c1_LIR.cpp

/*
 * Copyright (c) 2000, 2021, 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_CodeStubs.hpp"
#include "c1/c1_InstructionPrinter.hpp"
#include "c1/c1_LIR.hpp"
#include "c1/c1_LIRAssembler.hpp"
#include "c1/c1_ValueStack.hpp"
#include "ci/ciInstance.hpp"
#include "runtime/safepointMechanism.inline.hpp"
#include "runtime/sharedRuntime.hpp"
#include "runtime/vm_version.hpp"

Register LIR_OprDesc::as_register() const {
  return FrameMap::cpu_rnr2reg(cpu_regnr());
}

Register LIR_OprDesc::as_register_lo() const {
  return FrameMap::cpu_rnr2reg(cpu_regnrLo());
}

Register LIR_OprDesc::as_register_hi() const {
  return FrameMap::cpu_rnr2reg(cpu_regnrHi());
}

LIR_Opr LIR_OprFact::illegalOpr = LIR_OprFact::illegal();

LIR_Opr LIR_OprFact::value_type(ValueType* type) {
  ValueTag tag = type->tag();
  switch (tag) {
  case metaDataTag : {
    ClassConstant* c = type->as_ClassConstant();
    if (c != NULL && !c->value()->is_loaded()) {
      return LIR_OprFact::metadataConst(NULL);
    } else if (c != NULL) {
      return LIR_OprFact::metadataConst(c->value()->constant_encoding());
    } else {
      MethodConstant* m = type->as_MethodConstant();
      assert (m != NULL, "not a class or a method?");
      return LIR_OprFact::metadataConst(m->value()->constant_encoding());
    }
  }
  case objectTag : {
      return LIR_OprFact::oopConst(type->as_ObjectType()->encoding());
    }
  case addressTag: return LIR_OprFact::addressConst(type->as_AddressConstant()->value());
  case intTag    : return LIR_OprFact::intConst(type->as_IntConstant()->value());
  case floatTag  : return LIR_OprFact::floatConst(type->as_FloatConstant()->value());
  case longTag   : return LIR_OprFact::longConst(type->as_LongConstant()->value());
  case doubleTag : return LIR_OprFact::doubleConst(type->as_DoubleConstant()->value());
  default: ShouldNotReachHere(); return LIR_OprFact::intConst(-1);
  }
}


//---------------------------------------------------


LIR_Address::Scale LIR_Address::scale(BasicType type) {
  int elem_size = type2aelembytes(type);
  switch (elem_size) {
  case 1: return LIR_Address::times_1;
  case 2: return LIR_Address::times_2;
  case 4: return LIR_Address::times_4;
  case 8: return LIR_Address::times_8;
  }
  ShouldNotReachHere();
  return LIR_Address::times_1;
}

//---------------------------------------------------

char LIR_OprDesc::type_char(BasicType t) {
  switch (t) {
    case T_ARRAY:
      t = T_OBJECT;
    case T_BOOLEAN:
    case T_CHAR:
    case T_FLOAT:
    case T_DOUBLE:
    case T_BYTE:
    case T_SHORT:
    case T_INT:
    case T_LONG:
    case T_OBJECT:
    case T_ADDRESS:
    case T_VOID:
      return ::type2char(t);
    case T_METADATA:
      return 'M';
    case T_ILLEGAL:
      return '?';

    default:
      ShouldNotReachHere();
      return '?';
  }
}

#ifndef PRODUCT
void LIR_OprDesc::validate_type() const {

#ifdef ASSERT
  if (!is_pointer() && !is_illegal()) {
    OprKind kindfield = kind_field(); // Factored out because of compiler bug, see 8002160
    switch (as_BasicType(type_field())) {
    case T_LONG:
      assert((kindfield == cpu_register || kindfield == stack_value) &&
             size_field() == double_size, "must match");
      break;
    case T_FLOAT:
      // FP return values can be also in CPU registers on ARM and PPC32 (softfp ABI)
      assert((kindfield == fpu_register || kindfield == stack_value
             ARM_ONLY(|| kindfield == cpu_register)
             PPC32_ONLY(|| kindfield == cpu_register) ) &&
             size_field() == single_size, "must match");
      break;
    case T_DOUBLE:
      // FP return values can be also in CPU registers on ARM and PPC32 (softfp ABI)
      assert((kindfield == fpu_register || kindfield == stack_value
             ARM_ONLY(|| kindfield == cpu_register)
             PPC32_ONLY(|| kindfield == cpu_register) ) &&
             size_field() == double_size, "must match");
      break;
    case T_BOOLEAN:
    case T_CHAR:
    case T_BYTE:
    case T_SHORT:
    case T_INT:
    case T_ADDRESS:
    case T_OBJECT:
    case T_METADATA:
    case T_ARRAY:
      assert((kindfield == cpu_register || kindfield == stack_value) &&
             size_field() == single_size, "must match");
      break;

    case T_ILLEGAL:
      // XXX TKR also means unknown right now
      // assert(is_illegal(), "must match");
      break;

    default:
      ShouldNotReachHere();
    }
  }
#endif

}
#endif // PRODUCT


bool LIR_OprDesc::is_oop() const {
  if (is_pointer()) {
    return pointer()->is_oop_pointer();
  } else {
    OprType t= type_field();
    assert(t != unknown_type, "not set");
    return t == object_type;
  }
}



void LIR_Op2::verify() const {
#ifdef ASSERT
  switch (code()) {
    case lir_cmove:
    case lir_xchg:
      break;

    default:
      assert(!result_opr()->is_register() || !result_opr()->is_oop_register(),
             "can't produce oops from arith");
  }

  if (TwoOperandLIRForm) {

#ifdef ASSERT
    bool threeOperandForm = false;
#ifdef S390
    // There are 3 operand shifts on S390 (see LIR_Assembler::shift_op()).
    threeOperandForm =
      code() == lir_shl ||
      ((code() == lir_shr || code() == lir_ushr) && (result_opr()->is_double_cpu() || in_opr1()->type() == T_OBJECT));
#endif
#endif

    switch (code()) {
    case lir_add:
    case lir_sub:
    case lir_mul:
    case lir_div:
    case lir_rem:
    case lir_logic_and:
    case lir_logic_or:
    case lir_logic_xor:
    case lir_shl:
    case lir_shr:
      assert(in_opr1() == result_opr() || threeOperandForm, "opr1 and result must match");
      assert(in_opr1()->is_valid() && in_opr2()->is_valid(), "must be valid");
      break;

    // special handling for lir_ushr because of write barriers
    case lir_ushr:
      assert(in_opr1() == result_opr() || in_opr2()->is_constant() || threeOperandForm, "opr1 and result must match or shift count is constant");
      assert(in_opr1()->is_valid() && in_opr2()->is_valid(), "must be valid");
      break;

    default:
      break;
    }
  }
#endif
}


LIR_OpBranch::LIR_OpBranch(LIR_Condition cond, BlockBegin* block)
  : LIR_Op(lir_branch, LIR_OprFact::illegalOpr, (CodeEmitInfo*)NULL)
  , _cond(cond)
  , _label(block->label())
  , _block(block)
  , _ublock(NULL)
  , _stub(NULL) {
}

LIR_OpBranch::LIR_OpBranch(LIR_Condition cond, CodeStub* stub) :
  LIR_Op(lir_branch, LIR_OprFact::illegalOpr, (CodeEmitInfo*)NULL)
  , _cond(cond)
  , _label(stub->entry())
  , _block(NULL)
  , _ublock(NULL)
  , _stub(stub) {
}

LIR_OpBranch::LIR_OpBranch(LIR_Condition cond, BlockBegin* block, BlockBegin* ublock)
  : LIR_Op(lir_cond_float_branch, LIR_OprFact::illegalOpr, (CodeEmitInfo*)NULL)
  , _cond(cond)
  , _label(block->label())
  , _block(block)
  , _ublock(ublock)
  , _stub(NULL)
{
}

void LIR_OpBranch::change_block(BlockBegin* b) {
  assert(_block != NULL, "must have old block");
  assert(_block->label() == label(), "must be equal");

  _block = b;
  _label = b->label();
}

void LIR_OpBranch::change_ublock(BlockBegin* b) {
  assert(_ublock != NULL, "must have old block");
  _ublock = b;
}

void LIR_OpBranch::negate_cond() {
  switch (_cond) {
    case lir_cond_equal:        _cond = lir_cond_notEqual;     break;
    case lir_cond_notEqual:     _cond = lir_cond_equal;        break;
    case lir_cond_less:         _cond = lir_cond_greaterEqual; break;
    case lir_cond_lessEqual:    _cond = lir_cond_greater;      break;
    case lir_cond_greaterEqual: _cond = lir_cond_less;         break;
    case lir_cond_greater:      _cond = lir_cond_lessEqual;    break;
    default: ShouldNotReachHere();
  }
}


LIR_OpTypeCheck::LIR_OpTypeCheck(LIR_Code code, LIR_Opr result, LIR_Opr object, ciKlass* klass,
                                 LIR_Opr tmp1, LIR_Opr tmp2, LIR_Opr tmp3,
                                 bool fast_check, CodeEmitInfo* info_for_exception, CodeEmitInfo* info_for_patch,
                                 CodeStub* stub)

