コード例 #1
0
ファイル: c1_Canonicalizer.cpp プロジェクト: lizhekang/TCJDK
void Canonicalizer::do_ShiftOp        (ShiftOp*         x) {
  ValueType* t = x->x()->type();
  ValueType* t2 = x->y()->type();
  if (t->is_constant()) {
    switch (t->tag()) {
    case intTag   : if (t->as_IntConstant()->value() == 0)         { set_constant(0); return; } break;
    case longTag  : if (t->as_LongConstant()->value() == (jlong)0) { set_constant(jlong_cast(0)); return; } break;
    default       : ShouldNotReachHere();
    }
    if (t2->is_constant()) {
      if (t->tag() == intTag) {
        int value = t->as_IntConstant()->value();
        int shift = t2->as_IntConstant()->value() & 31;
        jint mask = ~(~0 << (32 - shift));
        if (shift == 0) mask = ~0;
        switch (x->op()) {
          case Bytecodes::_ishl:  set_constant(value << shift); return;
          case Bytecodes::_ishr:  set_constant(value >> shift); return;
          case Bytecodes::_iushr: set_constant((value >> shift) & mask); return;
        }
      } else if (t->tag() == longTag) {
        jlong value = t->as_LongConstant()->value();
        int shift = t2->as_IntConstant()->value() & 63;
        jlong mask = ~(~jlong_cast(0) << (64 - shift));
        if (shift == 0) mask = ~jlong_cast(0);
        switch (x->op()) {
          case Bytecodes::_lshl:  set_constant(value << shift); return;
          case Bytecodes::_lshr:  set_constant(value >> shift); return;
          case Bytecodes::_lushr: set_constant((value >> shift) & mask); return;
        }
      }
コード例 #2
0
ファイル: c1_Canonicalizer.cpp プロジェクト: lizhekang/TCJDK
void Canonicalizer::do_NegateOp(NegateOp* x) {
  ValueType* t = x->x()->type();
  if (t->is_constant()) {
    switch (t->tag()) {
      case intTag   : set_constant(-t->as_IntConstant   ()->value()); return;
      case longTag  : set_constant(-t->as_LongConstant  ()->value()); return;
      case floatTag : set_constant(-t->as_FloatConstant ()->value()); return;
      case doubleTag: set_constant(-t->as_DoubleConstant()->value()); return;
      default       : ShouldNotReachHere();
    }
  }
}
コード例 #3
0
void Canonicalizer::do_ShiftOp        (ShiftOp*         x) {
  ValueType* t = x->x()->type();
  if (t->is_constant()) {
    switch (t->tag()) {
      case intTag   : if (t->as_IntConstant()->value() == 0)  set_constant(0); return;
      case longTag  : if (t->as_LongConstant()->value() == (jlong)0) set_constant(jlong_cast(0)); return;
      default       : ShouldNotReachHere();
    }
  }
  ValueType* t2 = x->y()->type();
  if (t2->is_constant()) {
    switch (t2->tag()) {
      case intTag   : if (t2->as_IntConstant()->value() == 0)  set_canonical(x->x()); return;
      default       : ShouldNotReachHere();
    }
  }
}
コード例 #4
0
void Canonicalizer::do_If(If* x) {
  // move const to right
  if (x->x()->type()->is_constant()) x->swap_operands();
  // simplify
  const Value l = x->x(); ValueType* lt = l->type();
  const Value r = x->y(); ValueType* rt = r->type();
  if (lt->is_constant() && rt->is_constant()) {
    // pattern: If (lc cond rc) => simplify to: Goto
    Goto* g = NULL;
    switch (lt->tag()) {
      case intTag:
        g = new Goto(x->sux_for(is_true(lt->as_IntConstant ()->value(), x->cond(), rt->as_IntConstant ()->value())), x->is_safepoint());
        break;
      case longTag:
        g = new Goto(x->sux_for(is_true(lt->as_LongConstant()->value(), x->cond(), rt->as_LongConstant()->value())), x->is_safepoint());
        break;
      // other cases not implemented (must be extremely careful with floats & doubles!)
    }
    if (g != NULL) {
      // If this If is a safepoint then the debug information should come from the state_before of the If.
      g->set_state_before(x->state_before());
      set_canonical(g);
    }
  } else if (rt->as_IntConstant() != NULL) {
    // pattern: If (l cond rc) => investigate further
    const jint rc = rt->as_IntConstant()->value();
    if (l->as_CompareOp() != NULL) {
      // pattern: If ((a cmp b) cond rc) => simplify to: If (x cond y) or: Goto
      CompareOp* cmp = l->as_CompareOp();
      bool unordered_is_less = cmp->op() == Bytecodes::_fcmpl || cmp->op() == Bytecodes::_dcmpl;
      BlockBegin* lss_sux = x->sux_for(is_true(-1, x->cond(), rc)); // successor for a < b
      BlockBegin* eql_sux = x->sux_for(is_true( 0, x->cond(), rc)); // successor for a = b
      BlockBegin* gtr_sux = x->sux_for(is_true(+1, x->cond(), rc)); // successor for a > b
      BlockBegin* nan_sux = unordered_is_less ? lss_sux : gtr_sux ; // successor for unordered
      // Note: At this point all successors (lss_sux, eql_sux, gtr_sux, nan_sux) are
      //       equal to x->tsux() or x->fsux(). Furthermore, nan_sux equals either
      //       lss_sux or gtr_sux.
      if (lss_sux == eql_sux && eql_sux == gtr_sux) {
        // all successors identical => simplify to: Goto
        set_canonical(new Goto(lss_sux, x->is_safepoint()));
      } else {
        // two successors differ and two successors are the same => simplify to: If (x cmp y)
        // determine new condition & successors
        If::Condition cond;
        BlockBegin* tsux = NULL;
        BlockBegin* fsux = NULL;
             if (lss_sux == eql_sux) { cond = If::leq; tsux = lss_sux; fsux = gtr_sux; }
        else if (lss_sux == gtr_sux) { cond = If::neq; tsux = lss_sux; fsux = eql_sux; }
        else if (eql_sux == gtr_sux) { cond = If::geq; tsux = eql_sux; fsux = lss_sux; }
        else                         { ShouldNotReachHere();                           }
        set_canonical(new If(cmp->x(), cond, nan_sux == tsux, cmp->y(), tsux, fsux, cmp->state_before(), x->is_safepoint()));
        set_bci(cmp->bci());
      }
    } else if (l->as_InstanceOf() != NULL) {
      // NOTE: Code permanently disabled for now since it leaves the old InstanceOf
      //       instruction in the graph (it is pinned). Need to fix this at some point.
      return;
      // pattern: If ((obj instanceof klass) cond rc) => simplify to: IfInstanceOf or: Goto
      InstanceOf* inst = l->as_InstanceOf();
      BlockBegin* is_inst_sux = x->sux_for(is_true(1, x->cond(), rc)); // successor for instanceof == 1
      BlockBegin* no_inst_sux = x->sux_for(is_true(0, x->cond(), rc)); // successor for instanceof == 0
      if (is_inst_sux == no_inst_sux && inst->is_loaded()) {
        // both successors identical and klass is loaded => simplify to: Goto
        set_canonical(new Goto(is_inst_sux, x->is_safepoint()));       
      } else {
        // successors differ => simplify to: IfInstanceOf
        set_canonical(new IfInstanceOf(inst->klass(), inst->obj(), true, inst->bci(), is_inst_sux, no_inst_sux));
      }
    }
  }
}