1860 lines
69 KiB
C++
1860 lines
69 KiB
C++
/*
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* Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*
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*/
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#include "precompiled.hpp"
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#include "ci/ciTypeFlow.hpp"
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#include "memory/allocation.inline.hpp"
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#include "memory/resourceArea.hpp"
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#include "opto/addnode.hpp"
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#include "opto/castnode.hpp"
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#include "opto/cfgnode.hpp"
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#include "opto/connode.hpp"
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#include "opto/loopnode.hpp"
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#include "opto/phaseX.hpp"
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#include "opto/runtime.hpp"
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#include "opto/rootnode.hpp"
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#include "opto/subnode.hpp"
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// Portions of code courtesy of Clifford Click
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// Optimization - Graph Style
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#ifndef PRODUCT
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extern int explicit_null_checks_elided;
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#endif
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//=============================================================================
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//------------------------------Value------------------------------------------
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// Return a tuple for whichever arm of the IF is reachable
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const Type* IfNode::Value(PhaseGVN* phase) const {
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if( !in(0) ) return Type::TOP;
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if( phase->type(in(0)) == Type::TOP )
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return Type::TOP;
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const Type *t = phase->type(in(1));
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if( t == Type::TOP ) // data is undefined
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return TypeTuple::IFNEITHER; // unreachable altogether
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if( t == TypeInt::ZERO ) // zero, or false
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return TypeTuple::IFFALSE; // only false branch is reachable
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if( t == TypeInt::ONE ) // 1, or true
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return TypeTuple::IFTRUE; // only true branch is reachable
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assert( t == TypeInt::BOOL, "expected boolean type" );
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return TypeTuple::IFBOTH; // No progress
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}
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const RegMask &IfNode::out_RegMask() const {
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return RegMask::Empty;
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}
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//------------------------------split_if---------------------------------------
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// Look for places where we merge constants, then test on the merged value.
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// If the IF test will be constant folded on the path with the constant, we
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// win by splitting the IF to before the merge point.
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static Node* split_if(IfNode *iff, PhaseIterGVN *igvn) {
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// I could be a lot more general here, but I'm trying to squeeze this
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// in before the Christmas '98 break so I'm gonna be kinda restrictive
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// on the patterns I accept. CNC
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// Look for a compare of a constant and a merged value
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Node *i1 = iff->in(1);
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if( !i1->is_Bool() ) return NULL;
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BoolNode *b = i1->as_Bool();
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Node *cmp = b->in(1);
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if( !cmp->is_Cmp() ) return NULL;
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i1 = cmp->in(1);
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if( i1 == NULL || !i1->is_Phi() ) return NULL;
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PhiNode *phi = i1->as_Phi();
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if( phi->is_copy() ) return NULL;
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Node *con2 = cmp->in(2);
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if( !con2->is_Con() ) return NULL;
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// See that the merge point contains some constants
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Node *con1=NULL;
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uint i4;
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for( i4 = 1; i4 < phi->req(); i4++ ) {
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con1 = phi->in(i4);
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if( !con1 ) return NULL; // Do not optimize partially collapsed merges
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if( con1->is_Con() ) break; // Found a constant
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// Also allow null-vs-not-null checks
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const TypePtr *tp = igvn->type(con1)->isa_ptr();
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if( tp && tp->_ptr == TypePtr::NotNull )
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break;
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}
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if( i4 >= phi->req() ) return NULL; // Found no constants
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igvn->C->set_has_split_ifs(true); // Has chance for split-if
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// Make sure that the compare can be constant folded away
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Node *cmp2 = cmp->clone();
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cmp2->set_req(1,con1);
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cmp2->set_req(2,con2);
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const Type *t = cmp2->Value(igvn);
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// This compare is dead, so whack it!
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igvn->remove_dead_node(cmp2);
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if( !t->singleton() ) return NULL;
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// No intervening control, like a simple Call
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Node *r = iff->in(0);
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if( !r->is_Region() ) return NULL;
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if (r->is_Loop() && r->in(LoopNode::LoopBackControl)->is_top()) return NULL; // going away anyway
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if( phi->region() != r ) return NULL;
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// No other users of the cmp/bool
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if (b->outcnt() != 1 || cmp->outcnt() != 1) {
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//tty->print_cr("many users of cmp/bool");
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return NULL;
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}
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// Make sure we can determine where all the uses of merged values go
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for (DUIterator_Fast jmax, j = r->fast_outs(jmax); j < jmax; j++) {
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Node* u = r->fast_out(j);
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if( u == r ) continue;
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if( u == iff ) continue;
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if( u->outcnt() == 0 ) continue; // use is dead & ignorable
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if( !u->is_Phi() ) {
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/*
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if( u->is_Start() ) {
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tty->print_cr("Region has inlined start use");
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} else {
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tty->print_cr("Region has odd use");
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u->dump(2);
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}*/
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return NULL;
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}
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if( u != phi ) {
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// CNC - do not allow any other merged value
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//tty->print_cr("Merging another value");
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//u->dump(2);
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return NULL;
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}
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// Make sure we can account for all Phi uses
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for (DUIterator_Fast kmax, k = u->fast_outs(kmax); k < kmax; k++) {
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Node* v = u->fast_out(k); // User of the phi
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// CNC - Allow only really simple patterns.
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// In particular I disallow AddP of the Phi, a fairly common pattern
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if (v == cmp) continue; // The compare is OK
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if (v->is_ConstraintCast()) {
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// If the cast is derived from data flow edges, it may not have a control edge.
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// If so, it should be safe to split. But follow-up code can not deal with
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// this (l. 359). So skip.
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if (v->in(0) == NULL) {
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return NULL;
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}
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if (v->in(0)->in(0) == iff) {
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continue; // CastPP/II of the IfNode is OK
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}
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}
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// Disabled following code because I cannot tell if exactly one
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// path dominates without a real dominator check. CNC 9/9/1999
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//uint vop = v->Opcode();
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//if( vop == Op_Phi ) { // Phi from another merge point might be OK
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// Node *r = v->in(0); // Get controlling point
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// if( !r ) return NULL; // Degraded to a copy
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// // Find exactly one path in (either True or False doms, but not IFF)
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// int cnt = 0;
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// for( uint i = 1; i < r->req(); i++ )
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// if( r->in(i) && r->in(i)->in(0) == iff )
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// cnt++;
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// if( cnt == 1 ) continue; // Exactly one of True or False guards Phi
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//}
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if( !v->is_Call() ) {
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/*
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if( v->Opcode() == Op_AddP ) {
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tty->print_cr("Phi has AddP use");
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} else if( v->Opcode() == Op_CastPP ) {
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tty->print_cr("Phi has CastPP use");
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} else if( v->Opcode() == Op_CastII ) {
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tty->print_cr("Phi has CastII use");
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} else {
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tty->print_cr("Phi has use I cant be bothered with");
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}
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*/
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}
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return NULL;
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/* CNC - Cut out all the fancy acceptance tests
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// Can we clone this use when doing the transformation?
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// If all uses are from Phis at this merge or constants, then YES.
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if( !v->in(0) && v != cmp ) {
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tty->print_cr("Phi has free-floating use");
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v->dump(2);
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return NULL;
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}
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for( uint l = 1; l < v->req(); l++ ) {
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if( (!v->in(l)->is_Phi() || v->in(l)->in(0) != r) &&
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!v->in(l)->is_Con() ) {
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tty->print_cr("Phi has use");
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v->dump(2);
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return NULL;
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} // End of if Phi-use input is neither Phi nor Constant
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} // End of for all inputs to Phi-use
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*/
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} // End of for all uses of Phi
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} // End of for all uses of Region
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// Only do this if the IF node is in a sane state
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if (iff->outcnt() != 2)
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return NULL;
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// Got a hit! Do the Mondo Hack!
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//
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//ABC a1c def ghi B 1 e h A C a c d f g i
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// R - Phi - Phi - Phi Rc - Phi - Phi - Phi Rx - Phi - Phi - Phi
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// cmp - 2 cmp - 2 cmp - 2
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// bool bool_c bool_x
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// if if_c if_x
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// T F T F T F
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// ..s.. ..t .. ..s.. ..t.. ..s.. ..t..
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//
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// Split the paths coming into the merge point into 2 separate groups of
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// merges. On the left will be all the paths feeding constants into the
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// Cmp's Phi. On the right will be the remaining paths. The Cmp's Phi
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// will fold up into a constant; this will let the Cmp fold up as well as
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// all the control flow. Below the original IF we have 2 control
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// dependent regions, 's' and 't'. Now we will merge the two paths
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// just prior to 's' and 't' from the two IFs. At least 1 path (and quite
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// likely 2 or more) will promptly constant fold away.
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PhaseGVN *phase = igvn;
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// Make a region merging constants and a region merging the rest
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uint req_c = 0;
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Node* predicate_proj = NULL;
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int nb_predicate_proj = 0;
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for (uint ii = 1; ii < r->req(); ii++) {
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if (phi->in(ii) == con1) {
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req_c++;
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}
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Node* proj = PhaseIdealLoop::find_predicate(r->in(ii));
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if (proj != NULL) {
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nb_predicate_proj++;
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predicate_proj = proj;
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}
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}
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// If all the defs of the phi are the same constant, we already have the desired end state.
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// Skip the split that would create empty phi and region nodes.
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if((r->req() - req_c) == 1) {
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return NULL;
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}
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if (nb_predicate_proj > 1) {
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// Can happen in case of loop unswitching and when the loop is
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// optimized out: it's not a loop anymore so we don't care about
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// predicates.
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assert(!r->is_Loop(), "this must not be a loop anymore");
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predicate_proj = NULL;
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}
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Node* predicate_c = NULL;
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Node* predicate_x = NULL;
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bool counted_loop = r->is_CountedLoop();
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if (counted_loop) {
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// Ignore counted loops for now because the split-if logic does not work
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// in all the cases (for example, with strip mined loops). Also, above
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// checks only pass for already degraded loops without a tripcount phi
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// and these are essentially dead and will go away during igvn.
