "Region is a copy of some non-null control");
1.515 + assert(!igvn->eqv(parent_ctrl, this), "Close dead loop");
1.516 + }
1.517 + if (!add_to_worklist)
1.518 + igvn->add_users_to_worklist(this); // Check for further allowed opts
1.519 + for (DUIterator_Last imin, i = last_outs(imin); i >= imin; --i) {
1.520 + Node* n = last_out(i);
1.521 + igvn->hash_delete(n); // Remove from worklist before modifying edges
1.522 + if( n->is_Phi() ) { // Collapse all Phis
1.523 + // Eagerly replace phis to avoid copies generation.
1.524 + igvn->add_users_to_worklist(n);
1.525 + igvn->hash_delete(n); // Yank from hash before hacking edges
1.526 + if( cnt == 0 ) {
1.527 + assert( n->req() == 1, "No data inputs expected" );
1.528 + igvn->subsume_node(n, parent_ctrl); // replaced by top
1.529 + } else {
1.530 + assert( n->req() == 2 && n->in(1) != NULL, "Only one data input expected" );
1.531 + Node* in1 = n->in(1); // replaced by unique input
1.532 + if( n->as_Phi()->is_unsafe_data_reference(in1) )
1.533 + in1 = phase->C->top(); // replaced by top
1.534 + igvn->subsume_node(n, in1);
1.535 + }
1.536 + }
1.537 + else if( n->is_Region() ) { // Update all incoming edges
1.538 + assert( !igvn->eqv(n, this), "Must be removed from DefUse edges");
1.539 + uint uses_found = 0;
1.540 + for( uint k=1; k < n->req(); k++ ) {
1.541 + if( n->in(k) == this ) {
1.542 + n->set_req(k, parent_ctrl);
1.543 + uses_found++;
1.544 + }
1.545 + }
1.546 + if( uses_found > 1 ) { // (--i) done at the end of the loop.
1.547 + i -= (uses_found - 1);
1.548 + }
1.549 + }
1.550 + else {
1.551 + assert( igvn->eqv(n->in(0), this), "Expect RegionNode to be control parent");
1.552 + n->set_req(0, parent_ctrl);
1.553 + }
1.554 +#ifdef ASSERT
1.555 + for( uint k=0; k < n->req(); k++ ) {
1.556 + assert( !igvn->eqv(n->in(k), this), "All uses of RegionNode should be gone");
1.557 + }
1.558 +#endif
1.559 + }
1.560 + // Remove the RegionNode itself from DefUse info
1.561 + igvn->remove_dead_node(this);
1.562 + return NULL;
1.563 + }
1.564 + return this; // Record progress
1.565 + }
1.566 +
1.567 +
1.568 + // If a Region flows into a Region, merge into one big happy merge.
1.569 + if (can_reshape) {
1.570 + Node *m = merge_region(this, phase);
1.571 + if (m != NULL) return m;
1.572 + }
1.573 +
1.574 + // Check if this region is the root of a clipping idiom on floats
1.575 + if( ConvertFloat2IntClipping && can_reshape && req() == 4 ) {
1.576 + // Check that only one use is a Phi and that it simplifies to two constants +
1.577 + PhiNode* phi = has_unique_phi();
1.578 + if (phi != NULL) { // One Phi user
1.579 + // Check inputs to the Phi
1.580 + ConNode *min;
1.581 + ConNode *max;
1.582 + Node *val;
1.583 + uint min_idx;
1.584 + uint max_idx;
1.585 + uint val_idx;
1.586 + if( check_phi_clipping( phi, min, min_idx, max, max_idx, val, val_idx ) ) {
1.587 + IfNode *top_if;
1.588 + IfNode *bot_if;
1.589 + if( check_if_clipping( this, bot_if, top_if ) ) {
1.590 + // Control pattern checks, now verify compares
1.591 + Node *top_in = NULL; // value being compared against
1.592 + Node *bot_in = NULL;
1.593 + if( check_compare_clipping( true, bot_if, min, bot_in ) &&
1.594 + check_compare_clipping( false, top_if, max, top_in ) ) {
1.595 + if( bot_in == top_in ) {
1.596 + PhaseIterGVN *gvn = phase->is_IterGVN();
1.597 + assert( gvn != NULL, "Only had DefUse info in IterGVN");
1.598 + // Only remaining check is that bot_in == top_in == (Phi's val + mods)
1.599 +
1.600 + // Check for the ConvF2INode
1.601 + ConvF2INode *convf2i;
1.602 + if( check_convf2i_clipping( phi, val_idx, convf2i, min, max ) &&
1.603 + convf2i->in(1) == bot_in ) {
1.604 + // Matched pattern, including LShiftI; RShiftI, replace with integer compares
1.605 + // max test
1.606 + Node *cmp = gvn->register_new_node_with_optimizer(new (phase->C, 3) CmpINode( convf2i, min ));
1.607 + Node *boo = gvn->register_new_node_with_optimizer(new (phase->C, 2) BoolNode( cmp, BoolTest::lt ));
1.608 + 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 ));
1.609 + Node *if_min= gvn->register_new_node_with_optimizer(new (phase->C, 1) IfTrueNode (iff));
1.610 + Node *ifF = gvn->register_new_node_with_optimizer(new (phase->C, 1) IfFalseNode(iff));
1.611 + // min test
1.612 + cmp = gvn->register_new_node_with_optimizer(new (phase->C, 3) CmpINode( convf2i, max ));
1.613 + boo = gvn->register_new_node_with_optimizer(new (phase->C, 2) BoolNode( cmp, BoolTest::gt ));
1.614 + iff = (IfNode*)gvn->register_new_node_with_optimizer(new (phase->C, 2) IfNode( ifF, boo, PROB_UNLIKELY_MAG(5), bot_if->_fcnt ));
1.615 + Node *if_max= gvn->register_new_node_with_optimizer(new (phase->C, 1) IfTrueNode (iff));
1.616 + ifF = gvn->register_new_node_with_optimizer(new (phase->C, 1) IfFalseNode(iff));
1.617 + // update input edges to region node
1.618 + set_req_X( min_idx, if_min, gvn );
1.619 + set_req_X( max_idx, if_max, gvn );
1.620 + set_req_X( val_idx, ifF, gvn );
1.621 + // remove unnecessary 'LShiftI; RShiftI' idiom
1.622 + gvn->hash_delete(phi);
1.623 + phi->set_req_X( val_idx, convf2i, gvn );
1.624 + gvn->hash_find_insert(phi);
1.625 + // Return transformed region node
1.626 + return this;
1.627 + }
1.628 + }
1.629 + }
1.630 + }
1.631 + }
1.632 + }
1.633 + }
1.634 +
1.635 + return NULL;
1.636 +}
1.637 +
1.638 +
1.639 +
1.640 +const RegMask &RegionNode::out_RegMask() const {
1.641 + return RegMask::Empty;
1.642 +}
1.643 +
1.644 +// Find the one non-null required input. RegionNode only
1.645 +Node *Node::nonnull_req() const {
1.646 + assert( is_Region(), "" );
1.647 + for( uint i = 1; i < _cnt; i++ )
1.648 + if( in(i) )
1.649 + return in(i);
1.650 + ShouldNotReachHere();
1.651 + return NULL;
1.652 +}
1.653 +
1.654 +
1.655 +//=============================================================================
1.656 +// note that these functions assume that the _adr_type field is flattened
1.657 +uint PhiNode::hash() const {
1.658 + const Type* at = _adr_type;
1.659 + return TypeNode::hash() + (at ? at->hash() : 0);
1.660 +}
1.661 +uint PhiNode::cmp( const Node &n ) const {
1.662 + return TypeNode::cmp(n) && _adr_type == ((PhiNode&)n)._adr_type;
1.663 +}
1.664 +static inline
1.665 +const TypePtr* flatten_phi_adr_type(const TypePtr* at) {
1.666 + if (at == NULL || at == TypePtr::BOTTOM) return at;
1.667 + return Compile::current()->alias_type(at)->adr_type();
1.668 +}
1.669 +
1.670 +//----------------------------make---------------------------------------------
1.671 +// create a new phi with edges matching r and set (initially) to x
1.672 +PhiNode* PhiNode::make(Node* r, Node* x, const Type *t, const TypePtr* at) {
1.673 + uint preds = r->req(); // Number of predecessor paths
1.674 + assert(t != Type::MEMORY || at == flatten_phi_adr_type(at), "flatten at");
1.675 + PhiNode* p = new (Compile::current(), preds) PhiNode(r, t, at);
1.676 + for (uint j = 1; j < preds; j++) {
1.677 + // Fill in all inputs, except those which the region does not yet have
1.678 + if (r->in(j) != NULL)
1.679 + p->init_req(j, x);
1.680 + }
1.681 + return p;
1.682 +}
1.683 +PhiNode* PhiNode::make(Node* r, Node* x) {
1.684 + const Type* t = x->bottom_type();
1.685 + const TypePtr* at = NULL;
1.686 + if (t == Type::MEMORY) at = flatten_phi_adr_type(x->adr_type());
1.687 + return make(r, x, t, at);
1.688 +}
1.689 +PhiNode* PhiNode::make_blank(Node* r, Node* x) {
1.690 + const Type* t = x->bottom_type();
1.691 + const TypePtr* at = NULL;
1.692 + if (t == Type::MEMORY) at = flatten_phi_adr_type(x->adr_type());
1.693 + return new (Compile::current(), r->req()) PhiNode(r, t, at);
1.694 +}
1.695 +
1.696 +
1.697 +//------------------------slice_memory-----------------------------------------
1.698 +// create a new phi with narrowed memory type
1.699 +PhiNode* PhiNode::slice_memory(const TypePtr* adr_type) const {
1.700 + PhiNode* mem = (PhiNode*) clone();
1.701 + *(const TypePtr**)&mem->_adr_type = adr_type;
1.702 + // convert self-loops, or else we get a bad graph
1.703 + for (uint i = 1; i < req(); i++) {
1.704 + if ((const Node*)in(i) == this) mem->set_req(i, mem);
1.705 + }
1.706 + mem->verify_adr_type();
1.707 + return mem;
1.708 +}
1.709 +
1.710 +//------------------------verify_adr_type--------------------------------------
1.711 +#ifdef ASSERT
1.712 +void PhiNode::verify_adr_type(VectorSet& visited, const TypePtr* at) const {
1.713 + if (visited.test_set(_idx)) return; //already visited
1.714 +
1.715 + // recheck constructor invariants:
1.716 + verify_adr_type(false);
1.717 +
1.718 + // recheck local phi/phi consistency:
1.719 + assert(_adr_type == at || _adr_type == TypePtr::BOTTOM,
1.720 + "adr_type must be consistent across phi nest");
1.721 +
1.722 + // walk around
1.723 + for (uint i = 1; i < req(); i++) {
1.724 + Node* n = in(i);
1.725 + if (n == NULL) continue;
1.726 + const Node* np = in(i);
1.727 + if (np->is_Phi()) {
1.728 + np->as_Phi()->verify_adr_type(visited, at);
1.729 + } else if (n->bottom_type() == Type::TOP
1.730 + || (n->is_Mem() && n->in(MemNode::Address)->bottom_type() == Type::TOP)) {
1.731 + // ignore top inputs
1.732 + } else {
1.733 + const TypePtr* nat = flatten_phi_adr_type(n->adr_type());
1.734 + // recheck phi/non-phi consistency at leaves:
1.735 + assert((nat != NULL) == (at != NULL), "");
1.736 + assert(nat == at || nat == TypePtr::BOTTOM,
1.737 + "adr_type must be consistent at leaves of phi nest");
1.738 + }
1.739 + }
1.740 +}
1.741 +
1.742 +// Verify a whole nest of phis rooted at this one.