  : LIR_Op(code, result, NULL)
  , _object(object)
  , _array(LIR_OprFact::illegalOpr)
  , _klass(klass)
  , _tmp1(tmp1)
  , _tmp2(tmp2)
  , _tmp3(tmp3)
  , _fast_check(fast_check)
  , _info_for_patch(info_for_patch)
  , _info_for_exception(info_for_exception)
  , _stub(stub)
  , _profiled_method(NULL)
  , _profiled_bci(-1)
  , _should_profile(false)
{
  if (code == lir_checkcast) {
    assert(info_for_exception != NULL, "checkcast throws exceptions");
  } else if (code == lir_instanceof) {
    assert(info_for_exception == NULL, "instanceof throws no exceptions");
  } else {
    ShouldNotReachHere();
  }
}



LIR_OpTypeCheck::LIR_OpTypeCheck(LIR_Code code, LIR_Opr object, LIR_Opr array, LIR_Opr tmp1, LIR_Opr tmp2, LIR_Opr tmp3, CodeEmitInfo* info_for_exception)
  : LIR_Op(code, LIR_OprFact::illegalOpr, NULL)
  , _object(object)
  , _array(array)
  , _klass(NULL)
  , _tmp1(tmp1)
  , _tmp2(tmp2)
  , _tmp3(tmp3)
  , _fast_check(false)
  , _info_for_patch(NULL)
  , _info_for_exception(info_for_exception)
  , _stub(NULL)
  , _profiled_method(NULL)
  , _profiled_bci(-1)
  , _should_profile(false)
{
  if (code == lir_store_check) {
    _stub = new ArrayStoreExceptionStub(object, info_for_exception);
    assert(info_for_exception != NULL, "store_check throws exceptions");
  } else {
    ShouldNotReachHere();
  }
}


LIR_OpArrayCopy::LIR_OpArrayCopy(LIR_Opr src, LIR_Opr src_pos, LIR_Opr dst, LIR_Opr dst_pos, LIR_Opr length,
                                 LIR_Opr tmp, ciArrayKlass* expected_type, int flags, CodeEmitInfo* info)
  : LIR_Op(lir_arraycopy, LIR_OprFact::illegalOpr, info)
  , _src(src)
  , _src_pos(src_pos)
  , _dst(dst)
  , _dst_pos(dst_pos)
  , _length(length)
  , _tmp(tmp)
  , _expected_type(expected_type)
  , _flags(flags) {
  _stub = new ArrayCopyStub(this);
}

LIR_OpUpdateCRC32::LIR_OpUpdateCRC32(LIR_Opr crc, LIR_Opr val, LIR_Opr res)
  : LIR_Op(lir_updatecrc32, res, NULL)
  , _crc(crc)
  , _val(val) {
}

//-------------------verify--------------------------

void LIR_Op1::verify() const {
  switch(code()) {
  case lir_move:
    assert(in_opr()->is_valid() && result_opr()->is_valid(), "must be");
    break;
  case lir_null_check:
    assert(in_opr()->is_register(), "must be");
    break;
  case lir_return:
    assert(in_opr()->is_register() || in_opr()->is_illegal(), "must be");
    break;
  default:
    break;
  }
}

void LIR_OpRTCall::verify() const {
  assert(strcmp(Runtime1::name_for_address(addr()), "<unknown function>") != 0, "unknown function");
}

//-------------------visits--------------------------

// complete rework of LIR instruction visitor.
// The virtual call for each instruction type is replaced by a big
// switch that adds the operands for each instruction

void LIR_OpVisitState::visit(LIR_Op* op) {
  // copy information from the LIR_Op
  reset();
  set_op(op);

  switch (op->code()) {

// LIR_Op0
    case lir_backwardbranch_target:    // result and info always invalid
    case lir_fpop_raw:                 // result and info always invalid
    case lir_breakpoint:               // result and info always invalid
    case lir_membar:                   // result and info always invalid
    case lir_membar_acquire:           // result and info always invalid
    case lir_membar_release:           // result and info always invalid
    case lir_membar_loadload:          // result and info always invalid
    case lir_membar_storestore:        // result and info always invalid
    case lir_membar_loadstore:         // result and info always invalid
    case lir_membar_storeload:         // result and info always invalid
    case lir_on_spin_wait:
    {
      assert(op->as_Op0() != NULL, "must be");
      assert(op->_info == NULL, "info not used by this instruction");
      assert(op->_result->is_illegal(), "not used");
      break;
    }

    case lir_nop:                      // may have info, result always invalid
    case lir_std_entry:                // may have result, info always invalid
    case lir_osr_entry:                // may have result, info always invalid
    case lir_get_thread:               // may have result, info always invalid
    {
      assert(op->as_Op0() != NULL, "must be");
      if (op->_info != NULL)           do_info(op->_info);
      if (op->_result->is_valid())     do_output(op->_result);
      break;
    }


// LIR_OpLabel
    case lir_label:                    // result and info always invalid
    {
      assert(op->as_OpLabel() != NULL, "must be");
      assert(op->_info == NULL, "info not used by this instruction");
      assert(op->_result->is_illegal(), "not used");
      break;
    }


// LIR_Op1
    case lir_fxch:           // input always valid, result and info always invalid
    case lir_fld:            // input always valid, result and info always invalid
    case lir_push:           // input always valid, result and info always invalid
    case lir_pop:            // input always valid, result and info always invalid
    case lir_leal:           // input and result always valid, info always invalid
    case lir_monaddr:        // input and result always valid, info always invalid
    case lir_null_check:     // input and info always valid, result always invalid
    case lir_move:           // input and result always valid, may have info
    {
      assert(op->as_Op1() != NULL, "must be");
      LIR_Op1* op1 = (LIR_Op1*)op;

      if (op1->_info)                  do_info(op1->_info);
      if (op1->_opr->is_valid())       do_input(op1->_opr);
      if (op1->_result->is_valid())    do_output(op1->_result);

      break;
    }

    case lir_return:
    {
      assert(op->as_OpReturn() != NULL, "must be");
      LIR_OpReturn* op_ret = (LIR_OpReturn*)op;

      if (op_ret->_info)               do_info(op_ret->_info);
      if (op_ret->_opr->is_valid())    do_input(op_ret->_opr);
      if (op_ret->_result->is_valid()) do_output(op_ret->_result);
      if (op_ret->stub() != NULL)      do_stub(op_ret->stub());

      break;
    }

    case lir_safepoint:
    {
      assert(op->as_Op1() != NULL, "must be");
      LIR_Op1* op1 = (LIR_Op1*)op;

      assert(op1->_info != NULL, "");  do_info(op1->_info);
      if (op1->_opr->is_valid())       do_temp(op1->_opr); // safepoints on SPARC need temporary register
      assert(op1->_result->is_illegal(), "safepoint does not produce value");

      break;
    }

// LIR_OpConvert;
    case lir_convert:        // input and result always valid, info always invalid
    {
      assert(op->as_OpConvert() != NULL, "must be");
      LIR_OpConvert* opConvert = (LIR_OpConvert*)op;

      assert(opConvert->_info == NULL, "must be");
      if (opConvert->_opr->is_valid())       do_input(opConvert->_opr);
      if (opConvert->_result->is_valid())    do_output(opConvert->_result);
#ifdef PPC32
      if (opConvert->_tmp1->is_valid())      do_temp(opConvert->_tmp1);
      if (opConvert->_tmp2->is_valid())      do_temp(opConvert->_tmp2);
#endif
      do_stub(opConvert->_stub);

      break;
    }

// LIR_OpBranch;
    case lir_branch:                   // may have info, input and result register always invalid
    case lir_cond_float_branch:        // may have info, input and result register always invalid
    {
      assert(op->as_OpBranch() != NULL, "must be");
      LIR_OpBranch* opBranch = (LIR_OpBranch*)op;

      if (opBranch->_info != NULL)     do_info(opBranch->_info);
      assert(opBranch->_result->is_illegal(), "not used");
      if (opBranch->_stub != NULL)     opBranch->stub()->visit(this);

      break;
    }


// LIR_OpAllocObj
    case lir_alloc_object:
    {
      assert(op->as_OpAllocObj() != NULL, "must be");
      LIR_OpAllocObj* opAllocObj = (LIR_OpAllocObj*)op;

      if (opAllocObj->_info)                     do_info(opAllocObj->_info);
      if (opAllocObj->_opr->is_valid()) {        do_input(opAllocObj->_opr);
                                                 do_temp(opAllocObj->_opr);
                                        }
      if (opAllocObj->_tmp1->is_valid())         do_temp(opAllocObj->_tmp1);
      if (opAllocObj->_tmp2->is_valid())         do_temp(opAllocObj->_tmp2);
      if (opAllocObj->_tmp3->is_valid())         do_temp(opAllocObj->_tmp3);
      if (opAllocObj->_tmp4->is_valid())         do_temp(opAllocObj->_tmp4);
      if (opAllocObj->_result->is_valid())       do_output(opAllocObj->_result);
                                                 do_stub(opAllocObj->_stub);
      break;
    }