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return NULL;
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}
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Node *region_c = new RegionNode(req_c + 1);
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Node *phi_c = con1;
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uint len = r->req();
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Node *region_x = new RegionNode(len - req_c);
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Node *phi_x = PhiNode::make_blank(region_x, phi);
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for (uint i = 1, i_c = 1, i_x = 1; i < len; i++) {
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if (phi->in(i) == con1) {
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region_c->init_req( i_c++, r ->in(i) );
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if (r->in(i) == predicate_proj)
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predicate_c = predicate_proj;
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} else {
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region_x->init_req( i_x, r ->in(i) );
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phi_x ->init_req( i_x++, phi->in(i) );
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if (r->in(i) == predicate_proj)
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predicate_x = predicate_proj;
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}
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}
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if (predicate_c != NULL && (req_c > 1)) {
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assert(predicate_x == NULL, "only one predicate entry expected");
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predicate_c = NULL; // Do not clone predicate below merge point
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}
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if (predicate_x != NULL && ((len - req_c) > 2)) {
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assert(predicate_c == NULL, "only one predicate entry expected");
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predicate_x = NULL; // Do not clone predicate below merge point
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}
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// Register the new RegionNodes but do not transform them. Cannot
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// transform until the entire Region/Phi conglomerate has been hacked
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// as a single huge transform.
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igvn->register_new_node_with_optimizer( region_c );
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igvn->register_new_node_with_optimizer( region_x );
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// Prevent the untimely death of phi_x. Currently he has no uses. He is
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// about to get one. If this only use goes away, then phi_x will look dead.
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// However, he will be picking up some more uses down below.
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Node *hook = new Node(4);
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hook->init_req(0, phi_x);
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hook->init_req(1, phi_c);
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phi_x = phase->transform( phi_x );
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// Make the compare
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Node *cmp_c = phase->makecon(t);
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Node *cmp_x = cmp->clone();
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cmp_x->set_req(1,phi_x);
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cmp_x->set_req(2,con2);
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cmp_x = phase->transform(cmp_x);
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// Make the bool
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Node *b_c = phase->transform(new BoolNode(cmp_c,b->_test._test));
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Node *b_x = phase->transform(new BoolNode(cmp_x,b->_test._test));
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// Make the IfNode
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IfNode* iff_c = iff->clone()->as_If();
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iff_c->set_req(0, region_c);
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iff_c->set_req(1, b_c);
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igvn->set_type_bottom(iff_c);
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igvn->_worklist.push(iff_c);
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hook->init_req(2, iff_c);
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IfNode* iff_x = iff->clone()->as_If();
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iff_x->set_req(0, region_x);
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iff_x->set_req(1, b_x);
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igvn->set_type_bottom(iff_x);
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igvn->_worklist.push(iff_x);
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hook->init_req(3, iff_x);
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// Make the true/false arms
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Node *iff_c_t = phase->transform(new IfTrueNode (iff_c));
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Node *iff_c_f = phase->transform(new IfFalseNode(iff_c));
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if (predicate_c != NULL) {
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assert(predicate_x == NULL, "only one predicate entry expected");
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// Clone loop predicates to each path
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iff_c_t = igvn->clone_loop_predicates(predicate_c, iff_c_t, !counted_loop);
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iff_c_f = igvn->clone_loop_predicates(predicate_c, iff_c_f, !counted_loop);
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}
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Node *iff_x_t = phase->transform(new IfTrueNode (iff_x));
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Node *iff_x_f = phase->transform(new IfFalseNode(iff_x));
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if (predicate_x != NULL) {
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assert(predicate_c == NULL, "only one predicate entry expected");
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// Clone loop predicates to each path
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iff_x_t = igvn->clone_loop_predicates(predicate_x, iff_x_t, !counted_loop);
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iff_x_f = igvn->clone_loop_predicates(predicate_x, iff_x_f, !counted_loop);
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}
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// Merge the TRUE paths
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Node *region_s = new RegionNode(3);
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igvn->_worklist.push(region_s);
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region_s->init_req(1, iff_c_t);
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region_s->init_req(2, iff_x_t);
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igvn->register_new_node_with_optimizer( region_s );
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// Merge the FALSE paths
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Node *region_f = new RegionNode(3);
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igvn->_worklist.push(region_f);
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region_f->init_req(1, iff_c_f);
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region_f->init_req(2, iff_x_f);
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igvn->register_new_node_with_optimizer( region_f );
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igvn->hash_delete(cmp);// Remove soon-to-be-dead node from hash table.
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cmp->set_req(1,NULL); // Whack the inputs to cmp because it will be dead
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cmp->set_req(2,NULL);
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// Check for all uses of the Phi and give them a new home.
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// The 'cmp' got cloned, but CastPP/IIs need to be moved.
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Node *phi_s = NULL; // do not construct unless needed
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Node *phi_f = NULL; // do not construct unless needed
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for (DUIterator_Last i2min, i2 = phi->last_outs(i2min); i2 >= i2min; --i2) {
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Node* v = phi->last_out(i2);// User of the phi
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igvn->rehash_node_delayed(v); // Have to fixup other Phi users
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uint vop = v->Opcode();
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Node *proj = NULL;
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if( vop == Op_Phi ) { // Remote merge point
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Node *r = v->in(0);
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for (uint i3 = 1; i3 < r->req(); i3++)
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if (r->in(i3) && r->in(i3)->in(0) == iff) {
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proj = r->in(i3);
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break;
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}
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} else if( v->is_ConstraintCast() ) {
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proj = v->in(0); // Controlling projection
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} else {
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assert( 0, "do not know how to handle this guy" );
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}
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guarantee(proj != NULL, "sanity");
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Node *proj_path_data, *proj_path_ctrl;
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if( proj->Opcode() == Op_IfTrue ) {
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if( phi_s == NULL ) {
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// Only construct phi_s if needed, otherwise provides
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// interfering use.
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phi_s = PhiNode::make_blank(region_s,phi);
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phi_s->init_req( 1, phi_c );
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phi_s->init_req( 2, phi_x );
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hook->add_req(phi_s);
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phi_s = phase->transform(phi_s);
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}
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proj_path_data = phi_s;
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proj_path_ctrl = region_s;
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} else {
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if( phi_f == NULL ) {
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// Only construct phi_f if needed, otherwise provides
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// interfering use.
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phi_f = PhiNode::make_blank(region_f,phi);
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phi_f->init_req( 1, phi_c );
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phi_f->init_req( 2, phi_x );
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hook->add_req(phi_f);
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phi_f = phase->transform(phi_f);
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}
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proj_path_data = phi_f;
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proj_path_ctrl = region_f;
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}
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// Fixup 'v' for for the split
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if( vop == Op_Phi ) { // Remote merge point
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uint i;
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for( i = 1; i < v->req(); i++ )
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if( v->in(i) == phi )
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break;
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v->set_req(i, proj_path_data );
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} else if( v->is_ConstraintCast() ) {
|
|
v->set_req(0, proj_path_ctrl );
|
|
v->set_req(1, proj_path_data );
|
|
} else
|
|
ShouldNotReachHere();
|
|
}
|
|
|
|
// Now replace the original iff's True/False with region_s/region_t.
|
|
// This makes the original iff go dead.
|
|
for (DUIterator_Last i3min, i3 = iff->last_outs(i3min); i3 >= i3min; --i3) {
|
|
Node* p = iff->last_out(i3);
|
|
assert( p->Opcode() == Op_IfTrue || p->Opcode() == Op_IfFalse, "" );
|
|
Node *u = (p->Opcode() == Op_IfTrue) ? region_s : region_f;
|
|
// Replace p with u
|
|
igvn->add_users_to_worklist(p);
|
|
for (DUIterator_Last lmin, l = p->last_outs(lmin); l >= lmin;) {
|
|
Node* x = p->last_out(l);
|
|
igvn->hash_delete(x);
|
|
uint uses_found = 0;
|
|
for( uint j = 0; j < x->req(); j++ ) {
|
|
if( x->in(j) == p ) {
|
|
x->set_req(j, u);
|
|
uses_found++;
|
|
}
|
|
}
|
|
l -= uses_found; // we deleted 1 or more copies of this edge
|
|
}
|
|
igvn->remove_dead_node(p);
|
|
}
|
|
|
|
// Force the original merge dead
|
|
igvn->hash_delete(r);
|
|
// First, remove region's dead users.
|
|
for (DUIterator_Last lmin, l = r->last_outs(lmin); l >= lmin;) {
|
|
Node* u = r->last_out(l);
|
|
if( u == r ) {
|
|
r->set_req(0, NULL);
|
|
} else {
|
|
assert(u->outcnt() == 0, "only dead users");
|
|
igvn->remove_dead_node(u);
|
|
}
|
|
l -= 1;
|
|
}
|
|
igvn->remove_dead_node(r);
|
|
|
|
// Now remove the bogus extra edges used to keep things alive
|
|
igvn->remove_dead_node( hook );
|
|
|
|
// Must return either the original node (now dead) or a new node
|
|
// (Do not return a top here, since that would break the uniqueness of top.)
|
|
return new ConINode(TypeInt::ZERO);
|
|
}
|
|
|
|
// if this IfNode follows a range check pattern return the projection
|
|
// for the failed path
|
|
ProjNode* IfNode::range_check_trap_proj(int& flip_test, Node*& l, Node*& r) {
|
|
if (outcnt() != 2) {
|
|
return NULL;
|
|
}
|
|
Node* b = in(1);
|
|
if (b == NULL || !b->is_Bool()) return NULL;
|
|
BoolNode* bn = b->as_Bool();
|
|
Node* cmp = bn->in(1);
|
|
if (cmp == NULL) return NULL;
|
|
if (cmp->Opcode() != Op_CmpU) return NULL;
|
|
|
|
l = cmp->in(1);
|
|
r = cmp->in(2);
|
|
flip_test = 1;
|
|
if (bn->_test._test == BoolTest::le) {
|
|
l = cmp->in(2);
|
|
r = cmp->in(1);
|
|
flip_test = 2;
|
|
} else if (bn->_test._test != BoolTest::lt) {
|
|
return NULL;
|
|
}
|
|
if (l->is_top()) return NULL; // Top input means dead test
|
|
if (r->Opcode() != Op_LoadRange && !is_RangeCheck()) return NULL;
|
|
|
|
// We have recognized one of these forms:
|
|
// Flip 1: If (Bool[<] CmpU(l, LoadRange)) ...
|
|
// Flip 2: If (Bool[<=] CmpU(LoadRange, l)) ...
|
|
|
|
ProjNode* iftrap = proj_out_or_null(flip_test == 2 ? true : false);
|
|
return iftrap;
|
|
}
|
|
|
|
|
|
//------------------------------is_range_check---------------------------------
|
|
// Return 0 if not a range check. Return 1 if a range check and set index and
|
|
// offset. Return 2 if we had to negate the test. Index is NULL if the check
|
|
// is versus a constant.
|
|
int RangeCheckNode::is_range_check(Node* &range, Node* &index, jint &offset) {
|
|
int flip_test = 0;
|
|
Node* l = NULL;
|
|
Node* r = NULL;
|
|
ProjNode* iftrap = range_check_trap_proj(flip_test, l, r);
|
|
|
|
if (iftrap == NULL) {
|
|
return 0;
|
|
}
|
|
|
|
// Make sure it's a real range check by requiring an uncommon trap
|
|
// along the OOB path. Otherwise, it's possible that the user wrote
|
|
// something which optimized to look like a range check but behaves
|
|
// in some other way.
