duke@435: /* mikael@4153: * Copyright (c) 2000, 2012, Oracle and/or its affiliates. All rights reserved. duke@435: * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. duke@435: * duke@435: * This code is free software; you can redistribute it and/or modify it duke@435: * under the terms of the GNU General Public License version 2 only, as duke@435: * published by the Free Software Foundation. duke@435: * duke@435: * This code is distributed in the hope that it will be useful, but WITHOUT duke@435: * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or duke@435: * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License duke@435: * version 2 for more details (a copy is included in the LICENSE file that duke@435: * accompanied this code). duke@435: * duke@435: * You should have received a copy of the GNU General Public License version duke@435: * 2 along with this work; if not, write to the Free Software Foundation, duke@435: * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. duke@435: * trims@1907: * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA trims@1907: * or visit www.oracle.com if you need additional information or have any trims@1907: * questions. duke@435: * duke@435: */ duke@435: stefank@2314: #include "precompiled.hpp" stefank@2314: #include "memory/allocation.inline.hpp" stefank@2314: #include "opto/addnode.hpp" stefank@2314: #include "opto/cfgnode.hpp" stefank@2314: #include "opto/connode.hpp" kvn@2727: #include "opto/loopnode.hpp" stefank@2314: #include "opto/phaseX.hpp" stefank@2314: #include "opto/runtime.hpp" stefank@2314: #include "opto/subnode.hpp" stefank@2314: duke@435: // Portions of code courtesy of Clifford Click duke@435: duke@435: // Optimization - Graph Style duke@435: duke@435: duke@435: extern int explicit_null_checks_elided; duke@435: duke@435: //============================================================================= duke@435: //------------------------------Value------------------------------------------ duke@435: // Return a tuple for whichever arm of the IF is reachable duke@435: const Type *IfNode::Value( PhaseTransform *phase ) const { duke@435: if( !in(0) ) return Type::TOP; duke@435: if( phase->type(in(0)) == Type::TOP ) duke@435: return Type::TOP; duke@435: const Type *t = phase->type(in(1)); duke@435: if( t == Type::TOP ) // data is undefined duke@435: return TypeTuple::IFNEITHER; // unreachable altogether duke@435: if( t == TypeInt::ZERO ) // zero, or false duke@435: return TypeTuple::IFFALSE; // only false branch is reachable duke@435: if( t == TypeInt::ONE ) // 1, or true duke@435: return TypeTuple::IFTRUE; // only true branch is reachable duke@435: assert( t == TypeInt::BOOL, "expected boolean type" ); duke@435: duke@435: return TypeTuple::IFBOTH; // No progress duke@435: } duke@435: duke@435: const RegMask &IfNode::out_RegMask() const { duke@435: return RegMask::Empty; duke@435: } duke@435: duke@435: //------------------------------split_if--------------------------------------- duke@435: // Look for places where we merge constants, then test on the merged value. duke@435: // If the IF test will be constant folded on the path with the constant, we duke@435: // win by splitting the IF to before the merge point. duke@435: static Node* split_if(IfNode *iff, PhaseIterGVN *igvn) { duke@435: // I could be a lot more general here, but I'm trying to squeeze this duke@435: // in before the Christmas '98 break so I'm gonna be kinda restrictive duke@435: // on the patterns I accept. CNC duke@435: duke@435: // Look for a compare of a constant and a merged value duke@435: Node *i1 = iff->in(1); duke@435: if( !i1->is_Bool() ) return NULL; duke@435: BoolNode *b = i1->as_Bool(); duke@435: Node *cmp = b->in(1); rbackman@5791: if( cmp->is_FlagsProj() ) return NULL; duke@435: if( !cmp->is_Cmp() ) return NULL; duke@435: i1 = cmp->in(1); duke@435: if( i1 == NULL || !i1->is_Phi() ) return NULL; duke@435: PhiNode *phi = i1->as_Phi(); duke@435: if( phi->is_copy() ) return NULL; duke@435: Node *con2 = cmp->in(2); duke@435: if( !con2->is_Con() ) return NULL; duke@435: // See that the merge point contains some constants duke@435: Node *con1=NULL; duke@435: uint i4; duke@435: for( i4 = 1; i4 < phi->req(); i4++ ) { duke@435: con1 = phi->in(i4); twisti@1040: if( !con1 ) return NULL; // Do not optimize partially collapsed merges duke@435: if( con1->is_Con() ) break; // Found a constant duke@435: // Also allow null-vs-not-null checks duke@435: const TypePtr *tp = igvn->type(con1)->isa_ptr(); duke@435: if( tp && tp->_ptr == TypePtr::NotNull ) duke@435: break; duke@435: } duke@435: if( i4 >= phi->req() ) return NULL; // Found no constants duke@435: duke@435: igvn->C->set_has_split_ifs(true); // Has chance for split-if duke@435: duke@435: // Make sure that the compare can be constant folded away duke@435: Node *cmp2 = cmp->clone(); duke@435: cmp2->set_req(1,con1); duke@435: cmp2->set_req(2,con2); duke@435: const Type *t = cmp2->Value(igvn); duke@435: // This compare is dead, so whack it! duke@435: igvn->remove_dead_node(cmp2); duke@435: if( !t->singleton() ) return NULL; duke@435: duke@435: // No intervening control, like a simple Call duke@435: Node *r = iff->in(0); duke@435: if( !r->is_Region() ) return NULL; duke@435: if( phi->region() != r ) return NULL; duke@435: // No other users of the cmp/bool duke@435: if (b->outcnt() != 1 || cmp->outcnt() != 1) { duke@435: //tty->print_cr("many users of cmp/bool"); duke@435: return NULL; duke@435: } duke@435: duke@435: // Make sure we can determine where all the uses of merged values go duke@435: for (DUIterator_Fast jmax, j = r->fast_outs(jmax); j < jmax; j++) { duke@435: Node* u = r->fast_out(j); duke@435: if( u == r ) continue; duke@435: if( u == iff ) continue; duke@435: if( u->outcnt() == 0 ) continue; // use is dead & ignorable duke@435: if( !u->is_Phi() ) { duke@435: /* duke@435: if( u->is_Start() ) { duke@435: tty->print_cr("Region has inlined start use"); duke@435: } else { duke@435: tty->print_cr("Region has odd use"); duke@435: u->dump(2); duke@435: }*/ duke@435: return NULL; duke@435: } duke@435: if( u != phi ) { duke@435: // CNC - do not allow any other merged value