jdk8-mips64-public/hotspot: src/share/vm/c1/c1_RangeCheckElimination.cpp@2a9d97b57920 (annotated)

src/share/vm/c1/c1_RangeCheckElimination.cpp@2a9d97b57920 (annotated)

src/share/vm/c1/c1_RangeCheckElimination.cpp

Fri, 19 Apr 2013 03:13:04 -0400

author: bharadwaj
date: Fri, 19 Apr 2013 03:13:04 -0400
changeset 4954: 2a9d97b57920
parent 4869: d595e8ddadd9
child 4972: 6a3629cf7075
permissions: -rw-r--r--

Merge

 /*
  * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  *
  */
 #include "precompiled.hpp"
 #include "c1/c1_ValueStack.hpp"
 #include "c1/c1_RangeCheckElimination.hpp"
 #include "c1/c1_IR.hpp"
 #include "c1/c1_Canonicalizer.hpp"
 #include "c1/c1_ValueMap.hpp"
 #include "ci/ciMethodData.hpp"
 #include "runtime/deoptimization.hpp"
 // Macros for the Trace and the Assertion flag
 #ifdef ASSERT
 #define TRACE_RANGE_CHECK_ELIMINATION(code) if (TraceRangeCheckElimination) { code; }
 #define ASSERT_RANGE_CHECK_ELIMINATION(code) if (AssertRangeCheckElimination) { code; }
 #define TRACE_OR_ASSERT_RANGE_CHECK_ELIMINATION(code) if (TraceRangeCheckElimination || AssertRangeCheckElimination) { code; }
 #else
 #define TRACE_RANGE_CHECK_ELIMINATION(code)
 #define ASSERT_RANGE_CHECK_ELIMINATION(code)
 #define TRACE_OR_ASSERT_RANGE_CHECK_ELIMINATION(code)
 #endif
 // Entry point for the optimization
 void RangeCheckElimination::eliminate(IR *ir) {
   bool do_elimination = ir->compilation()->has_access_indexed();
   ASSERT_RANGE_CHECK_ELIMINATION(do_elimination = true);
   if (do_elimination) {
     RangeCheckEliminator rce(ir);
   }
 }
 // Constructor
 RangeCheckEliminator::RangeCheckEliminator(IR *ir) :
   _bounds(Instruction::number_of_instructions(), NULL),
   _access_indexed_info(Instruction::number_of_instructions(), NULL)
 {
   _visitor.set_range_check_eliminator(this);
   _ir = ir;
   _number_of_instructions = Instruction::number_of_instructions();
   _optimistic = ir->compilation()->is_optimistic();
   TRACE_RANGE_CHECK_ELIMINATION(
     tty->print_cr("");
     tty->print_cr("Range check elimination");
     ir->method()->print_name(tty);
     tty->print_cr("");
   );
   TRACE_RANGE_CHECK_ELIMINATION(
     tty->print_cr("optimistic=%d", (int)_optimistic);
   );
 #ifdef ASSERT
   // Verifies several conditions that must be true on the IR-input. Only used for debugging purposes.
   TRACE_RANGE_CHECK_ELIMINATION(
     tty->print_cr("Verification of IR . . .");
   );
   Verification verification(ir);
 #endif
   // Set process block flags
   // Optimization so a blocks is only processed if it contains an access indexed instruction or if
   // one of its children in the dominator tree contains an access indexed instruction.
   set_process_block_flags(ir->start());
   // Pass over instructions in the dominator tree
   TRACE_RANGE_CHECK_ELIMINATION(
     tty->print_cr("Starting pass over dominator tree . . .")
   );
   calc_bounds(ir->start(), NULL);
   TRACE_RANGE_CHECK_ELIMINATION(
     tty->print_cr("Finished!")
   );
 }
 // Instruction specific work for some instructions
 // Constant
 void RangeCheckEliminator::Visitor::do_Constant(Constant *c) {
   IntConstant *ic = c->type()->as_IntConstant();
   if (ic != NULL) {
     int value = ic->value();
     _bound = new Bound(value, NULL, value, NULL);
   }
 }
 // LogicOp
 void RangeCheckEliminator::Visitor::do_LogicOp(LogicOp *lo) {
   if (lo->type()->as_IntType() && lo->op() == Bytecodes::_iand && (lo->x()->as_Constant() || lo->y()->as_Constant())) {
     int constant = 0;
     Constant *c = lo->x()->as_Constant();
     if (c != NULL) {
       constant = c->type()->as_IntConstant()->value();
     } else {
       constant = lo->y()->as_Constant()->type()->as_IntConstant()->value();
     }
     if (constant >= 0) {
       _bound = new Bound(0, NULL, constant, NULL);
     }
   }
 }
 // Phi
 void RangeCheckEliminator::Visitor::do_Phi(Phi *phi) {
   if (!phi->type()->as_IntType() && !phi->type()->as_ObjectType()) return;
   BlockBegin *block = phi->block();
   int op_count = phi->operand_count();
   bool has_upper = true;
   bool has_lower = true;
   assert(phi, "Phi must not be null");
   Bound *bound = NULL;
   // TODO: support more difficult phis
   for (int i=0; i<op_count; i++) {
     Value v = phi->operand_at(i);
     if (v == phi) continue;
     // Check if instruction is connected with phi itself
     Op2 *op2 = v->as_Op2();
     if (op2 != NULL) {
       Value x = op2->x();
       Value y = op2->y();
       if ((x == phi || y == phi)) {
         Value other = x;
         if (other == phi) {
           other = y;
         }
         ArithmeticOp *ao = v->as_ArithmeticOp();
         if (ao != NULL && ao->op() == Bytecodes::_iadd) {
           assert(ao->op() == Bytecodes::_iadd, "Has to be add!");
           if (ao->type()->as_IntType()) {
             Constant *c = other->as_Constant();
             if (c != NULL) {
               assert(c->type()->as_IntConstant(), "Constant has to be of type integer");
               int value = c->type()->as_IntConstant()->value();
               if (value == 1) {
                 has_upper = false;
               } else if (value > 1) {
                 // Overflow not guaranteed
                 has_upper = false;
                 has_lower = false;
               } else if (value < 0) {
                 has_lower = false;
               }
               continue;
             }
           }
         }
       }
     }
     // No connection -> new bound
     Bound *v_bound = _rce->get_bound(v);
     Bound *cur_bound;
     int cur_constant = 0;
     Value cur_value = v;
     if (v->type()->as_IntConstant()) {
       cur_constant = v->type()->as_IntConstant()->value();
       cur_value = NULL;
     }
     if (!v_bound->has_upper() || !v_bound->has_lower()) {
       cur_bound = new Bound(cur_constant, cur_value, cur_constant, cur_value);
     } else {
       cur_bound = v_bound;
     }
     if (cur_bound) {
       if (!bound) {
         bound = cur_bound->copy();
       } else {
         bound->or_op(cur_bound);
       }
     } else {
       // No bound!