|
|
if (iftrap->is_uncommon_trap_proj(Deoptimization::Reason_range_check) == NULL) {
|
|
return 0;
|
|
}
|
|
|
|
// Look for index+offset form
|
|
Node* ind = l;
|
|
jint off = 0;
|
|
if (l->is_top()) {
|
|
return 0;
|
|
} else if (l->Opcode() == Op_AddI) {
|
|
if ((off = l->in(1)->find_int_con(0)) != 0) {
|
|
ind = l->in(2)->uncast();
|
|
} else if ((off = l->in(2)->find_int_con(0)) != 0) {
|
|
ind = l->in(1)->uncast();
|
|
}
|
|
} else if ((off = l->find_int_con(-1)) >= 0) {
|
|
// constant offset with no variable index
|
|
ind = NULL;
|
|
} else {
|
|
// variable index with no constant offset (or dead negative index)
|
|
off = 0;
|
|
}
|
|
|
|
// Return all the values:
|
|
index = ind;
|
|
offset = off;
|
|
range = r;
|
|
return flip_test;
|
|
}
|
|
|
|
//------------------------------adjust_check-----------------------------------
|
|
// Adjust (widen) a prior range check
|
|
static void adjust_check(Node* proj, Node* range, Node* index,
|
|
int flip, jint off_lo, PhaseIterGVN* igvn) {
|
|
PhaseGVN *gvn = igvn;
|
|
// Break apart the old check
|
|
Node *iff = proj->in(0);
|
|
Node *bol = iff->in(1);
|
|
if( bol->is_top() ) return; // In case a partially dead range check appears
|
|
// bail (or bomb[ASSERT/DEBUG]) if NOT projection-->IfNode-->BoolNode
|
|
DEBUG_ONLY( if( !bol->is_Bool() ) { proj->dump(3); fatal("Expect projection-->IfNode-->BoolNode"); } )
|
|
if( !bol->is_Bool() ) return;
|
|
|
|
Node *cmp = bol->in(1);
|
|
// Compute a new check
|
|
Node *new_add = gvn->intcon(off_lo);
|
|
if( index ) {
|
|
new_add = off_lo ? gvn->transform(new AddINode( index, new_add )) : index;
|
|
}
|
|
Node *new_cmp = (flip == 1)
|
|
? new CmpUNode( new_add, range )
|
|
: new CmpUNode( range, new_add );
|
|
new_cmp = gvn->transform(new_cmp);
|
|
// See if no need to adjust the existing check
|
|
if( new_cmp == cmp ) return;
|
|
// Else, adjust existing check
|
|
Node *new_bol = gvn->transform( new BoolNode( new_cmp, bol->as_Bool()->_test._test ) );
|
|
igvn->rehash_node_delayed( iff );
|
|
iff->set_req_X( 1, new_bol, igvn );
|
|
}
|
|
|
|
//------------------------------up_one_dom-------------------------------------
|
|
// Walk up the dominator tree one step. Return NULL at root or true
|
|
// complex merges. Skips through small diamonds.
|
|
Node* IfNode::up_one_dom(Node *curr, bool linear_only) {
|
|
Node *dom = curr->in(0);
|
|
if( !dom ) // Found a Region degraded to a copy?
|
|
return curr->nonnull_req(); // Skip thru it
|
|
|
|
if( curr != dom ) // Normal walk up one step?
|
|
return dom;
|
|
|
|
// Use linear_only if we are still parsing, since we cannot
|
|
// trust the regions to be fully filled in.
|
|
if (linear_only)
|
|
return NULL;
|
|
|
|
if( dom->is_Root() )
|
|
return NULL;
|
|
|
|
// Else hit a Region. Check for a loop header
|
|
if( dom->is_Loop() )
|
|
return dom->in(1); // Skip up thru loops
|
|
|
|
// Check for small diamonds
|
|
Node *din1, *din2, *din3, *din4;
|
|
if( dom->req() == 3 && // 2-path merge point
|
|
(din1 = dom ->in(1)) && // Left path exists
|
|
(din2 = dom ->in(2)) && // Right path exists
|
|
(din3 = din1->in(0)) && // Left path up one
|
|
(din4 = din2->in(0)) ) { // Right path up one
|
|
if( din3->is_Call() && // Handle a slow-path call on either arm
|
|
(din3 = din3->in(0)) )
|
|
din3 = din3->in(0);
|
|
if( din4->is_Call() && // Handle a slow-path call on either arm
|
|
(din4 = din4->in(0)) )
|
|
din4 = din4->in(0);
|
|
if( din3 == din4 && din3->is_If() )
|
|
return din3; // Skip around diamonds
|
|
}
|
|
|
|
// Give up the search at true merges
|
|
return NULL; // Dead loop? Or hit root?
|
|
}
|
|
|
|
|
|
//------------------------------filtered_int_type--------------------------------
|
|
// Return a possibly more restrictive type for val based on condition control flow for an if
|
|
const TypeInt* IfNode::filtered_int_type(PhaseGVN* gvn, Node *val, Node* if_proj) {
|
|
assert(if_proj &&
|
|
(if_proj->Opcode() == Op_IfTrue || if_proj->Opcode() == Op_IfFalse), "expecting an if projection");
|
|
if (if_proj->in(0) && if_proj->in(0)->is_If()) {
|
|
IfNode* iff = if_proj->in(0)->as_If();
|
|
if (iff->in(1) && iff->in(1)->is_Bool()) {
|
|
BoolNode* bol = iff->in(1)->as_Bool();
|
|
if (bol->in(1) && bol->in(1)->is_Cmp()) {
|
|
const CmpNode* cmp = bol->in(1)->as_Cmp();
|
|
if (cmp->in(1) == val) {
|
|
const TypeInt* cmp2_t = gvn->type(cmp->in(2))->isa_int();
|
|
if (cmp2_t != NULL) {
|
|
jint lo = cmp2_t->_lo;
|
|
jint hi = cmp2_t->_hi;
|
|
BoolTest::mask msk = if_proj->Opcode() == Op_IfTrue ? bol->_test._test : bol->_test.negate();
|
|
switch (msk) {
|
|
case BoolTest::ne:
|
|
// Can't refine type
|
|
return NULL;
|
|
case BoolTest::eq:
|
|
return cmp2_t;
|
|
case BoolTest::lt:
|
|
lo = TypeInt::INT->_lo;
|
|
if (hi - 1 < hi) {
|
|
hi = hi - 1;
|
|
}
|
|
break;
|
|
case BoolTest::le:
|
|
lo = TypeInt::INT->_lo;
|
|
break;
|
|
case BoolTest::gt:
|
|
if (lo + 1 > lo) {
|
|
lo = lo + 1;
|
|
}
|
|
hi = TypeInt::INT->_hi;
|
|
break;
|
|
case BoolTest::ge:
|
|
// lo unchanged
|
|
hi = TypeInt::INT->_hi;
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
const TypeInt* rtn_t = TypeInt::make(lo, hi, cmp2_t->_widen);
|
|
return rtn_t;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
//------------------------------fold_compares----------------------------
|
|
// See if a pair of CmpIs can be converted into a CmpU. In some cases
|
|
// the direction of this if is determined by the preceding if so it
|
|
// can be eliminate entirely.
|
|
//
|
|
// Given an if testing (CmpI n v) check for an immediately control
|
|
// dependent if that is testing (CmpI n v2) and has one projection
|
|
// leading to this if and the other projection leading to a region
|
|
// that merges one of this ifs control projections.
|
|
//
|
|
// If
|
|
// / |
|
|
// / |
|
|
// / |
|
|
// If |
|
|
// /\ |
|
|
// / \ |
|
|
// / \ |
|
|
// / Region
|
|
//
|
|
// Or given an if testing (CmpI n v) check for a dominating if that is
|
|
// testing (CmpI n v2), both having one projection leading to an
|
|
// uncommon trap. Allow Another independent guard in between to cover
|
|
// an explicit range check:
|
|
// if (index < 0 || index >= array.length) {
|
|
// which may need a null check to guard the LoadRange
|
|
//
|
|
// If
|
|
// / \
|
|
// / \
|
|
// / \
|
|
// If unc
|
|
// /\
|
|
// / \
|
|
// / \
|
|
// / unc
|
|
//
|
|
|
|
// Is the comparison for this If suitable for folding?
|
|
bool IfNode::cmpi_folds(PhaseIterGVN* igvn) {
|
|
return in(1) != NULL &&
|
|
in(1)->is_Bool() &&
|
|
in(1)->in(1) != NULL &&
|
|
in(1)->in(1)->Opcode() == Op_CmpI &&
|
|
in(1)->in(1)->in(2) != NULL &&
|
|
in(1)->in(1)->in(2) != igvn->C->top() &&
|
|
(in(1)->as_Bool()->_test.is_less() ||
|
|
in(1)->as_Bool()->_test.is_greater());
|
|
}
|
|
|
|
// Is a dominating control suitable for folding with this if?
|
|
bool IfNode::is_ctrl_folds(Node* ctrl, PhaseIterGVN* igvn) {
|
|
return ctrl != NULL &&
|
|
ctrl->is_Proj() &&
|
|
ctrl->in(0) != NULL &&
|
|
ctrl->in(0)->Opcode() == Op_If &&
|
|
ctrl->in(0)->outcnt() == 2 &&
|
|
ctrl->in(0)->as_If()->cmpi_folds(igvn) &&
|
|
// Must compare same value
|
|
ctrl->in(0)->in(1)->in(1)->in(1) != NULL &&
|
|
ctrl->in(0)->in(1)->in(1)->in(1) == in(1)->in(1)->in(1);
|
|
}
|
|
|
|
// Do this If and the dominating If share a region?
|
|
bool IfNode::has_shared_region(ProjNode* proj, ProjNode*& success, ProjNode*& fail) {
|
|
ProjNode* otherproj = proj->other_if_proj();
|
|
Node* otherproj_ctrl_use = otherproj->unique_ctrl_out();
|
|
RegionNode* region = (otherproj_ctrl_use != NULL && otherproj_ctrl_use->is_Region()) ? otherproj_ctrl_use->as_Region() : NULL;
|
|
success = NULL;
|
|
fail = NULL;
|
|
|
|
if (otherproj->outcnt() == 1 && region != NULL && !region->has_phi()) {
|
|
for (int i = 0; i < 2; i++) {
|
|
ProjNode* proj = proj_out(i);
|
|
if (success == NULL && proj->outcnt() == 1 && proj->unique_out() == region) {
|
|
success = proj;
|
|
} else if (fail == NULL) {
|
|
fail = proj;
|
|
} else {
|
|
success = fail = NULL;
|
|
}
|
|
}
|
|
}
|
|
return success != NULL && fail != NULL;
|
|
}
|
|
|
|
bool IfNode::is_dominator_unc(CallStaticJavaNode* dom_unc, CallStaticJavaNode* unc) {
|
|
// Different methods and methods containing jsrs are not supported.