1.743 +void PhiNode::verify_adr_type(bool recursive) const {
1.744 + if (is_error_reported()) return; // muzzle asserts when debugging an error
1.745 + if (Node::in_dump()) return; // muzzle asserts when printing
1.746 +
1.747 + assert((_type == Type::MEMORY) == (_adr_type != NULL), "adr_type for memory phis only");
1.748 +
1.749 + if (!VerifyAliases) return; // verify thoroughly only if requested
1.750 +
1.751 + assert(_adr_type == flatten_phi_adr_type(_adr_type),
1.752 + "Phi::adr_type must be pre-normalized");
1.753 +
1.754 + if (recursive) {
1.755 + VectorSet visited(Thread::current()->resource_area());
1.756 + verify_adr_type(visited, _adr_type);
1.757 + }
1.758 +}
1.759 +#endif
1.760 +
1.761 +
1.762 +//------------------------------Value------------------------------------------
1.763 +// Compute the type of the PhiNode
1.764 +const Type *PhiNode::Value( PhaseTransform *phase ) const {
1.765 + Node *r = in(0); // RegionNode
1.766 + if( !r ) // Copy or dead
1.767 + return in(1) ? phase->type(in(1)) : Type::TOP;
1.768 +
1.769 + // Note: During parsing, phis are often transformed before their regions.
1.770 + // This means we have to use type_or_null to defend against untyped regions.
1.771 + if( phase->type_or_null(r) == Type::TOP ) // Dead code?
1.772 + return Type::TOP;
1.773 +
1.774 + // Check for trip-counted loop. If so, be smarter.
1.775 + CountedLoopNode *l = r->is_CountedLoop() ? r->as_CountedLoop() : NULL;
1.776 + if( l && l->can_be_counted_loop(phase) &&
1.777 + ((const Node*)l->phi() == this) ) { // Trip counted loop!
1.778 + // protect against init_trip() or limit() returning NULL
1.779 + const Node *init = l->init_trip();
1.780 + const Node *limit = l->limit();
1.781 + if( init != NULL && limit != NULL && l->stride_is_con() ) {
1.782 + const TypeInt *lo = init ->bottom_type()->isa_int();
1.783 + const TypeInt *hi = limit->bottom_type()->isa_int();
1.784 + if( lo && hi ) { // Dying loops might have TOP here
1.785 + int stride = l->stride_con();
1.786 + if( stride < 0 ) { // Down-counter loop
1.787 + const TypeInt *tmp = lo; lo = hi; hi = tmp;
1.788 + stride = -stride;
1.789 + }
1.790 + if( lo->_hi < hi->_lo ) // Reversed endpoints are well defined :-(
1.791 + return TypeInt::make(lo->_lo,hi->_hi,3);
1.792 + }
1.793 + }
1.794 + }
1.795 +
1.796 + // Until we have harmony between classes and interfaces in the type
1.797 + // lattice, we must tread carefully around phis which implicitly
1.798 + // convert the one to the other.
1.799 + const TypeInstPtr* ttip = _type->isa_instptr();
1.800 + bool is_intf = false;
1.801 + if (ttip != NULL) {
1.802 + ciKlass* k = ttip->klass();
1.803 + if (k->is_loaded() && k->is_interface())
1.804 + is_intf = true;
1.805 + }
1.806 +
1.807 + // Default case: merge all inputs
1.808 + const Type *t = Type::TOP; // Merged type starting value
1.809 + for (uint i = 1; i < req(); ++i) {// For all paths in
1.810 + // Reachable control path?
1.811 + if (r->in(i) && phase->type(r->in(i)) == Type::CONTROL) {
1.812 + const Type* ti = phase->type(in(i));
1.813 + // We assume that each input of an interface-valued Phi is a true
1.814 + // subtype of that interface. This might not be true of the meet
1.815 + // of all the input types. The lattice is not distributive in
1.816 + // such cases. Ward off asserts in type.cpp by refusing to do
1.817 + // meets between interfaces and proper classes.
1.818 + const TypeInstPtr* tiip = ti->isa_instptr();
1.819 + if (tiip) {
1.820 + bool ti_is_intf = false;
1.821 + ciKlass* k = tiip->klass();
1.822 + if (k->is_loaded() && k->is_interface())
1.823 + ti_is_intf = true;
1.824 + if (is_intf != ti_is_intf)
1.825 + { t = _type; break; }
1.826 + }
1.827 + t = t->meet(ti);
1.828 + }
1.829 + }
1.830 +
1.831 + // The worst-case type (from ciTypeFlow) should be consistent with "t".
1.832 + // That is, we expect that "t->higher_equal(_type)" holds true.
1.833 + // There are various exceptions:
1.834 + // - Inputs which are phis might in fact be widened unnecessarily.
1.835 + // For example, an input might be a widened int while the phi is a short.
1.836 + // - Inputs might be BotPtrs but this phi is dependent on a null check,
1.837 + // and postCCP has removed the cast which encodes the result of the check.
1.838 + // - The type of this phi is an interface, and the inputs are classes.
1.839 + // - Value calls on inputs might produce fuzzy results.
1.840 + // (Occurrences of this case suggest improvements to Value methods.)
1.841 + //
1.842 + // It is not possible to see Type::BOTTOM values as phi inputs,
1.843 + // because the ciTypeFlow pre-pass produces verifier-quality types.
1.844 + const Type* ft = t->filter(_type); // Worst case type
1.845 +
1.846 +#ifdef ASSERT
1.847 + // The following logic has been moved into TypeOopPtr::filter.
1.848 + const Type* jt = t->join(_type);
1.849 + if( jt->empty() ) { // Emptied out???
1.850 +
1.851 + // Check for evil case of 't' being a class and '_type' expecting an
1.852 + // interface. This can happen because the bytecodes do not contain
1.853 + // enough type info to distinguish a Java-level interface variable
1.854 + // from a Java-level object variable. If we meet 2 classes which
1.855 + // both implement interface I, but their meet is at 'j/l/O' which
1.856 + // doesn't implement I, we have no way to tell if the result should
1.857 + // be 'I' or 'j/l/O'. Thus we'll pick 'j/l/O'. If this then flows
1.858 + // into a Phi which "knows" it's an Interface type we'll have to
1.859 + // uplift the type.
1.860 + if( !t->empty() && ttip && ttip->is_loaded() && ttip->klass()->is_interface() )
1.861 + { assert(ft == _type, ""); } // Uplift to interface
1.862 + // Otherwise it's something stupid like non-overlapping int ranges
1.863 + // found on dying counted loops.