       bound = NULL;
       break;
     }
   }
   if (bound) {
     if (!has_upper) {
       bound->remove_upper();
     }
     if (!has_lower) {
       bound->remove_lower();
     }
     _bound = bound;
   } else {
     _bound = new Bound();
   }
 }
 // ArithmeticOp
 void RangeCheckEliminator::Visitor::do_ArithmeticOp(ArithmeticOp *ao) {
   Value x = ao->x();
   Value y = ao->y();
   if (ao->op() == Bytecodes::_irem) {
     Bound* x_bound = _rce->get_bound(x);
     Bound* y_bound = _rce->get_bound(y);
     if (x_bound->lower() >= 0 && x_bound->lower_instr() == NULL && y->as_ArrayLength() != NULL) {
       _bound = new Bound(0, NULL, -1, y);
     } else {
       _bound = new Bound();
     }
   } else if (!x->as_Constant() || !y->as_Constant()) {
     assert(!x->as_Constant() || !y->as_Constant(), "One of the operands must be non-constant!");
     if (((x->as_Constant() || y->as_Constant()) && (ao->op() == Bytecodes::_iadd)) || (y->as_Constant() && ao->op() == Bytecodes::_isub)) {
       assert(ao->op() == Bytecodes::_iadd || ao->op() == Bytecodes::_isub, "Operand must be iadd or isub");
       if (y->as_Constant()) {
         Value tmp = x;
         x = y;
         y = tmp;
       }
       assert(x->as_Constant()->type()->as_IntConstant(), "Constant must be int constant!");
       // Constant now in x
       int const_value = x->as_Constant()->type()->as_IntConstant()->value();
       if (ao->op() == Bytecodes::_iadd || const_value != min_jint) {
         if (ao->op() == Bytecodes::_isub) {
           const_value = -const_value;
         }
         Bound * bound = _rce->get_bound(y);
         if (bound->has_upper() && bound->has_lower()) {
           int new_lower = bound->lower() + const_value;
           jlong new_lowerl = ((jlong)bound->lower()) + const_value;
           int new_upper = bound->upper() + const_value;
           jlong new_upperl = ((jlong)bound->upper()) + const_value;
           if (((jlong)new_lower) == new_lowerl && ((jlong)new_upper == new_upperl)) {
             Bound *newBound = new Bound(new_lower, bound->lower_instr(), new_upper, bound->upper_instr());
             _bound = newBound;
           } else {
             // overflow
             _bound = new Bound();
           }
         } else {
           _bound = new Bound();
         }
       } else {
         _bound = new Bound();
       }
     } else {
       Bound *bound = _rce->get_bound(x);
       if (ao->op() == Bytecodes::_isub) {
         if (bound->lower_instr() == y) {
           _bound = new Bound(Instruction::geq, NULL, bound->lower());
         } else {
           _bound = new Bound();
         }
       } else {
         _bound = new Bound();
       }
     }
   }
 }
 // IfOp
 void RangeCheckEliminator::Visitor::do_IfOp(IfOp *ifOp)
 {
   if (ifOp->tval()->type()->as_IntConstant() && ifOp->fval()->type()->as_IntConstant()) {
     int min = ifOp->tval()->type()->as_IntConstant()->value();
     int max = ifOp->fval()->type()->as_IntConstant()->value();
     if (min > max) {
       // min ^= max ^= min ^= max;
       int tmp = min;
       min = max;
       max = tmp;
     }
     _bound = new Bound(min, NULL, max, NULL);
   }
 }
 // Get bound. Returns the current bound on Value v. Normally this is the topmost element on the bound stack.
 RangeCheckEliminator::Bound *RangeCheckEliminator::get_bound(Value v) {
   // Wrong type or NULL -> No bound
   if (!v || (!v->type()->as_IntType() && !v->type()->as_ObjectType())) return NULL;
   if (!_bounds[v->id()]) {
     // First (default) bound is calculated
     // Create BoundStack
     _bounds[v->id()] = new BoundStack();
     _visitor.clear_bound();
     Value visit_value = v;
     visit_value->visit(&_visitor);
     Bound *bound = _visitor.bound();
     if (bound) {
       _bounds[v->id()]->push(bound);
     }
     if (_bounds[v->id()]->length() == 0) {
       assert(!(v->as_Constant() && v->type()->as_IntConstant()), "constants not handled here");
       _bounds[v->id()]->push(new Bound());
     }
   } else if (_bounds[v->id()]->length() == 0) {
     // To avoid endless loops, bound is currently in calculation -> nothing known about it
     return new Bound();
   }
   // Return bound
   return _bounds[v->id()]->top();
 }
 // Update bound
 void RangeCheckEliminator::update_bound(IntegerStack &pushed, Value v, Instruction::Condition cond, Value value, int constant) {
   if (cond == Instruction::gtr) {
     cond = Instruction::geq;
     constant++;
   } else if (cond == Instruction::lss) {
     cond = Instruction::leq;
     constant--;
   }
   Bound *bound = new Bound(cond, value, constant);
   update_bound(pushed, v, bound);
 }
 // Checks for loop invariance. Returns true if the instruction is outside of the loop which is identified by loop_header.
 bool RangeCheckEliminator::loop_invariant(BlockBegin *loop_header, Instruction *instruction) {
   assert(loop_header, "Loop header must not be null!");
   if (!instruction) return true;
   return instruction->dominator_depth() < loop_header->dominator_depth();
 }
 // Update bound. Pushes a new bound onto the stack. Tries to do a conjunction with the current bound.
 void RangeCheckEliminator::update_bound(IntegerStack &pushed, Value v, Bound *bound) {
   if (v->as_Constant()) {
     // No bound update for constants
     return;
   }
   if (!_bounds[v->id()]) {
     get_bound(v);
     assert(_bounds[v->id()], "Now Stack must exist");
   }
   Bound *top = NULL;
   if (_bounds[v->id()]->length() > 0) {
     top = _bounds[v->id()]->top();
   }
   if (top) {
     bound->and_op(top);
   }
   _bounds[v->id()]->push(bound);
   pushed.append(v->id());
 }
 // Add instruction + idx for in block motion
 void RangeCheckEliminator::add_access_indexed_info(InstructionList &indices, int idx, Value instruction, AccessIndexed *ai) {
   int id = instruction->id();
   AccessIndexedInfo *aii = _access_indexed_info[id];
   if (aii == NULL) {
     aii = new AccessIndexedInfo();
     _access_indexed_info[id] = aii;
     indices.append(instruction);
     aii->_min = idx;
     aii->_max = idx;
     aii->_list = new AccessIndexedList();
   } else if (idx >= aii->_min && idx <= aii->_max) {
     remove_range_check(ai);
     return;
   }
   aii->_min = MIN2(aii->_min, idx);
   aii->_max = MAX2(aii->_max, idx);
   aii->_list->append(ai);
 }
 // In block motion. Tries to reorder checks in order to reduce some of them.
 // Example:
 // a[i] = 0;
 // a[i+2] = 0;
 // a[i+1] = 0;
 // In this example the check for a[i+1] would be considered as unnecessary during the first iteration.