// LIR_OpRoundFP;
    case lir_roundfp: {
      assert(op->as_OpRoundFP() != NULL, "must be");
      LIR_OpRoundFP* opRoundFP = (LIR_OpRoundFP*)op;

      assert(op->_info == NULL, "info not used by this instruction");
      assert(opRoundFP->_tmp->is_illegal(), "not used");
      do_input(opRoundFP->_opr);
      do_output(opRoundFP->_result);

      break;
    }


// LIR_Op2
    case lir_cmp:
    case lir_cmp_l2i:
    case lir_ucmp_fd2i:
    case lir_cmp_fd2i:
    case lir_add:
    case lir_sub:
    case lir_rem:
    case lir_sqrt:
    case lir_abs:
    case lir_neg:
    case lir_logic_and:
    case lir_logic_or:
    case lir_logic_xor:
    case lir_shl:
    case lir_shr:
    case lir_ushr:
    case lir_xadd:
    case lir_xchg:
    case lir_assert:
    {
      assert(op->as_Op2() != NULL, "must be");
      LIR_Op2* op2 = (LIR_Op2*)op;
      assert(op2->_tmp2->is_illegal() && op2->_tmp3->is_illegal() &&
             op2->_tmp4->is_illegal() && op2->_tmp5->is_illegal(), "not used");

      if (op2->_info)                     do_info(op2->_info);
      if (op2->_opr1->is_valid())         do_input(op2->_opr1);
      if (op2->_opr2->is_valid())         do_input(op2->_opr2);
      if (op2->_tmp1->is_valid())         do_temp(op2->_tmp1);
      if (op2->_result->is_valid())       do_output(op2->_result);
      if (op->code() == lir_xchg || op->code() == lir_xadd) {
        // on ARM and PPC, return value is loaded first so could
        // destroy inputs. On other platforms that implement those
        // (x86, sparc), the extra constrainsts are harmless.
        if (op2->_opr1->is_valid())       do_temp(op2->_opr1);
        if (op2->_opr2->is_valid())       do_temp(op2->_opr2);
      }

      break;
    }

    // special handling for cmove: right input operand must not be equal
    // to the result operand, otherwise the backend fails
    case lir_cmove:
    {
      assert(op->as_Op2() != NULL, "must be");
      LIR_Op2* op2 = (LIR_Op2*)op;

      assert(op2->_info == NULL && op2->_tmp1->is_illegal() && op2->_tmp2->is_illegal() &&
             op2->_tmp3->is_illegal() && op2->_tmp4->is_illegal() && op2->_tmp5->is_illegal(), "not used");
      assert(op2->_opr1->is_valid() && op2->_opr2->is_valid() && op2->_result->is_valid(), "used");

      do_input(op2->_opr1);
      do_input(op2->_opr2);
      do_temp(op2->_opr2);
      do_output(op2->_result);

      break;
    }

    // vspecial handling for strict operations: register input operands
    // as temp to guarantee that they do not overlap with other
    // registers
    case lir_mul:
    case lir_div:
    {
      assert(op->as_Op2() != NULL, "must be");
      LIR_Op2* op2 = (LIR_Op2*)op;

      assert(op2->_info == NULL, "not used");
      assert(op2->_opr1->is_valid(), "used");
      assert(op2->_opr2->is_valid(), "used");
      assert(op2->_result->is_valid(), "used");
      assert(op2->_tmp2->is_illegal() && op2->_tmp3->is_illegal() &&
             op2->_tmp4->is_illegal() && op2->_tmp5->is_illegal(), "not used");

      do_input(op2->_opr1); do_temp(op2->_opr1);
      do_input(op2->_opr2); do_temp(op2->_opr2);
      if (op2->_tmp1->is_valid()) do_temp(op2->_tmp1);
      do_output(op2->_result);

      break;
    }

    case lir_throw: {
      assert(op->as_Op2() != NULL, "must be");
      LIR_Op2* op2 = (LIR_Op2*)op;

      if (op2->_info)                     do_info(op2->_info);
      if (op2->_opr1->is_valid())         do_temp(op2->_opr1);
      if (op2->_opr2->is_valid())         do_input(op2->_opr2); // exception object is input parameter
      assert(op2->_result->is_illegal(), "no result");
      assert(op2->_tmp2->is_illegal() && op2->_tmp3->is_illegal() &&
             op2->_tmp4->is_illegal() && op2->_tmp5->is_illegal(), "not used");

      break;
    }

    case lir_unwind: {
      assert(op->as_Op1() != NULL, "must be");
      LIR_Op1* op1 = (LIR_Op1*)op;

      assert(op1->_info == NULL, "no info");
      assert(op1->_opr->is_valid(), "exception oop");         do_input(op1->_opr);
      assert(op1->_result->is_illegal(), "no result");

      break;
    }

// LIR_Op3
    case lir_idiv:
    case lir_irem: {
      assert(op->as_Op3() != NULL, "must be");
      LIR_Op3* op3= (LIR_Op3*)op;

      if (op3->_info)                     do_info(op3->_info);
      if (op3->_opr1->is_valid())         do_input(op3->_opr1);

      // second operand is input and temp, so ensure that second operand
      // and third operand get not the same register
      if (op3->_opr2->is_valid())         do_input(op3->_opr2);
      if (op3->_opr2->is_valid())         do_temp(op3->_opr2);
      if (op3->_opr3->is_valid())         do_temp(op3->_opr3);

      if (op3->_result->is_valid())       do_output(op3->_result);

      break;
    }

    case lir_fmad:
    case lir_fmaf: {
      assert(op->as_Op3() != NULL, "must be");
      LIR_Op3* op3= (LIR_Op3*)op;
      assert(op3->_info == NULL, "no info");
      do_input(op3->_opr1);
      do_input(op3->_opr2);
      do_input(op3->_opr3);
      do_output(op3->_result);
      break;
    }

// LIR_OpJavaCall
    case lir_static_call:
    case lir_optvirtual_call:
    case lir_icvirtual_call:
    case lir_dynamic_call: {
      LIR_OpJavaCall* opJavaCall = op->as_OpJavaCall();
      assert(opJavaCall != NULL, "must be");

      if (opJavaCall->_receiver->is_valid())     do_input(opJavaCall->_receiver);

      // only visit register parameters
      int n = opJavaCall->_arguments->length();
      for (int i = opJavaCall->_receiver->is_valid() ? 1 : 0; i < n; i++) {
        if (!opJavaCall->_arguments->at(i)->is_pointer()) {
          do_input(*opJavaCall->_arguments->adr_at(i));
        }
      }

      if (opJavaCall->_info)                     do_info(opJavaCall->_info);
      if (FrameMap::method_handle_invoke_SP_save_opr() != LIR_OprFact::illegalOpr &&
          opJavaCall->is_method_handle_invoke()) {
        opJavaCall->_method_handle_invoke_SP_save_opr = FrameMap::method_handle_invoke_SP_save_opr();
        do_temp(opJavaCall->_method_handle_invoke_SP_save_opr);
      }
      do_call();
      if (opJavaCall->_result->is_valid())       do_output(opJavaCall->_result);

      break;
    }


// LIR_OpRTCall
    case lir_rtcall: {
      assert(op->as_OpRTCall() != NULL, "must be");
      LIR_OpRTCall* opRTCall = (LIR_OpRTCall*)op;

      // only visit register parameters
      int n = opRTCall->_arguments->length();
      for (int i = 0; i < n; i++) {
        if (!opRTCall->_arguments->at(i)->is_pointer()) {
          do_input(*opRTCall->_arguments->adr_at(i));
        }
      }
      if (opRTCall->_info)                     do_info(opRTCall->_info);
      if (opRTCall->_tmp->is_valid())          do_temp(opRTCall->_tmp);
      do_call();
      if (opRTCall->_result->is_valid())       do_output(opRTCall->_result);

      break;
    }


// LIR_OpArrayCopy
    case lir_arraycopy: {
      assert(op->as_OpArrayCopy() != NULL, "must be");
      LIR_OpArrayCopy* opArrayCopy = (LIR_OpArrayCopy*)op;

      assert(opArrayCopy->_result->is_illegal(), "unused");
      assert(opArrayCopy->_src->is_valid(), "used");          do_input(opArrayCopy->_src);     do_temp(opArrayCopy->_src);
      assert(opArrayCopy->_src_pos->is_valid(), "used");      do_input(opArrayCopy->_src_pos); do_temp(opArrayCopy->_src_pos);
      assert(opArrayCopy->_dst->is_valid(), "used");          do_input(opArrayCopy->_dst);     do_temp(opArrayCopy->_dst);
      assert(opArrayCopy->_dst_pos->is_valid(), "used");      do_input(opArrayCopy->_dst_pos); do_temp(opArrayCopy->_dst_pos);
      assert(opArrayCopy->_length->is_valid(), "used");       do_input(opArrayCopy->_length);  do_temp(opArrayCopy->_length);
      assert(opArrayCopy->_tmp->is_valid(), "used");          do_temp(opArrayCopy->_tmp);
      if (opArrayCopy->_info)                     do_info(opArrayCopy->_info);

      // the implementation of arraycopy always has a call into the runtime
      do_call();

      break;
    }


// LIR_OpUpdateCRC32
    case lir_updatecrc32: {
      assert(op->as_OpUpdateCRC32() != NULL, "must be");
      LIR_OpUpdateCRC32* opUp = (LIR_OpUpdateCRC32*)op;

      assert(opUp->_crc->is_valid(), "used");          do_input(opUp->_crc);     do_temp(opUp->_crc);
      assert(opUp->_val->is_valid(), "used");          do_input(opUp->_val);     do_temp(opUp->_val);
      assert(opUp->_result->is_valid(), "used");       do_output(opUp->_result);
      assert(opUp->_info == NULL, "no info for LIR_OpUpdateCRC32");

      break;
    }


// LIR_OpLock
    case lir_lock:
    case lir_unlock: {
      assert(op->as_OpLock() != NULL, "must be");
      LIR_OpLock* opLock = (LIR_OpLock*)op;

      if (opLock->_info)                          do_info(opLock->_info);