|
|
ciMethod* method = unc->jvms()->method();
|
|
ciMethod* dom_method = dom_unc->jvms()->method();
|
|
if (method != dom_method || method->has_jsrs()) {
|
|
return false;
|
|
}
|
|
// Check that both traps are in the same activation of the method (instead
|
|
// of two activations being inlined through different call sites) by verifying
|
|
// that the call stacks are equal for both JVMStates.
|
|
JVMState* dom_caller = dom_unc->jvms()->caller();
|
|
JVMState* caller = unc->jvms()->caller();
|
|
if ((dom_caller == NULL) != (caller == NULL)) {
|
|
// The current method must either be inlined into both dom_caller and
|
|
// caller or must not be inlined at all (top method). Bail out otherwise.
|
|
return false;
|
|
} else if (dom_caller != NULL && !dom_caller->same_calls_as(caller)) {
|
|
return false;
|
|
}
|
|
// Check that the bci of the dominating uncommon trap dominates the bci
|
|
// of the dominated uncommon trap. Otherwise we may not re-execute
|
|
// the dominated check after deoptimization from the merged uncommon trap.
|
|
ciTypeFlow* flow = dom_method->get_flow_analysis();
|
|
int bci = unc->jvms()->bci();
|
|
int dom_bci = dom_unc->jvms()->bci();
|
|
if (!flow->is_dominated_by(bci, dom_bci)) {
|
|
return false;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
// Return projection that leads to an uncommon trap if any
|
|
ProjNode* IfNode::uncommon_trap_proj(CallStaticJavaNode*& call) const {
|
|
for (int i = 0; i < 2; i++) {
|
|
call = proj_out(i)->is_uncommon_trap_proj(Deoptimization::Reason_none);
|
|
if (call != NULL) {
|
|
return proj_out(i);
|
|
}
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
// Do this If and the dominating If both branch out to an uncommon trap
|
|
bool IfNode::has_only_uncommon_traps(ProjNode* proj, ProjNode*& success, ProjNode*& fail, PhaseIterGVN* igvn) {
|
|
ProjNode* otherproj = proj->other_if_proj();
|
|
CallStaticJavaNode* dom_unc = otherproj->is_uncommon_trap_proj(Deoptimization::Reason_none);
|
|
|
|
if (otherproj->outcnt() == 1 && dom_unc != NULL) {
|
|
// We need to re-execute the folded Ifs after deoptimization from the merged traps
|
|
if (!dom_unc->jvms()->should_reexecute()) {
|
|
return false;
|
|
}
|
|
|
|
CallStaticJavaNode* unc = NULL;
|
|
ProjNode* unc_proj = uncommon_trap_proj(unc);
|
|
if (unc_proj != NULL && unc_proj->outcnt() == 1) {
|
|
if (dom_unc == unc) {
|
|
// Allow the uncommon trap to be shared through a region
|
|
RegionNode* r = unc->in(0)->as_Region();
|
|
if (r->outcnt() != 2 || r->req() != 3 || r->find_edge(otherproj) == -1 || r->find_edge(unc_proj) == -1) {
|
|
return false;
|
|
}
|
|
assert(r->has_phi() == NULL, "simple region shouldn't have a phi");
|
|
} else if (dom_unc->in(0) != otherproj || unc->in(0) != unc_proj) {
|
|
return false;
|
|
}
|
|
|
|
if (!is_dominator_unc(dom_unc, unc)) {
|
|
return false;
|
|
}
|
|
|
|
// See merge_uncommon_traps: the reason of the uncommon trap
|
|
// will be changed and the state of the dominating If will be
|
|
// used. Checked that we didn't apply this transformation in a
|
|
// previous compilation and it didn't cause too many traps
|
|
ciMethod* dom_method = dom_unc->jvms()->method();
|
|
int dom_bci = dom_unc->jvms()->bci();
|
|
if (!igvn->C->too_many_traps(dom_method, dom_bci, Deoptimization::Reason_unstable_fused_if) &&
|
|
!igvn->C->too_many_traps(dom_method, dom_bci, Deoptimization::Reason_range_check)) {
|
|
success = unc_proj;
|
|
fail = unc_proj->other_if_proj();
|
|
return true;
|
|
}
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
// Check that the 2 CmpI can be folded into as single CmpU and proceed with the folding
|
|
bool IfNode::fold_compares_helper(ProjNode* proj, ProjNode* success, ProjNode* fail, PhaseIterGVN* igvn) {
|
|
Node* this_cmp = in(1)->in(1);
|
|
BoolNode* this_bool = in(1)->as_Bool();
|
|
IfNode* dom_iff = proj->in(0)->as_If();
|
|
BoolNode* dom_bool = dom_iff->in(1)->as_Bool();
|
|
Node* lo = dom_iff->in(1)->in(1)->in(2);
|
|
Node* hi = this_cmp->in(2);
|
|
Node* n = this_cmp->in(1);
|
|
ProjNode* otherproj = proj->other_if_proj();
|
|
|
|
const TypeInt* lo_type = IfNode::filtered_int_type(igvn, n, otherproj);
|
|
const TypeInt* hi_type = IfNode::filtered_int_type(igvn, n, success);
|
|
|
|
BoolTest::mask lo_test = dom_bool->_test._test;
|
|
BoolTest::mask hi_test = this_bool->_test._test;
|
|
BoolTest::mask cond = hi_test;
|
|
|
|
// convert:
|
|
//
|
|
// dom_bool = x {<,<=,>,>=} a
|
|
// / \
|
|
// proj = {True,False} / \ otherproj = {False,True}
|
|
// /
|
|
// this_bool = x {<,<=} b
|
|
// / \
|
|
// fail = {True,False} / \ success = {False,True}
|
|
// /
|
|
//
|
|
// (Second test guaranteed canonicalized, first one may not have
|
|
// been canonicalized yet)
|
|
//
|
|
// into:
|
|
//
|
|
// cond = (x - lo) {<u,<=u,>u,>=u} adjusted_lim
|
|
// / \
|
|
// fail / \ success
|
|
// /
|
|
//
|
|
|
|
// Figure out which of the two tests sets the upper bound and which
|
|
// sets the lower bound if any.
|
|
Node* adjusted_lim = NULL;
|
|
if (lo_type != NULL && hi_type != NULL && hi_type->_lo > lo_type->_hi &&
|
|
hi_type->_hi == max_jint && lo_type->_lo == min_jint) {
|
|
assert((dom_bool->_test.is_less() && !proj->_con) ||
|
|
(dom_bool->_test.is_greater() && proj->_con), "incorrect test");
|
|
// this test was canonicalized
|
|
assert(this_bool->_test.is_less() && fail->_con, "incorrect test");
|
|
|
|
// this_bool = <
|
|
// dom_bool = >= (proj = True) or dom_bool = < (proj = False)
|
|
// x in [a, b[ on the fail (= True) projection, b > a-1 (because of hi_type->_lo > lo_type->_hi test above):
|
|
// lo = a, hi = b, adjusted_lim = b-a, cond = <u
|
|
// dom_bool = > (proj = True) or dom_bool = <= (proj = False)
|
|
// x in ]a, b[ on the fail (= True) projection, b > a:
|
|
// lo = a+1, hi = b, adjusted_lim = b-a-1, cond = <u
|
|
// this_bool = <=
|
|
// dom_bool = >= (proj = True) or dom_bool = < (proj = False)
|
|
// x in [a, b] on the fail (= True) projection, b+1 > a-1:
|
|
// lo = a, hi = b, adjusted_lim = b-a+1, cond = <u
|
|
// lo = a, hi = b, adjusted_lim = b-a, cond = <=u doesn't work because b = a - 1 is possible, then b-a = -1
|
|
// dom_bool = > (proj = True) or dom_bool = <= (proj = False)
|
|
// x in ]a, b] on the fail (= True) projection b+1 > a:
|
|
// lo = a+1, hi = b, adjusted_lim = b-a, cond = <u
|
|
// lo = a+1, hi = b, adjusted_lim = b-a-1, cond = <=u doesn't work because a = b is possible, then b-a-1 = -1
|
|
|
|
if (hi_test == BoolTest::lt) {
|
|
if (lo_test == BoolTest::gt || lo_test == BoolTest::le) {
|
|
lo = igvn->transform(new AddINode(lo, igvn->intcon(1)));
|
|
}
|
|
} else {
|
|
assert(hi_test == BoolTest::le, "bad test");
|
|
if (lo_test == BoolTest::ge || lo_test == BoolTest::lt) {
|
|
adjusted_lim = igvn->transform(new SubINode(hi, lo));
|
|
adjusted_lim = igvn->transform(new AddINode(adjusted_lim, igvn->intcon(1)));
|
|
cond = BoolTest::lt;
|
|
} else {
|
|
assert(lo_test == BoolTest::gt || lo_test == BoolTest::le, "bad test");
|
|
adjusted_lim = igvn->transform(new SubINode(hi, lo));
|
|
lo = igvn->transform(new AddINode(lo, igvn->intcon(1)));
|
|
cond = BoolTest::lt;
|
|
}
|
|
}
|
|
} else if (lo_type != NULL && hi_type != NULL && lo_type->_lo > hi_type->_hi &&
|
|
lo_type->_hi == max_jint && hi_type->_lo == min_jint) {
|
|
|
|
// this_bool = <
|
|
// dom_bool = < (proj = True) or dom_bool = >= (proj = False)
|
|
// x in [b, a[ on the fail (= False) projection, a > b-1 (because of lo_type->_lo > hi_type->_hi above):
|
|
// lo = b, hi = a, adjusted_lim = a-b, cond = >=u
|
|
// dom_bool = <= (proj = True) or dom_bool = > (proj = False)
|
|
// x in [b, a] on the fail (= False) projection, a+1 > b-1:
|
|
// lo = b, hi = a, adjusted_lim = a-b+1, cond = >=u
|
|
// lo = b, hi = a, adjusted_lim = a-b, cond = >u doesn't work because a = b - 1 is possible, then b-a = -1
|
|
// this_bool = <=
|
|
// dom_bool = < (proj = True) or dom_bool = >= (proj = False)
|
|
// x in ]b, a[ on the fail (= False) projection, a > b:
|
|
// lo = b+1, hi = a, adjusted_lim = a-b-1, cond = >=u
|
|
// dom_bool = <= (proj = True) or dom_bool = > (proj = False)
|
|
// x in ]b, a] on the fail (= False) projection, a+1 > b:
|
|
// lo = b+1, hi = a, adjusted_lim = a-b, cond = >=u
|
|
// lo = b+1, hi = a, adjusted_lim = a-b-1, cond = >u doesn't work because a = b is possible, then b-a-1 = -1
|
|
|
|
swap(lo, hi);
|
|
swap(lo_type, hi_type);
|
|
swap(lo_test, hi_test);
|
|
|
|
assert((dom_bool->_test.is_less() && proj->_con) ||
|
|
(dom_bool->_test.is_greater() && !proj->_con), "incorrect test");
|
|
// this test was canonicalized
|
|
assert(this_bool->_test.is_less() && !fail->_con, "incorrect test");
|
|
|
|
cond = (hi_test == BoolTest::le || hi_test == BoolTest::gt) ? BoolTest::gt : BoolTest::ge;
|
|
|
|
if (lo_test == BoolTest::lt) {
|
|
if (hi_test == BoolTest::lt || hi_test == BoolTest::ge) {
|
|
cond = BoolTest::ge;
|
|
} else {
|
|
assert(hi_test == BoolTest::le || hi_test == BoolTest::gt, "bad test");
|
|