 // After this i is only checked once for i >= 0 and i+2 < a.length before the first array access. If this
 // check fails, deoptimization is called.
 void RangeCheckEliminator::in_block_motion(BlockBegin *block, AccessIndexedList &accessIndexed, InstructionList &arrays) {
   InstructionList indices;
   // Now iterate over all arrays
   for (int i=0; i<arrays.length(); i++) {
     int max_constant = -1;
     AccessIndexedList list_constant;
     Value array = arrays.at(i);
     // For all AccessIndexed-instructions in this block concerning the current array.
     for(int j=0; j<accessIndexed.length(); j++) {
       AccessIndexed *ai = accessIndexed.at(j);
       if (ai->array() != array || !ai->check_flag(Instruction::NeedsRangeCheckFlag)) continue;
       Value index = ai->index();
       Constant *c = index->as_Constant();
       if (c != NULL) {
         int constant_value = c->type()->as_IntConstant()->value();
         if (constant_value >= 0) {
           if (constant_value <= max_constant) {
             // No range check needed for this
             remove_range_check(ai);
           } else {
             max_constant = constant_value;
             list_constant.append(ai);
           }
         }
       } else {
         int last_integer = 0;
         Instruction *last_instruction = index;
         int base = 0;
         ArithmeticOp *ao = index->as_ArithmeticOp();
         while (ao != NULL && (ao->x()->as_Constant() || ao->y()->as_Constant()) && (ao->op() == Bytecodes::_iadd || ao->op() == Bytecodes::_isub)) {
           c = ao->y()->as_Constant();
           Instruction *other = ao->x();
           if (!c && ao->op() == Bytecodes::_iadd) {
             c = ao->x()->as_Constant();
             other = ao->y();
           }
           if (c) {
             int value = c->type()->as_IntConstant()->value();
             if (value != min_jint) {
               if (ao->op() == Bytecodes::_isub) {
                 value = -value;
               }
               base += value;
               last_integer = base;
               last_instruction = other;
             }
             index = other;
           } else {
             break;
           }
           ao = index->as_ArithmeticOp();
         }
         add_access_indexed_info(indices, last_integer, last_instruction, ai);
       }
     }
     // Iterate over all different indices
     if (_optimistic) {
       for (int i=0; i<indices.length(); i++) {
         Instruction *index_instruction = indices.at(i);
         AccessIndexedInfo *info = _access_indexed_info[index_instruction->id()];
         assert(info != NULL, "Info must not be null");
         // if idx < 0, max > 0, max + idx may fall between 0 and
         // length-1 and if min < 0, min + idx may overflow and be >=
         // 0. The predicate wouldn't trigger but some accesses could
         // be with a negative index. This test guarantees that for the
         // min and max value that are kept the predicate can't let
         // some incorrect accesses happen.
         bool range_cond = (info->_max < 0 || info->_max + min_jint <= info->_min);
         // Generate code only if more than 2 range checks can be eliminated because of that.
         // 2 because at least 2 comparisons are done
         if (info->_list->length() > 2 && range_cond) {
           AccessIndexed *first = info->_list->at(0);
           Instruction *insert_position = first->prev();
           assert(insert_position->next() == first, "prev was calculated");
           ValueStack *state = first->state_before();
           // Load min Constant
           Constant *min_constant = NULL;
           if (info->_min != 0) {
             min_constant = new Constant(new IntConstant(info->_min));
             NOT_PRODUCT(min_constant->set_printable_bci(first->printable_bci()));
             insert_position = insert_position->insert_after(min_constant);
           }
           // Load max Constant
           Constant *max_constant = NULL;
           if (info->_max != 0) {
             max_constant = new Constant(new IntConstant(info->_max));
             NOT_PRODUCT(max_constant->set_printable_bci(first->printable_bci()));
             insert_position = insert_position->insert_after(max_constant);
           }
           // Load array length
           Value length_instr = first->length();
           if (!length_instr) {
             ArrayLength *length = new ArrayLength(array, first->state_before()->copy());
             length->set_exception_state(length->state_before());
             length->set_flag(Instruction::DeoptimizeOnException, true);
             insert_position = insert_position->insert_after_same_bci(length);
             length_instr = length;
           }
           // Calculate lower bound
           Instruction *lower_compare = index_instruction;
           if (min_constant) {
             ArithmeticOp *ao = new ArithmeticOp(Bytecodes::_iadd, min_constant, lower_compare, false, NULL);
             insert_position = insert_position->insert_after_same_bci(ao);
             lower_compare = ao;
           }
           // Calculate upper bound
           Instruction *upper_compare = index_instruction;
           if (max_constant) {
             ArithmeticOp *ao = new ArithmeticOp(Bytecodes::_iadd, max_constant, upper_compare, false, NULL);
             insert_position = insert_position->insert_after_same_bci(ao);
             upper_compare = ao;
           }
           // Trick with unsigned compare is done
           int bci = NOT_PRODUCT(first->printable_bci()) PRODUCT_ONLY(-1);
           insert_position = predicate(upper_compare, Instruction::aeq, length_instr, state, insert_position, bci);
           insert_position = predicate_cmp_with_const(lower_compare, Instruction::leq, -1, state, insert_position);
           for (int j = 0; j<info->_list->length(); j++) {
             AccessIndexed *ai = info->_list->at(j);
             remove_range_check(ai);
           }
         }
         _access_indexed_info[index_instruction->id()] = NULL;
       }
       indices.clear();
       if (list_constant.length() > 1) {
         AccessIndexed *first = list_constant.at(0);
         Instruction *insert_position = first->prev();
         ValueStack *state = first->state_before();
         // Load max Constant
         Constant *constant = new Constant(new IntConstant(max_constant));
         NOT_PRODUCT(constant->set_printable_bci(first->printable_bci()));
         insert_position = insert_position->insert_after(constant);
         Instruction *compare_instr = constant;
         Value length_instr = first->length();
         if (!length_instr) {
           ArrayLength *length = new ArrayLength(array, state->copy());
           length->set_exception_state(length->state_before());
           length->set_flag(Instruction::DeoptimizeOnException, true);
           insert_position = insert_position->insert_after_same_bci(length);
           length_instr = length;
         }
         // Compare for greater or equal to array length
         insert_position = predicate(compare_instr, Instruction::geq, length_instr, state, insert_position);
         for (int j = 0; j<list_constant.length(); j++) {
           AccessIndexed *ai = list_constant.at(j);
           remove_range_check(ai);
         }
       }
     }
   }
 }
 bool RangeCheckEliminator::set_process_block_flags(BlockBegin *block) {
   Instruction *cur = block;
   bool process = false;
   while (cur) {
     process |= (cur->as_AccessIndexed() != NULL);
     cur = cur->next();
   }
   BlockList *dominates = block->dominates();
   for (int i=0; i<dominates->length(); i++) {
     BlockBegin *next = dominates->at(i);
     process |= set_process_block_flags(next);
   }
   if (!process) {
     block->set(BlockBegin::donot_eliminate_range_checks);
   }
   return process;
 }
 bool RangeCheckEliminator::is_ok_for_deoptimization(Instruction *insert_position, Instruction *array_instr, Instruction *length_instr, Instruction *lower_instr, int lower, Instruction *upper_instr, int upper) {
   bool upper_check = true;
   assert(lower_instr || lower >= 0, "If no lower_instr present, lower must be greater 0");
   assert(!lower_instr || lower_instr->dominator_depth() <= insert_position->dominator_depth(), "Dominator depth must be smaller");
   assert(!upper_instr || upper_instr->dominator_depth() <= insert_position->dominator_depth(), "Dominator depth must be smaller");
   assert(array_instr, "Array instruction must exist");
   assert(array_instr->dominator_depth() <= insert_position->dominator_depth(), "Dominator depth must be smaller");
   assert(!length_instr || length_instr->dominator_depth() <= insert_position->dominator_depth(), "Dominator depth must be smaller");
   if (upper_instr && upper_instr->as_ArrayLength() && upper_instr->as_ArrayLength()->array() == array_instr) {
     // static check
     if (upper >= 0) return false; // would always trigger a deopt:
                                   // array_length + x >= array_length, x >= 0 is always true
     upper_check = false;
   }
   if (lower_instr && lower_instr->as_ArrayLength() && lower_instr->as_ArrayLength()->array() == array_instr) {
     if (lower > 0) return false;
   }
   // No upper check required -> skip
   if (upper_check && upper_instr && upper_instr->type()->as_ObjectType() && upper_instr == array_instr) {
     // upper_instr is object means that the upper bound is the length
     // of the upper_instr.