      // TODO: check if these operands really have to be temp
      // (or if input is sufficient). This may have influence on the oop map!
      assert(opLock->_lock->is_valid(), "used");  do_temp(opLock->_lock);
      assert(opLock->_hdr->is_valid(),  "used");  do_temp(opLock->_hdr);
      assert(opLock->_obj->is_valid(),  "used");  do_temp(opLock->_obj);

      if (opLock->_scratch->is_valid())           do_temp(opLock->_scratch);
      assert(opLock->_result->is_illegal(), "unused");

      do_stub(opLock->_stub);

      break;
    }


// LIR_OpDelay
    case lir_delay_slot: {
      assert(op->as_OpDelay() != NULL, "must be");
      LIR_OpDelay* opDelay = (LIR_OpDelay*)op;

      visit(opDelay->delay_op());
      break;
    }

// LIR_OpTypeCheck
    case lir_instanceof:
    case lir_checkcast:
    case lir_store_check: {
      assert(op->as_OpTypeCheck() != NULL, "must be");
      LIR_OpTypeCheck* opTypeCheck = (LIR_OpTypeCheck*)op;

      if (opTypeCheck->_info_for_exception)       do_info(opTypeCheck->_info_for_exception);
      if (opTypeCheck->_info_for_patch)           do_info(opTypeCheck->_info_for_patch);
      if (opTypeCheck->_object->is_valid())       do_input(opTypeCheck->_object);
      if (op->code() == lir_store_check && opTypeCheck->_object->is_valid()) {
        do_temp(opTypeCheck->_object);
      }
      if (opTypeCheck->_array->is_valid())        do_input(opTypeCheck->_array);
      if (opTypeCheck->_tmp1->is_valid())         do_temp(opTypeCheck->_tmp1);
      if (opTypeCheck->_tmp2->is_valid())         do_temp(opTypeCheck->_tmp2);
      if (opTypeCheck->_tmp3->is_valid())         do_temp(opTypeCheck->_tmp3);
      if (opTypeCheck->_result->is_valid())       do_output(opTypeCheck->_result);
                                                  do_stub(opTypeCheck->_stub);
      break;
    }

// LIR_OpCompareAndSwap
    case lir_cas_long:
    case lir_cas_obj:
    case lir_cas_int: {
      assert(op->as_OpCompareAndSwap() != NULL, "must be");
      LIR_OpCompareAndSwap* opCompareAndSwap = (LIR_OpCompareAndSwap*)op;

      assert(opCompareAndSwap->_addr->is_valid(),      "used");
      assert(opCompareAndSwap->_cmp_value->is_valid(), "used");
      assert(opCompareAndSwap->_new_value->is_valid(), "used");
      if (opCompareAndSwap->_info)                    do_info(opCompareAndSwap->_info);
                                                      do_input(opCompareAndSwap->_addr);
                                                      do_temp(opCompareAndSwap->_addr);
                                                      do_input(opCompareAndSwap->_cmp_value);
                                                      do_temp(opCompareAndSwap->_cmp_value);
                                                      do_input(opCompareAndSwap->_new_value);
                                                      do_temp(opCompareAndSwap->_new_value);
      if (opCompareAndSwap->_tmp1->is_valid())        do_temp(opCompareAndSwap->_tmp1);
      if (opCompareAndSwap->_tmp2->is_valid())        do_temp(opCompareAndSwap->_tmp2);
      if (opCompareAndSwap->_result->is_valid())      do_output(opCompareAndSwap->_result);

      break;
    }


// LIR_OpAllocArray;
    case lir_alloc_array: {
      assert(op->as_OpAllocArray() != NULL, "must be");
      LIR_OpAllocArray* opAllocArray = (LIR_OpAllocArray*)op;

      if (opAllocArray->_info)                        do_info(opAllocArray->_info);
      if (opAllocArray->_klass->is_valid())           do_input(opAllocArray->_klass); do_temp(opAllocArray->_klass);
      if (opAllocArray->_len->is_valid())             do_input(opAllocArray->_len);   do_temp(opAllocArray->_len);
      if (opAllocArray->_tmp1->is_valid())            do_temp(opAllocArray->_tmp1);
      if (opAllocArray->_tmp2->is_valid())            do_temp(opAllocArray->_tmp2);
      if (opAllocArray->_tmp3->is_valid())            do_temp(opAllocArray->_tmp3);
      if (opAllocArray->_tmp4->is_valid())            do_temp(opAllocArray->_tmp4);
      if (opAllocArray->_result->is_valid())          do_output(opAllocArray->_result);
                                                      do_stub(opAllocArray->_stub);
      break;
    }

// LIR_OpProfileCall:
    case lir_profile_call: {
      assert(op->as_OpProfileCall() != NULL, "must be");
      LIR_OpProfileCall* opProfileCall = (LIR_OpProfileCall*)op;

      if (opProfileCall->_recv->is_valid())              do_temp(opProfileCall->_recv);
      assert(opProfileCall->_mdo->is_valid(), "used");   do_temp(opProfileCall->_mdo);
      assert(opProfileCall->_tmp1->is_valid(), "used");  do_temp(opProfileCall->_tmp1);
      break;
    }

// LIR_OpProfileType:
    case lir_profile_type: {
      assert(op->as_OpProfileType() != NULL, "must be");
      LIR_OpProfileType* opProfileType = (LIR_OpProfileType*)op;

      do_input(opProfileType->_mdp); do_temp(opProfileType->_mdp);
      do_input(opProfileType->_obj);
      do_temp(opProfileType->_tmp);
      break;
    }
  default:
    op->visit(this);
  }
}

void LIR_Op::visit(LIR_OpVisitState* state) {
  ShouldNotReachHere();
}

void LIR_OpVisitState::do_stub(CodeStub* stub) {
  if (stub != NULL) {
    stub->visit(this);
  }
}

XHandlers* LIR_OpVisitState::all_xhandler() {
  XHandlers* result = NULL;

  int i;
  for (i = 0; i < info_count(); i++) {
    if (info_at(i)->exception_handlers() != NULL) {
      result = info_at(i)->exception_handlers();
      break;
    }
  }

#ifdef ASSERT
  for (i = 0; i < info_count(); i++) {
    assert(info_at(i)->exception_handlers() == NULL ||
           info_at(i)->exception_handlers() == result,
           "only one xhandler list allowed per LIR-operation");
  }
#endif

  if (result != NULL) {
    return result;
  } else {
    return new XHandlers();
  }

  return result;
}


#ifdef ASSERT
bool LIR_OpVisitState::no_operands(LIR_Op* op) {
  visit(op);

  return opr_count(inputMode) == 0 &&
         opr_count(outputMode) == 0 &&
         opr_count(tempMode) == 0 &&
         info_count() == 0 &&
         !has_call() &&
         !has_slow_case();
}
#endif

// LIR_OpReturn
LIR_OpReturn::LIR_OpReturn(LIR_Opr opr) :
    LIR_Op1(lir_return, opr, (CodeEmitInfo*)NULL /* info */),
    _stub(NULL) {
  if (VM_Version::supports_stack_watermark_barrier()) {
    _stub = new C1SafepointPollStub();
  }
}

//---------------------------------------------------


void LIR_OpJavaCall::emit_code(LIR_Assembler* masm) {
  masm->emit_call(this);
}

void LIR_OpRTCall::emit_code(LIR_Assembler* masm) {
  masm->emit_rtcall(this);
}

void LIR_OpLabel::emit_code(LIR_Assembler* masm) {
  masm->emit_opLabel(this);
}

void LIR_OpArrayCopy::emit_code(LIR_Assembler* masm) {
  masm->emit_arraycopy(this);
  masm->append_code_stub(stub());
}

void LIR_OpUpdateCRC32::emit_code(LIR_Assembler* masm) {
  masm->emit_updatecrc32(this);
}

void LIR_Op0::emit_code(LIR_Assembler* masm) {
  masm->emit_op0(this);
}

void LIR_Op1::emit_code(LIR_Assembler* masm) {
  masm->emit_op1(this);
}

void LIR_OpAllocObj::emit_code(LIR_Assembler* masm) {
  masm->emit_alloc_obj(this);
  masm->append_code_stub(stub());
}

void LIR_OpBranch::emit_code(LIR_Assembler* masm) {
  masm->emit_opBranch(this);
  if (stub()) {
    masm->append_code_stub(stub());
  }
}

void LIR_OpConvert::emit_code(LIR_Assembler* masm) {
  masm->emit_opConvert(this);
  if (stub() != NULL) {
    masm->append_code_stub(stub());
  }
}

void LIR_Op2::emit_code(LIR_Assembler* masm) {
  masm->emit_op2(this);
}

void LIR_OpAllocArray::emit_code(LIR_Assembler* masm) {
  masm->emit_alloc_array(this);
  masm->append_code_stub(stub());
}

void LIR_OpTypeCheck::emit_code(LIR_Assembler* masm) {
  masm->emit_opTypeCheck(this);
  if (stub()) {
    masm->append_code_stub(stub());
  }
}

void LIR_OpCompareAndSwap::emit_code(LIR_Assembler* masm) {
  masm->emit_compare_and_swap(this);
}

void LIR_Op3::emit_code(LIR_Assembler* masm) {
  masm->emit_op3(this);
}

void LIR_OpLock::emit_code(LIR_Assembler* masm) {
  masm->emit_lock(this);
  if (stub()) {
    masm->append_code_stub(stub());
  }
}