1.864 + else
1.865 + { assert(ft == Type::TOP, ""); } // Canonical empty value
1.866 + }
1.867 +
1.868 + else {
1.869 +
1.870 + // If we have an interface-typed Phi and we narrow to a class type, the join
1.871 + // should report back the class. However, if we have a J/L/Object
1.872 + // class-typed Phi and an interface flows in, it's possible that the meet &
1.873 + // join report an interface back out. This isn't possible but happens
1.874 + // because the type system doesn't interact well with interfaces.
1.875 + const TypeInstPtr *jtip = jt->isa_instptr();
1.876 + if( jtip && ttip ) {
1.877 + if( jtip->is_loaded() && jtip->klass()->is_interface() &&
1.878 + ttip->is_loaded() && !ttip->klass()->is_interface() )
1.879 + // Happens in a CTW of rt.jar, 320-341, no extra flags
1.880 + { assert(ft == ttip->cast_to_ptr_type(jtip->ptr()), ""); jt = ft; }
1.881 + }
1.882 + if (jt != ft && jt->base() == ft->base()) {
1.883 + if (jt->isa_int() &&
1.884 + jt->is_int()->_lo == ft->is_int()->_lo &&
1.885 + jt->is_int()->_hi == ft->is_int()->_hi)
1.886 + jt = ft;
1.887 + if (jt->isa_long() &&
1.888 + jt->is_long()->_lo == ft->is_long()->_lo &&
1.889 + jt->is_long()->_hi == ft->is_long()->_hi)
1.890 + jt = ft;
1.891 + }
1.892 + if (jt != ft) {
1.893 + tty->print("merge type: "); t->dump(); tty->cr();
1.894 + tty->print("kill type: "); _type->dump(); tty->cr();
1.895 + tty->print("join type: "); jt->dump(); tty->cr();
1.896 + tty->print("filter type: "); ft->dump(); tty->cr();
1.897 + }
1.898 + assert(jt == ft, "");
1.899 + }
1.900 +#endif //ASSERT
1.901 +
1.902 + // Deal with conversion problems found in data loops.
1.903 + ft = phase->saturate(ft, phase->type_or_null(this), _type);
1.904 +
1.905 + return ft;
1.906 +}
1.907 +
1.908 +
1.909 +//------------------------------is_diamond_phi---------------------------------
1.910 +// Does this Phi represent a simple well-shaped diamond merge? Return the
1.911 +// index of the true path or 0 otherwise.
1.912 +int PhiNode::is_diamond_phi() const {
1.913 + // Check for a 2-path merge
1.914 + Node *region = in(0);
1.915 + if( !region ) return 0;
1.916 + if( region->req() != 3 ) return 0;
1.917 + if( req() != 3 ) return 0;
1.918 + // Check that both paths come from the same If
1.919 + Node *ifp1 = region->in(1);
1.920 + Node *ifp2 = region->in(2);
1.921 + if( !ifp1 || !ifp2 ) return 0;
1.922 + Node *iff = ifp1->in(0);
1.923 + if( !iff || !iff->is_If() ) return 0;
1.924 + if( iff != ifp2->in(0) ) return 0;
1.925 + // Check for a proper bool/cmp
1.926 + const Node *b = iff->in(1);
1.927 + if( !b->is_Bool() ) return 0;
1.928 + const Node *cmp = b->in(1);
1.929 + if( !cmp->is_Cmp() ) return 0;
1.930 +
1.931 + // Check for branching opposite expected
1.932 + if( ifp2->Opcode() == Op_IfTrue ) {
1.933 + assert( ifp1->Opcode() == Op_IfFalse, "" );
1.934 + return 2;
1.935 + } else {
1.936 + assert( ifp1->Opcode() == Op_IfTrue, "" );
1.937 + return 1;
1.938 + }
1.939 +}
1.940 +
1.941 +//----------------------------check_cmove_id-----------------------------------
1.942 +// Check for CMove'ing a constant after comparing against the constant.
1.943 +// Happens all the time now, since if we compare equality vs a constant in
1.944 +// the parser, we "know" the variable is constant on one path and we force
1.945 +// it. Thus code like "if( x==0 ) {/*EMPTY*/}" ends up inserting a
1.946 +// conditional move: "x = (x==0)?0:x;". Yucko. This fix is slightly more
1.947 +// general in that we don't need constants. Since CMove's are only inserted
1.948 +// in very special circumstances, we do it here on generic Phi's.
1.949 +Node* PhiNode::is_cmove_id(PhaseTransform* phase, int true_path) {
1.950 + assert(true_path !=0, "only diamond shape graph expected");
1.951 +
1.952 + // is_diamond_phi() has guaranteed the correctness of the nodes sequence:
1.953 + // phi->region->if_proj->ifnode->bool->cmp
1.954 + Node* region = in(0);
1.955 + Node* iff = region->in(1)->in(0);
1.956 + BoolNode* b = iff->in(1)->as_Bool();
1.957 + Node* cmp = b->in(1);
1.958 + Node* tval = in(true_path);
1.959 + Node* fval = in(3-true_path);
1.960 + Node* id = CMoveNode::is_cmove_id(phase, cmp, tval, fval, b);
1.961 + if (id == NULL)
1.962 + return NULL;
1.963 +
1.964 + // Either value might be a cast that depends on a branch of 'iff'.
1.965 + // Since the 'id' value will float free of the diamond, either
1.966 + // decast or return failure.
1.967 + Node* ctl = id->in(0);
1.968 + if (ctl != NULL && ctl->in(0) == iff) {
1.969 + if (id->is_ConstraintCast()) {
1.970 + return id->in(1);
1.971 + } else {
1.972 + // Don't know how to disentangle this value.
1.973 + return NULL;
1.974 + }
1.975 + }
1.976 +
1.977 + return id;
1.978 +}
1.979 +
1.980 +//------------------------------Identity---------------------------------------
1.981 +// Check for Region being Identity.
1.982 +Node *PhiNode::Identity( PhaseTransform *phase ) {
1.983 + // Check for no merging going on
1.984 + // (There used to be special-case code here when this->region->is_Loop.
1.985 + // It would check for a tributary phi on the backedge that the main phi
1.986 + // trivially, perhaps with a single cast. The unique_input method
1.987 + // does all this and more, by reducing such tributaries to 'this'.)
1.988 + Node* uin = unique_input(phase);
1.989 + if (uin != NULL) {
1.990 + return uin;
1.991 + }
1.992 +
1.993 + int true_path = is_diamond_phi();
1.994 + if (true_path != 0) {
1.995 + Node* id = is_cmove_id(phase, true_path);
1.996 + if (id != NULL) return id;
1.997 + }
1.998 +
1.999 + return this; // No identity
1.1000 +}
1.1001 +
1.1002 +//-----------------------------unique_input------------------------------------
1.1003 +// Find the unique value, discounting top, self-loops, and casts.
1.1004 +// Return top if there are no inputs, and self if there are multiple.
1.1005 +Node* PhiNode::unique_input(PhaseTransform* phase) {
1.1006 + // 1) One unique direct input, or
1.1007 + // 2) some of the inputs have an intervening ConstraintCast and
1.1008 + // the type of input is the same or sharper (more specific)
1.1009 + // than the phi's type.
1.1010 + // 3) an input is a self loop
1.1011 + //
1.1012 + // 1) input or 2) input or 3) input __
1.1013 + // / \ / \ \ / \
1.1014 + // \ / | cast phi cast
1.1015 + // phi \ / / \ /
1.1016 + // phi / --
1.1017 +
1.1018 + Node* r = in(0); // RegionNode
1.1019 + if (r == NULL) return in(1); // Already degraded to a Copy
1.1020 + Node* uncasted_input = NULL; // The unique uncasted input (ConstraintCasts removed)
1.1021 + Node* direct_input = NULL; // The unique direct input
1.1022 +
1.1023 + for (uint i = 1, cnt = req(); i < cnt; ++i) {
1.1024 + Node* rc = r->in(i);
1.1025 + if (rc == NULL || phase->type(rc) == Type::TOP)
1.1026 + continue; // ignore unreachable control path
1.1027 + Node* n = in(i);
1.1028 + Node* un = n->uncast();
1.1029 + if (un == NULL || un == this || phase->type(un) == Type::TOP) {
1.1030 + continue; // ignore if top, or in(i) and "this" are in a data cycle
1.1031 + }
1.1032 + // Check for a unique uncasted input
1.1033 + if (uncasted_input == NULL) {
1.1034 + uncasted_input = un;
1.1035 + } else if (uncasted_input != un) {
1.1036 + uncasted_input = NodeSentinel; // no unique uncasted input
1.1037 + }
1.1038 + // Check for a unique direct input
1.1039 + if (direct_input == NULL) {
1.1040 + direct_input = n;
1.1041 + } else if (direct_input != n) {
1.1042 + direct_input = NodeSentinel; // no unique direct input
1.1043 + }
1.1044 + }
1.1045 + if (direct_input == NULL) {
1.1046 + return phase->C->top(); // no inputs
1.1047 + }
1.1048 + assert(uncasted_input != NULL,"");
1.1049 +
1.1050 + if (direct_input != NodeSentinel) {
1.1051 + return direct_input; // one unique direct input
1.1052 + }
1.1053 + if (uncasted_input != NodeSentinel &&
1.1054 + phase->type(uncasted_input)->higher_equal(type())) {
1.1055 + return uncasted_input; // one unique uncasted input
1.1056 + }
1.1057 +
1.1058 + // Nothing.