adjusted_lim = igvn->transform(new SubINode(hi, lo));
|
|
adjusted_lim = igvn->transform(new AddINode(adjusted_lim, igvn->intcon(1)));
|
|
cond = BoolTest::ge;
|
|
}
|
|
} else if (lo_test == BoolTest::le) {
|
|
if (hi_test == BoolTest::lt || hi_test == BoolTest::ge) {
|
|
lo = igvn->transform(new AddINode(lo, igvn->intcon(1)));
|
|
cond = BoolTest::ge;
|
|
} else {
|
|
assert(hi_test == BoolTest::le || hi_test == BoolTest::gt, "bad test");
|
|
adjusted_lim = igvn->transform(new SubINode(hi, lo));
|
|
lo = igvn->transform(new AddINode(lo, igvn->intcon(1)));
|
|
cond = BoolTest::ge;
|
|
}
|
|
}
|
|
} else {
|
|
const TypeInt* failtype = filtered_int_type(igvn, n, proj);
|
|
if (failtype != NULL) {
|
|
const TypeInt* type2 = filtered_int_type(igvn, n, fail);
|
|
if (type2 != NULL) {
|
|
failtype = failtype->join(type2)->is_int();
|
|
if (failtype->_lo > failtype->_hi) {
|
|
// previous if determines the result of this if so
|
|
// replace Bool with constant
|
|
igvn->_worklist.push(in(1));
|
|
igvn->replace_input_of(this, 1, igvn->intcon(success->_con));
|
|
return true;
|
|
}
|
|
}
|
|
}
|
|
lo = NULL;
|
|
hi = NULL;
|
|
}
|
|
|
|
if (lo && hi) {
|
|
// Merge the two compares into a single unsigned compare by building (CmpU (n - lo) (hi - lo))
|
|
Node* adjusted_val = igvn->transform(new SubINode(n, lo));
|
|
if (adjusted_lim == NULL) {
|
|
adjusted_lim = igvn->transform(new SubINode(hi, lo));
|
|
}
|
|
Node* newcmp = igvn->transform(new CmpUNode(adjusted_val, adjusted_lim));
|
|
Node* newbool = igvn->transform(new BoolNode(newcmp, cond));
|
|
|
|
igvn->replace_input_of(dom_iff, 1, igvn->intcon(proj->_con));
|
|
igvn->_worklist.push(in(1));
|
|
igvn->replace_input_of(this, 1, newbool);
|
|
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
// Merge the branches that trap for this If and the dominating If into
|
|
// a single region that branches to the uncommon trap for the
|
|
// dominating If
|
|
Node* IfNode::merge_uncommon_traps(ProjNode* proj, ProjNode* success, ProjNode* fail, PhaseIterGVN* igvn) {
|
|
Node* res = this;
|
|
assert(success->in(0) == this, "bad projection");
|
|
|
|
ProjNode* otherproj = proj->other_if_proj();
|
|
|
|
CallStaticJavaNode* unc = success->is_uncommon_trap_proj(Deoptimization::Reason_none);
|
|
CallStaticJavaNode* dom_unc = otherproj->is_uncommon_trap_proj(Deoptimization::Reason_none);
|
|
|
|
if (unc != dom_unc) {
|
|
Node* r = new RegionNode(3);
|
|
|
|
r->set_req(1, otherproj);
|
|
r->set_req(2, success);
|
|
r = igvn->transform(r);
|
|
assert(r->is_Region(), "can't go away");
|
|
|
|
// Make both If trap at the state of the first If: once the CmpI
|
|
// nodes are merged, if we trap we don't know which of the CmpI
|
|
// nodes would have caused the trap so we have to restart
|
|
// execution at the first one
|
|
igvn->replace_input_of(dom_unc, 0, r);
|
|
igvn->replace_input_of(unc, 0, igvn->C->top());
|
|
}
|
|
int trap_request = dom_unc->uncommon_trap_request();
|
|
Deoptimization::DeoptReason reason = Deoptimization::trap_request_reason(trap_request);
|
|
Deoptimization::DeoptAction action = Deoptimization::trap_request_action(trap_request);
|
|
|
|
int flip_test = 0;
|
|
Node* l = NULL;
|
|
Node* r = NULL;
|
|
|
|
if (success->in(0)->as_If()->range_check_trap_proj(flip_test, l, r) != NULL) {
|
|
// If this looks like a range check, change the trap to
|
|
// Reason_range_check so the compiler recognizes it as a range
|
|
// check and applies the corresponding optimizations
|
|
trap_request = Deoptimization::make_trap_request(Deoptimization::Reason_range_check, action);
|
|
|
|
improve_address_types(l, r, fail, igvn);
|
|
|
|
res = igvn->transform(new RangeCheckNode(in(0), in(1), _prob, _fcnt));
|
|
} else if (unc != dom_unc) {
|
|
// If we trap we won't know what CmpI would have caused the trap
|
|
// so use a special trap reason to mark this pair of CmpI nodes as
|
|
// bad candidate for folding. On recompilation we won't fold them
|
|
// and we may trap again but this time we'll know what branch
|
|
// traps
|
|
trap_request = Deoptimization::make_trap_request(Deoptimization::Reason_unstable_fused_if, action);
|
|
}
|
|
igvn->replace_input_of(dom_unc, TypeFunc::Parms, igvn->intcon(trap_request));
|
|
return res;
|
|
}
|
|
|
|
// If we are turning 2 CmpI nodes into a CmpU that follows the pattern
|
|
// of a rangecheck on index i, on 64 bit the compares may be followed
|
|
// by memory accesses using i as index. In that case, the CmpU tells
|
|
// us something about the values taken by i that can help the compiler
|
|
// (see Compile::conv_I2X_index())
|
|
void IfNode::improve_address_types(Node* l, Node* r, ProjNode* fail, PhaseIterGVN* igvn) {
|
|
#ifdef _LP64
|
|
ResourceMark rm;
|
|
Node_Stack stack(2);
|
|
|
|
assert(r->Opcode() == Op_LoadRange, "unexpected range check");
|
|
const TypeInt* array_size = igvn->type(r)->is_int();
|
|
|
|
stack.push(l, 0);
|
|
|
|
while(stack.size() > 0) {
|
|
Node* n = stack.node();
|
|
uint start = stack.index();
|
|
|
|
uint i = start;
|
|
for (; i < n->outcnt(); i++) {
|
|
Node* use = n->raw_out(i);
|
|
if (stack.size() == 1) {
|
|
if (use->Opcode() == Op_ConvI2L) {
|
|
const TypeLong* bounds = use->as_Type()->type()->is_long();
|
|
if (bounds->_lo <= array_size->_lo && bounds->_hi >= array_size->_hi &&
|
|
(bounds->_lo != array_size->_lo || bounds->_hi != array_size->_hi)) {
|
|
stack.set_index(i+1);
|
|
stack.push(use, 0);
|
|
break;
|
|
}
|
|
}
|
|
} else if (use->is_Mem()) {
|
|
Node* ctrl = use->in(0);
|
|
for (int i = 0; i < 10 && ctrl != NULL && ctrl != fail; i++) {
|
|
ctrl = up_one_dom(ctrl);
|
|
}
|
|
if (ctrl == fail) {
|
|
Node* init_n = stack.node_at(1);
|
|
assert(init_n->Opcode() == Op_ConvI2L, "unexpected first node");
|
|
// Create a new narrow ConvI2L node that is dependent on the range check
|
|
Node* new_n = igvn->C->conv_I2X_index(igvn, l, array_size, fail);
|
|
|
|
// The type of the ConvI2L may be widen and so the new
|
|
// ConvI2L may not be better than an existing ConvI2L
|
|
if (new_n != init_n) {
|
|
for (uint j = 2; j < stack.size(); j++) {
|
|
Node* n = stack.node_at(j);
|
|
Node* clone = n->clone();
|
|
int rep = clone->replace_edge(init_n, new_n);
|
|
assert(rep > 0, "can't find expected node?");
|
|
clone = igvn->transform(clone);
|
|
init_n = n;
|
|
new_n = clone;
|
|
}
|
|
igvn->hash_delete(use);
|
|
int rep = use->replace_edge(init_n, new_n);
|
|
assert(rep > 0, "can't find expected node?");
|
|
igvn->transform(use);
|
|
if (init_n->outcnt() == 0) {
|
|
igvn->_worklist.push(init_n);
|
|
}
|
|
}
|
|
}
|
|
} else if (use->in(0) == NULL && (igvn->type(use)->isa_long() ||
|
|
igvn->type(use)->isa_ptr())) {
|
|
stack.set_index(i+1);
|
|
stack.push(use, 0);
|
|
break;
|
|
}
|
|
}
|
|
if (i == n->outcnt()) {
|
|
stack.pop();
|
|
}
|
|
}
|
|
#endif
|
|
}
|
|
|
|
bool IfNode::is_cmp_with_loadrange(ProjNode* proj) {
|
|
if (in(1) != NULL &&
|
|
in(1)->in(1) != NULL &&
|
|
in(1)->in(1)->in(2) != NULL) {
|
|
Node* other = in(1)->in(1)->in(2);
|
|
if (other->Opcode() == Op_LoadRange &&
|
|
((other->in(0) != NULL && other->in(0) == proj) ||
|
|
(other->in(0) == NULL &&
|
|
other->in(2) != NULL &&
|
|
other->in(2)->is_AddP() &&
|
|
other->in(2)->in(1) != NULL &&
|
|
other->in(2)->in(1)->Opcode() == Op_CastPP &&
|
|
other->in(2)->in(1)->in(0) == proj))) {
|
|
return true;
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
bool IfNode::is_null_check(ProjNode* proj, PhaseIterGVN* igvn) {
|
|
Node* other = in(1)->in(1)->in(2);
|
|
if (other->in(MemNode::Address) != NULL &&
|
|
proj->in(0)->in(1) != NULL &&
|
|
proj->in(0)->in(1)->is_Bool() &&
|
|
proj->in(0)->in(1)->in(1) != NULL &&
|
|
proj->in(0)->in(1)->in(1)->Opcode() == Op_CmpP &&
|
|
proj->in(0)->in(1)->in(1)->in(2) != NULL &&
|
|
proj->in(0)->in(1)->in(1)->in(1) == other->in(MemNode::Address)->in(AddPNode::Address)->uncast() &&
|
|
igvn->type(proj->in(0)->in(1)->in(1)->in(2)) == TypePtr::NULL_PTR) {
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
// Check that the If that is in between the 2 integer comparisons has
|
|
// no side effect
|
|
bool IfNode::is_side_effect_free_test(ProjNode* proj, PhaseIterGVN* igvn) {
|
|
if (proj == NULL) {
|
|
return false;
|
|
}
|
|
CallStaticJavaNode* unc = proj->is_uncommon_trap_if_pattern(Deoptimization::Reason_none);
|
|
if (unc != NULL && proj->outcnt() <= 2) {
|
|
if (proj->outcnt() == 1 ||
|
|
// Allow simple null check from LoadRange
|
|
(is_cmp_with_loadrange(proj) && is_null_check(proj, igvn))) {
|
|
CallStaticJavaNode* unc = proj->is_uncommon_trap_if_pattern(Deoptimization::Reason_none);
|
|
CallStaticJavaNode* dom_unc = proj->in(0)->in(0)->as_Proj()->is_uncommon_trap_if_pattern(Deoptimization::Reason_none);
|
|
assert(dom_unc != NULL, "is_uncommon_trap_if_pattern returned NULL");
|
|
|
|
// reroute_side_effect_free_unc changes the state of this
|
|
// uncommon trap to restart execution at the previous
|
|
// CmpI. Check that this change in a previous compilation didn't
|
|
// cause too many traps.