#ifdef ASSERT
void LIR_OpAssert::emit_code(LIR_Assembler* masm) {
  masm->emit_assert(this);
}
#endif

void LIR_OpDelay::emit_code(LIR_Assembler* masm) {
  masm->emit_delay(this);
}

void LIR_OpProfileCall::emit_code(LIR_Assembler* masm) {
  masm->emit_profile_call(this);
}

void LIR_OpProfileType::emit_code(LIR_Assembler* masm) {
  masm->emit_profile_type(this);
}

// LIR_List
LIR_List::LIR_List(Compilation* compilation, BlockBegin* block)
  : _operations(8)
  , _compilation(compilation)
#ifndef PRODUCT
  , _block(block)
#endif
#ifdef ASSERT
  , _file(NULL)
  , _line(0)
#endif
{ }


#ifdef ASSERT
void LIR_List::set_file_and_line(const char * file, int line) {
  const char * f = strrchr(file, '/');
  if (f == NULL) f = strrchr(file, '\\');
  if (f == NULL) {
    f = file;
  } else {
    f++;
  }
  _file = f;
  _line = line;
}
#endif


void LIR_List::append(LIR_InsertionBuffer* buffer) {
  assert(this == buffer->lir_list(), "wrong lir list");
  const int n = _operations.length();

  if (buffer->number_of_ops() > 0) {
    // increase size of instructions list
    _operations.at_grow(n + buffer->number_of_ops() - 1, NULL);
    // insert ops from buffer into instructions list
    int op_index = buffer->number_of_ops() - 1;
    int ip_index = buffer->number_of_insertion_points() - 1;
    int from_index = n - 1;
    int to_index = _operations.length() - 1;
    for (; ip_index >= 0; ip_index --) {
      int index = buffer->index_at(ip_index);
      // make room after insertion point
      while (index < from_index) {
        _operations.at_put(to_index --, _operations.at(from_index --));
      }
      // insert ops from buffer
      for (int i = buffer->count_at(ip_index); i > 0; i --) {
        _operations.at_put(to_index --, buffer->op_at(op_index --));
      }
    }
  }

  buffer->finish();
}


void LIR_List::oop2reg_patch(jobject o, LIR_Opr reg, CodeEmitInfo* info) {
  assert(reg->type() == T_OBJECT, "bad reg");
  append(new LIR_Op1(lir_move, LIR_OprFact::oopConst(o),  reg, T_OBJECT, lir_patch_normal, info));
}

void LIR_List::klass2reg_patch(Metadata* o, LIR_Opr reg, CodeEmitInfo* info) {
  assert(reg->type() == T_METADATA, "bad reg");
  append(new LIR_Op1(lir_move, LIR_OprFact::metadataConst(o), reg, T_METADATA, lir_patch_normal, info));
}

void LIR_List::load(LIR_Address* addr, LIR_Opr src, CodeEmitInfo* info, LIR_PatchCode patch_code) {
  append(new LIR_Op1(
            lir_move,
            LIR_OprFact::address(addr),
            src,
            addr->type(),
            patch_code,
            info));
}


void LIR_List::volatile_load_mem_reg(LIR_Address* address, LIR_Opr dst, CodeEmitInfo* info, LIR_PatchCode patch_code) {
  append(new LIR_Op1(
            lir_move,
            LIR_OprFact::address(address),
            dst,
            address->type(),
            patch_code,
            info, lir_move_volatile));
}

void LIR_List::volatile_load_unsafe_reg(LIR_Opr base, LIR_Opr offset, LIR_Opr dst, BasicType type, CodeEmitInfo* info, LIR_PatchCode patch_code) {
  append(new LIR_Op1(
            lir_move,
            LIR_OprFact::address(new LIR_Address(base, offset, type)),
            dst,
            type,
            patch_code,
            info, lir_move_volatile));
}


void LIR_List::store_mem_int(jint v, LIR_Opr base, int offset_in_bytes, BasicType type, CodeEmitInfo* info, LIR_PatchCode patch_code) {
  append(new LIR_Op1(
            lir_move,
            LIR_OprFact::intConst(v),
            LIR_OprFact::address(new LIR_Address(base, offset_in_bytes, type)),
            type,
            patch_code,
            info));
}


void LIR_List::store_mem_oop(jobject o, LIR_Opr base, int offset_in_bytes, BasicType type, CodeEmitInfo* info, LIR_PatchCode patch_code) {
  append(new LIR_Op1(
            lir_move,
            LIR_OprFact::oopConst(o),
            LIR_OprFact::address(new LIR_Address(base, offset_in_bytes, type)),
            type,
            patch_code,
            info));
}


void LIR_List::store(LIR_Opr src, LIR_Address* addr, CodeEmitInfo* info, LIR_PatchCode patch_code) {
  append(new LIR_Op1(
            lir_move,
            src,
            LIR_OprFact::address(addr),
            addr->type(),
            patch_code,
            info));
}


void LIR_List::volatile_store_mem_reg(LIR_Opr src, LIR_Address* addr, CodeEmitInfo* info, LIR_PatchCode patch_code) {
  append(new LIR_Op1(
            lir_move,
            src,
            LIR_OprFact::address(addr),
            addr->type(),
            patch_code,
            info,
            lir_move_volatile));
}

void LIR_List::volatile_store_unsafe_reg(LIR_Opr src, LIR_Opr base, LIR_Opr offset, BasicType type, CodeEmitInfo* info, LIR_PatchCode patch_code) {
  append(new LIR_Op1(
            lir_move,
            src,
            LIR_OprFact::address(new LIR_Address(base, offset, type)),
            type,
            patch_code,
            info, lir_move_volatile));
}


void LIR_List::idiv(LIR_Opr left, LIR_Opr right, LIR_Opr res, LIR_Opr tmp, CodeEmitInfo* info) {
  append(new LIR_Op3(
                    lir_idiv,
                    left,
                    right,
                    tmp,
                    res,
                    info));
}


void LIR_List::idiv(LIR_Opr left, int right, LIR_Opr res, LIR_Opr tmp, CodeEmitInfo* info) {
  append(new LIR_Op3(
                    lir_idiv,
                    left,
                    LIR_OprFact::intConst(right),
                    tmp,
                    res,
                    info));
}


void LIR_List::irem(LIR_Opr left, LIR_Opr right, LIR_Opr res, LIR_Opr tmp, CodeEmitInfo* info) {
  append(new LIR_Op3(
                    lir_irem,
                    left,
                    right,
                    tmp,
                    res,
                    info));
}


void LIR_List::irem(LIR_Opr left, int right, LIR_Opr res, LIR_Opr tmp, CodeEmitInfo* info) {
  append(new LIR_Op3(
                    lir_irem,
                    left,
                    LIR_OprFact::intConst(right),
                    tmp,
                    res,
                    info));
}


void LIR_List::cmp_mem_int(LIR_Condition condition, LIR_Opr base, int disp, int c, CodeEmitInfo* info) {
  append(new LIR_Op2(
                    lir_cmp,
                    condition,
                    LIR_OprFact::address(new LIR_Address(base, disp, T_INT)),
                    LIR_OprFact::intConst(c),
                    info));
}


void LIR_List::cmp_reg_mem(LIR_Condition condition, LIR_Opr reg, LIR_Address* addr, CodeEmitInfo* info) {
  append(new LIR_Op2(
                    lir_cmp,
                    condition,
                    reg,
                    LIR_OprFact::address(addr),
                    info));
}

void LIR_List::allocate_object(LIR_Opr dst, LIR_Opr t1, LIR_Opr t2, LIR_Opr t3, LIR_Opr t4,
                               int header_size, int object_size, LIR_Opr klass, bool init_check, CodeStub* stub) {
  append(new LIR_OpAllocObj(
                           klass,
                           dst,
                           t1,
                           t2,
                           t3,
                           t4,
                           header_size,
                           object_size,
                           init_check,
                           stub));
}

void LIR_List::allocate_array(LIR_Opr dst, LIR_Opr len, LIR_Opr t1,LIR_Opr t2, LIR_Opr t3,LIR_Opr t4, BasicType type, LIR_Opr klass, CodeStub* stub) {
  append(new LIR_OpAllocArray(
                           klass,
                           len,
                           dst,
                           t1,
                           t2,
                           t3,
                           t4,
                           type,
                           stub));
}

void LIR_List::shift_left(LIR_Opr value, LIR_Opr count, LIR_Opr dst, LIR_Opr tmp) {
 append(new LIR_Op2(
                    lir_shl,
                    value,
                    count,
                    dst,
                    tmp));
}

void LIR_List::shift_right(LIR_Opr value, LIR_Opr count, LIR_Opr dst, LIR_Opr tmp) {
 append(new LIR_Op2(
                    lir_shr,
                    value,
                    count,
                    dst,
                    tmp));
}


void LIR_List::unsigned_shift_right(LIR_Opr value, LIR_Opr count, LIR_Opr dst, LIR_Opr tmp) {
 append(new LIR_Op2(
                    lir_ushr,
                    value,
                    count,
                    dst,
                    tmp));
}