1.1059 + return NULL;
1.1060 +}
1.1061 +
1.1062 +//------------------------------is_x2logic-------------------------------------
1.1063 +// Check for simple convert-to-boolean pattern
1.1064 +// If:(C Bool) Region:(IfF IfT) Phi:(Region 0 1)
1.1065 +// Convert Phi to an ConvIB.
1.1066 +static Node *is_x2logic( PhaseGVN *phase, PhiNode *phi, int true_path ) {
1.1067 + assert(true_path !=0, "only diamond shape graph expected");
1.1068 + // Convert the true/false index into an expected 0/1 return.
1.1069 + // Map 2->0 and 1->1.
1.1070 + int flipped = 2-true_path;
1.1071 +
1.1072 + // is_diamond_phi() has guaranteed the correctness of the nodes sequence:
1.1073 + // phi->region->if_proj->ifnode->bool->cmp
1.1074 + Node *region = phi->in(0);
1.1075 + Node *iff = region->in(1)->in(0);
1.1076 + BoolNode *b = (BoolNode*)iff->in(1);
1.1077 + const CmpNode *cmp = (CmpNode*)b->in(1);
1.1078 +
1.1079 + Node *zero = phi->in(1);
1.1080 + Node *one = phi->in(2);
1.1081 + const Type *tzero = phase->type( zero );
1.1082 + const Type *tone = phase->type( one );
1.1083 +
1.1084 + // Check for compare vs 0
1.1085 + const Type *tcmp = phase->type(cmp->in(2));
1.1086 + if( tcmp != TypeInt::ZERO && tcmp != TypePtr::NULL_PTR ) {
1.1087 + // Allow cmp-vs-1 if the other input is bounded by 0-1
1.1088 + if( !(tcmp == TypeInt::ONE && phase->type(cmp->in(1)) == TypeInt::BOOL) )
1.1089 + return NULL;
1.1090 + flipped = 1-flipped; // Test is vs 1 instead of 0!
1.1091 + }
1.1092 +
1.1093 + // Check for setting zero/one opposite expected
1.1094 + if( tzero == TypeInt::ZERO ) {
1.1095 + if( tone == TypeInt::ONE ) {
1.1096 + } else return NULL;
1.1097 + } else if( tzero == TypeInt::ONE ) {
1.1098 + if( tone == TypeInt::ZERO ) {
1.1099 + flipped = 1-flipped;
1.1100 + } else return NULL;
1.1101 + } else return NULL;
1.1102 +
1.1103 + // Check for boolean test backwards
1.1104 + if( b->_test._test == BoolTest::ne ) {
1.1105 + } else if( b->_test._test == BoolTest::eq ) {
1.1106 + flipped = 1-flipped;
1.1107 + } else return NULL;
1.1108 +
1.1109 + // Build int->bool conversion
1.1110 + Node *n = new (phase->C, 2) Conv2BNode( cmp->in(1) );
1.1111 + if( flipped )
1.1112 + n = new (phase->C, 3) XorINode( phase->transform(n), phase->intcon(1) );
1.1113 +
1.1114 + return n;
1.1115 +}
1.1116 +
1.1117 +//------------------------------is_cond_add------------------------------------
1.1118 +// Check for simple conditional add pattern: "(P < Q) ? X+Y : X;"
1.1119 +// To be profitable the control flow has to disappear; there can be no other
1.1120 +// values merging here. We replace the test-and-branch with:
1.1121 +// "(sgn(P-Q))&Y) + X". Basically, convert "(P < Q)" into 0 or -1 by
1.1122 +// moving the carry bit from (P-Q) into a register with 'sbb EAX,EAX'.
1.1123 +// Then convert Y to 0-or-Y and finally add.
1.1124 +// This is a key transform for SpecJava _201_compress.
1.1125 +static Node* is_cond_add(PhaseGVN *phase, PhiNode *phi, int true_path) {
1.1126 + assert(true_path !=0, "only diamond shape graph expected");
1.1127 +
1.1128 + // is_diamond_phi() has guaranteed the correctness of the nodes sequence:
1.1129 + // phi->region->if_proj->ifnode->bool->cmp
1.1130 + RegionNode *region = (RegionNode*)phi->in(0);
1.1131 + Node *iff = region->in(1)->in(0);
1.1132 + BoolNode* b = iff->in(1)->as_Bool();
1.1133 + const CmpNode *cmp = (CmpNode*)b->in(1);
1.1134 +
1.1135 + // Make sure only merging this one phi here
1.1136 + if (region->has_unique_phi() != phi) return NULL;
1.1137 +
1.1138 + // Make sure each arm of the diamond has exactly one output, which we assume
1.1139 + // is the region. Otherwise, the control flow won't disappear.
1.1140 + if (region->in(1)->outcnt() != 1) return NULL;
1.1141 + if (region->in(2)->outcnt() != 1) return NULL;
1.1142 +
1.1143 + // Check for "(P < Q)" of type signed int
1.1144 + if (b->_test._test != BoolTest::lt) return NULL;
1.1145 + if (cmp->Opcode() != Op_CmpI) return NULL;
1.1146 +
1.1147 + Node *p = cmp->in(1);
1.1148 + Node *q = cmp->in(2);
1.1149 + Node *n1 = phi->in( true_path);
1.1150 + Node *n2 = phi->in(3-true_path);
1.1151 +
1.1152 + int op = n1->Opcode();
1.1153 + if( op != Op_AddI // Need zero as additive identity
1.1154 + /*&&op != Op_SubI &&
1.1155 + op != Op_AddP &&
1.1156 + op != Op_XorI &&
1.1157 + op != Op_OrI*/ )
1.1158 + return NULL;
1.1159 +
1.1160 + Node *x = n2;
1.1161 + Node *y = n1->in(1);
1.1162 + if( n2 == n1->in(1) ) {
1.1163 + y = n1->in(2);
1.1164 + } else if( n2 == n1->in(1) ) {
1.1165 + } else return NULL;
1.1166 +
1.1167 + // Not so profitable if compare and add are constants
1.1168 + if( q->is_Con() && phase->type(q) != TypeInt::ZERO && y->is_Con() )
1.1169 + return NULL;
1.1170 +
1.1171 + Node *cmplt = phase->transform( new (phase->C, 3) CmpLTMaskNode(p,q) );
1.1172 + Node *j_and = phase->transform( new (phase->C, 3) AndINode(cmplt,y) );
1.1173 + return new (phase->C, 3) AddINode(j_and,x);
1.1174 +}
1.1175 +
1.1176 +//------------------------------is_absolute------------------------------------
1.1177 +// Check for absolute value.
1.1178 +static Node* is_absolute( PhaseGVN *phase, PhiNode *phi_root, int true_path) {
1.1179 + assert(true_path !=0, "only diamond shape graph expected");
1.1180 +
1.1181 + int cmp_zero_idx = 0; // Index of compare input where to look for zero
1.1182 + int phi_x_idx = 0; // Index of phi input where to find naked x
1.1183 +
1.1184 + // ABS ends with the merge of 2 control flow paths.
1.1185 + // Find the false path from the true path. With only 2 inputs, 3 - x works nicely.
1.1186 + int false_path = 3 - true_path;
1.1187 +
1.1188 + // is_diamond_phi() has guaranteed the correctness of the nodes sequence:
1.1189 + // phi->region->if_proj->ifnode->bool->cmp
1.1190 + BoolNode *bol = phi_root->in(0)->in(1)->in(0)->in(1)->as_Bool();
1.1191 +
1.1192 + // Check bool sense
1.1193 + switch( bol->_test._test ) {
1.1194 + case BoolTest::lt: cmp_zero_idx = 1; phi_x_idx = true_path; break;
1.1195 + case BoolTest::le: cmp_zero_idx = 2; phi_x_idx = false_path; break;
1.1196 + case BoolTest::gt: cmp_zero_idx = 2; phi_x_idx = true_path; break;
1.1197 + case BoolTest::ge: cmp_zero_idx = 1; phi_x_idx = false_path; break;
1.1198 + default: return NULL; break;
1.1199 + }
1.1200 +
1.1201 + // Test is next
1.1202 + Node *cmp = bol->in(1);
1.1203 + const Type *tzero = NULL;
1.1204 + switch( cmp->Opcode() ) {
1.1205 + case Op_CmpF: tzero = TypeF::ZERO; break; // Float ABS
1.1206 + case Op_CmpD: tzero = TypeD::ZERO; break; // Double ABS
1.1207 + default: return NULL;
1.1208 + }
1.1209 +
1.1210 + // Find zero input of compare; the other input is being abs'd
1.1211 + Node *x = NULL;
1.1212 + bool flip = false;
1.1213 + if( phase->type(cmp->in(cmp_zero_idx)) == tzero ) {
1.1214 + x = cmp->in(3 - cmp_zero_idx);
1.1215 + } else if( phase->type(cmp->in(3 - cmp_zero_idx)) == tzero ) {
1.1216 + // The test is inverted, we should invert the result...
1.1217 + x = cmp->in(cmp_zero_idx);
1.1218 + flip = true;
1.1219 + } else {
1.1220 + return NULL;
1.1221 + }
1.1222 +
1.1223 + // Next get the 2 pieces being selected, one is the original value
1.1224 + // and the other is the negated value.