     return false;
   }
   return true;
 }
 Instruction* RangeCheckEliminator::insert_after(Instruction* insert_position, Instruction* instr, int bci) {
   if (bci != -1) {
     NOT_PRODUCT(instr->set_printable_bci(bci));
     return insert_position->insert_after(instr);
   } else {
     return insert_position->insert_after_same_bci(instr);
   }
 }
 Instruction* RangeCheckEliminator::predicate(Instruction* left, Instruction::Condition cond, Instruction* right, ValueStack* state, Instruction *insert_position, int bci) {
   RangeCheckPredicate *deoptimize = new RangeCheckPredicate(left, cond, true, right, state->copy());
   return insert_after(insert_position, deoptimize, bci);
 }
 Instruction* RangeCheckEliminator::predicate_cmp_with_const(Instruction* instr, Instruction::Condition cond, int constant, ValueStack* state, Instruction *insert_position, int bci) {
   Constant *const_instr = new Constant(new IntConstant(constant));
   insert_position = insert_after(insert_position, const_instr, bci);
   return predicate(instr, cond, const_instr, state, insert_position);
 }
 Instruction* RangeCheckEliminator::predicate_add(Instruction* left, int left_const, Instruction::Condition cond, Instruction* right, ValueStack* state, Instruction *insert_position, int bci) {
   Constant *constant = new Constant(new IntConstant(left_const));
   insert_position = insert_after(insert_position, constant, bci);
   ArithmeticOp *ao = new ArithmeticOp(Bytecodes::_iadd, constant, left, false, NULL);
   insert_position = insert_position->insert_after_same_bci(ao);
   return predicate(ao, cond, right, state, insert_position);
 }
 Instruction* RangeCheckEliminator::predicate_add_cmp_with_const(Instruction* left, int left_const, Instruction::Condition cond, int constant, ValueStack* state, Instruction *insert_position, int bci) {
   Constant *const_instr = new Constant(new IntConstant(constant));
   insert_position = insert_after(insert_position, const_instr, bci);
   return predicate_add(left, left_const, cond, const_instr, state, insert_position);
 }
 // Insert deoptimization
 void RangeCheckEliminator::insert_deoptimization(ValueStack *state, Instruction *insert_position, Instruction *array_instr, Instruction *length_instr, Instruction *lower_instr, int lower, Instruction *upper_instr, int upper, AccessIndexed *ai) {
   assert(is_ok_for_deoptimization(insert_position, array_instr, length_instr, lower_instr, lower, upper_instr, upper), "should have been tested before");
   bool upper_check = !(upper_instr && upper_instr->as_ArrayLength() && upper_instr->as_ArrayLength()->array() == array_instr);
   int bci = NOT_PRODUCT(ai->printable_bci()) PRODUCT_ONLY(-1);
   if (lower_instr) {
     assert(!lower_instr->type()->as_ObjectType(), "Must not be object type");
     if (lower == 0) {
       // Compare for less than 0
       insert_position = predicate_cmp_with_const(lower_instr, Instruction::lss, 0, state, insert_position, bci);
     } else if (lower > 0) {
       // Compare for smaller 0
       insert_position = predicate_add_cmp_with_const(lower_instr, lower, Instruction::lss, 0, state, insert_position, bci);
     } else {
       assert(lower < 0, "");
       // Add 1
       lower++;
       lower = -lower;
       // Compare for smaller or equal 0
       insert_position = predicate_cmp_with_const(lower_instr, Instruction::leq, lower, state, insert_position, bci);
     }
   }
   // No upper check required -> skip
   if (!upper_check) return;
   // We need to know length of array
   if (!length_instr) {
     // Load length if necessary
     ArrayLength *length = new ArrayLength(array_instr, state->copy());
     NOT_PRODUCT(length->set_printable_bci(ai->printable_bci()));
     length->set_exception_state(length->state_before());
     length->set_flag(Instruction::DeoptimizeOnException, true);
     insert_position = insert_position->insert_after(length);
     length_instr = length;
   }
   if (!upper_instr) {
     // Compare for geq array.length
     insert_position = predicate_cmp_with_const(length_instr, Instruction::leq, upper, state, insert_position, bci);
   } else {
     if (upper_instr->type()->as_ObjectType()) {
       assert(state, "must not be null");
       assert(upper_instr != array_instr, "should be");
       ArrayLength *length = new ArrayLength(upper_instr, state->copy());
       NOT_PRODUCT(length->set_printable_bci(ai->printable_bci()));
       length->set_flag(Instruction::DeoptimizeOnException, true);
       length->set_exception_state(length->state_before());
       insert_position = insert_position->insert_after(length);
       upper_instr = length;
     }
     assert(upper_instr->type()->as_IntType(), "Must not be object type!");
     if (upper == 0) {
       // Compare for geq array.length
       insert_position = predicate(upper_instr, Instruction::geq, length_instr, state, insert_position, bci);
     } else if (upper < 0) {
       // Compare for geq array.length
       insert_position = predicate_add(upper_instr, upper, Instruction::geq, length_instr, state, insert_position, bci);
     } else {
       assert(upper > 0, "");
       upper = -upper;
       // Compare for geq array.length
       insert_position = predicate_add(length_instr, upper, Instruction::leq, upper_instr, state, insert_position, bci);
     }
   }
 }
 // Add if condition
 void RangeCheckEliminator::add_if_condition(IntegerStack &pushed, Value x, Value y, Instruction::Condition condition) {
   if (y->as_Constant()) return;
   int const_value = 0;
   Value instr_value = x;
   Constant *c = x->as_Constant();
   ArithmeticOp *ao = x->as_ArithmeticOp();
   if (c != NULL) {
     const_value = c->type()->as_IntConstant()->value();
     instr_value = NULL;
   } else if (ao != NULL &&  (!ao->x()->as_Constant() || !ao->y()->as_Constant()) && ((ao->op() == Bytecodes::_isub && ao->y()->as_Constant()) || ao->op() == Bytecodes::_iadd)) {
     assert(!ao->x()->as_Constant() || !ao->y()->as_Constant(), "At least one operator must be non-constant!");
     assert(ao->op() == Bytecodes::_isub || ao->op() == Bytecodes::_iadd, "Operation has to be add or sub!");