void LIR_List::fcmp2int(LIR_Opr left, LIR_Opr right, LIR_Opr dst, bool is_unordered_less) {
  append(new LIR_Op2(is_unordered_less ? lir_ucmp_fd2i : lir_cmp_fd2i,
                     left,
                     right,
                     dst));
}

void LIR_List::lock_object(LIR_Opr hdr, LIR_Opr obj, LIR_Opr lock, LIR_Opr scratch, CodeStub* stub, CodeEmitInfo* info) {
  append(new LIR_OpLock(
                    lir_lock,
                    hdr,
                    obj,
                    lock,
                    scratch,
                    stub,
                    info));
}

void LIR_List::unlock_object(LIR_Opr hdr, LIR_Opr obj, LIR_Opr lock, LIR_Opr scratch, CodeStub* stub) {
  append(new LIR_OpLock(
                    lir_unlock,
                    hdr,
                    obj,
                    lock,
                    scratch,
                    stub,
                    NULL));
}


void check_LIR() {
  // cannot do the proper checking as PRODUCT and other modes return different results
  // guarantee(sizeof(LIR_OprDesc) == wordSize, "may not have a v-table");
}



void LIR_List::checkcast (LIR_Opr result, LIR_Opr object, ciKlass* klass,
                          LIR_Opr tmp1, LIR_Opr tmp2, LIR_Opr tmp3, bool fast_check,
                          CodeEmitInfo* info_for_exception, CodeEmitInfo* info_for_patch, CodeStub* stub,
                          ciMethod* profiled_method, int profiled_bci) {
  LIR_OpTypeCheck* c = new LIR_OpTypeCheck(lir_checkcast, result, object, klass,
                                           tmp1, tmp2, tmp3, fast_check, info_for_exception, info_for_patch, stub);
  if (profiled_method != NULL) {
    c->set_profiled_method(profiled_method);
    c->set_profiled_bci(profiled_bci);
    c->set_should_profile(true);
  }
  append(c);
}

void LIR_List::instanceof(LIR_Opr result, LIR_Opr object, ciKlass* klass, LIR_Opr tmp1, LIR_Opr tmp2, LIR_Opr tmp3, bool fast_check, CodeEmitInfo* info_for_patch, ciMethod* profiled_method, int profiled_bci) {
  LIR_OpTypeCheck* c = new LIR_OpTypeCheck(lir_instanceof, result, object, klass, tmp1, tmp2, tmp3, fast_check, NULL, info_for_patch, NULL);
  if (profiled_method != NULL) {
    c->set_profiled_method(profiled_method);
    c->set_profiled_bci(profiled_bci);
    c->set_should_profile(true);
  }
  append(c);
}


void LIR_List::store_check(LIR_Opr object, LIR_Opr array, LIR_Opr tmp1, LIR_Opr tmp2, LIR_Opr tmp3,
                           CodeEmitInfo* info_for_exception, ciMethod* profiled_method, int profiled_bci) {
  LIR_OpTypeCheck* c = new LIR_OpTypeCheck(lir_store_check, object, array, tmp1, tmp2, tmp3, info_for_exception);
  if (profiled_method != NULL) {
    c->set_profiled_method(profiled_method);
    c->set_profiled_bci(profiled_bci);
    c->set_should_profile(true);
  }
  append(c);
}

void LIR_List::null_check(LIR_Opr opr, CodeEmitInfo* info, bool deoptimize_on_null) {
  if (deoptimize_on_null) {
    // Emit an explicit null check and deoptimize if opr is null
    CodeStub* deopt = new DeoptimizeStub(info, Deoptimization::Reason_null_check, Deoptimization::Action_none);
    cmp(lir_cond_equal, opr, LIR_OprFact::oopConst(NULL));
    branch(lir_cond_equal, deopt);
  } else {
    // Emit an implicit null check
    append(new LIR_Op1(lir_null_check, opr, info));
  }
}

void LIR_List::cas_long(LIR_Opr addr, LIR_Opr cmp_value, LIR_Opr new_value,
                        LIR_Opr t1, LIR_Opr t2, LIR_Opr result) {
  append(new LIR_OpCompareAndSwap(lir_cas_long, addr, cmp_value, new_value, t1, t2, result));
}

void LIR_List::cas_obj(LIR_Opr addr, LIR_Opr cmp_value, LIR_Opr new_value,
                       LIR_Opr t1, LIR_Opr t2, LIR_Opr result) {
  append(new LIR_OpCompareAndSwap(lir_cas_obj, addr, cmp_value, new_value, t1, t2, result));
}

void LIR_List::cas_int(LIR_Opr addr, LIR_Opr cmp_value, LIR_Opr new_value,
                       LIR_Opr t1, LIR_Opr t2, LIR_Opr result) {
  append(new LIR_OpCompareAndSwap(lir_cas_int, addr, cmp_value, new_value, t1, t2, result));
}


#ifdef PRODUCT

void print_LIR(BlockList* blocks) {
}

#else
// LIR_OprDesc
void LIR_OprDesc::print() const {
  print(tty);
}

void LIR_OprDesc::print(outputStream* out) const {
  if (is_illegal()) {
    return;
  }

  out->print("[");
  if (is_pointer()) {
    pointer()->print_value_on(out);
  } else if (is_single_stack()) {
    out->print("stack:%d", single_stack_ix());
  } else if (is_double_stack()) {
    out->print("dbl_stack:%d",double_stack_ix());
  } else if (is_virtual()) {
    out->print("R%d", vreg_number());
  } else if (is_single_cpu()) {
    out->print("%s", as_register()->name());
  } else if (is_double_cpu()) {
    out->print("%s", as_register_hi()->name());
    out->print("%s", as_register_lo()->name());
#if defined(X86)
  } else if (is_single_xmm()) {
    out->print("%s", as_xmm_float_reg()->name());
  } else if (is_double_xmm()) {
    out->print("%s", as_xmm_double_reg()->name());
  } else if (is_single_fpu()) {
    out->print("fpu%d", fpu_regnr());
  } else if (is_double_fpu()) {
    out->print("fpu%d", fpu_regnrLo());
#elif defined(AARCH64)
  } else if (is_single_fpu()) {
    out->print("fpu%d", fpu_regnr());
  } else if (is_double_fpu()) {
    out->print("fpu%d", fpu_regnrLo());
#elif defined(ARM)
  } else if (is_single_fpu()) {
    out->print("s%d", fpu_regnr());
  } else if (is_double_fpu()) {
    out->print("d%d", fpu_regnrLo() >> 1);
#else
  } else if (is_single_fpu()) {
    out->print("%s", as_float_reg()->name());
  } else if (is_double_fpu()) {
    out->print("%s", as_double_reg()->name());
#endif

  } else if (is_illegal()) {
    out->print("-");
  } else {
    out->print("Unknown Operand");
  }
  if (!is_illegal()) {
    out->print("|%c", type_char());
  }
  if (is_register() && is_last_use()) {
    out->print("(last_use)");
  }
  out->print("]");
}


// LIR_Address
void LIR_Const::print_value_on(outputStream* out) const {
  switch (type()) {
    case T_ADDRESS:out->print("address:%d",as_jint());          break;
    case T_INT:    out->print("int:%d",   as_jint());           break;
    case T_LONG:   out->print("lng:" JLONG_FORMAT, as_jlong()); break;
    case T_FLOAT:  out->print("flt:%f",   as_jfloat());         break;
    case T_DOUBLE: out->print("dbl:%f",   as_jdouble());        break;
    case T_OBJECT: out->print("obj:" INTPTR_FORMAT, p2i(as_jobject()));        break;
    case T_METADATA: out->print("metadata:" INTPTR_FORMAT, p2i(as_metadata()));break;
    default:       out->print("%3d:0x" UINT64_FORMAT_X, type(), (uint64_t)as_jlong()); break;
  }
}

// LIR_Address
void LIR_Address::print_value_on(outputStream* out) const {
  out->print("Base:"); _base->print(out);
  if (!_index->is_illegal()) {
    out->print(" Index:"); _index->print(out);
    switch (scale()) {
    case times_1: break;
    case times_2: out->print(" * 2"); break;
    case times_4: out->print(" * 4"); break;
    case times_8: out->print(" * 8"); break;
    }
  }
  out->print(" Disp: " INTX_FORMAT, _disp);
}

// debug output of block header without InstructionPrinter
//       (because phi functions are not necessary for LIR)
static void print_block(BlockBegin* x) {
  // print block id
  BlockEnd* end = x->end();
  tty->print("B%d ", x->block_id());

  // print flags
  if (x->is_set(BlockBegin::std_entry_flag))               tty->print("std ");
  if (x->is_set(BlockBegin::osr_entry_flag))               tty->print("osr ");
  if (x->is_set(BlockBegin::exception_entry_flag))         tty->print("ex ");
  if (x->is_set(BlockBegin::subroutine_entry_flag))        tty->print("jsr ");
  if (x->is_set(BlockBegin::backward_branch_target_flag))  tty->print("bb ");
  if (x->is_set(BlockBegin::linear_scan_loop_header_flag)) tty->print("lh ");
  if (x->is_set(BlockBegin::linear_scan_loop_end_flag))    tty->print("le ");

  // print block bci range
  tty->print("[%d, %d] ", x->bci(), (end == NULL ? -1 : end->printable_bci()));