|
|
int trap_request = unc->uncommon_trap_request();
|
|
Deoptimization::DeoptReason reason = Deoptimization::trap_request_reason(trap_request);
|
|
|
|
if (igvn->C->too_many_traps(dom_unc->jvms()->method(), dom_unc->jvms()->bci(), reason)) {
|
|
return false;
|
|
}
|
|
|
|
if (!is_dominator_unc(dom_unc, unc)) {
|
|
return false;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
// Make the If between the 2 integer comparisons trap at the state of
|
|
// the first If: the last CmpI is the one replaced by a CmpU and the
|
|
// first CmpI is eliminated, so the test between the 2 CmpI nodes
|
|
// won't be guarded by the first CmpI anymore. It can trap in cases
|
|
// where the first CmpI would have prevented it from executing: on a
|
|
// trap, we need to restart execution at the state of the first CmpI
|
|
void IfNode::reroute_side_effect_free_unc(ProjNode* proj, ProjNode* dom_proj, PhaseIterGVN* igvn) {
|
|
CallStaticJavaNode* dom_unc = dom_proj->is_uncommon_trap_if_pattern(Deoptimization::Reason_none);
|
|
ProjNode* otherproj = proj->other_if_proj();
|
|
CallStaticJavaNode* unc = proj->is_uncommon_trap_if_pattern(Deoptimization::Reason_none);
|
|
Node* call_proj = dom_unc->unique_ctrl_out();
|
|
Node* halt = call_proj->unique_ctrl_out();
|
|
|
|
Node* new_unc = dom_unc->clone();
|
|
call_proj = call_proj->clone();
|
|
halt = halt->clone();
|
|
Node* c = otherproj->clone();
|
|
|
|
c = igvn->transform(c);
|
|
new_unc->set_req(TypeFunc::Parms, unc->in(TypeFunc::Parms));
|
|
new_unc->set_req(0, c);
|
|
new_unc = igvn->transform(new_unc);
|
|
call_proj->set_req(0, new_unc);
|
|
call_proj = igvn->transform(call_proj);
|
|
halt->set_req(0, call_proj);
|
|
halt = igvn->transform(halt);
|
|
|
|
igvn->replace_node(otherproj, igvn->C->top());
|
|
igvn->C->root()->add_req(halt);
|
|
}
|
|
|
|
Node* IfNode::fold_compares(PhaseIterGVN* igvn) {
|
|
if (Opcode() != Op_If) return NULL;
|
|
|
|
if (cmpi_folds(igvn)) {
|
|
Node* ctrl = in(0);
|
|
if (is_ctrl_folds(ctrl, igvn) &&
|
|
ctrl->outcnt() == 1) {
|
|
// A integer comparison immediately dominated by another integer
|
|
// comparison
|
|
ProjNode* success = NULL;
|
|
ProjNode* fail = NULL;
|
|
ProjNode* dom_cmp = ctrl->as_Proj();
|
|
if (has_shared_region(dom_cmp, success, fail) &&
|
|
// Next call modifies graph so must be last
|
|
fold_compares_helper(dom_cmp, success, fail, igvn)) {
|
|
return this;
|
|
}
|
|
if (has_only_uncommon_traps(dom_cmp, success, fail, igvn) &&
|
|
// Next call modifies graph so must be last
|
|
fold_compares_helper(dom_cmp, success, fail, igvn)) {
|
|
return merge_uncommon_traps(dom_cmp, success, fail, igvn);
|
|
}
|
|
return NULL;
|
|
} else if (ctrl->in(0) != NULL &&
|
|
ctrl->in(0)->in(0) != NULL) {
|
|
ProjNode* success = NULL;
|
|
ProjNode* fail = NULL;
|
|
Node* dom = ctrl->in(0)->in(0);
|
|
ProjNode* dom_cmp = dom->isa_Proj();
|
|
ProjNode* other_cmp = ctrl->isa_Proj();
|
|
|
|
// Check if it's an integer comparison dominated by another
|
|
// integer comparison with another test in between
|
|
if (is_ctrl_folds(dom, igvn) &&
|
|
has_only_uncommon_traps(dom_cmp, success, fail, igvn) &&
|
|
is_side_effect_free_test(other_cmp, igvn) &&
|
|
// Next call modifies graph so must be last
|
|
fold_compares_helper(dom_cmp, success, fail, igvn)) {
|
|
reroute_side_effect_free_unc(other_cmp, dom_cmp, igvn);
|
|
return merge_uncommon_traps(dom_cmp, success, fail, igvn);
|
|
}
|
|
}
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
//------------------------------remove_useless_bool----------------------------
|
|
// Check for people making a useless boolean: things like
|
|
// if( (x < y ? true : false) ) { ... }
|
|
// Replace with if( x < y ) { ... }
|
|
static Node *remove_useless_bool(IfNode *iff, PhaseGVN *phase) {
|
|
Node *i1 = iff->in(1);
|
|
if( !i1->is_Bool() ) return NULL;
|
|
BoolNode *bol = i1->as_Bool();
|
|
|
|
Node *cmp = bol->in(1);
|
|
if( cmp->Opcode() != Op_CmpI ) return NULL;
|
|
|
|
// Must be comparing against a bool
|
|
const Type *cmp2_t = phase->type( cmp->in(2) );
|
|
if( cmp2_t != TypeInt::ZERO &&
|
|
cmp2_t != TypeInt::ONE )
|
|
return NULL;
|
|
|
|
// Find a prior merge point merging the boolean
|
|
i1 = cmp->in(1);
|
|
if( !i1->is_Phi() ) return NULL;
|
|
PhiNode *phi = i1->as_Phi();
|
|
if( phase->type( phi ) != TypeInt::BOOL )
|
|
return NULL;
|
|
|
|
// Check for diamond pattern
|
|
int true_path = phi->is_diamond_phi();
|
|
if( true_path == 0 ) return NULL;
|
|
|
|
// Make sure that iff and the control of the phi are different. This
|
|
// should really only happen for dead control flow since it requires
|
|
// an illegal cycle.
|
|
if (phi->in(0)->in(1)->in(0) == iff) return NULL;
|
|
|
|
// phi->region->if_proj->ifnode->bool->cmp
|
|
BoolNode *bol2 = phi->in(0)->in(1)->in(0)->in(1)->as_Bool();
|
|
|
|
// Now get the 'sense' of the test correct so we can plug in
|
|
// either iff2->in(1) or its complement.
|
|
int flip = 0;
|
|
if( bol->_test._test == BoolTest::ne ) flip = 1-flip;
|
|
else if( bol->_test._test != BoolTest::eq ) return NULL;
|
|
if( cmp2_t == TypeInt::ZERO ) flip = 1-flip;
|
|
|
|
const Type *phi1_t = phase->type( phi->in(1) );
|
|
const Type *phi2_t = phase->type( phi->in(2) );
|
|
// Check for Phi(0,1) and flip
|
|
if( phi1_t == TypeInt::ZERO ) {
|
|
if( phi2_t != TypeInt::ONE ) return NULL;
|
|
flip = 1-flip;
|
|
} else {
|
|
// Check for Phi(1,0)
|
|
if( phi1_t != TypeInt::ONE ) return NULL;
|
|
if( phi2_t != TypeInt::ZERO ) return NULL;
|
|
}
|
|
if( true_path == 2 ) {
|
|
flip = 1-flip;
|
|
}
|
|
|
|
Node* new_bol = (flip ? phase->transform( bol2->negate(phase) ) : bol2);
|
|
assert(new_bol != iff->in(1), "must make progress");
|
|
iff->set_req(1, new_bol);
|
|
// Intervening diamond probably goes dead
|
|
phase->C->set_major_progress();
|
|
return iff;
|
|
}
|
|
|
|
static IfNode* idealize_test(PhaseGVN* phase, IfNode* iff);
|
|
|
|
struct RangeCheck {
|
|
Node* ctl;
|
|
jint off;
|
|
};
|
|
|
|
Node* IfNode::Ideal_common(PhaseGVN *phase, bool can_reshape) {
|
|
if (remove_dead_region(phase, can_reshape)) return this;
|
|
// No Def-Use info?