1.1225 + if( phi_root->in(phi_x_idx) != x ) return NULL;
1.1226 +
1.1227 + // Check other phi input for subtract node
1.1228 + Node *sub = phi_root->in(3 - phi_x_idx);
1.1229 +
1.1230 + // Allow only Sub(0,X) and fail out for all others; Neg is not OK
1.1231 + if( tzero == TypeF::ZERO ) {
1.1232 + if( sub->Opcode() != Op_SubF ||
1.1233 + sub->in(2) != x ||
1.1234 + phase->type(sub->in(1)) != tzero ) return NULL;
1.1235 + x = new (phase->C, 2) AbsFNode(x);
1.1236 + if (flip) {
1.1237 + x = new (phase->C, 3) SubFNode(sub->in(1), phase->transform(x));
1.1238 + }
1.1239 + } else {
1.1240 + if( sub->Opcode() != Op_SubD ||
1.1241 + sub->in(2) != x ||
1.1242 + phase->type(sub->in(1)) != tzero ) return NULL;
1.1243 + x = new (phase->C, 2) AbsDNode(x);
1.1244 + if (flip) {
1.1245 + x = new (phase->C, 3) SubDNode(sub->in(1), phase->transform(x));
1.1246 + }
1.1247 + }
1.1248 +
1.1249 + return x;
1.1250 +}
1.1251 +
1.1252 +//------------------------------split_once-------------------------------------
1.1253 +// Helper for split_flow_path
1.1254 +static void split_once(PhaseIterGVN *igvn, Node *phi, Node *val, Node *n, Node *newn) {
1.1255 + igvn->hash_delete(n); // Remove from hash before hacking edges
1.1256 +
1.1257 + uint j = 1;
1.1258 + for( uint i = phi->req()-1; i > 0; i-- ) {
1.1259 + if( phi->in(i) == val ) { // Found a path with val?
1.1260 + // Add to NEW Region/Phi, no DU info
1.1261 + newn->set_req( j++, n->in(i) );
1.1262 + // Remove from OLD Region/Phi
1.1263 + n->del_req(i);
1.1264 + }
1.1265 + }
1.1266 +
1.1267 + // Register the new node but do not transform it. Cannot transform until the
1.1268 + // entire Region/Phi conglerate has been hacked as a single huge transform.
1.1269 + igvn->register_new_node_with_optimizer( newn );
1.1270 + // Now I can point to the new node.
1.1271 + n->add_req(newn);
1.1272 + igvn->_worklist.push(n);
1.1273 +}
1.1274 +
1.1275 +//------------------------------split_flow_path--------------------------------
1.1276 +// Check for merging identical values and split flow paths
1.1277 +static Node* split_flow_path(PhaseGVN *phase, PhiNode *phi) {
1.1278 + BasicType bt = phi->type()->basic_type();
1.1279 + if( bt == T_ILLEGAL || type2size[bt] <= 0 )
1.1280 + return NULL; // Bail out on funny non-value stuff
1.1281 + if( phi->req() <= 3 ) // Need at least 2 matched inputs and a
1.1282 + return NULL; // third unequal input to be worth doing
1.1283 +
1.1284 + // Scan for a constant
1.1285 + uint i;
1.1286 + for( i = 1; i < phi->req()-1; i++ ) {
1.1287 + Node *n = phi->in(i);
1.1288 + if( !n ) return NULL;
1.1289 + if( phase->type(n) == Type::TOP ) return NULL;
1.1290 + if( n->Opcode() == Op_ConP )
1.1291 + break;
1.1292 + }
1.1293 + if( i >= phi->req() ) // Only split for constants
1.1294 + return NULL;
1.1295 +
1.1296 + Node *val = phi->in(i); // Constant to split for
1.1297 + uint hit = 0; // Number of times it occurs
1.1298 +
1.1299 + for( ; i < phi->req(); i++ ){ // Count occurances of constant
1.1300 + Node *n = phi->in(i);
1.1301 + if( !n ) return NULL;
1.1302 + if( phase->type(n) == Type::TOP ) return NULL;
1.1303 + if( phi->in(i) == val )
1.1304 + hit++;
1.1305 + }
1.1306 +
1.1307 + if( hit <= 1 || // Make sure we find 2 or more
1.1308 + hit == phi->req()-1 ) // and not ALL the same value
1.1309 + return NULL;
1.1310 +
1.1311 + // Now start splitting out the flow paths that merge the same value.
1.1312 + // Split first the RegionNode.
1.1313 + PhaseIterGVN *igvn = phase->is_IterGVN();
1.1314 + Node *r = phi->region();
1.1315 + RegionNode *newr = new (phase->C, hit+1) RegionNode(hit+1);
1.1316 + split_once(igvn, phi, val, r, newr);
1.1317 +
1.1318 + // Now split all other Phis than this one
1.1319 + for (DUIterator_Fast kmax, k = r->fast_outs(kmax); k < kmax; k++) {
1.1320 + Node* phi2 = r->fast_out(k);
1.1321 + if( phi2->is_Phi() && phi2->as_Phi() != phi ) {
1.1322 + PhiNode *newphi = PhiNode::make_blank(newr, phi2);
1.1323 + split_once(igvn, phi, val, phi2, newphi);
1.1324 + }
1.1325 + }
1.1326 +
1.1327 + // Clean up this guy
1.1328 + igvn->hash_delete(phi);
1.1329 + for( i = phi->req()-1; i > 0; i-- ) {
1.1330 + if( phi->in(i) == val ) {
1.1331 + phi->del_req(i);
1.1332 + }
1.1333 + }
1.1334 + phi->add_req(val);
1.1335 +
1.1336 + return phi;
1.1337 +}
1.1338 +
1.1339 +//=============================================================================
1.1340 +//------------------------------simple_data_loop_check-------------------------
1.1341 +// Try to determing if the phi node in a simple safe/unsafe data loop.
1.1342 +// Returns:
1.1343 +// enum LoopSafety { Safe = 0, Unsafe, UnsafeLoop };
1.1344 +// Safe - safe case when the phi and it's inputs reference only safe data
1.1345 +// nodes;
1.1346 +// Unsafe - the phi and it's inputs reference unsafe data nodes but there
1.1347 +// is no reference back to the phi - need a graph walk
1.1348 +// to determine if it is in a loop;
1.1349 +// UnsafeLoop - unsafe case when the phi references itself directly or through
1.1350 +// unsafe data node.
1.1351 +// Note: a safe data node is a node which could/never reference itself during
1.1352 +// GVN transformations. For now it is Con, Proj, Phi, CastPP, CheckCastPP.
1.1353 +// I mark Phi nodes as safe node not only because they can reference itself
1.1354 +// but also to prevent mistaking the fallthrough case inside an outer loop
1.1355 +// as dead loop when the phi references itselfs through an other phi.
1.1356 +PhiNode::LoopSafety PhiNode::simple_data_loop_check(Node *in) const {
1.1357 + // It is unsafe loop if the phi node references itself directly.
1.1358 + if (in == (Node*)this)
1.1359 + return UnsafeLoop; // Unsafe loop
1.1360 + // Unsafe loop if the phi node references itself through an unsafe data node.
1.1361 + // Exclude cases with null inputs or data nodes which could reference
1.1362 + // itself (safe for dead loops).
1.1363 + if (in != NULL && !in->is_dead_loop_safe()) {
1.1364 + // Check inputs of phi's inputs also.
1.1365 + // It is much less expensive then full graph walk.
1.1366 + uint cnt = in->req();
1.1367 + for (uint i = 1; i < cnt; ++i) {
1.1368 + Node* m = in->in(i);
1.1369 + if (m == (Node*)this)
1.1370 + return UnsafeLoop; // Unsafe loop
1.1371 + if (m != NULL && !m->is_dead_loop_safe()) {
1.1372 + // Check the most common case (about 30% of all cases):
1.1373 + // phi->Load/Store->AddP->(ConP ConP Con)/(Parm Parm Con).
1.1374 + Node *m1 = (m->is_AddP() && m->req() > 3) ? m->in(1) : NULL;
1.1375 + if (m1 == (Node*)this)
1.1376 + return UnsafeLoop; // Unsafe loop
1.1377 + if (m1 != NULL && m1 == m->in(2) &&
1.1378 + m1->is_dead_loop_safe() && m->in(3)->is_Con()) {
1.1379 + continue; // Safe case
1.1380 + }
1.1381 + // The phi references an unsafe node - need full analysis.
1.1382 + return Unsafe;
1.1383 + }
1.1384 + }
1.1385 + }
1.1386 + return Safe; // Safe case - we can optimize the phi node.
1.1387 +}
1.1388 +
1.1389 +//------------------------------is_unsafe_data_reference-----------------------
1.1390 +// If phi can be reached through the data input - it is data loop.
1.1391 +bool PhiNode::is_unsafe_data_reference(Node *in) const {
1.1392 + assert(req() > 1, "");
1.1393 + // First, check simple cases when phi references itself directly or
1.1394 + // through an other node.
1.1395 + LoopSafety safety = simple_data_loop_check(in);
1.1396 + if (safety == UnsafeLoop)
1.1397 + return true; // phi references itself - unsafe loop
1.1398 + else if (safety == Safe)
1.1399 + return false; // Safe case - phi could be replaced with the unique input.