duke@435: //tty->print_cr("Merging another value"); duke@435: //u->dump(2); duke@435: return NULL; duke@435: } duke@435: // Make sure we can account for all Phi uses duke@435: for (DUIterator_Fast kmax, k = u->fast_outs(kmax); k < kmax; k++) { duke@435: Node* v = u->fast_out(k); // User of the phi duke@435: // CNC - Allow only really simple patterns. duke@435: // In particular I disallow AddP of the Phi, a fairly common pattern duke@435: if( v == cmp ) continue; // The compare is OK duke@435: if( (v->is_ConstraintCast()) && duke@435: v->in(0)->in(0) == iff ) duke@435: continue; // CastPP/II of the IfNode is OK duke@435: // Disabled following code because I cannot tell if exactly one duke@435: // path dominates without a real dominator check. CNC 9/9/1999 duke@435: //uint vop = v->Opcode(); duke@435: //if( vop == Op_Phi ) { // Phi from another merge point might be OK duke@435: // Node *r = v->in(0); // Get controlling point duke@435: // if( !r ) return NULL; // Degraded to a copy duke@435: // // Find exactly one path in (either True or False doms, but not IFF) duke@435: // int cnt = 0; duke@435: // for( uint i = 1; i < r->req(); i++ ) duke@435: // if( r->in(i) && r->in(i)->in(0) == iff ) duke@435: // cnt++; duke@435: // if( cnt == 1 ) continue; // Exactly one of True or False guards Phi duke@435: //} duke@435: if( !v->is_Call() ) { duke@435: /* duke@435: if( v->Opcode() == Op_AddP ) { duke@435: tty->print_cr("Phi has AddP use"); duke@435: } else if( v->Opcode() == Op_CastPP ) { duke@435: tty->print_cr("Phi has CastPP use"); duke@435: } else if( v->Opcode() == Op_CastII ) { duke@435: tty->print_cr("Phi has CastII use"); duke@435: } else { duke@435: tty->print_cr("Phi has use I cant be bothered with"); duke@435: } duke@435: */ duke@435: } duke@435: return NULL; duke@435: duke@435: /* CNC - Cut out all the fancy acceptance tests duke@435: // Can we clone this use when doing the transformation? duke@435: // If all uses are from Phis at this merge or constants, then YES. duke@435: if( !v->in(0) && v != cmp ) { duke@435: tty->print_cr("Phi has free-floating use"); duke@435: v->dump(2); duke@435: return NULL; duke@435: } duke@435: for( uint l = 1; l < v->req(); l++ ) { duke@435: if( (!v->in(l)->is_Phi() || v->in(l)->in(0) != r) && duke@435: !v->in(l)->is_Con() ) { duke@435: tty->print_cr("Phi has use"); duke@435: v->dump(2); duke@435: return NULL; duke@435: } // End of if Phi-use input is neither Phi nor Constant duke@435: } // End of for all inputs to Phi-use duke@435: */ duke@435: } // End of for all uses of Phi duke@435: } // End of for all uses of Region duke@435: duke@435: // Only do this if the IF node is in a sane state duke@435: if (iff->outcnt() != 2) duke@435: return NULL; duke@435: duke@435: // Got a hit! Do the Mondo Hack! duke@435: // duke@435: //ABC a1c def ghi B 1 e h A C a c d f g i duke@435: // R - Phi - Phi - Phi Rc - Phi - Phi - Phi Rx - Phi - Phi - Phi duke@435: // cmp - 2 cmp - 2 cmp - 2 duke@435: // bool bool_c bool_x duke@435: // if if_c if_x duke@435: // T F T F T F duke@435: // ..s.. ..t .. ..s.. ..t.. ..s.. ..t.. duke@435: // twisti@1040: // Split the paths coming into the merge point into 2 separate groups of duke@435: // merges. On the left will be all the paths feeding constants into the duke@435: // Cmp's Phi. On the right will be the remaining paths. The Cmp's Phi duke@435: // will fold up into a constant; this will let the Cmp fold up as well as duke@435: // all the control flow. Below the original IF we have 2 control duke@435: // dependent regions, 's' and 't'. Now we will merge the two paths duke@435: // just prior to 's' and 't' from the two IFs. At least 1 path (and quite duke@435: // likely 2 or more) will promptly constant fold away. duke@435: PhaseGVN *phase = igvn; duke@435: duke@435: // Make a region merging constants and a region merging the rest duke@435: uint req_c = 0; kvn@2727: Node* predicate_proj = NULL; duke@435: for (uint ii = 1; ii < r->req(); ii++) { kvn@2727: if (phi->in(ii) == con1) { duke@435: req_c++; duke@435: } kvn@2727: Node* proj = PhaseIdealLoop::find_predicate(r->in(ii)); kvn@2727: if (proj != NULL) { kvn@2727: assert(predicate_proj == NULL, "only one predicate entry expected"); kvn@2727: predicate_proj = proj; kvn@2727: } duke@435: } kvn@2727: Node* predicate_c = NULL; kvn@2727: Node* predicate_x = NULL; kvn@2877: bool counted_loop = r->is_CountedLoop(); kvn@2727: kvn@4115: Node *region_c = new (igvn->C) RegionNode(req_c + 1); duke@435: Node *phi_c = con1; duke@435: uint len = r->req(); kvn@4115: Node *region_x = new (igvn->C) RegionNode(len - req_c); duke@435: Node *phi_x = PhiNode::make_blank(region_x, phi); duke@435: for (uint i = 1, i_c = 1, i_x = 1; i < len; i++) { kvn@2727: if (phi->in(i) == con1) { duke@435: region_c->init_req( i_c++, r ->in(i) ); kvn@2727: if (r->in(i) == predicate_proj) kvn@2727: predicate_c = predicate_proj; duke@435: } else { duke@435: region_x->init_req( i_x, r ->in(i) ); duke@435: phi_x ->init_req( i_x++, phi->in(i) ); kvn@2727: if (r->in(i) == predicate_proj) kvn@2727: predicate_x = predicate_proj; duke@435: } duke@435: } kvn@3043: if (predicate_c != NULL && (req_c > 1)) { kvn@3043: assert(predicate_x == NULL, "only one predicate entry expected"); kvn@3043: predicate_c = NULL; // Do not clone predicate below merge point kvn@3043: } kvn@3043: if (predicate_x != NULL && ((len - req_c) > 2)) { kvn@3043: assert(predicate_c == NULL, "only one predicate entry expected"); kvn@3043: predicate_x = NULL; // Do not clone predicate below merge point kvn@3043: } duke@435: duke@435: // Register the new RegionNodes but do not transform them. Cannot twisti@1040: // transform until the entire Region/Phi conglomerate has been hacked duke@435: // as a single huge transform. duke@435: igvn->register_new_node_with_optimizer( region_c ); duke@435: igvn->register_new_node_with_optimizer( region_x ); duke@435: // Prevent the untimely death of phi_x. Currently he has no uses. He is duke@435: // about to get one. If this only use goes away, then phi_x will look dead. duke@435: // However, he will be picking up some more uses down below. kvn@4115: Node *hook = new (igvn->C) Node(4); duke@435: hook->init_req(0, phi_x); duke@435: hook->init_req(1, phi_c); kvn@1448: phi_x = phase->transform( phi_x ); duke@435: duke@435: // Make the compare duke@435: Node *cmp_c = phase->makecon(t); duke@435: Node *cmp_x = cmp->clone(); duke@435: cmp_x->set_req(1,phi_x); duke@435: cmp_x->set_req(2,con2); duke@435: cmp_x = phase->transform(cmp_x); duke@435: // Make the bool kvn@4115: Node *b_c = phase->transform(new (igvn->C) BoolNode(cmp_c,b->_test._test)); kvn@4115: Node *b_x = phase->transform(new (igvn->C) BoolNode(cmp_x,b->_test._test)); duke@435: // Make the IfNode kvn@4115: IfNode *iff_c = new (igvn->C) IfNode(region_c,b_c,iff->_prob,iff->_fcnt); duke@435: igvn->set_type_bottom(iff_c); duke@435: igvn->_worklist.push(iff_c); duke@435: hook->init_req(2, iff_c); duke@435: kvn@4115: IfNode *iff_x = new (igvn->C) IfNode(region_x,b_x,iff->_prob, iff->_fcnt); duke@435: igvn->set_type_bottom(iff_x); duke@435: igvn->_worklist.push(iff_x); duke@435: hook->init_req(3, iff_x); duke@435: duke@435: // Make the true/false arms kvn@4115: Node *iff_c_t = phase->transform(new (igvn->C) IfTrueNode (iff_c)); kvn@4115: Node *iff_c_f = phase->transform(new (igvn->C) IfFalseNode(iff_c)); kvn@2727: if (predicate_c != NULL) { kvn@2727: assert(predicate_x == NULL, "only one predicate entry expected"); kvn@2727: // Clone loop predicates to each path kvn@2877: iff_c_t = igvn->clone_loop_predicates(predicate_c, iff_c_t, !counted_loop); kvn@2877: iff_c_f = igvn->clone_loop_predicates(predicate_c, iff_c_f, !counted_loop); kvn@2727: } kvn@4115: Node *iff_x_t = phase->transform(new (igvn->C) IfTrueNode (iff_x)); kvn@4115: Node *iff_x_f = phase->transform(new (igvn->C) IfFalseNode(iff_x)); kvn@2727: if (predicate_x != NULL) { kvn@2727: assert(predicate_c == NULL, "only one predicate entry expected"); kvn@2727: // Clone loop predicates to each path kvn@2877: iff_x_t = igvn->clone_loop_predicates(predicate_x, iff_x_t, !counted_loop); kvn@2877: iff_x_f = igvn->clone_loop_predicates(predicate_x, iff_x_f, !counted_loop); kvn@2727: } duke@435: duke@435: // Merge the TRUE paths kvn@4115: Node *region_s = new (igvn->C) RegionNode(3); duke@435: igvn->_worklist.push(region_s); duke@435: region_s->init_req(1, iff_c_t); duke@435: region_s->init_req(2, iff_x_t); duke@435: igvn->register_new_node_with_optimizer( region_s ); duke@435: duke@435: // Merge the FALSE paths kvn@4115: Node *region_f = new (igvn->C) RegionNode(3); duke@435: igvn->_worklist.push(region_f); duke@435: region_f->init_req(1, iff_c_f); duke@435: region_f->init_req(2, iff_x_f); duke@435: igvn->register_new_node_with_optimizer( region_f ); duke@435: duke@435: igvn->hash_delete(cmp);// Remove soon-to-be-dead node from hash table. duke@435: cmp->set_req(1,NULL); // Whack the inputs to cmp because it will be dead duke@435: cmp->set_req(2,NULL); duke@435: // Check for all uses of the Phi and give them a new home. duke@435: // The 'cmp' got cloned, but CastPP/IIs need to be moved. duke@435: Node *phi_s = NULL; // do not construct unless needed duke@435: Node *phi_f = NULL; // do not construct unless needed duke@435: for (DUIterator_Last i2min, i2 = phi->last_outs(i2min); i2 >= i2min; --i2) { duke@435: Node* v = phi->last_out(i2);// User of the phi kvn@3847: igvn->rehash_node_delayed(v); // Have to fixup other Phi users duke@435: uint vop = v->Opcode(); duke@435: Node *proj = NULL; duke@435: if( vop == Op_Phi ) { // Remote merge point duke@435: Node *r = v->in(0); duke@435: for (uint i3 = 1; i3 < r->req(); i3++) duke@435: if (r->in(i3) && r->in(i3)->in(0) == iff) { duke@435: proj = r->in(i3); duke@435: break; duke@435: } duke@435: } else if( v->is_ConstraintCast() ) { duke@435: proj = v->in(0); // Controlling projection duke@435: } else { duke@435: assert( 0, "do not know how to handle this guy" ); duke@435: } duke@435: duke@435: Node *proj_path_data, *proj_path_ctrl; duke@435: if( proj->Opcode() == Op_IfTrue ) { duke@435: if( phi_s == NULL ) { duke@435: // Only construct phi_s if needed, otherwise provides duke@435: // interfering use. duke@435: phi_s = PhiNode::make_blank(region_s,phi); duke@435: phi_s->init_req( 1, phi_c ); duke@435: phi_s->init_req( 2, phi_x ); kvn@1448: hook->add_req(phi_s); duke@435: phi_s = phase->transform(phi_s); duke@435: } duke@435: proj_path_data = phi_s; duke@435: proj_path_ctrl = region_s; duke@435: } else { duke@435: if( phi_f == NULL ) { duke@435: // Only construct phi_f if needed, otherwise provides duke@435: // interfering use. duke@435: phi_f = PhiNode::make_blank(region_f,phi); duke@435: phi_f->init_req( 1, phi_c ); duke@435: phi_f->init_req( 2, phi_x ); kvn@1448: hook->add_req(phi_f); duke@435: phi_f = phase->transform(phi_f); duke@435: } duke@435: proj_path_data = phi_f; duke@435: proj_path_ctrl = region_f; duke@435: } duke@435: duke@435: // Fixup 'v' for for the split duke@435: if( vop == Op_Phi ) { // Remote merge point duke@435: uint i; duke@435: for( i = 1; i < v->req(); i++ ) duke@435: if( v->in(i) == phi ) duke@435: break; duke@435: v->set_req(i, proj_path_data ); duke@435: } else if( v->is_ConstraintCast() ) { duke@435: v->set_req(0, proj_path_ctrl ); duke@435: v->set_req(1, proj_path_data ); duke@435: } else duke@435: ShouldNotReachHere(); duke@435: } duke@435: duke@435: // Now replace the original iff's True/False with region_s/region_t. duke@435: // This makes the original iff go dead. duke@435: for (DUIterator_Last i3min, i3 = iff->last_outs(i3min); i3 >= i3min; --i3) { duke@435: Node* p = iff->last_out(i3); duke@435: assert( p->Opcode() == Op_IfTrue || p->Opcode() == Op_IfFalse, "" ); duke@435: Node *u = (p->Opcode() == Op_IfTrue) ? region_s : region_f; duke@435: // Replace p with u duke@435: igvn->add_users_to_worklist(p); duke@435: for (DUIterator_Last lmin, l = p->last_outs(lmin); l >= lmin;) { duke@435: Node* x = p->last_out(l); duke@435: igvn->hash_delete(x); duke@435: uint uses_found = 0; duke@435: for( uint j = 0; j < x->req(); j++ ) { duke@435: if( x->in(j) == p ) { duke@435: x->set_req(j, u); duke@435: uses_found++; duke@435: } duke@435: } duke@435: l -= uses_found; // we deleted 1 or more copies of this edge duke@435: } duke@435: igvn->remove_dead_node(p); duke@435: } duke@435: duke@435: // Force