|
|
if (!can_reshape) return NULL;
|
|
|
|
// Don't bother trying to transform a dead if
|
|
if (in(0)->is_top()) return NULL;
|
|
// Don't bother trying to transform an if with a dead test
|
|
if (in(1)->is_top()) return NULL;
|
|
// Another variation of a dead test
|
|
if (in(1)->is_Con()) return NULL;
|
|
// Another variation of a dead if
|
|
if (outcnt() < 2) return NULL;
|
|
|
|
// Canonicalize the test.
|
|
Node* idt_if = idealize_test(phase, this);
|
|
if (idt_if != NULL) return idt_if;
|
|
|
|
// Try to split the IF
|
|
PhaseIterGVN *igvn = phase->is_IterGVN();
|
|
Node *s = split_if(this, igvn);
|
|
if (s != NULL) return s;
|
|
|
|
return NodeSentinel;
|
|
}
|
|
|
|
//------------------------------Ideal------------------------------------------
|
|
// Return a node which is more "ideal" than the current node. Strip out
|
|
// control copies
|
|
Node* IfNode::Ideal(PhaseGVN *phase, bool can_reshape) {
|
|
Node* res = Ideal_common(phase, can_reshape);
|
|
if (res != NodeSentinel) {
|
|
return res;
|
|
}
|
|
|
|
// Check for people making a useless boolean: things like
|
|
// if( (x < y ? true : false) ) { ... }
|
|
// Replace with if( x < y ) { ... }
|
|
Node *bol2 = remove_useless_bool(this, phase);
|
|
if( bol2 ) return bol2;
|
|
|
|
if (in(0) == NULL) return NULL; // Dead loop?
|
|
|
|
PhaseIterGVN *igvn = phase->is_IterGVN();
|
|
Node* result = fold_compares(igvn);
|
|
if (result != NULL) {
|
|
return result;
|
|
}
|
|
|
|
// Scan for an equivalent test
|
|
Node *cmp;
|
|
int dist = 0; // Cutoff limit for search
|
|
int op = Opcode();
|
|
if( op == Op_If &&
|
|
(cmp=in(1)->in(1))->Opcode() == Op_CmpP ) {
|
|
if( cmp->in(2) != NULL && // make sure cmp is not already dead
|
|
cmp->in(2)->bottom_type() == TypePtr::NULL_PTR ) {
|
|
dist = 64; // Limit for null-pointer scans
|
|
} else {
|
|
dist = 4; // Do not bother for random pointer tests
|
|
}
|
|
} else {
|
|
dist = 4; // Limit for random junky scans
|
|
}
|
|
|
|
Node* prev_dom = search_identical(dist);
|
|
|
|
if (prev_dom == NULL) {
|
|
return NULL;
|
|
}
|
|
|
|
// Replace dominated IfNode
|
|
return dominated_by(prev_dom, igvn);
|
|
}
|
|
|
|
//------------------------------dominated_by-----------------------------------
|
|
Node* IfNode::dominated_by(Node* prev_dom, PhaseIterGVN *igvn) {
|
|
#ifndef PRODUCT
|
|
if (TraceIterativeGVN) {
|
|
tty->print(" Removing IfNode: "); this->dump();
|
|
}
|
|
if (VerifyOpto && !igvn->allow_progress()) {
|
|
// Found an equivalent dominating test,
|
|
// we can not guarantee reaching a fix-point for these during iterativeGVN
|
|
// since intervening nodes may not change.
|
|
return NULL;
|
|
}
|
|
#endif
|
|
|
|
igvn->hash_delete(this); // Remove self to prevent spurious V-N
|
|
Node *idom = in(0);
|
|
// Need opcode to decide which way 'this' test goes
|
|
int prev_op = prev_dom->Opcode();
|
|
Node *top = igvn->C->top(); // Shortcut to top
|
|
|
|
// Loop predicates may have depending checks which should not
|
|
// be skipped. For example, range check predicate has two checks
|
|
// for lower and upper bounds.
|
|
ProjNode* unc_proj = proj_out(1 - prev_dom->as_Proj()->_con)->as_Proj();
|
|
if (unc_proj->is_uncommon_trap_proj(Deoptimization::Reason_predicate) != NULL ||
|
|
unc_proj->is_uncommon_trap_proj(Deoptimization::Reason_profile_predicate) != NULL) {
|
|
prev_dom = idom;
|
|
}
|
|
|
|
// Now walk the current IfNode's projections.
|
|
// Loop ends when 'this' has no more uses.
|
|
for (DUIterator_Last imin, i = last_outs(imin); i >= imin; --i) {
|
|
Node *ifp = last_out(i); // Get IfTrue/IfFalse
|
|
igvn->add_users_to_worklist(ifp);
|
|
// Check which projection it is and set target.
|
|
// Data-target is either the dominating projection of the same type
|
|
// or TOP if the dominating projection is of opposite type.
|
|
// Data-target will be used as the new control edge for the non-CFG
|
|
// nodes like Casts and Loads.
|
|
Node *data_target = (ifp->Opcode() == prev_op) ? prev_dom : top;
|
|
// Control-target is just the If's immediate dominator or TOP.
|
|
Node *ctrl_target = (ifp->Opcode() == prev_op) ? idom : top;
|
|
|
|
// For each child of an IfTrue/IfFalse projection, reroute.
|
|
// Loop ends when projection has no more uses.
|
|
for (DUIterator_Last jmin, j = ifp->last_outs(jmin); j >= jmin; --j) {
|
|
Node* s = ifp->last_out(j); // Get child of IfTrue/IfFalse
|
|
if( !s->depends_only_on_test() ) {
|
|
// Find the control input matching this def-use edge.
|
|
// For Regions it may not be in slot 0.
|
|
uint l;
|
|
for( l = 0; s->in(l) != ifp; l++ ) { }
|
|
igvn->replace_input_of(s, l, ctrl_target);
|
|
} else { // Else, for control producers,
|
|
igvn->replace_input_of(s, 0, data_target); // Move child to data-target
|
|
}
|
|
} // End for each child of a projection
|
|
|
|
igvn->remove_dead_node(ifp);
|
|
} // End for each IfTrue/IfFalse child of If
|
|
|
|
// Kill the IfNode
|
|
igvn->remove_dead_node(this);
|
|
|
|
// Must return either the original node (now dead) or a new node
|
|
// (Do not return a top here, since that would break the uniqueness of top.)
|
|
return new ConINode(TypeInt::ZERO);
|
|
}
|
|
|
|
Node* IfNode::search_identical(int dist) {
|
|
// Setup to scan up the CFG looking for a dominating test
|
|
Node* dom = in(0);
|
|
Node* prev_dom = this;
|
|
int op = Opcode();
|
|
// Search up the dominator tree for an If with an identical test
|
|
while (dom->Opcode() != op || // Not same opcode?
|
|
dom->in(1) != in(1) || // Not same input 1?
|
|
prev_dom->in(0) != dom) { // One path of test does not dominate?
|
|
if (dist < 0) return NULL;
|
|
|
|
dist--;
|
|
prev_dom = dom;
|
|
dom = up_one_dom(dom);
|
|
if (!dom) return NULL;
|
|
}
|
|
|
|
// Check that we did not follow a loop back to ourselves
|
|
if (this == dom) {
|
|
return NULL;
|
|
}
|
|
|
|
#ifndef PRODUCT
|
|
if (dist > 2) { // Add to count of NULL checks elided
|
|
explicit_null_checks_elided++;
|
|
}
|
|
#endif
|
|
|
|
return prev_dom;
|
|
}
|
|
|
|
//------------------------------Identity---------------------------------------
|
|
// If the test is constant & we match, then we are the input Control
|
|
Node* IfProjNode::Identity(PhaseGVN* phase) {
|
|
// Can only optimize if cannot go the other way
|
|
const TypeTuple *t = phase->type(in(0))->is_tuple();
|
|
if (t == TypeTuple::IFNEITHER || (always_taken(t) &&
|
|
// During parsing (GVN) we don't remove dead code aggressively.
|
|
// Cut off dead branch and let PhaseRemoveUseless take care of it.
|
|
(!phase->is_IterGVN() ||
|
|
// During IGVN, first wait for the dead branch to be killed.
|
|
// Otherwise, the IfNode's control will have two control uses (the IfNode
|
|
// that doesn't go away because it still has uses and this branch of the
|
|
// If) which breaks other optimizations. Node::has_special_unique_user()
|
|
// will cause this node to be reprocessed once the dead branch is killed.
|
|
in(0)->outcnt() == 1))) {
|
|
// IfNode control
|
|
return in(0)->in(0);
|
|
}
|
|
// no progress
|
|
return this;
|
|
}
|
|
|
|
#ifndef PRODUCT
|
|
//-------------------------------related---------------------------------------
|
|
// An IfProjNode's related node set consists of its input (an IfNode) including
|
|
// the IfNode's condition, plus all of its outputs at level 1. In compact mode,
|
|
// the restrictions for IfNode apply (see IfNode::rel).
|
|
void IfProjNode::related(GrowableArray<Node*> *in_rel, GrowableArray<Node*> *out_rel, bool compact) const {
|
|
Node* ifNode = this->in(0);
|
|
in_rel->append(ifNode);
|
|
if (compact) {
|
|
ifNode->collect_nodes(in_rel, 3, false, true);
|
|
} else {
|
|
ifNode->collect_nodes_in_all_data(in_rel, false);
|
|
}
|
|
this->collect_nodes(out_rel, -1, false, false);
|
|
}
|
|
|
|
//------------------------------dump_spec--------------------------------------
|
|
void IfNode::dump_spec(outputStream *st) const {
|
|
st->print("P=%f, C=%f",_prob,_fcnt);
|
|
}
|
|
|
|
//-------------------------------related---------------------------------------
|
|
// For an IfNode, the set of related output nodes is just the output nodes till
|
|
// depth 2, i.e, the IfTrue/IfFalse projection nodes plus the nodes they refer.
|
|
// The related input nodes contain no control nodes, but all data nodes
|
|
// pertaining to the condition. In compact mode, the input nodes are collected
|
|
// up to a depth of 3.
|
|
void IfNode::related(GrowableArray <Node *> *in_rel, GrowableArray <Node *> *out_rel, bool compact) const {
|
|
if (compact) {
|
|
this->collect_nodes(in_rel, 3, false, true);
|
|
} else {
|
|
this->collect_nodes_in_all_data(in_rel, false);
|
|
}
|
|
this->collect_nodes(out_rel, -2, false, false);
|
|
}
|
|
#endif
|
|
|
|
//------------------------------idealize_test----------------------------------
|
|
// Try to canonicalize tests better. Peek at the Cmp/Bool/If sequence and
|
|
// come up with a canonical sequence. Bools getting 'eq', 'gt' and 'ge' forms
|
|
// converted to 'ne', 'le' and 'lt' forms. IfTrue/IfFalse get swapped as
|
|
// needed.