1.1400 +
1.1401 + // Unsafe case when we should go through data graph to determine
1.1402 + // if the phi references itself.
1.1403 +
1.1404 + ResourceMark rm;
1.1405 +
1.1406 + Arena *a = Thread::current()->resource_area();
1.1407 + Node_List nstack(a);
1.1408 + VectorSet visited(a);
1.1409 +
1.1410 + nstack.push(in); // Start with unique input.
1.1411 + visited.set(in->_idx);
1.1412 + while (nstack.size() != 0) {
1.1413 + Node* n = nstack.pop();
1.1414 + uint cnt = n->req();
1.1415 + for (uint i = 1; i < cnt; i++) { // Only data paths
1.1416 + Node* m = n->in(i);
1.1417 + if (m == (Node*)this) {
1.1418 + return true; // Data loop
1.1419 + }
1.1420 + if (m != NULL && !m->is_dead_loop_safe()) { // Only look for unsafe cases.
1.1421 + if (!visited.test_set(m->_idx))
1.1422 + nstack.push(m);
1.1423 + }
1.1424 + }
1.1425 + }
1.1426 + return false; // The phi is not reachable from its inputs
1.1427 +}
1.1428 +
1.1429 +
1.1430 +//------------------------------Ideal------------------------------------------
1.1431 +// Return a node which is more "ideal" than the current node. Must preserve
1.1432 +// the CFG, but we can still strip out dead paths.
1.1433 +Node *PhiNode::Ideal(PhaseGVN *phase, bool can_reshape) {
1.1434 + // The next should never happen after 6297035 fix.
1.1435 + if( is_copy() ) // Already degraded to a Copy ?
1.1436 + return NULL; // No change
1.1437 +
1.1438 + Node *r = in(0); // RegionNode
1.1439 + assert(r->in(0) == NULL || !r->in(0)->is_Root(), "not a specially hidden merge");
1.1440 +
1.1441 + // Note: During parsing, phis are often transformed before their regions.
1.1442 + // This means we have to use type_or_null to defend against untyped regions.
1.1443 + if( phase->type_or_null(r) == Type::TOP ) // Dead code?
1.1444 + return NULL; // No change
1.1445 +
1.1446 + Node *top = phase->C->top();
1.1447 +
1.1448 + // The are 2 situations when only one valid phi's input is left
1.1449 + // (in addition to Region input).
1.1450 + // One: region is not loop - replace phi with this input.
1.1451 + // Two: region is loop - replace phi with top since this data path is dead
1.1452 + // and we need to break the dead data loop.
1.1453 + Node* progress = NULL; // Record if any progress made
1.1454 + for( uint j = 1; j < req(); ++j ){ // For all paths in
1.1455 + // Check unreachable control paths
1.1456 + Node* rc = r->in(j);
1.1457 + Node* n = in(j); // Get the input
1.1458 + if (rc == NULL || phase->type(rc) == Type::TOP) {
1.1459 + if (n != top) { // Not already top?
1.1460 + set_req(j, top); // Nuke it down
1.1461 + progress = this; // Record progress
1.1462 + }
1.1463 + }
1.1464 + }
1.1465 +
1.1466 + Node* uin = unique_input(phase);
1.1467 + if (uin == top) { // Simplest case: no alive inputs.
1.1468 + if (can_reshape) // IGVN transformation
1.1469 + return top;
1.1470 + else
1.1471 + return NULL; // Identity will return TOP
1.1472 + } else if (uin != NULL) {
1.1473 + // Only one not-NULL unique input path is left.
1.1474 + // Determine if this input is backedge of a loop.
1.1475 + // (Skip new phis which have no uses and dead regions).
1.1476 + if( outcnt() > 0 && r->in(0) != NULL ) {
1.1477 + // First, take the short cut when we know it is a loop and
1.1478 + // the EntryControl data path is dead.
1.1479 + assert(!r->is_Loop() || r->req() == 3, "Loop node should have 3 inputs");
1.1480 + // Then, check if there is a data loop when phi references itself directly
1.1481 + // or through other data nodes.
1.1482 + if( r->is_Loop() && !phase->eqv_uncast(uin, in(LoopNode::EntryControl)) ||
1.1483 + !r->is_Loop() && is_unsafe_data_reference(uin) ) {
1.1484 + // Break this data loop to avoid creation of a dead loop.
1.1485 + if (can_reshape) {
1.1486 + return top;
1.1487 + } else {
1.1488 + // We can't return top if we are in Parse phase - cut inputs only
1.1489 + // let Identity to handle the case.
1.1490 + replace_edge(uin, top);
1.1491 + return NULL;
1.1492 + }
1.1493 + }
1.1494 + }
1.1495 +
1.1496 + // One unique input.
1.1497 + debug_only(Node* ident = Identity(phase));
1.1498 + // The unique input must eventually be detected by the Identity call.
1.1499 +#ifdef ASSERT
1.1500 + if (ident != uin && !ident->is_top()) {
1.1501 + // print this output before failing assert
1.1502 + r->dump(3);
1.1503 + this->dump(3);
1.1504 + ident->dump();
1.1505 + uin->dump();
1.1506 + }
1.1507 +#endif
1.1508 + assert(ident == uin || ident->is_top(), "Identity must clean this up");
1.1509 + return NULL;
1.1510 + }
1.1511 +
1.1512 +
1.1513 + Node* opt = NULL;
1.1514 + int true_path = is_diamond_phi();
1.1515 + if( true_path != 0 ) {
1.1516 + // Check for CMove'ing identity. If it would be unsafe,
1.1517 + // handle it here. In the safe case, let Identity handle it.
1.1518 + Node* unsafe_id = is_cmove_id(phase, true_path);
1.1519 + if( unsafe_id != NULL && is_unsafe_data_reference(unsafe_id) )
1.1520 + opt = unsafe_id;
1.1521 +
1.1522 + // Check for simple convert-to-boolean pattern
1.1523 + if( opt == NULL )
1.1524 + opt = is_x2logic(phase, this, true_path);
1.1525 +
1.1526 + // Check for absolute value
1.1527 + if( opt == NULL )
1.1528 + opt = is_absolute(phase, this, true_path);
1.1529 +
1.1530 + // Check for conditional add
1.1531 + if( opt == NULL && can_reshape )
1.1532 + opt = is_cond_add(phase, this, true_path);
1.1533 +
1.1534 + // These 4 optimizations could subsume the phi:
1.1535 + // have to check for a dead data loop creation.
1.1536 + if( opt != NULL ) {
1.1537 + if( opt == unsafe_id || is_unsafe_data_reference(opt) ) {
1.1538 + // Found dead loop.
1.1539 + if( can_reshape )
1.1540 + return top;
1.1541 + // We can't return top if we are in Parse phase - cut inputs only
1.1542 + // to stop further optimizations for this phi. Identity will return TOP.
1.1543 + assert(req() == 3, "only diamond merge phi here");
1.1544 + set_req(1, top);
1.1545 + set_req(2, top);
1.1546 + return NULL;
1.1547 + } else {
1.1548 + return opt;
1.1549 + }
1.1550 + }
1.1551 + }
1.1552 +
1.1553 + // Check for merging identical values and split flow paths
1.1554 + if (can_reshape) {
1.1555 + opt = split_flow_path(phase, this);
1.1556 + // This optimization only modifies phi - don't need to check for dead loop.
1.1557 + assert(opt == NULL || phase->eqv(opt, this), "do not elide phi");
1.1558 + if (opt != NULL) return opt;
1.1559 + }
1.1560 +
1.1561 + if (in(1) != NULL && in(1)->Opcode() == Op_AddP && can_reshape) {
1.1562 + // Try to undo Phi of AddP:
1.1563 + // (Phi (AddP base base y) (AddP base2 base2 y))
1.1564 + // becomes:
1.1565 + // newbase := (Phi base base2)
1.1566 + // (AddP newbase newbase y)
1.1567 + //
1.1568 + // This occurs as a result of unsuccessful split_thru_phi and
1.1569 + // interferes with taking advantage of addressing modes. See the
1.1570 + // clone_shift_expressions code in matcher.cpp
1.1571 + Node* addp = in(1);
1.1572 + const Type* type = addp->in(AddPNode::Base)->bottom_type();
1.1573 + Node* y = addp->in(AddPNode::Offset);
1.1574 + if (y != NULL && addp->in(AddPNode::Base) == addp->in(AddPNode::Address)) {
1.1575 + // make sure that all the inputs are similar to the first one,
1.1576 + // i.e. AddP with base == address and same offset as first AddP
1.1577 + bool doit = true;
1.1578 + for (uint i = 2; i < req(); i++) {
1.1579 + if (in(i) == NULL ||
1.1580 + in(i)->Opcode() != Op_AddP ||
1.1581 + in(i)->in(AddPNode::Base) != in(i)->in(AddPNode::Address) ||
1.1582 + in(i)->in(AddPNode::Offset) != y) {
1.1583 + doit = false;
1.1584 + break;
1.1585 + }
1.1586 + // Accumulate type for resulting Phi
1.1587 + type = type->meet(in(i)->in(AddPNode::Base)->bottom_type());
1.1588 + }
1.1589 + Node* base = NULL;
1.1590 + if (doit) {
1.1591 + // Check for neighboring AddP nodes in a tree.