     c = ao->x()->as_Constant();
     if (c != NULL) {
       const_value = c->type()->as_IntConstant()->value();
       instr_value = ao->y();
     } else {
       c = ao->y()->as_Constant();
       if (c != NULL) {
         const_value = c->type()->as_IntConstant()->value();
         instr_value = ao->x();
       }
     }
     if (ao->op() == Bytecodes::_isub) {
       assert(ao->y()->as_Constant(), "1 - x not supported, only x - 1 is valid!");
       if (const_value > min_jint) {
         const_value = -const_value;
       } else {
         const_value = 0;
         instr_value = x;
       }
     }
   }
   update_bound(pushed, y, condition, instr_value, const_value);
 }
 // Process If
 void RangeCheckEliminator::process_if(IntegerStack &pushed, BlockBegin *block, If *cond) {
   // Only if we are direct true / false successor and NOT both ! (even this may occur)
   if ((cond->tsux() == block || cond->fsux() == block) && cond->tsux() != cond->fsux()) {
     Instruction::Condition condition = cond->cond();
     if (cond->fsux() == block) {
       condition = Instruction::negate(condition);
     }
     Value x = cond->x();
     Value y = cond->y();
     if (x->type()->as_IntType() && y->type()->as_IntType()) {
       add_if_condition(pushed, y, x, condition);
       add_if_condition(pushed, x, y, Instruction::mirror(condition));
     }
   }
 }
 // Process access indexed
 void RangeCheckEliminator::process_access_indexed(BlockBegin *loop_header, BlockBegin *block, AccessIndexed *ai) {
   TRACE_RANGE_CHECK_ELIMINATION(
     tty->fill_to(block->dominator_depth()*2)
   );
   TRACE_RANGE_CHECK_ELIMINATION(
     tty->print_cr("Access indexed: index=%d length=%d", ai->index()->id(), (ai->length() != NULL ? ai->length()->id() :-1 ))
   );
   if (ai->check_flag(Instruction::NeedsRangeCheckFlag)) {
     Bound *index_bound = get_bound(ai->index());
     if (!index_bound->has_lower() || !index_bound->has_upper()) {
       TRACE_RANGE_CHECK_ELIMINATION(
         tty->fill_to(block->dominator_depth()*2);
         tty->print_cr("Index instruction %d has no lower and/or no upper bound!", ai->index()->id())
       );
       return;
     }
     Bound *array_bound;
     if (ai->length()) {
       array_bound = get_bound(ai->length());
     } else {
       array_bound = get_bound(ai->array());
     }
     if (in_array_bound(index_bound, ai->array()) ||
       (index_bound && array_bound && index_bound->is_smaller(array_bound) && !index_bound->lower_instr() && index_bound->lower() >= 0)) {
         TRACE_RANGE_CHECK_ELIMINATION(
           tty->fill_to(block->dominator_depth()*2);
           tty->print_cr("Bounds check for instruction %d in block B%d can be fully eliminated!", ai->id(), ai->block()->block_id())
         );
         remove_range_check(ai);
     } else if (_optimistic && loop_header) {
       assert(ai->array(), "Array must not be null!");
       assert(ai->index(), "Index must not be null!");
       // Array instruction
       Instruction *array_instr = ai->array();
       if (!loop_invariant(loop_header, array_instr)) {
         TRACE_RANGE_CHECK_ELIMINATION(
           tty->fill_to(block->dominator_depth()*2);
           tty->print_cr("Array %d is not loop invariant to header B%d", ai->array()->id(), loop_header->block_id())
         );
         return;
       }
       // Lower instruction
       Value index_instr = ai->index();
       Value lower_instr = index_bound->lower_instr();
       if (!loop_invariant(loop_header, lower_instr)) {
         TRACE_RANGE_CHECK_ELIMINATION(
           tty->fill_to(block->dominator_depth()*2);
           tty->print_cr("Lower instruction %d not loop invariant!", lower_instr->id())
         );
         return;
       }
       if (!lower_instr && index_bound->lower() < 0) {
         TRACE_RANGE_CHECK_ELIMINATION(
           tty->fill_to(block->dominator_depth()*2);
           tty->print_cr("Lower bound smaller than 0 (%d)!", index_bound->lower())
         );
         return;
       }
       // Upper instruction
       Value upper_instr = index_bound->upper_instr();
       if (!loop_invariant(loop_header, upper_instr)) {
         TRACE_RANGE_CHECK_ELIMINATION(
           tty->fill_to(block->dominator_depth()*2);
           tty->print_cr("Upper instruction %d not loop invariant!", upper_instr->id())
         );
         return;
       }
       // Length instruction
       Value length_instr = ai->length();
       if (!loop_invariant(loop_header, length_instr)) {
         // Generate length instruction yourself!
         length_instr = NULL;
       }
       TRACE_RANGE_CHECK_ELIMINATION(
         tty->fill_to(block->dominator_depth()*2);
         tty->print_cr("LOOP INVARIANT access indexed %d found in block B%d!", ai->id(), ai->block()->block_id())
       );
       BlockBegin *pred_block = loop_header->dominator();
       assert(pred_block != NULL, "Every loop header has a dominator!");
       BlockEnd *pred_block_end = pred_block->end();
       Instruction *insert_position = pred_block_end->prev();
       ValueStack *state = pred_block_end->state_before();
       if (pred_block_end->as_Goto() && state == NULL) state = pred_block_end->state();
       assert(state, "State must not be null");
       // Add deoptimization to dominator of loop header
       TRACE_RANGE_CHECK_ELIMINATION(
         tty->fill_to(block->dominator_depth()*2);
         tty->print_cr("Inserting deopt at bci %d in block B%d!", state->bci(), insert_position->block()->block_id())
       );
       if (!is_ok_for_deoptimization(insert_position, array_instr, length_instr, lower_instr, index_bound->lower(), upper_instr, index_bound->upper())) {
         TRACE_RANGE_CHECK_ELIMINATION(
           tty->fill_to(block->dominator_depth()*2);
           tty->print_cr("Could not eliminate because of static analysis!")
         );
         return;
       }
       insert_deoptimization(state, insert_position, array_instr, length_instr, lower_instr, index_bound->lower(), upper_instr, index_bound->upper(), ai);
       // Finally remove the range check!