|
|
static IfNode* idealize_test(PhaseGVN* phase, IfNode* iff) {
|
|
assert(iff->in(0) != NULL, "If must be live");
|
|
|
|
if (iff->outcnt() != 2) return NULL; // Malformed projections.
|
|
Node* old_if_f = iff->proj_out(false);
|
|
Node* old_if_t = iff->proj_out(true);
|
|
|
|
// CountedLoopEnds want the back-control test to be TRUE, irregardless of
|
|
// whether they are testing a 'gt' or 'lt' condition. The 'gt' condition
|
|
// happens in count-down loops
|
|
if (iff->is_CountedLoopEnd()) return NULL;
|
|
if (!iff->in(1)->is_Bool()) return NULL; // Happens for partially optimized IF tests
|
|
BoolNode *b = iff->in(1)->as_Bool();
|
|
BoolTest bt = b->_test;
|
|
// Test already in good order?
|
|
if( bt.is_canonical() )
|
|
return NULL;
|
|
|
|
// Flip test to be canonical. Requires flipping the IfFalse/IfTrue and
|
|
// cloning the IfNode.
|
|
Node* new_b = phase->transform( new BoolNode(b->in(1), bt.negate()) );
|
|
if( !new_b->is_Bool() ) return NULL;
|
|
b = new_b->as_Bool();
|
|
|
|
PhaseIterGVN *igvn = phase->is_IterGVN();
|
|
assert( igvn, "Test is not canonical in parser?" );
|
|
|
|
// The IF node never really changes, but it needs to be cloned
|
|
iff = iff->clone()->as_If();
|
|
iff->set_req(1, b);
|
|
iff->_prob = 1.0-iff->_prob;
|
|
|
|
Node *prior = igvn->hash_find_insert(iff);
|
|
if( prior ) {
|
|
igvn->remove_dead_node(iff);
|
|
iff = (IfNode*)prior;
|
|
} else {
|
|
// Cannot call transform on it just yet
|
|
igvn->set_type_bottom(iff);
|
|
}
|
|
igvn->_worklist.push(iff);
|
|
|
|
// Now handle projections. Cloning not required.
|
|
Node* new_if_f = (Node*)(new IfFalseNode( iff ));
|
|
Node* new_if_t = (Node*)(new IfTrueNode ( iff ));
|
|
|
|
igvn->register_new_node_with_optimizer(new_if_f);
|
|
igvn->register_new_node_with_optimizer(new_if_t);
|
|
// Flip test, so flip trailing control
|
|
igvn->replace_node(old_if_f, new_if_t);
|
|
igvn->replace_node(old_if_t, new_if_f);
|
|
|
|
// Progress
|
|
return iff;
|
|
}
|
|
|
|
Node* RangeCheckNode::Ideal(PhaseGVN *phase, bool can_reshape) {
|
|
Node* res = Ideal_common(phase, can_reshape);
|
|
if (res != NodeSentinel) {
|
|
return res;
|
|
}
|
|
|
|
PhaseIterGVN *igvn = phase->is_IterGVN();
|
|
// Setup to scan up the CFG looking for a dominating test
|
|
Node* prev_dom = this;
|
|
|
|
// Check for range-check vs other kinds of tests
|
|
Node* index1;
|
|
Node* range1;
|
|
jint offset1;
|
|
int flip1 = is_range_check(range1, index1, offset1);
|
|
if (flip1) {
|
|
Node* dom = in(0);
|
|
// Try to remove extra range checks. All 'up_one_dom' gives up at merges
|
|
// so all checks we inspect post-dominate the top-most check we find.
|
|
// If we are going to fail the current check and we reach the top check
|
|
// then we are guaranteed to fail, so just start interpreting there.
|
|
// We 'expand' the top 3 range checks to include all post-dominating
|
|
// checks.
|
|
|
|
// The top 3 range checks seen
|
|
const int NRC =3;
|
|
RangeCheck prev_checks[NRC];
|
|
int nb_checks = 0;
|
|
|
|
// Low and high offsets seen so far
|
|
jint off_lo = offset1;
|
|
jint off_hi = offset1;
|
|
|
|
bool found_immediate_dominator = false;
|
|
|
|
// Scan for the top checks and collect range of offsets
|
|
for (int dist = 0; dist < 999; dist++) { // Range-Check scan limit
|
|
if (dom->Opcode() == Op_RangeCheck && // Not same opcode?
|
|
prev_dom->in(0) == dom) { // One path of test does dominate?
|
|
if (dom == this) return NULL; // dead loop
|
|
// See if this is a range check
|
|
Node* index2;
|
|
Node* range2;
|
|
jint offset2;
|
|
int flip2 = dom->as_RangeCheck()->is_range_check(range2, index2, offset2);
|
|
// See if this is a _matching_ range check, checking against
|
|
// the same array bounds.
|
|
if (flip2 == flip1 && range2 == range1 && index2 == index1 &&
|
|
dom->outcnt() == 2) {
|
|
if (nb_checks == 0 && dom->in(1) == in(1)) {
|
|
// Found an immediately dominating test at the same offset.
|
|
// This kind of back-to-back test can be eliminated locally,
|
|
// and there is no need to search further for dominating tests.
|
|
assert(offset2 == offset1, "Same test but different offsets");
|
|
found_immediate_dominator = true;
|
|
break;
|
|
}
|
|
// Gather expanded bounds
|
|
off_lo = MIN2(off_lo,offset2);
|
|
off_hi = MAX2(off_hi,offset2);
|
|
// Record top NRC range checks
|
|
prev_checks[nb_checks%NRC].ctl = prev_dom;
|
|
prev_checks[nb_checks%NRC].off = offset2;
|
|
nb_checks++;
|
|
}
|
|
}
|
|
prev_dom = dom;
|
|
dom = up_one_dom(dom);
|
|
if (!dom) break;
|
|
}
|
|
|
|
if (!found_immediate_dominator) {
|
|
// Attempt to widen the dominating range check to cover some later
|
|
// ones. Since range checks "fail" by uncommon-trapping to the
|
|
// interpreter, widening a check can make us speculatively enter
|
|
// the interpreter. If we see range-check deopt's, do not widen!
|
|
if (!phase->C->allow_range_check_smearing()) return NULL;
|
|
|
|
// Didn't find prior covering check, so cannot remove anything.
|
|
if (nb_checks == 0) {
|
|
return NULL;
|
|
}
|
|
// Constant indices only need to check the upper bound.
|
|
// Non-constant indices must check both low and high.
|
|
int chk0 = (nb_checks - 1) % NRC;
|
|
if (index1) {
|
|
if (nb_checks == 1) {
|
|
return NULL;
|
|
} else {
|
|
// If the top range check's constant is the min or max of
|
|
// all constants we widen the next one to cover the whole
|
|
// range of constants.
|
|
RangeCheck rc0 = prev_checks[chk0];
|
|
int chk1 = (nb_checks - 2) % NRC;
|
|
RangeCheck rc1 = prev_checks[chk1];
|
|
if (rc0.off == off_lo) {
|
|
adjust_check(rc1.ctl, range1, index1, flip1, off_hi, igvn);
|
|
prev_dom = rc1.ctl;
|
|
} else if (rc0.off == off_hi) {
|
|
adjust_check(rc1.ctl, range1, index1, flip1, off_lo, igvn);
|
|
prev_dom = rc1.ctl;
|
|
} else {
|
|
// If the top test's constant is not the min or max of all
|
|
// constants, we need 3 range checks. We must leave the
|
|
// top test unchanged because widening it would allow the
|
|
// accesses it protects to successfully read/write out of
|
|
// bounds.
|
|
if (nb_checks == 2) {
|
|
return NULL;
|
|
}
|
|
int chk2 = (nb_checks - 3) % NRC;
|
|
RangeCheck rc2 = prev_checks[chk2];
|
|
// The top range check a+i covers interval: -a <= i < length-a
|
|
// The second range check b+i covers interval: -b <= i < length-b
|
|
if (rc1.off <= rc0.off) {
|
|
// if b <= a, we change the second range check to:
|
|
// -min_of_all_constants <= i < length-min_of_all_constants
|
|
// Together top and second range checks now cover:
|
|
// -min_of_all_constants <= i < length-a
|
|
// which is more restrictive than -b <= i < length-b:
|
|
// -b <= -min_of_all_constants <= i < length-a <= length-b
|
|
// The third check is then changed to:
|
|
// -max_of_all_constants <= i < length-max_of_all_constants
|
|
// so 2nd and 3rd checks restrict allowed values of i to:
|
|
// -min_of_all_constants <= i < length-max_of_all_constants
|
|
adjust_check(rc1.ctl, range1, index1, flip1, off_lo, igvn);
|
|
adjust_check(rc2.ctl, range1, index1, flip1, off_hi, igvn);
|
|
} else {
|
|
// if b > a, we change the second range check to:
|
|
// -max_of_all_constants <= i < length-max_of_all_constants
|
|
// Together top and second range checks now cover:
|
|
// -a <= i < length-max_of_all_constants
|
|
// which is more restrictive than -b <= i < length-b:
|
|
// -b < -a <= i < length-max_of_all_constants <= length-b
|
|
// The third check is then changed to:
|
|
// -max_of_all_constants <= i < length-max_of_all_constants
|
|
// so 2nd and 3rd checks restrict allowed values of i to:
|
|
// -min_of_all_constants <= i < length-max_of_all_constants
|
|
adjust_check(rc1.ctl, range1, index1, flip1, off_hi, igvn);
|
|
adjust_check(rc2.ctl, range1, index1, flip1, off_lo, igvn);
|
|
}
|
|
prev_dom = rc2.ctl;
|
|
}
|
|
}
|
|
} else {
|
|
RangeCheck rc0 = prev_checks[chk0];
|
|
// 'Widen' the offset of the 1st and only covering check
|
|
adjust_check(rc0.ctl, range1, index1, flip1, off_hi, igvn);
|
|
// Test is now covered by prior checks, dominate it out
|
|
prev_dom = rc0.ctl;
|
|
}
|
|
}
|
|
} else {
|
|
prev_dom = search_identical(4);
|
|
|
|
if (prev_dom == NULL) {
|
|
return NULL;
|
|
}
|
|
}
|
|
|
|
// Replace dominated IfNode
|
|
return dominated_by(prev_dom, igvn);
|
|
}
|