  // print predecessors and successors
  if (x->number_of_preds() > 0) {
    tty->print("preds: ");
    for (int i = 0; i < x->number_of_preds(); i ++) {
      tty->print("B%d ", x->pred_at(i)->block_id());
    }
  }

  if (x->number_of_sux() > 0) {
    tty->print("sux: ");
    for (int i = 0; i < x->number_of_sux(); i ++) {
      tty->print("B%d ", x->sux_at(i)->block_id());
    }
  }

  // print exception handlers
  if (x->number_of_exception_handlers() > 0) {
    tty->print("xhandler: ");
    for (int i = 0; i < x->number_of_exception_handlers();  i++) {
      tty->print("B%d ", x->exception_handler_at(i)->block_id());
    }
  }

  tty->cr();
}

void print_LIR(BlockList* blocks) {
  tty->print_cr("LIR:");
  int i;
  for (i = 0; i < blocks->length(); i++) {
    BlockBegin* bb = blocks->at(i);
    print_block(bb);
    tty->print("__id_Instruction___________________________________________"); tty->cr();
    bb->lir()->print_instructions();
  }
}

void LIR_List::print_instructions() {
  for (int i = 0; i < _operations.length(); i++) {
    _operations.at(i)->print(); tty->cr();
  }
  tty->cr();
}

// LIR_Ops printing routines
// LIR_Op
void LIR_Op::print_on(outputStream* out) const {
  if (id() != -1 || PrintCFGToFile) {
    out->print("%4d ", id());
  } else {
    out->print("     ");
  }
  out->print("%s ", name());
  print_instr(out);
  if (info() != NULL) out->print(" [bci:%d]", info()->stack()->bci());
#ifdef ASSERT
  if (Verbose && _file != NULL) {
    out->print(" (%s:%d)", _file, _line);
  }
#endif
}

const char * LIR_Op::name() const {
  const char* s = NULL;
  switch(code()) {
     // LIR_Op0
     case lir_membar:                s = "membar";        break;
     case lir_membar_acquire:        s = "membar_acquire"; break;
     case lir_membar_release:        s = "membar_release"; break;
     case lir_membar_loadload:       s = "membar_loadload";   break;
     case lir_membar_storestore:     s = "membar_storestore"; break;
     case lir_membar_loadstore:      s = "membar_loadstore";  break;
     case lir_membar_storeload:      s = "membar_storeload";  break;
     case lir_label:                 s = "label";         break;
     case lir_nop:                   s = "nop";           break;
     case lir_on_spin_wait:          s = "on_spin_wait";  break;
     case lir_backwardbranch_target: s = "backbranch";    break;
     case lir_std_entry:             s = "std_entry";     break;
     case lir_osr_entry:             s = "osr_entry";     break;
     case lir_fpop_raw:              s = "fpop_raw";      break;
     case lir_breakpoint:            s = "breakpoint";    break;
     case lir_get_thread:            s = "get_thread";    break;
     // LIR_Op1
     case lir_fxch:                  s = "fxch";          break;
     case lir_fld:                   s = "fld";           break;
     case lir_push:                  s = "push";          break;
     case lir_pop:                   s = "pop";           break;
     case lir_null_check:            s = "null_check";    break;
     case lir_return:                s = "return";        break;
     case lir_safepoint:             s = "safepoint";     break;
     case lir_leal:                  s = "leal";          break;
     case lir_branch:                s = "branch";        break;
     case lir_cond_float_branch:     s = "flt_cond_br";   break;
     case lir_move:                  s = "move";          break;
     case lir_roundfp:               s = "roundfp";       break;
     case lir_rtcall:                s = "rtcall";        break;
     case lir_throw:                 s = "throw";         break;
     case lir_unwind:                s = "unwind";        break;
     case lir_convert:               s = "convert";       break;
     case lir_alloc_object:          s = "alloc_obj";     break;
     case lir_monaddr:               s = "mon_addr";      break;
     // LIR_Op2
     case lir_cmp:                   s = "cmp";           break;
     case lir_cmp_l2i:               s = "cmp_l2i";       break;
     case lir_ucmp_fd2i:             s = "ucomp_fd2i";    break;
     case lir_cmp_fd2i:              s = "comp_fd2i";     break;
     case lir_cmove:                 s = "cmove";         break;
     case lir_add:                   s = "add";           break;
     case lir_sub:                   s = "sub";           break;
     case lir_mul:                   s = "mul";           break;
     case lir_div:                   s = "div";           break;
     case lir_rem:                   s = "rem";           break;
     case lir_abs:                   s = "abs";           break;
     case lir_neg:                   s = "neg";           break;
     case lir_sqrt:                  s = "sqrt";          break;
     case lir_logic_and:             s = "logic_and";     break;
     case lir_logic_or:              s = "logic_or";      break;
     case lir_logic_xor:             s = "logic_xor";     break;
     case lir_shl:                   s = "shift_left";    break;
     case lir_shr:                   s = "shift_right";   break;
     case lir_ushr:                  s = "ushift_right";  break;
     case lir_alloc_array:           s = "alloc_array";   break;
     case lir_xadd:                  s = "xadd";          break;
     case lir_xchg:                  s = "xchg";          break;
     // LIR_Op3
     case lir_idiv:                  s = "idiv";          break;
     case lir_irem:                  s = "irem";          break;
     case lir_fmad:                  s = "fmad";          break;
     case lir_fmaf:                  s = "fmaf";          break;
     // LIR_OpJavaCall
     case lir_static_call:           s = "static";        break;
     case lir_optvirtual_call:       s = "optvirtual";    break;
     case lir_icvirtual_call:        s = "icvirtual";     break;
     case lir_dynamic_call:          s = "dynamic";       break;
     // LIR_OpArrayCopy
     case lir_arraycopy:             s = "arraycopy";     break;
     // LIR_OpUpdateCRC32
     case lir_updatecrc32:           s = "updatecrc32";   break;
     // LIR_OpLock
     case lir_lock:                  s = "lock";          break;
     case lir_unlock:                s = "unlock";        break;
     // LIR_OpDelay
     case lir_delay_slot:            s = "delay";         break;
     // LIR_OpTypeCheck
     case lir_instanceof:            s = "instanceof";    break;
     case lir_checkcast:             s = "checkcast";     break;
     case lir_store_check:           s = "store_check";   break;
     // LIR_OpCompareAndSwap
     case lir_cas_long:              s = "cas_long";      break;
     case lir_cas_obj:               s = "cas_obj";      break;
     case lir_cas_int:               s = "cas_int";      break;
     // LIR_OpProfileCall
     case lir_profile_call:          s = "profile_call";  break;
     // LIR_OpProfileType
     case lir_profile_type:          s = "profile_type";  break;
     // LIR_OpAssert
#ifdef ASSERT
     case lir_assert:                s = "assert";        break;
#endif
     case lir_none:                  ShouldNotReachHere();break;
    default:                         s = "illegal_op";    break;
  }
  return s;
}

// LIR_OpJavaCall
void LIR_OpJavaCall::print_instr(outputStream* out) const {
  out->print("call: ");
  out->print("[addr: " INTPTR_FORMAT "]", p2i(address()));
  if (receiver()->is_valid()) {
    out->print(" [recv: ");   receiver()->print(out);   out->print("]");
  }
  if (result_opr()->is_valid()) {
    out->print(" [result: "); result_opr()->print(out); out->print("]");
  }
}

// LIR_OpLabel
void LIR_OpLabel::print_instr(outputStream* out) const {
  out->print("[label:" INTPTR_FORMAT "]", p2i(_label));
}

// LIR_OpArrayCopy
void LIR_OpArrayCopy::print_instr(outputStream* out) const {
  src()->print(out);     out->print(" ");
  src_pos()->print(out); out->print(" ");
  dst()->print(out);     out->print(" ");
  dst_pos()->print(out); out->print(" ");
  length()->print(out);  out->print(" ");
  tmp()->print(out);     out->print(" ");
}

// LIR_OpUpdateCRC32
void LIR_OpUpdateCRC32::print_instr(outputStream* out) const {
  crc()->print(out);     out->print(" ");
  val()->print(out);     out->print(" ");
  result_opr()->print(out); out->print(" ");
}

// LIR_OpCompareAndSwap
void LIR_OpCompareAndSwap::print_instr(outputStream* out) const {
  addr()->print(out);      out->print(" ");
  cmp_value()->print(out); out->print(" ");
  new_value()->print(out); out->print(" ");
  tmp1()->print(out);      out->print(" ");
  tmp2()->print(out);      out->print(" ");

}

// LIR_Op0
void LIR_Op0::print_instr(outputStream* out) const {
  result_opr()->print(out);
}

// LIR_Op1
const char * LIR_Op1::name() const {
  if (code() == lir_move) {
    switch (move_kind()) {
    case lir_move_normal:
      return "move";
    case lir_move_unaligned:
      return "unaligned move";
    case lir_move_volatile:
      return "volatile_move";
    case lir_move_wide:
      return "wide_move";
    default:
      ShouldNotReachHere();
    return "illegal_op";
    }
  } else {
    return LIR_Op::name();
  }
}


void LIR_Op1::print_instr(outputStream* out) const {
  _opr->print(out);         out->print(" ");
  result_opr()->print(out); out->print(" ");
  print_patch_code(out, patch_code());
}