       remove_range_check(ai);
     }
   }
 }
 void RangeCheckEliminator::remove_range_check(AccessIndexed *ai) {
   ai->set_flag(Instruction::NeedsRangeCheckFlag, false);
   // no range check, no need for the length instruction anymore
   ai->clear_length();
   TRACE_RANGE_CHECK_ELIMINATION(
     tty->fill_to(ai->dominator_depth()*2);
     tty->print_cr("Range check for instruction %d eliminated!", ai->id());
   );
   ASSERT_RANGE_CHECK_ELIMINATION(
     Value array_length = ai->length();
     if (!array_length) {
       array_length = ai->array();
       assert(array_length->type()->as_ObjectType(), "Has to be object type!");
     }
     int cur_constant = -1;
     Value cur_value = array_length;
     if (cur_value->type()->as_IntConstant()) {
       cur_constant += cur_value->type()->as_IntConstant()->value();
       cur_value = NULL;
     }
     Bound *new_index_bound = new Bound(0, NULL, cur_constant, cur_value);
     add_assertions(new_index_bound, ai->index(), ai);
   );
 }
 // Calculate bounds for instruction in this block and children blocks in the dominator tree
 void RangeCheckEliminator::calc_bounds(BlockBegin *block, BlockBegin *loop_header) {
   // Ensures a valid loop_header
   assert(!loop_header || loop_header->is_set(BlockBegin::linear_scan_loop_header_flag), "Loop header has to be real !");
   // Tracing output
   TRACE_RANGE_CHECK_ELIMINATION(
     tty->fill_to(block->dominator_depth()*2);
     tty->print_cr("Block B%d", block->block_id());
   );
   // Pushed stack for conditions
   IntegerStack pushed;
   // Process If
   BlockBegin *parent = block->dominator();
   if (parent != NULL) {
     If *cond = parent->end()->as_If();
     if (cond != NULL) {
       process_if(pushed, block, cond);
     }
   }
   // Interate over current block
   InstructionList arrays;
   AccessIndexedList accessIndexed;
   Instruction *cur = block;
   while (cur) {
     // Ensure cur wasn't inserted during the elimination
     if (cur->id() < this->_bounds.length()) {
       // Process only if it is an access indexed instruction
       AccessIndexed *ai = cur->as_AccessIndexed();
       if (ai != NULL) {
         process_access_indexed(loop_header, block, ai);
         accessIndexed.append(ai);
         if (!arrays.contains(ai->array())) {
           arrays.append(ai->array());
         }
         Bound *b = get_bound(ai->index());
         if (!b->lower_instr()) {
           // Lower bound is constant
           update_bound(pushed, ai->index(), Instruction::geq, NULL, 0);
         }
         if (!b->has_upper()) {
           if (ai->length() && ai->length()->type()->as_IntConstant()) {
             int value = ai->length()->type()->as_IntConstant()->value();
             update_bound(pushed, ai->index(), Instruction::lss, NULL, value);
           } else {
             // Has no upper bound
             Instruction *instr = ai->length();
             if (instr != NULL) instr = ai->array();
             update_bound(pushed, ai->index(), Instruction::lss, instr, 0);
           }
         }
       }
     }
     cur = cur->next();
   }
   // Output current condition stack
   TRACE_RANGE_CHECK_ELIMINATION(dump_condition_stack(block));
   // Do in block motion of range checks
   in_block_motion(block, accessIndexed, arrays);
   // Call all dominated blocks
   for (int i=0; i<block->dominates()->length(); i++) {
     BlockBegin *next = block->dominates()->at(i);
     if (!next->is_set(BlockBegin::donot_eliminate_range_checks)) {
       // if current block is a loop header and:
       // - next block belongs to the same loop
       // or
       // - next block belongs to an inner loop
       // then current block is the loop header for next block
       if (block->is_set(BlockBegin::linear_scan_loop_header_flag) && (block->loop_index() == next->loop_index() || next->loop_depth() > block->loop_depth())) {
         calc_bounds(next, block);
       } else {
         calc_bounds(next, loop_header);
       }
     }
   }
   // Reset stack
   for (int i=0; i<pushed.length(); i++) {
     _bounds[pushed[i]]->pop();
   }
 }
 #ifndef PRODUCT
 // Dump condition stack
 void RangeCheckEliminator::dump_condition_stack(BlockBegin *block) {
   for (int i=0; i<_ir->linear_scan_order()->length(); i++) {
     BlockBegin *cur_block = _ir->linear_scan_order()->at(i);
     Instruction *instr = cur_block;
     for_each_phi_fun(cur_block, phi,
                      BoundStack *bound_stack = _bounds.at(phi->id());
                      if (bound_stack && bound_stack->length() > 0) {
                        Bound *bound = bound_stack->top();
                        if ((bound->has_lower() || bound->has_upper()) && (bound->lower_instr() != phi || bound->upper_instr() != phi || bound->lower() != 0 || bound->upper() != 0)) {
                            TRACE_RANGE_CHECK_ELIMINATION(tty->fill_to(2*block->dominator_depth());
                                                          tty->print("i%d", phi->id());
                                                          tty->print(": ");
                                                          bound->print();
                                                          tty->print_cr("");
                            );
                          }
                      });
     while (!instr->as_BlockEnd()) {
       if (instr->id() < _bounds.length()) {
         BoundStack *bound_stack = _bounds.at(instr->id());
         if (bound_stack && bound_stack->length() > 0) {
           Bound *bound = bound_stack->top();
           if ((bound->has_lower() || bound->has_upper()) && (bound->lower_instr() != instr || bound->upper_instr() != instr || bound->lower() != 0 || bound->upper() != 0)) {
               TRACE_RANGE_CHECK_ELIMINATION(tty->fill_to(2*block->dominator_depth());
                                             tty->print("i%d", instr->id());
                                             tty->print(": ");
                                             bound->print();
                                             tty->print_cr("");
               );
           }
         }
       }
       instr = instr->next();
     }
   }
 }
 #endif
 // Verification or the IR
 RangeCheckEliminator::Verification::Verification(IR *ir) : _used(BlockBegin::number_of_blocks(), false) {
   this->_ir = ir;
   ir->iterate_linear_scan_order(this);
 }
 // Verify this block
 void RangeCheckEliminator::Verification::block_do(BlockBegin *block) {
   If *cond = block->end()->as_If();
   // Watch out: tsux and fsux can be the same!
   if (block->number_of_sux() > 1) {
     for (int i=0; i<block->number_of_sux(); i++) {
       BlockBegin *sux = block->sux_at(i);
       BlockBegin *pred = NULL;
       for (int j=0; j<sux->number_of_preds(); j++) {
         BlockBegin *cur = sux->pred_at(j);
         assert(cur != NULL, "Predecessor must not be null");
         if (!pred) {
           pred = cur;
         }
         assert(cur == pred, "Block must not have more than one predecessor if its predecessor has more than one successor");
       }
       assert(sux->number_of_preds() >= 1, "Block must have at least one predecessor");
       assert(sux->pred_at(0) == block, "Wrong successor");
     }
   }
   BlockBegin *dominator = block->dominator();
   if (dominator) {
     assert(block != _ir->start(), "Start block must not have a dominator!");
     assert(can_reach(dominator, block), "Dominator can't reach his block !");
     assert(can_reach(_ir->start(), dominator), "Dominator is unreachable !");
     assert(!can_reach(_ir->start(), block, dominator), "Wrong dominator ! Block can be reached anyway !");
     BlockList *all_blocks = _ir->linear_scan_order();
     for (int i=0; i<all_blocks->length(); i++) {
       BlockBegin *cur = all_blocks->at(i);
       if (cur != dominator && cur != block) {
         assert(can_reach(dominator, block, cur), "There has to be another dominator!");
       }
     }
   } else {
     assert(block == _ir->start(), "Only start block must not have a dominator");
   }
   if (block->is_set(BlockBegin::linear_scan_loop_header_flag)) {
     int loop_index = block->loop_index();
     BlockList *all_blocks = _ir->linear_scan_order();
     assert(block->number_of_preds() >= 1, "Block must have at least one predecessor");
     assert(!block->is_set(BlockBegin::exception_entry_flag), "Loop header must not be exception handler!");
     // Sometimes, the backbranch comes from an exception handler. In
     // this case, loop indexes/loop depths may not appear correct.