1.1592 + // If they have a base, use that it.
1.1593 + for (DUIterator_Fast kmax, k = this->fast_outs(kmax); k < kmax; k++) {
1.1594 + Node* u = this->fast_out(k);
1.1595 + if (u->is_AddP()) {
1.1596 + Node* base2 = u->in(AddPNode::Base);
1.1597 + if (base2 != NULL && !base2->is_top()) {
1.1598 + if (base == NULL)
1.1599 + base = base2;
1.1600 + else if (base != base2)
1.1601 + { doit = false; break; }
1.1602 + }
1.1603 + }
1.1604 + }
1.1605 + }
1.1606 + if (doit) {
1.1607 + if (base == NULL) {
1.1608 + base = new (phase->C, in(0)->req()) PhiNode(in(0), type, NULL);
1.1609 + for (uint i = 1; i < req(); i++) {
1.1610 + base->init_req(i, in(i)->in(AddPNode::Base));
1.1611 + }
1.1612 + phase->is_IterGVN()->register_new_node_with_optimizer(base);
1.1613 + }
1.1614 + return new (phase->C, 4) AddPNode(base, base, y);
1.1615 + }
1.1616 + }
1.1617 + }
1.1618 +
1.1619 + // Split phis through memory merges, so that the memory merges will go away.
1.1620 + // Piggy-back this transformation on the search for a unique input....
1.1621 + // It will be as if the merged memory is the unique value of the phi.
1.1622 + // (Do not attempt this optimization unless parsing is complete.
1.1623 + // It would make the parser's memory-merge logic sick.)
1.1624 + // (MergeMemNode is not dead_loop_safe - need to check for dead loop.)
1.1625 + if (progress == NULL && can_reshape && type() == Type::MEMORY) {
1.1626 + // see if this phi should be sliced
1.1627 + uint merge_width = 0;
1.1628 + bool saw_self = false;
1.1629 + for( uint i=1; i<req(); ++i ) {// For all paths in
1.1630 + Node *ii = in(i);
1.1631 + if (ii->is_MergeMem()) {
1.1632 + MergeMemNode* n = ii->as_MergeMem();
1.1633 + merge_width = MAX2(merge_width, n->req());
1.1634 + saw_self = saw_self || phase->eqv(n->base_memory(), this);
1.1635 + }
1.1636 + }
1.1637 +
1.1638 + // This restriction is temporarily necessary to ensure termination:
1.1639 + if (!saw_self && adr_type() == TypePtr::BOTTOM) merge_width = 0;
1.1640 +
1.1641 + if (merge_width > Compile::AliasIdxRaw) {
1.1642 + // found at least one non-empty MergeMem
1.1643 + const TypePtr* at = adr_type();
1.1644 + if (at != TypePtr::BOTTOM) {
1.1645 + // Patch the existing phi to select an input from the merge:
1.1646 + // Phi:AT1(...MergeMem(m0, m1, m2)...) into
1.1647 + // Phi:AT1(...m1...)
1.1648 + int alias_idx = phase->C->get_alias_index(at);
1.1649 + for (uint i=1; i<req(); ++i) {
1.1650 + Node *ii = in(i);
1.1651 + if (ii->is_MergeMem()) {
1.1652 + MergeMemNode* n = ii->as_MergeMem();
1.1653 + // compress paths and change unreachable cycles to TOP
1.1654 + // If not, we can update the input infinitely along a MergeMem cycle
1.1655 + // Equivalent code is in MemNode::Ideal_common
1.1656 + Node *m = phase->transform(n);
1.1657 + // If tranformed to a MergeMem, get the desired slice
1.1658 + // Otherwise the returned node represents memory for every slice
1.1659 + Node *new_mem = (m->is_MergeMem()) ?
1.1660 + m->as_MergeMem()->memory_at(alias_idx) : m;
1.1661 + // Update input if it is progress over what we have now
1.1662 + if (new_mem != ii) {
1.1663 + set_req(i, new_mem);
1.1664 + progress = this;
1.1665 + }
1.1666 + }
1.1667 + }
1.1668 + } else {
1.1669 + // We know that at least one MergeMem->base_memory() == this
1.1670 + // (saw_self == true). If all other inputs also references this phi
1.1671 + // (directly or through data nodes) - it is dead loop.
1.1672 + bool saw_safe_input = false;
1.1673 + for (uint j = 1; j < req(); ++j) {
1.1674 + Node *n = in(j);
1.1675 + if (n->is_MergeMem() && n->as_MergeMem()->base_memory() == this)
1.1676 + continue; // skip known cases
1.1677 + if (!is_unsafe_data_reference(n)) {
1.1678 + saw_safe_input = true; // found safe input
1.1679 + break;
1.1680 + }
1.1681 + }
1.1682 + if (!saw_safe_input)
1.1683 + return top; // all inputs reference back to this phi - dead loop
1.1684 +
1.1685 + // Phi(...MergeMem(m0, m1:AT1, m2:AT2)...) into
1.1686 + // MergeMem(Phi(...m0...), Phi:AT1(...m1...), Phi:AT2(...m2...))
1.1687 + PhaseIterGVN *igvn = phase->is_IterGVN();
1.1688 + Node* hook = new (phase->C, 1) Node(1);
1.1689 + PhiNode* new_base = (PhiNode*) clone();
1.1690 + // Must eagerly register phis, since they participate in loops.
1.1691 + if (igvn) {
1.1692 + igvn->register_new_node_with_optimizer(new_base);
1.1693 + hook->add_req(new_base);
1.1694 + }
1.1695 + MergeMemNode* result = MergeMemNode::make(phase->C, new_base);
1.1696 + for (uint i = 1; i < req(); ++i) {
1.1697 + Node *ii = in(i);
1.1698 + if (ii->is_MergeMem()) {
1.1699 + MergeMemNode* n = ii->as_MergeMem();
1.1700 + for (MergeMemStream mms(result, n); mms.next_non_empty2(); ) {
1.1701 + // If we have not seen this slice yet, make a phi for it.
1.1702 + bool made_new_phi = false;
1.1703 + if (mms.is_empty()) {
1.1704 + Node* new_phi = new_base->slice_memory(mms.adr_type(phase->C));
1.1705 + made_new_phi = true;
1.1706 + if (igvn) {
1.1707 + igvn->register_new_node_with_optimizer(new_phi);
1.1708 + hook->add_req(new_phi);
1.1709 + }
1.1710 + mms.set_memory(new_phi);
1.1711 + }
1.1712 + Node* phi = mms.memory();
1.1713 + assert(made_new_phi || phi->in(i) == n, "replace the i-th merge by a slice");
1.1714 + phi->set_req(i, mms.memory2());
1.1715 + }
1.1716 + }
1.1717 + }
1.1718 + // Distribute all self-loops.
1.1719 + { // (Extra braces to hide mms.)
1.1720 + for (MergeMemStream mms(result); mms.next_non_empty(); ) {
1.1721 + Node* phi = mms.memory();
1.1722 + for (uint i = 1; i < req(); ++i) {
1.1723 + if (phi->in(i) == this) phi->set_req(i, phi);
1.1724 + }
1.1725 + }
1.1726 + }
1.1727 + // now transform the new nodes, and return the mergemem
1.1728 + for (MergeMemStream mms(result); mms.next_non_empty(); ) {
1.1729 + Node* phi = mms.memory();
1.1730 + mms.set_memory(phase->transform(phi));
1.1731 + }
1.1732 + if (igvn) { // Unhook.
1.1733 + igvn->hash_delete(hook);
1.1734 + for (uint i = 1; i < hook->req(); i++) {
1.1735 + hook->set_req(i, NULL);
1.1736 + }
1.1737 + }
1.1738 + // Replace self with the result.
1.1739 + return result;
1.1740 + }
1.1741 + }
1.1742 + }
1.1743 +
1.1744 + return progress; // Return any progress
1.1745 +}
1.1746 +
1.1747 +//------------------------------out_RegMask------------------------------------
1.1748 +const RegMask &PhiNode::in_RegMask(uint i) const {
1.1749 + return i ? out_RegMask() : RegMask::Empty;
1.1750 +}
1.1751 +
1.1752 +const RegMask &PhiNode::out_RegMask() const {
1.1753 + uint ideal_reg = Matcher::base2reg[_type->base()];
1.1754 + assert( ideal_reg != Node::NotAMachineReg, "invalid type at Phi" );
1.1755 + if( ideal_reg == 0 ) return RegMask::Empty;
1.1756 + return *(Compile::current()->matcher()->idealreg2spillmask[ideal_reg]);
1.1757 +}
1.1758 +
1.1759 +#ifndef PRODUCT
1.1760 +void PhiNode::dump_spec(outputStream *st) const {
1.1761 + TypeNode::dump_spec(st);
1.1762 + if (in(0) != NULL &&
1.1763 + in(0)->is_CountedLoop() &&
1.1764 + in(0)->as_CountedLoop()->phi() == this) {
1.1765 + st->print(" #tripcount");
1.1766 + }
1.1767 +}
1.1768 +#endif
1.1769 +
1.1770 +
1.1771 +//=============================================================================
1.1772 +const Type *GotoNode::Value( PhaseTransform *phase ) const {
1.1773 + // If the input is reachable, then we are executed.