the original merge dead duke@435: igvn->hash_delete(r); kvn@1286: // First, remove region's dead users. kvn@1286: for (DUIterator_Last lmin, l = r->last_outs(lmin); l >= lmin;) { kvn@1286: Node* u = r->last_out(l); kvn@1286: if( u == r ) { kvn@1286: r->set_req(0, NULL); kvn@1286: } else { kvn@1286: assert(u->outcnt() == 0, "only dead users"); kvn@1286: igvn->remove_dead_node(u); kvn@1286: } kvn@1286: l -= 1; kvn@1286: } kvn@1286: igvn->remove_dead_node(r); duke@435: duke@435: // Now remove the bogus extra edges used to keep things alive duke@435: igvn->remove_dead_node( hook ); duke@435: duke@435: // Must return either the original node (now dead) or a new node duke@435: // (Do not return a top here, since that would break the uniqueness of top.) kvn@4115: return new (igvn->C) ConINode(TypeInt::ZERO); duke@435: } duke@435: duke@435: //------------------------------is_range_check--------------------------------- duke@435: // Return 0 if not a range check. Return 1 if a range check and set index and duke@435: // offset. Return 2 if we had to negate the test. Index is NULL if the check duke@435: // is versus a constant. duke@435: int IfNode::is_range_check(Node* &range, Node* &index, jint &offset) { duke@435: Node* b = in(1); duke@435: if (b == NULL || !b->is_Bool()) return 0; duke@435: BoolNode* bn = b->as_Bool(); duke@435: Node* cmp = bn->in(1); duke@435: if (cmp == NULL) return 0; duke@435: if (cmp->Opcode() != Op_CmpU) return 0; duke@435: duke@435: Node* l = cmp->in(1); duke@435: Node* r = cmp->in(2); duke@435: int flip_test = 1; duke@435: if (bn->_test._test == BoolTest::le) { duke@435: l = cmp->in(2); duke@435: r = cmp->in(1); duke@435: flip_test = 2; duke@435: } else if (bn->_test._test != BoolTest::lt) { duke@435: return 0; duke@435: } duke@435: if (l->is_top()) return 0; // Top input means dead test duke@435: if (r->Opcode() != Op_LoadRange) return 0; duke@435: duke@435: // We have recognized one of these forms: duke@435: // Flip 1: If (Bool[<] CmpU(l, LoadRange)) ... duke@435: // Flip 2: If (Bool[<=] CmpU(LoadRange, l)) ... duke@435: duke@435: // Make sure it's a real range check by requiring an uncommon trap duke@435: // along the OOB path. Otherwise, it's possible that the user wrote duke@435: // something which optimized to look like a range check but behaves duke@435: // in some other way. duke@435: Node* iftrap = proj_out(flip_test == 2 ? true : false); duke@435: bool found_trap = false; duke@435: if (iftrap != NULL) { duke@435: Node* u = iftrap->unique_ctrl_out(); duke@435: if (u != NULL) { duke@435: // It could be a merge point (Region) for uncommon trap. duke@435: if (u->is_Region()) { duke@435: Node* c = u->unique_ctrl_out(); duke@435: if (c != NULL) { duke@435: iftrap = u; duke@435: u = c; duke@435: } duke@435: } duke@435: if (u->in(0) == iftrap && u->is_CallStaticJava()) { duke@435: int req = u->as_CallStaticJava()->uncommon_trap_request(); duke@435: if (Deoptimization::trap_request_reason(req) == duke@435: Deoptimization::Reason_range_check) { duke@435: found_trap = true; duke@435: } duke@435: } duke@435: } duke@435: } duke@435: if (!found_trap) return 0; // sorry, no cigar duke@435: duke@435: // Look for index+offset form duke@435: Node* ind = l; duke@435: jint off = 0; duke@435: if (l->is_top()) { duke@435: return 0; duke@435: } else if (l->is_Add()) { duke@435: if ((off = l->in(1)->find_int_con(0)) != 0) { duke@435: ind = l->in(2); duke@435: } else if ((off = l->in(2)->find_int_con(0)) != 0) { duke@435: ind = l->in(1); duke@435: } duke@435: } else if ((off = l->find_int_con(-1)) >= 0) { duke@435: // constant offset with no variable index duke@435: ind = NULL; duke@435: } else { duke@435: // variable index with no constant offset (or dead negative index) duke@435: off = 0; duke@435: } duke@435: duke@435: // Return all the values: duke@435: index = ind; duke@435: offset = off; duke@435: range = r; duke@435: return flip_test; duke@435: } duke@435: duke@435: //------------------------------adjust_check----------------------------------- duke@435: // Adjust (widen) a prior range check duke@435: static void adjust_check(Node* proj, Node* range, Node* index, duke@435: int flip, jint off_lo, PhaseIterGVN* igvn) { duke@435: PhaseGVN *gvn = igvn; duke@435: // Break apart the old check duke@435: Node *iff = proj->in(0); duke@435: Node *bol = iff->in(1); duke@435: if( bol->is_top() ) return; // In case a partially dead range check appears duke@435: // bail (or bomb[ASSERT/DEBUG]) if NOT projection-->IfNode-->BoolNode duke@435: DEBUG_ONLY( if( !bol->is_Bool() ) { proj->dump(3); fatal("Expect projection-->IfNode-->BoolNode"); } ) duke@435: if( !bol->is_Bool() ) return; duke@435: duke@435: Node *cmp = bol->in(1); duke@435: // Compute a new check duke@435: Node *new_add = gvn->intcon(off_lo); duke@435: if( index ) { kvn@4115: new_add = off_lo ? gvn->transform(new (gvn->C) AddINode( index, new_add )) : index; duke@435: } duke@435: Node *new_cmp = (flip == 1) kvn@4115: ? new (gvn->C) CmpUNode( new_add, range ) kvn@4115: : new (gvn->C) CmpUNode( range, new_add ); duke@435: new_cmp = gvn->transform(new_cmp); duke@435: // See if no need to adjust the existing check duke@435: if( new_cmp == cmp ) return; duke@435: // Else, adjust existing check kvn@4115: Node *new_bol = gvn->transform( new (gvn->C) BoolNode( new_cmp, bol->as_Bool()->_test._test ) ); kvn@3847: igvn->rehash_node_delayed( iff ); duke@435: iff->set_req_X( 1, new_bol, igvn ); duke@435: } duke@435: duke@435: //------------------------------up_one_dom------------------------------------- duke@435: // Walk up the dominator tree one step. Return NULL at root or true duke@435: // complex merges. Skips through small diamonds. duke@435: Node* IfNode::up_one_dom(Node *curr, bool linear_only) { duke@435: Node *dom = curr->in(0); duke@435: if( !dom ) // Found a Region degraded to a copy? duke@435: return curr->nonnull_req(); // Skip thru it duke@435: duke@435: if( curr != dom ) // Normal walk up one step? duke@435: return dom; duke@435: duke@435: // Use linear_only if we are still parsing, since we cannot duke@435: // trust the regions to be fully filled in. duke@435: if (linear_only) duke@435: return