     bool loop_through_xhandler = false;
     for (int i = 0; i < block->number_of_exception_handlers(); i++) {
       BlockBegin *xhandler = block->exception_handler_at(i);
       for (int j = 0; j < block->number_of_preds(); j++) {
         if (dominates(xhandler, block->pred_at(j)) || xhandler == block->pred_at(j)) {
           loop_through_xhandler = true;
         }
       }
     }
     for (int i=0; i<block->number_of_sux(); i++) {
       BlockBegin *sux = block->sux_at(i);
       assert(sux->loop_depth() != block->loop_depth() || sux->loop_index() == block->loop_index() || loop_through_xhandler, "Loop index has to be same");
       assert(sux->loop_depth() == block->loop_depth() || sux->loop_index() != block->loop_index(), "Loop index has to be different");
     }
     for (int i=0; i<all_blocks->length(); i++) {
       BlockBegin *cur = all_blocks->at(i);
       if (cur->loop_index() == loop_index && cur != block) {
         assert(dominates(block->dominator(), cur), "Dominator of loop header must dominate all loop blocks");
       }
     }
   }
   Instruction *cur = block;
   while (cur) {
     assert(cur->block() == block, "Block begin has to be set correctly!");
     cur = cur->next();
   }
 }
 // Loop header must dominate all loop blocks
 bool RangeCheckEliminator::Verification::dominates(BlockBegin *dominator, BlockBegin *block) {
   BlockBegin *cur = block->dominator();
   while (cur && cur != dominator) {
     cur = cur->dominator();
   }
   return cur == dominator;
 }
 // Try to reach Block end beginning in Block start and not using Block dont_use
 bool RangeCheckEliminator::Verification::can_reach(BlockBegin *start, BlockBegin *end, BlockBegin *dont_use /* = NULL */) {
   if (start == end) return start != dont_use;
   // Simple BSF from start to end
   //  BlockBeginList _current;
   for (int i=0; i<_used.length(); i++) {
     _used[i] = false;
   }
   _current.truncate(0);
   _successors.truncate(0);
   if (start != dont_use) {
     _current.push(start);
     _used[start->block_id()] = true;
   }
   //  BlockBeginList _successors;
   while (_current.length() > 0) {
     BlockBegin *cur = _current.pop();
     // Add exception handlers to list
     for (int i=0; i<cur->number_of_exception_handlers(); i++) {
       BlockBegin *xhandler = cur->exception_handler_at(i);
       _successors.push(xhandler);
       // Add exception handlers of _successors to list
       for (int j=0; j<xhandler->number_of_exception_handlers(); j++) {
         BlockBegin *sux_xhandler = xhandler->exception_handler_at(j);
         _successors.push(sux_xhandler);
       }
     }
     // Add normal _successors to list
     for (int i=0; i<cur->number_of_sux(); i++) {
       BlockBegin *sux = cur->sux_at(i);
       _successors.push(sux);
       // Add exception handlers of _successors to list
       for (int j=0; j<sux->number_of_exception_handlers(); j++) {
         BlockBegin *xhandler = sux->exception_handler_at(j);
         _successors.push(xhandler);
       }
     }
     for (int i=0; i<_successors.length(); i++) {
       BlockBegin *sux = _successors[i];
       assert(sux != NULL, "Successor must not be NULL!");
       if (sux == end) {
         return true;
       }
       if (sux != dont_use && !_used[sux->block_id()]) {
         _used[sux->block_id()] = true;
         _current.push(sux);
       }
     }
     _successors.truncate(0);
   }
   return false;
 }
 // Bound
 RangeCheckEliminator::Bound::~Bound() {
 }
 // Bound constructor
 RangeCheckEliminator::Bound::Bound() {
   init();
   this->_lower = min_jint;
   this->_upper = max_jint;
   this->_lower_instr = NULL;
   this->_upper_instr = NULL;
 }
 // Bound constructor
 RangeCheckEliminator::Bound::Bound(int lower, Value lower_instr, int upper, Value upper_instr) {
   init();
   assert(!lower_instr || !lower_instr->as_Constant() || !lower_instr->type()->as_IntConstant(), "Must not be constant!");
   assert(!upper_instr || !upper_instr->as_Constant() || !upper_instr->type()->as_IntConstant(), "Must not be constant!");
   this->_lower = lower;
   this->_upper = upper;
   this->_lower_instr = lower_instr;
   this->_upper_instr = upper_instr;
 }
 // Bound constructor
 RangeCheckEliminator::Bound::Bound(Instruction::Condition cond, Value v, int constant) {
   assert(!v || (v->type() && (v->type()->as_IntType() || v->type()->as_ObjectType())), "Type must be array or integer!");
   assert(!v || !v->as_Constant() || !v->type()->as_IntConstant(), "Must not be constant!");
   init();
   if (cond == Instruction::eql) {
     _lower = constant;
     _lower_instr = v;
     _upper = constant;
     _upper_instr = v;
   } else if (cond == Instruction::neq) {
     _lower = min_jint;
     _upper = max_jint;
     _lower_instr = NULL;
     _upper_instr = NULL;
     if (v == NULL) {
       if (constant == min_jint) {
         _lower++;
       }
       if (constant == max_jint) {
         _upper--;
       }
     }
   } else if (cond == Instruction::geq) {
     _lower = constant;
     _lower_instr = v;
     _upper = max_jint;
     _upper_instr = NULL;
   } else if (cond == Instruction::leq) {
     _lower = min_jint;
     _lower_instr = NULL;
     _upper = constant;
     _upper_instr = v;
   } else {
     ShouldNotReachHere();
   }
 }
 // Set lower
 void RangeCheckEliminator::Bound::set_lower(int value, Value v) {
   assert(!v || !v->as_Constant() || !v->type()->as_IntConstant(), "Must not be constant!");
   this->_lower = value;
   this->_lower_instr = v;
 }
 // Set upper
 void RangeCheckEliminator::Bound::set_upper(int value, Value v) {
   assert(!v || !v->as_Constant() || !v->type()->as_IntConstant(), "Must not be constant!");
   this->_upper = value;
   this->_upper_instr = v;
 }
 // Add constant -> no overflow may occur
 void RangeCheckEliminator::Bound::add_constant(int value) {
   this->_lower += value;
   this->_upper += value;
 }
 // Init
 void RangeCheckEliminator::Bound::init() {
 }
 // or
 void RangeCheckEliminator::Bound::or_op(Bound *b) {
   // Watch out, bound is not guaranteed not to overflow!