// LIR_Op1
void LIR_OpRTCall::print_instr(outputStream* out) const {
  intx a = (intx)addr();
  out->print("%s", Runtime1::name_for_address(addr()));
  out->print(" ");
  tmp()->print(out);
}

void LIR_Op1::print_patch_code(outputStream* out, LIR_PatchCode code) {
  switch(code) {
    case lir_patch_none:                                 break;
    case lir_patch_low:    out->print("[patch_low]");    break;
    case lir_patch_high:   out->print("[patch_high]");   break;
    case lir_patch_normal: out->print("[patch_normal]"); break;
    default: ShouldNotReachHere();
  }
}

// LIR_OpBranch
void LIR_OpBranch::print_instr(outputStream* out) const {
  print_condition(out, cond());             out->print(" ");
  if (block() != NULL) {
    out->print("[B%d] ", block()->block_id());
  } else if (stub() != NULL) {
    out->print("[");
    stub()->print_name(out);
    out->print(": " INTPTR_FORMAT "]", p2i(stub()));
    if (stub()->info() != NULL) out->print(" [bci:%d]", stub()->info()->stack()->bci());
  } else {
    out->print("[label:" INTPTR_FORMAT "] ", p2i(label()));
  }
  if (ublock() != NULL) {
    out->print("unordered: [B%d] ", ublock()->block_id());
  }
}

void LIR_Op::print_condition(outputStream* out, LIR_Condition cond) {
  switch(cond) {
    case lir_cond_equal:           out->print("[EQ]");      break;
    case lir_cond_notEqual:        out->print("[NE]");      break;
    case lir_cond_less:            out->print("[LT]");      break;
    case lir_cond_lessEqual:       out->print("[LE]");      break;
    case lir_cond_greaterEqual:    out->print("[GE]");      break;
    case lir_cond_greater:         out->print("[GT]");      break;
    case lir_cond_belowEqual:      out->print("[BE]");      break;
    case lir_cond_aboveEqual:      out->print("[AE]");      break;
    case lir_cond_always:          out->print("[AL]");      break;
    default:                       out->print("[%d]",cond); break;
  }
}

// LIR_OpConvert
void LIR_OpConvert::print_instr(outputStream* out) const {
  print_bytecode(out, bytecode());
  in_opr()->print(out);                  out->print(" ");
  result_opr()->print(out);              out->print(" ");
#ifdef PPC32
  if(tmp1()->is_valid()) {
    tmp1()->print(out); out->print(" ");
    tmp2()->print(out); out->print(" ");
  }
#endif
}

void LIR_OpConvert::print_bytecode(outputStream* out, Bytecodes::Code code) {
  switch(code) {
    case Bytecodes::_d2f: out->print("[d2f] "); break;
    case Bytecodes::_d2i: out->print("[d2i] "); break;
    case Bytecodes::_d2l: out->print("[d2l] "); break;
    case Bytecodes::_f2d: out->print("[f2d] "); break;
    case Bytecodes::_f2i: out->print("[f2i] "); break;
    case Bytecodes::_f2l: out->print("[f2l] "); break;
    case Bytecodes::_i2b: out->print("[i2b] "); break;
    case Bytecodes::_i2c: out->print("[i2c] "); break;
    case Bytecodes::_i2d: out->print("[i2d] "); break;
    case Bytecodes::_i2f: out->print("[i2f] "); break;
    case Bytecodes::_i2l: out->print("[i2l] "); break;
    case Bytecodes::_i2s: out->print("[i2s] "); break;
    case Bytecodes::_l2i: out->print("[l2i] "); break;
    case Bytecodes::_l2f: out->print("[l2f] "); break;
    case Bytecodes::_l2d: out->print("[l2d] "); break;
    default:
      out->print("[?%d]",code);
    break;
  }
}

void LIR_OpAllocObj::print_instr(outputStream* out) const {
  klass()->print(out);                      out->print(" ");
  obj()->print(out);                        out->print(" ");
  tmp1()->print(out);                       out->print(" ");
  tmp2()->print(out);                       out->print(" ");
  tmp3()->print(out);                       out->print(" ");
  tmp4()->print(out);                       out->print(" ");
  out->print("[hdr:%d]", header_size()); out->print(" ");
  out->print("[obj:%d]", object_size()); out->print(" ");
  out->print("[lbl:" INTPTR_FORMAT "]", p2i(stub()->entry()));
}

void LIR_OpRoundFP::print_instr(outputStream* out) const {
  _opr->print(out);         out->print(" ");
  tmp()->print(out);        out->print(" ");
  result_opr()->print(out); out->print(" ");
}

// LIR_Op2
void LIR_Op2::print_instr(outputStream* out) const {
  if (code() == lir_cmove || code() == lir_cmp) {
    print_condition(out, condition());         out->print(" ");
  }
  in_opr1()->print(out);    out->print(" ");
  in_opr2()->print(out);    out->print(" ");
  if (tmp1_opr()->is_valid()) { tmp1_opr()->print(out);    out->print(" "); }
  if (tmp2_opr()->is_valid()) { tmp2_opr()->print(out);    out->print(" "); }
  if (tmp3_opr()->is_valid()) { tmp3_opr()->print(out);    out->print(" "); }
  if (tmp4_opr()->is_valid()) { tmp4_opr()->print(out);    out->print(" "); }
  if (tmp5_opr()->is_valid()) { tmp5_opr()->print(out);    out->print(" "); }
  result_opr()->print(out);
}

void LIR_OpAllocArray::print_instr(outputStream* out) const {
  klass()->print(out);                   out->print(" ");
  len()->print(out);                     out->print(" ");
  obj()->print(out);                     out->print(" ");
  tmp1()->print(out);                    out->print(" ");
  tmp2()->print(out);                    out->print(" ");
  tmp3()->print(out);                    out->print(" ");
  tmp4()->print(out);                    out->print(" ");
  out->print("[type:0x%x]", type());     out->print(" ");
  out->print("[label:" INTPTR_FORMAT "]", p2i(stub()->entry()));
}


void LIR_OpTypeCheck::print_instr(outputStream* out) const {
  object()->print(out);                  out->print(" ");
  if (code() == lir_store_check) {
    array()->print(out);                 out->print(" ");
  }
  if (code() != lir_store_check) {
    klass()->print_name_on(out);         out->print(" ");
    if (fast_check())                 out->print("fast_check ");
  }
  tmp1()->print(out);                    out->print(" ");
  tmp2()->print(out);                    out->print(" ");
  tmp3()->print(out);                    out->print(" ");
  result_opr()->print(out);              out->print(" ");
  if (info_for_exception() != NULL) out->print(" [bci:%d]", info_for_exception()->stack()->bci());
}


// LIR_Op3
void LIR_Op3::print_instr(outputStream* out) const {
  in_opr1()->print(out);    out->print(" ");
  in_opr2()->print(out);    out->print(" ");
  in_opr3()->print(out);    out->print(" ");
  result_opr()->print(out);
}


void LIR_OpLock::print_instr(outputStream* out) const {
  hdr_opr()->print(out);   out->print(" ");
  obj_opr()->print(out);   out->print(" ");
  lock_opr()->print(out);  out->print(" ");
  if (_scratch->is_valid()) {
    _scratch->print(out);  out->print(" ");
  }
  out->print("[lbl:" INTPTR_FORMAT "]", p2i(stub()->entry()));
}

#ifdef ASSERT
void LIR_OpAssert::print_instr(outputStream* out) const {
  print_condition(out, condition()); out->print(" ");
  in_opr1()->print(out);             out->print(" ");
  in_opr2()->print(out);             out->print(", \"");
  out->print("%s", msg());          out->print("\"");
}
#endif


void LIR_OpDelay::print_instr(outputStream* out) const {
  _op->print_on(out);
}


// LIR_OpProfileCall
void LIR_OpProfileCall::print_instr(outputStream* out) const {
  profiled_method()->name()->print_symbol_on(out);
  out->print(".");
  profiled_method()->holder()->name()->print_symbol_on(out);
  out->print(" @ %d ", profiled_bci());
  mdo()->print(out);           out->print(" ");
  recv()->print(out);          out->print(" ");
  tmp1()->print(out);          out->print(" ");
}

// LIR_OpProfileType
void LIR_OpProfileType::print_instr(outputStream* out) const {
  out->print("exact = ");
  if  (exact_klass() == NULL) {
    out->print("unknown");
  } else {
    exact_klass()->print_name_on(out);
  }
  out->print(" current = "); ciTypeEntries::print_ciklass(out, current_klass());
  out->print(" ");
  mdp()->print(out);          out->print(" ");
  obj()->print(out);          out->print(" ");
  tmp()->print(out);          out->print(" ");
}

#endif // PRODUCT

// Implementation of LIR_InsertionBuffer

void LIR_InsertionBuffer::append(int index, LIR_Op* op) {
  assert(_index_and_count.length() % 2 == 0, "must have a count for each index");

  int i = number_of_insertion_points() - 1;
  if (i < 0 || index_at(i) < index) {
    append_new(index, 1);
  } else {
    assert(index_at(i) == index, "can append LIR_Ops in ascending order only");
    assert(count_at(i) > 0, "check");
    set_count_at(i, count_at(i) + 1);
  }
  _ops.push(op);

  DEBUG_ONLY(verify());
}

#ifdef ASSERT
void LIR_InsertionBuffer::verify() {
  int sum = 0;
  int prev_idx = -1;

  for (int i = 0; i < number_of_insertion_points(); i++) {
    assert(prev_idx < index_at(i), "index must be ordered ascending");
    sum += count_at(i);
  }
  assert(sum == number_of_ops(), "wrong total sum");
}
#endif