1.1774 + // If the input is not reachable, then we are not executed.
1.1775 + return phase->type(in(0));
1.1776 +}
1.1777 +
1.1778 +Node *GotoNode::Identity( PhaseTransform *phase ) {
1.1779 + return in(0); // Simple copy of incoming control
1.1780 +}
1.1781 +
1.1782 +const RegMask &GotoNode::out_RegMask() const {
1.1783 + return RegMask::Empty;
1.1784 +}
1.1785 +
1.1786 +//=============================================================================
1.1787 +const RegMask &JumpNode::out_RegMask() const {
1.1788 + return RegMask::Empty;
1.1789 +}
1.1790 +
1.1791 +//=============================================================================
1.1792 +const RegMask &JProjNode::out_RegMask() const {
1.1793 + return RegMask::Empty;
1.1794 +}
1.1795 +
1.1796 +//=============================================================================
1.1797 +const RegMask &CProjNode::out_RegMask() const {
1.1798 + return RegMask::Empty;
1.1799 +}
1.1800 +
1.1801 +
1.1802 +
1.1803 +//=============================================================================
1.1804 +
1.1805 +uint PCTableNode::hash() const { return Node::hash() + _size; }
1.1806 +uint PCTableNode::cmp( const Node &n ) const
1.1807 +{ return _size == ((PCTableNode&)n)._size; }
1.1808 +
1.1809 +const Type *PCTableNode::bottom_type() const {
1.1810 + const Type** f = TypeTuple::fields(_size);
1.1811 + for( uint i = 0; i < _size; i++ ) f[i] = Type::CONTROL;
1.1812 + return TypeTuple::make(_size, f);
1.1813 +}
1.1814 +
1.1815 +//------------------------------Value------------------------------------------
1.1816 +// Compute the type of the PCTableNode. If reachable it is a tuple of
1.1817 +// Control, otherwise the table targets are not reachable
1.1818 +const Type *PCTableNode::Value( PhaseTransform *phase ) const {
1.1819 + if( phase->type(in(0)) == Type::CONTROL )
1.1820 + return bottom_type();
1.1821 + return Type::TOP; // All paths dead? Then so are we
1.1822 +}
1.1823 +
1.1824 +//------------------------------Ideal------------------------------------------
1.1825 +// Return a node which is more "ideal" than the current node. Strip out
1.1826 +// control copies
1.1827 +Node *PCTableNode::Ideal(PhaseGVN *phase, bool can_reshape) {
1.1828 + return remove_dead_region(phase, can_reshape) ? this : NULL;
1.1829 +}
1.1830 +
1.1831 +//=============================================================================
1.1832 +uint JumpProjNode::hash() const {
1.1833 + return Node::hash() + _dest_bci;
1.1834 +}
1.1835 +
1.1836 +uint JumpProjNode::cmp( const Node &n ) const {
1.1837 + return ProjNode::cmp(n) &&
1.1838 + _dest_bci == ((JumpProjNode&)n)._dest_bci;
1.1839 +}
1.1840 +
1.1841 +#ifndef PRODUCT
1.1842 +void JumpProjNode::dump_spec(outputStream *st) const {
1.1843 + ProjNode::dump_spec(st);
1.1844 + st->print("@bci %d ",_dest_bci);
1.1845 +}
1.1846 +#endif
1.1847 +
1.1848 +//=============================================================================
1.1849 +//------------------------------Value------------------------------------------
1.1850 +// Check for being unreachable, or for coming from a Rethrow. Rethrow's cannot
1.1851 +// have the default "fall_through_index" path.
1.1852 +const Type *CatchNode::Value( PhaseTransform *phase ) const {
1.1853 + // Unreachable? Then so are all paths from here.
1.1854 + if( phase->type(in(0)) == Type::TOP ) return Type::TOP;
1.1855 + // First assume all paths are reachable
1.1856 + const Type** f = TypeTuple::fields(_size);
1.1857 + for( uint i = 0; i < _size; i++ ) f[i] = Type::CONTROL;
1.1858 + // Identify cases that will always throw an exception
1.1859 + // () rethrow call
1.1860 + // () virtual or interface call with NULL receiver
1.1861 + // () call is a check cast with incompatible arguments
1.1862 + if( in(1)->is_Proj() ) {
1.1863 + Node *i10 = in(1)->in(0);
1.1864 + if( i10->is_Call() ) {
1.1865 + CallNode *call = i10->as_Call();
1.1866 + // Rethrows always throw exceptions, never return
1.1867 + if (call->entry_point() == OptoRuntime::rethrow_stub()) {
1.1868 + f[CatchProjNode::fall_through_index] = Type::TOP;
1.1869 + } else if( call->req() > TypeFunc::Parms ) {
1.1870 + const Type *arg0 = phase->type( call->in(TypeFunc::Parms) );
1.1871 + // Check for null reciever to virtual or interface calls
1.1872 + if( call->is_CallDynamicJava() &&
1.1873 + arg0->higher_equal(TypePtr::NULL_PTR) ) {
1.1874 + f[CatchProjNode::fall_through_index] = Type::TOP;
1.1875 + }
1.1876 + } // End of if not a runtime stub
1.1877 + } // End of if have call above me
1.1878 + } // End of slot 1 is not a projection
1.1879 + return TypeTuple::make(_size, f);
1.1880 +}
1.1881 +
1.1882 +//=============================================================================
1.1883 +uint CatchProjNode::hash() const {
1.1884 + return Node::hash() + _handler_bci;
1.1885 +}
1.1886 +
1.1887 +
1.1888 +uint CatchProjNode::cmp( const Node &n ) const {
1.1889 + return ProjNode::cmp(n) &&
1.1890 + _handler_bci == ((CatchProjNode&)n)._handler_bci;
1.1891 +}
1.1892 +
1.1893 +
1.1894 +//------------------------------Identity---------------------------------------
1.1895 +// If only 1 target is possible, choose it if it is the main control
1.1896 +Node *CatchProjNode::Identity( PhaseTransform *phase ) {
1.1897 + // If my value is control and no other value is, then treat as ID
1.1898 + const TypeTuple *t = phase->type(in(0))->is_tuple();
1.1899 + if (t->field_at(_con) != Type::CONTROL) return this;
1.1900 + // If we remove the last CatchProj and elide the Catch/CatchProj, then we
1.1901 + // also remove any exception table entry. Thus we must know the call
1.1902 + // feeding the Catch will not really throw an exception. This is ok for
1.1903 + // the main fall-thru control (happens when we know a call can never throw
1.1904 + // an exception) or for "rethrow", because a further optimnization will
1.1905 + // yank the rethrow (happens when we inline a function that can throw an
1.1906 + // exception and the caller has no handler). Not legal, e.g., for passing
1.1907 + // a NULL receiver to a v-call, or passing bad types to a slow-check-cast.
1.1908 + // These cases MUST throw an exception via the runtime system, so the VM
1.1909 + // will be looking for a table entry.
1.1910 + Node *proj = in(0)->in(1); // Expect a proj feeding CatchNode
1.1911 + CallNode *call;
1.1912 + if (_con != TypeFunc::Control && // Bail out if not the main control.
1.1913 + !(proj->is_Proj() && // AND NOT a rethrow
1.1914 + proj->in(0)->is_Call() &&
1.1915 + (call = proj->in(0)->as_Call()) &&
1.1916 + call->entry_point() == OptoRuntime::rethrow_stub()))
1.1917 + return this;
1.1918 +
1.1919 + // Search for any other path being control
1.1920 + for (uint i = 0; i < t->cnt(); i++) {
1.1921 + if (i != _con && t->field_at(i) == Type::CONTROL)
1.1922 + return this;
1.1923 + }
1.1924 + // Only my path is possible; I am identity on control to the jump
1.1925 + return in(0)->in(0);
1.1926 +}
1.1927 +
1.1928 +
1.1929 +#ifndef PRODUCT
1.1930 +void CatchProjNode::dump_spec(outputStream *st) const {
1.1931 + ProjNode::dump_spec(st);
1.1932 + st->print("@bci %d ",_handler_bci);
1.1933 +}
1.1934 +#endif
1.1935 +
1.1936 +//=============================================================================
1.1937 +//------------------------------Identity---------------------------------------
1.1938 +// Check for CreateEx being Identity.
1.1939 +Node *CreateExNode::Identity( PhaseTransform *phase ) {
1.1940 + if( phase->type(in(1)) == Type::TOP ) return in(1);
1.1941 + if( phase->type(in(0)) == Type::TOP ) return in(0);
1.1942 + // We only come from CatchProj, unless the CatchProj goes away.
1.1943 + // If the CatchProj is optimized away, then we just carry the
1.1944 + // exception oop through.
1.1945 + CallNode *call = in(1)->in(0)->as_Call();
1.1946 +
1.1947 + return ( in(0)->is_CatchProj() && in(0)->in(0)->in(1) == in(1) )
1.1948 + ? this
1.1949 + : call->in(TypeFunc::Parms);
1.1950 +}
1.1951 +
1.1952 +//=============================================================================
1.1953 +#ifndef PRODUCT
1.1954 +void NeverBranchNode::format( PhaseRegAlloc *ra_, outputStream *st) const {
1.1955 + st->print("%s", Name());
1.1956 +}
1.1957 +#endif