NULL; duke@435: kvn@1588: if( dom->is_Root() ) kvn@1588: return NULL; kvn@1588: duke@435: // Else hit a Region. Check for a loop header duke@435: if( dom->is_Loop() ) duke@435: return dom->in(1); // Skip up thru loops duke@435: duke@435: // Check for small diamonds duke@435: Node *din1, *din2, *din3, *din4; duke@435: if( dom->req() == 3 && // 2-path merge point duke@435: (din1 = dom ->in(1)) && // Left path exists duke@435: (din2 = dom ->in(2)) && // Right path exists duke@435: (din3 = din1->in(0)) && // Left path up one duke@435: (din4 = din2->in(0)) ) { // Right path up one duke@435: if( din3->is_Call() && // Handle a slow-path call on either arm duke@435: (din3 = din3->in(0)) ) duke@435: din3 = din3->in(0); duke@435: if( din4->is_Call() && // Handle a slow-path call on either arm duke@435: (din4 = din4->in(0)) ) duke@435: din4 = din4->in(0); duke@435: if( din3 == din4 && din3->is_If() ) duke@435: return din3; // Skip around diamonds duke@435: } duke@435: duke@435: // Give up the search at true merges duke@435: return NULL; // Dead loop? Or hit root? duke@435: } duke@435: never@452: never@452: //------------------------------filtered_int_type-------------------------------- never@452: // Return a possibly more restrictive type for val based on condition control flow for an if never@452: const TypeInt* IfNode::filtered_int_type(PhaseGVN* gvn, Node *val, Node* if_proj) { never@452: assert(if_proj && never@452: (if_proj->Opcode() == Op_IfTrue || if_proj->Opcode() == Op_IfFalse), "expecting an if projection"); never@452: if (if_proj->in(0) && if_proj->in(0)->is_If()) { never@452: IfNode* iff = if_proj->in(0)->as_If(); never@452: if (iff->in(1) && iff->in(1)->is_Bool()) { never@452: BoolNode* bol = iff->in(1)->as_Bool(); never@452: if (bol->in(1) && bol->in(1)->is_Cmp()) { never@452: const CmpNode* cmp = bol->in(1)->as_Cmp(); never@452: if (cmp->in(1) == val) { never@452: const TypeInt* cmp2_t = gvn->type(cmp->in(2))->isa_int(); never@452: if (cmp2_t != NULL) { never@452: jint lo = cmp2_t->_lo; never@452: jint hi = cmp2_t->_hi; never@452: BoolTest::mask msk = if_proj->Opcode() == Op_IfTrue ? bol->_test._test : bol->_test.negate(); never@452: switch (msk) { never@452: case BoolTest::ne: never@452: // Can't refine type never@452: return NULL; never@452: case BoolTest::eq: never@452: return cmp2_t; never@452: case BoolTest::lt: never@452: lo = TypeInt::INT->_lo; never@452: if (hi - 1 < hi) { never@452: hi = hi - 1; never@452: } never@452: break; never@452: case BoolTest::le: never@452: lo = TypeInt::INT->_lo; never@452: break; never@452: case BoolTest::gt: never@452: if (lo + 1 > lo) { never@452: lo = lo + 1; never@452: } never@452: hi = TypeInt::INT->_hi; never@452: break; never@452: case BoolTest::ge: never@452: // lo unchanged never@452: hi = TypeInt::INT->_hi; never@452: break; never@452: } never@452: const TypeInt* rtn_t = TypeInt::make(lo, hi, cmp2_t->_widen); never@452: return rtn_t; never@452: } never@452: } never@452: } never@452: } never@452: } never@452: return NULL; never@452: } never@452: never@452: //------------------------------fold_compares---------------------------- never@452: // See if a pair of CmpIs can be converted into a CmpU. In some cases twisti@1040: // the direction of this if is determined by the preceding if so it never@452: // can be eliminate entirely. Given an if testing (CmpI n c) check never@452: // for an immediately control dependent if that is testing (CmpI n c2) never@452: // and has one projection leading to this if and the other projection never@452: // leading to a region that merges one of this ifs control never@452: // projections. never@452: // never@452: // If never@452: // / | never@452: // / | never@452: // / | never@452: // If | never@452: // /\ | never@452: // / \ | never@452: // / \ | never@452: // / Region never@452: // never@452: Node* IfNode::fold_compares(PhaseGVN* phase) { kvn@5110: if (!phase->C->eliminate_boxing() || Opcode() != Op_If) return NULL; never@452: never@452: Node* this_cmp = in(1)->in(1); never@452: if (this_cmp != NULL && this_cmp->Opcode() == Op_CmpI && never@452: this_cmp->in(2)->is_Con() && this_cmp->in(2) != phase->C->top()) { never@452: Node* ctrl = in(0); never@452: BoolNode* this_bool = in(1)->as_Bool(); never@452: Node* n = this_cmp->in(1); never@452: int hi = this_cmp->in(2)->get_int(); never@452: if (ctrl != NULL && ctrl->is_Proj() && ctrl->outcnt() == 1 && never@452: ctrl->in(0)->is_If() && never@452: ctrl->in(0)->outcnt() == 2 && never@452: ctrl->in(0)->in(1)->is_Bool() && never@452: ctrl->in(0)->in(1)->in(1)->Opcode() == Op_CmpI && never@452: ctrl->in(0)->in(1)->in(1)->in(2)->is_Con() && never@452: ctrl->in(0)->in(1)->in(1)->in(1) == n) { never@452: IfNode* dom_iff = ctrl->in(0)->as_If(); never@452: Node* otherproj = dom_iff->proj_out(!ctrl->as_Proj()->_con); never@452: if (otherproj->outcnt() == 1 && otherproj->unique_out()->is_Region() && never@452: this_bool->_test._test != BoolTest::ne && this_bool->_test._test != BoolTest::eq) { never@452: // Identify which proj goes to the region and which continues on never@452: RegionNode* region = otherproj->unique_out()->as_Region(); never@452: Node* success = NULL; never@452: Node* fail = NULL; never@452: for (int i = 0; i < 2; i++) { never@452: Node* proj = proj_out(i); never@452: if (success == NULL && proj->outcnt() == 1 && proj->unique_out() == region) { never@452: success = proj; never@452: } else if (fail == NULL) { never@452: fail = proj; never@452: } else { never@452: success = fail = NULL; never@452: } never@452: } never@452: if (success != NULL && fail != NULL && !region->has_phi()) { never@452: int lo = dom_iff->in(1)->in(1)->in(2)->get_int(); never@452: BoolNode* dom_bool = dom_iff->in(1)->as_Bool(); never@452: Node* dom_cmp = dom_bool->in(1); never@452: const TypeInt* failtype = filtered_int_type(phase, n, ctrl); never@452: if (failtype != NULL) { never@452: const TypeInt* type2 = filtered_int_type(phase, n, fail); never@452: if (type2 != NULL) { never@452: failtype = failtype->join(type2)->is_int(); never@452: } else { never@452: failtype = NULL; never@452: } never@452: } never@452: never@452: if (failtype != NULL && never@452: dom_bool->_test._test != BoolTest::ne && dom_bool->_test._test != BoolTest::eq) { never@452: int bound = failtype->_hi - failtype->_lo + 1; never@452: if (failtype->_hi != max_jint && failtype->_lo != min_jint && bound > 1) { never@452: // Merge the two compares into a single unsigned compare by building (CmpU (n - lo) hi) never@452: BoolTest::mask cond = fail->as_Proj()->_con ? BoolTest::lt : BoolTest::ge; kvn@4115: Node* adjusted = phase->transform(new (phase->C) SubINode(n, phase->intcon(failtype->_lo))); kvn@4115: Node* newcmp = phase->transform(new (phase->C) CmpUNode(adjusted, phase->intcon(bound))); kvn@4115: Node* newbool = phase->transform(new (phase->C) BoolNode(newcmp, cond)); kvn@3847: phase->is_IterGVN()->replace_input_of(dom_iff, 1, phase->intcon(ctrl->as_Proj()->_con)); never@452: phase->hash_delete(this); never@452: set_req(1, newbool); never@452: return this; never@452: } never@452: if (failtype->_lo > failtype->_hi) { never@452: // previous if determines the result of this if so never@452: // replace Bool with constant never@452: phase->hash_delete(this); never@452: set_req(1, phase->intcon(success->as_Proj()->_con)); never@452: return this; never@452: } never@452: } never@452: } never@452: } never@452: } never@452: } never@452: return NULL; never@452: } never@452: duke@435: //------------------------------remove_useless_bool---------------------------- duke@435: // Check for people making a useless boolean: things like duke@435: // if( (x < y ? true : false) ) { ... } duke@435: // Replace with if( x < y ) { ... } duke@435: static Node *remove_useless_bool(IfNode *iff, PhaseGVN *phase) { duke@435: Node *i1 = iff->in(1); duke@435: if( !i1->is_Bool() ) return NULL; duke@435: BoolNode *bol = i1->as_Bool(); duke@435: duke@435: Node *cmp = bol->in(1); duke@435: if( cmp->Opcode() != Op_CmpI ) return NULL; duke@435: duke@435: // Must be comparing against a bool duke@435: const Type *cmp2_t = phase->type( cmp->in(2) ); duke@435: if( cmp2_t != TypeInt::ZERO && duke@435: cmp2_t != TypeInt::ONE ) duke@435: return NULL; duke@435: duke@435: // Find a prior merge point merging the boolean duke@435: i1 = cmp->in(1); duke@435: if( !i1->is_Phi() ) return NULL; duke@435: PhiNode *phi = i1->as_Phi(); duke@435: if( phase->type( phi ) != TypeInt::BOOL ) duke@435: return NULL; duke@435: duke@435: // Check for diamond pattern duke@435: int true_path = phi->is_diamond_phi(); duke@435: if( true_path == 0 ) return NULL; duke@435: never@685: // Make sure that iff and the control of the phi are different. This never@685: // should really only happen for dead control flow since it requires never@685: // an illegal cycle. never@685: if (phi->in(0)->in(1)->in(0) == iff) return NULL; never@685: duke@435: // phi->region->if_proj->ifnode->bool->cmp duke@435: BoolNode *bol2 = phi->in(0)->in(1)->in(0)->in(1)->as_Bool(); duke@435: duke@435: // Now get the 'sense' of the test correct so we can plug in duke@435: // either iff2->in(1) or its complement. duke@435: int flip = 0; duke@435: if( bol->_test._test == BoolTest::ne ) flip = 1-flip; duke@435: else if( bol->_test._test != BoolTest::eq ) return NULL; duke@435: if( cmp2_t == TypeInt::ZERO ) flip = 1-flip; duke@435: duke@435: const Type *phi1_t = phase->type( phi->in(1) ); duke@435: const Type *phi2_t = phase->type( phi->in(2) ); duke@435: // Check for Phi(0,1) and flip duke@435: if( phi1_t == TypeInt::ZERO ) { duke@435: if( phi2_t != TypeInt::ONE ) return NULL; duke@435: flip = 1-flip; duke@435: } else { duke@435: // Check for Phi(1,0) duke@435: if( phi1_t != TypeInt::ONE ) return NULL; duke@435: if( phi2_t != TypeInt::ZERO ) return NULL; duke@435: } duke@435: if( true_path == 2 ) { duke@435: flip = 1-flip; duke@435: } duke@435: duke@435: Node* new_bol = (flip ? phase->transform( bol2->negate(phase) ) : bol2); never@685: assert(new_bol != iff->in(1), "must make progress"); duke@435: iff->set_req(1, new_bol); duke@435: // Intervening diamond probably goes dead duke@435: phase->C->set_major_progress(); duke@435: return iff; duke@435: } duke@435: duke@435: static IfNode* idealize_test(PhaseGVN* phase, IfNode* iff); duke@435: duke@435: //------------------------------Ideal------------------------------------------ duke@435: // Return a node which is more "ideal" than the current node. Strip out duke@435: // control copies duke@435: Node *IfNode::Ideal(PhaseGVN *phase, bool can_reshape) { duke@435: if (remove_dead_region(phase, can_reshape)) return this; duke@435: // No Def-Use info? duke@435: if (!can_reshape) return NULL; duke@435: PhaseIterGVN *igvn = phase->is_IterGVN(); duke@435: duke@435: // Don't bother trying to transform a dead if duke@435: if (in(0)->is_top()) return NULL; duke@435: // Don't bother trying to transform an if with a dead test duke@435: if (in(1)->is_top()) return NULL; duke@435: // Another variation of a dead test duke@435: if (in(1)->is_Con()) return NULL; duke@435: // Another variation of a dead if duke@435: if (outcnt() < 2) return NULL; duke@435: duke@435: // Canonicalize the test. duke@435: Node* idt_if = idealize_test(phase, this); duke@435: if (idt_if != NULL) return idt_if; duke@435: duke@435: // Try to split the IF duke@435: Node *s = split_if(this, igvn); duke@435: if (s != NULL) return s; duke@435: duke@435: // Check for people making a useless boolean: things like duke@435: // if( (x < y ? true : false) ) { ... } duke@435: // Replace with if( x < y ) { ... } duke@435: Node *bol2 = remove_useless_bool(this, phase); duke@435: if( bol2 ) return bol2; duke@435: duke@435: // Setup to scan up the CFG looking for a dominating test duke@435: Node *dom = in(0); duke@435: Node *prev_dom = this; duke@435: duke@435: // Check for range-check vs other kinds of tests duke@435: Node *index1, *range1; duke@435: jint offset1; duke@435: int flip1 = is_range_check(range1, index1, offset1); duke@435: if( flip1 ) { duke@435: Node *first_prev_dom = NULL; duke@435: duke@435: // Try to remove extra range checks. All 'up_one_dom' gives up at merges duke@435: // so all checks we inspect post-dominate the top-most check we find. duke@435: // If we are going to fail the current check and we reach the top check twisti@1040: // then we are guaranteed to fail, so just start interpreting there. duke@435: // We 'expand' the top 2 range checks to include all post-dominating duke@435: // checks. duke@435: duke@435: // The top 2 range checks seen duke@435: Node *prev_chk1 = NULL; duke@435: Node *prev_chk2 = NULL; duke@435: // Low and high offsets seen so far duke@435: jint off_lo = offset1; duke@435: jint off_hi = offset1; duke@435: duke@435: // Scan for the top 2 checks and collect range of offsets duke@435: for( int dist = 0; dist < 999; dist++ ) { // Range-Check scan limit duke@435: if( dom->Opcode() == Op_If && // Not same opcode? duke@435: prev_dom->in(0) == dom ) { // One path of test does dominate? duke@435: if( dom == this ) return NULL; // dead loop duke@435: // See if this is a range check duke@435: Node *index2, *range2; duke@435: jint offset2; duke@435: int flip2 = dom->as_If()->is_range_check(range2, index2, offset2); duke@435: // See if this is a _matching_ range check, checking against duke@435: // the same array bounds. duke@435: if( flip2 == flip1 && range2 == range1 && index2 == index1 && duke@435: dom->outcnt() == 2 ) { duke@435: // Gather expanded bounds duke@435: off_lo = MIN2(off_lo,offset2); duke@435: off_hi = MAX2(off_hi,offset2); duke@435: // Record top 2 range checks duke@435: prev_chk2 = prev_chk1; duke@435: prev_chk1 = prev_dom; duke@435: // If we match the test exactly, then the top test covers duke@435: // both our lower and upper bounds. duke@435: if( dom->in(1) == in(1) ) duke@435: prev_chk2 = prev_chk1; duke@435: } duke@435: } duke@435: prev_dom = dom; duke@435: dom = up_one_dom( dom ); duke@435: if( !dom ) break; duke@435: } duke@435: duke@435: duke@435: // Attempt to widen the dominating range check to cover some later duke@435: // ones. Since range checks "fail" by uncommon-trapping to the duke@435: // interpreter, widening a check can make us speculative enter the duke@435: // interpreter. If we see range-check deopt's, do not widen! duke@435: if (!phase->C->allow_range_check_smearing()) return NULL; duke@435: duke@435: // Constant indices only need to check the upper bound. duke@435: // Non-constance indices must check both low and high. duke@435: if( index1 ) { duke@435: // Didn't find 2 prior covering checks, so cannot remove anything. duke@435: if( !prev_chk2 ) return NULL; duke@435: // 'Widen' the offsets of the 1st and 2nd covering check duke@435: adjust_check( prev_chk1, range1, index1, flip1, off_lo, igvn ); duke@435: // Do not call adjust_check twice on the same projection duke@435: // as the first call may have transformed the BoolNode to a ConI duke@435: if( prev_chk1 != prev_chk2 ) { duke@435: adjust_check( prev_chk2, range1, index1, flip1, off_hi, igvn ); duke@435: } duke@435: // Test is now covered by prior checks, dominate it out duke@435: prev_dom = prev_chk2; duke@435: } else { duke@435: // Didn't find prior covering check, so cannot remove anything. duke@435: if( !prev_chk1 ) return NULL; duke@435: // 'Widen' the offset of the 1st and only covering check duke@435: adjust_check( prev_chk1, range1, index1, flip1, off_hi, igvn ); duke@435: // Test is now covered by prior checks, dominate it out duke@435: prev_dom = prev_chk1; duke@435: } duke@435: duke@435: duke@435: } else { // Scan for an equivalent test duke@435: duke@435: Node *cmp; duke@435: int dist = 0; // Cutoff limit for search duke@435: int op = Opcode(); duke@435: if( op == Op_If && duke@435: (cmp=in(1)->in(1))->Opcode() == Op_CmpP ) { duke@435: if( cmp->in(2) != NULL && // make sure cmp is not already dead duke@435: cmp->in(2)->bottom_type() == TypePtr::NULL_PTR ) { duke@435: dist = 64; // Limit for null-pointer scans duke@435: } else { duke@435: dist = 4; // Do not bother for random pointer tests duke@435: } duke@435: } else { duke@435: dist = 4; // Limit for random junky scans duke@435: } duke@435: duke@435: // Normal equivalent-test check. duke@435: if( !dom ) return NULL; // Dead loop? duke@435: never@452: Node* result = fold_compares(phase); never@452: if (result != NULL) { never@452: return result; never@452: } never@452: duke@435: // Search up the dominator tree for an If with an identical test duke@435: while( dom->Opcode() != op || // Not same opcode? duke@435: dom->in(1) != in(1) || // Not same input 1? duke@435: (req() == 3 && dom->in(2) != in(2)) || // Not same input 2? duke@435: prev_dom->in(0) != dom ) { // One path of test does not dominate? duke@435: if( dist < 0 ) return NULL; duke@435: duke@435: dist--; duke@435: prev_dom = dom; duke@435: dom = up_one_dom( dom ); duke@435: if( !dom ) return NULL; duke@435: } duke@435: duke@435: // Check that we did not follow a loop back to ourselves duke@435: if( this == dom ) duke@435: return NULL; duke@435: duke@435: if( dist > 2 ) // Add to count of NULL checks elided duke@435: explicit_null_checks_elided++; duke@435: duke@435: } // End of Else scan for an equivalent test duke@435: duke@435: // Hit! Remove this IF duke@435: #ifndef PRODUCT duke@435: if( TraceIterativeGVN ) { duke@435: tty->print(" Removing IfNode: "); this->dump(); duke@435: } duke@435: if( VerifyOpto && !phase->allow_progress() ) { duke@435: // Found an equivalent dominating test, duke@435: // we can not guarantee reaching a fix-point for these during iterativeGVN duke@435: // since intervening nodes may not change. duke@435: return NULL; duke@435: } duke@435: #endif duke@435: duke@435: // Replace dominated IfNode duke@435: dominated_by( prev_dom, igvn ); duke@435: duke@435: // Must return either the original node (now dead) or a new node duke@435: // (Do not return a top here, since that would break the uniqueness of top.) kvn@4115: return new (phase->C) ConINode(TypeInt::ZERO); duke@435: } duke@435: duke@435: //------------------------------dominated_by----------------------------------- duke@435: void IfNode::dominated_by( Node *prev_dom, PhaseIterGVN *igvn ) { duke@435: igvn->hash_delete(this); // Remove self to prevent spurious V-N duke@435: Node *idom = in(0); duke@435: // Need opcode to decide which way 'this' test goes duke@435: int prev_op = prev_dom->Opcode(); duke@435: Node *top = igvn->C->top(); // Shortcut to top duke@435: kvn@3038: // Loop predicates may have depending checks which should not kvn@3038: // be skipped. For example, range check predicate has two checks kvn@3038: // for lower and upper bounds. kvn@3038: ProjNode* unc_proj = proj_out(1 - prev_dom->as_Proj()->_con)->as_Proj(); kvn@3038: if (PhaseIdealLoop::is_uncommon_trap_proj(unc_proj, Deoptimization::Reason_predicate)) kvn@3038: prev_dom = idom; kvn@3038: duke@435: // Now walk the current IfNode's projections. duke@435: // Loop ends when 'this' has no more uses. duke@435: for (DUIterator_Last imin, i = last_outs(imin); i >= imin; --i) { duke@435: Node *ifp = last_out(i); // Get IfTrue/IfFalse duke@435: igvn->add_users_to_worklist(ifp); duke@435: // Check which projection it is and set target. duke@435: // Data-target is either the dominating projection of the same type duke@435: // or TOP if the dominating projection is of opposite type. duke@435: // Data-target will be used as the new control edge for the non-CFG duke@435: // nodes like Casts and Loads. kvn@3038: Node *data_target = (ifp->Opcode() == prev_op) ? prev_dom : top; duke@435: // Control-target is just the If's immediate dominator or TOP. kvn@3038: Node *ctrl_target = (ifp->Opcode() == prev_op) ? idom : top; duke@435: duke@435: // For each child of an IfTrue/IfFalse projection, reroute. duke@435: // Loop ends when projection has no more uses. duke@435: for (DUIterator_Last jmin, j = ifp->last_outs(jmin); j >= jmin; --j) { duke@435: Node* s = ifp->last_out(j); // Get child of IfTrue/IfFalse duke@435: if( !s->depends_only_on_test() ) { duke@435: // Find the control input matching this def-use edge. duke@435: // For Regions it may not be in slot 0. duke@435: uint l; duke@435: for( l = 0; s->in(l) != ifp; l++ ) { } kvn@3847: igvn->replace_input_of(s, l, ctrl_target); duke@435: } else { // Else, for control producers, kvn@3847: igvn->replace_input_of(s, 0, data_target); // Move child to data-target duke@435: } duke@435: } // End for each child of a projection duke@435: duke@435: igvn->remove_dead_node(ifp); duke@435: } // End for each IfTrue/IfFalse child of If duke@435: duke@435: // Kill the IfNode duke@435: igvn->remove_dead_node(this); duke@435: } duke@435: duke@435: //------------------------------Identity--------------------------------------- duke@435: // If the test is constant & we match, then we are the input Control duke@435: Node *IfTrueNode::Identity( PhaseTransform *phase ) { duke@435: // Can only optimize if cannot go the other way duke@435: const TypeTuple *t = phase->type(in(0))->is_tuple(); duke@435: return ( t == TypeTuple::IFNEITHER || t == TypeTuple::IFTRUE ) duke@435: ? in(0)->in(0) // IfNode control duke@435: : this; // no progress duke@435: } duke@435: duke@435: //------------------------------dump_spec-------------------------------------- duke@435: #ifndef PRODUCT duke@435: void IfNode::dump_spec(outputStream *st) const { duke@435: st->print("P=%f, C=%f",_prob,_fcnt); duke@435: } duke@435: #endif duke@435: duke@435: //------------------------------idealize_test---------------------------------- duke@435: // Try to canonicalize tests better. Peek at the Cmp/Bool/If sequence and duke@435: // come up with a canonical sequence. Bools getting 'eq', 'gt' and 'ge' forms duke@435: // converted to 'ne', 'le' and 'lt' forms. IfTrue/IfFalse get swapped as duke@435: // needed. duke@435: static IfNode* idealize_test(PhaseGVN* phase, IfNode* iff) { duke@435: assert(iff->in(0) != NULL, "If must be live"); duke@435: duke@435: if (iff->outcnt() != 2) return NULL; // Malformed projections. duke@435: Node* old_if_f = iff->proj_out(false); duke@435: Node* old_if_t = iff->proj_out(true); duke@435: duke@435: // CountedLoopEnds want the back-control test to be TRUE, irregardless of duke@435: // whether they are testing a 'gt' or 'lt' condition. The 'gt' condition duke@435: // happens in count-down loops duke@435: if (iff->is_CountedLoopEnd()) return NULL; duke@435: if (!iff->in(1)->is_Bool()) return NULL; // Happens for partially optimized IF tests duke@435: BoolNode *b = iff->in(1)->as_Bool(); duke@435: BoolTest bt = b->_test; duke@435: // Test already in good order? duke@435: if( bt.is_canonical() ) duke@435: return NULL; duke@435: duke@435: // Flip test to be canonical. Requires flipping the IfFalse/IfTrue and duke@435: // cloning the IfNode. kvn@4115: Node* new_b = phase->transform( new (phase->C) BoolNode(b->in(1), bt.negate()) ); duke@435: if( !new_b->is_Bool() ) return NULL; duke@435: b = new_b->as_Bool(); duke@435: duke@435: PhaseIterGVN *igvn = phase->is_IterGVN(); duke@435: assert( igvn, "Test is not canonical in parser?" ); duke@435: duke@435: // The IF node never really changes, but it needs to be cloned kvn@4115: iff = new (phase->C) IfNode( iff->in(0), b, 1.0-iff->_prob, iff->_fcnt); duke@435: duke@435: Node *prior = igvn->hash_find_insert(iff); duke@435: if( prior ) { duke@435: igvn->remove_dead_node(iff); duke@435: iff = (IfNode*)prior; duke@435: } else { duke@435: // Cannot call transform on it just yet duke@435: igvn->set_type_bottom(iff); duke@435: } duke@435: igvn->_worklist.push(iff); duke@435: duke@435: // Now handle projections. Cloning not required. kvn@4115: Node* new_if_f = (Node*)(new (phase->C) IfFalseNode( iff )); kvn@4115: Node* new_if_t = (Node*)(new (phase->C) IfTrueNode ( iff )); duke@435: duke@435: igvn->register_new_node_with_optimizer(new_if_f); duke@435: igvn->register_new_node_with_optimizer(new_if_t); duke@435: // Flip test, so flip trailing control kvn@1976: igvn->replace_node(old_if_f, new_if_t); kvn@1976: igvn->replace_node(old_if_t, new_if_f); duke@435: duke@435: // Progress duke@435: return iff; duke@435: } duke@435: duke@435: //------------------------------Identity--------------------------------------- duke@435: // If the test is constant & we match, then we are the input Control duke@435: Node *IfFalseNode::Identity( PhaseTransform *phase ) { duke@435: // Can only optimize if cannot go the other way duke@435: const TypeTuple *t = phase->type(in(0))->is_tuple(); duke@435: return ( t == TypeTuple::IFNEITHER || t == TypeTuple::IFFALSE ) duke@435: ? in(0)->in(0) // IfNode control duke@435: : this; // no progress duke@435: }