   // Update lower bound
   if (_lower_instr != b->_lower_instr || (_lower_instr && _lower != b->_lower)) {
     _lower_instr = NULL;
     _lower = min_jint;
   } else {
     _lower = MIN2(_lower, b->_lower);
   }
   // Update upper bound
   if (_upper_instr != b->_upper_instr || (_upper_instr && _upper != b->_upper)) {
     _upper_instr = NULL;
     _upper = max_jint;
   } else {
     _upper = MAX2(_upper, b->_upper);
   }
 }
 // and
 void RangeCheckEliminator::Bound::and_op(Bound *b) {
   // Update lower bound
   if (_lower_instr == b->_lower_instr) {
     _lower = MAX2(_lower, b->_lower);
   }
   if (b->has_lower()) {
     bool set = true;
     if (_lower_instr != NULL && b->_lower_instr != NULL) {
       set = (_lower_instr->dominator_depth() > b->_lower_instr->dominator_depth());
     }
     if (set) {
       _lower = b->_lower;
       _lower_instr = b->_lower_instr;
     }
   }
   // Update upper bound
   if (_upper_instr == b->_upper_instr) {
     _upper = MIN2(_upper, b->_upper);
   }
   if (b->has_upper()) {
     bool set = true;
     if (_upper_instr != NULL && b->_upper_instr != NULL) {
       set = (_upper_instr->dominator_depth() > b->_upper_instr->dominator_depth());
     }
     if (set) {
       _upper = b->_upper;
       _upper_instr = b->_upper_instr;
     }
   }
 }
 // has_upper
 bool RangeCheckEliminator::Bound::has_upper() {
   return _upper_instr != NULL || _upper < max_jint;
 }
 // is_smaller
 bool RangeCheckEliminator::Bound::is_smaller(Bound *b) {
   if (b->_lower_instr != _upper_instr) {
     return false;
   }
   return _upper < b->_lower;
 }
 // has_lower
 bool RangeCheckEliminator::Bound::has_lower() {
   return _lower_instr != NULL || _lower > min_jint;
 }
 // in_array_bound
 bool RangeCheckEliminator::in_array_bound(Bound *bound, Value array){
   if (!bound) return false;
   assert(array != NULL, "Must not be null!");
   assert(bound != NULL, "Must not be null!");
   if (bound->lower() >=0 && bound->lower_instr() == NULL && bound->upper() < 0 && bound->upper_instr() != NULL) {
     ArrayLength *len = bound->upper_instr()->as_ArrayLength();
     if (bound->upper_instr() == array || (len != NULL && len->array() == array)) {
       return true;
     }
   }
   return false;
 }
 // remove_lower
 void RangeCheckEliminator::Bound::remove_lower() {
   _lower = min_jint;
   _lower_instr = NULL;
 }
 // remove_upper
 void RangeCheckEliminator::Bound::remove_upper() {
   _upper = max_jint;
   _upper_instr = NULL;
 }
 // upper
 int RangeCheckEliminator::Bound::upper() {
   return _upper;
 }
 // lower
 int RangeCheckEliminator::Bound::lower() {
   return _lower;
 }
 // upper_instr
 Value RangeCheckEliminator::Bound::upper_instr() {
   return _upper_instr;
 }
 // lower_instr
 Value RangeCheckEliminator::Bound::lower_instr() {
   return _lower_instr;
 }
 // print
 void RangeCheckEliminator::Bound::print() {
   tty->print("");
   if (this->_lower_instr || this->_lower != min_jint) {
     if (this->_lower_instr) {
       tty->print("i%d", this->_lower_instr->id());
       if (this->_lower > 0) {
         tty->print("+%d", _lower);
       }
       if (this->_lower < 0) {
         tty->print("%d", _lower);
       }
     } else {
       tty->print("%d", _lower);
     }
     tty->print(" <= ");
   }
   tty->print("x");
   if (this->_upper_instr || this->_upper != max_jint) {
     tty->print(" <= ");
     if (this->_upper_instr) {
       tty->print("i%d", this->_upper_instr->id());
       if (this->_upper > 0) {
         tty->print("+%d", _upper);
       }
       if (this->_upper < 0) {
         tty->print("%d", _upper);
       }
     } else {
       tty->print("%d", _upper);
     }
   }
 }
 // Copy
 RangeCheckEliminator::Bound *RangeCheckEliminator::Bound::copy() {
   Bound *b = new Bound();
   b->_lower = _lower;
   b->_lower_instr = _lower_instr;
   b->_upper = _upper;
   b->_upper_instr = _upper_instr;
   return b;
 }
 #ifdef ASSERT
 // Add assertion
 void RangeCheckEliminator::Bound::add_assertion(Instruction *instruction, Instruction *position, int i, Value instr, Instruction::Condition cond) {
   Instruction *result = position;
   Instruction *compare_with = NULL;
   ValueStack *state = position->state_before();
   if (position->as_BlockEnd() && !position->as_Goto()) {
     state = position->as_BlockEnd()->state_before();
   }
   Instruction *instruction_before = position->prev();
   if (position->as_Return() && Compilation::current()->method()->is_synchronized() && instruction_before->as_MonitorExit()) {
     instruction_before = instruction_before->prev();
   }
   result = instruction_before;
   // Load constant only if needed
   Constant *constant = NULL;
   if (i != 0 || !instr) {
     constant = new Constant(new IntConstant(i));
     NOT_PRODUCT(constant->set_printable_bci(position->printable_bci()));
     result = result->insert_after(constant);
     compare_with = constant;
   }
   if (instr) {
     assert(instr->type()->as_ObjectType() || instr->type()->as_IntType(), "Type must be array or integer!");
     compare_with = instr;
     // Load array length if necessary
     Instruction *op = instr;
     if (instr->type()->as_ObjectType()) {
       assert(state, "must not be null");
       ArrayLength *length = new ArrayLength(instr, state->copy());
       NOT_PRODUCT(length->set_printable_bci(position->printable_bci()));
       length->set_exception_state(length->state_before());
       result = result->insert_after(length);
       op = length;
       compare_with = length;
     }
     // Add operation only if necessary
     if (constant) {
       ArithmeticOp *ao = new ArithmeticOp(Bytecodes::_iadd, constant, op, false, NULL);
       NOT_PRODUCT(ao->set_printable_bci(position->printable_bci()));
       result = result->insert_after(ao);
       compare_with = ao;
       // TODO: Check that add operation does not overflow!
     }
   }
   assert(compare_with != NULL, "You have to compare with something!");
   assert(instruction != NULL, "Instruction must not be null!");
   if (instruction->type()->as_ObjectType()) {
     // Load array length if necessary
     Instruction *op = instruction;
     assert(state, "must not be null");
     ArrayLength *length = new ArrayLength(instruction, state->copy());
     length->set_exception_state(length->state_before());
     NOT_PRODUCT(length->set_printable_bci(position->printable_bci()));
     result = result->insert_after(length);
     instruction = length;
   }
   Assert *assert = new Assert(instruction, cond, false, compare_with);
   NOT_PRODUCT(assert->set_printable_bci(position->printable_bci()));
   result->insert_after(assert);
 }
 // Add assertions
 void RangeCheckEliminator::add_assertions(Bound *bound, Instruction *instruction, Instruction *position) {
   // Add lower bound assertion
   if (bound->has_lower()) {
     bound->add_assertion(instruction, position, bound->lower(), bound->lower_instr(), Instruction::geq);
   }
   // Add upper bound assertion
   if (bound->has_upper()) {
     bound->add_assertion(instruction, position, bound->upper(), bound->upper_instr(), Instruction::leq);
   }
 }
 #endif

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/c1/c1_RangeCheckElimination.cpp@2a9d97b57920 (annotated)

src/share/vm/c1/c1_RangeCheckElimination.cpp