Exemple #1
0
//------------------------------find_unswitching_candidate-----------------------------
// Find candidate "if" for unswitching
IfNode* PhaseIdealLoop::find_unswitching_candidate(const IdealLoopTree *loop) const {

  // Find first invariant test that doesn't exit the loop
  LoopNode *head = loop->_head->as_Loop();
  IfNode* unswitch_iff = NULL;
  Node* n = head->in(LoopNode::LoopBackControl);
  while (n != head) {
    Node* n_dom = idom(n);
    if (n->is_Region()) {
      if (n_dom->is_If()) {
        IfNode* iff = n_dom->as_If();
        if (iff->in(1)->is_Bool()) {
          BoolNode* bol = iff->in(1)->as_Bool();
          if (bol->in(1)->is_Cmp()) {
            // If condition is invariant and not a loop exit,
            // then found reason to unswitch.
            if (loop->is_invariant(bol) && !loop->is_loop_exit(iff)) {
              unswitch_iff = iff;
            }
          }
        }
      }
    }
    n = n_dom;
  }
  return unswitch_iff;
}
Exemple #2
0
void
XmlRenderer::renderNode(const BoolNode& node)
{
  if (fShowNodeType) {
    StringBuffer attrs;
    attrs << " ty='" << xmlEncode(node.type().typeId()) << "'";
    displayEmptyTagAttrs(node.value() ? "true" : "false",
                         StrHelper(attrs.toString()));
  }
  else
    displayEmptyTag(node.value() ? "true" : "false");

  if (fShowNodeType)
    fReferencedTypes.insert(std::make_pair(node.type().typeId(),
                                           node.type()));
}
IfNode* MathExactNode::if_node() const {
  BoolNode* boolnode = bool_node();
  IfNode* ifnode = boolnode->unique_out()->as_If();
  assert(ifnode != NULL, "must have IfNode");
  return ifnode;
}
//=============================================================================
//------------------------------AbsNode----------------------------------------
Node *AbsNode::is_absolute( PhaseGVN *phase, Node *phi_root ) {

  int chs = 0;			// No need to change sign of result
  int abs = 1;			// Assume ABS is being performed
  int typ = 0;			// Assume integer ABS

  // ABS ends with the merge of 2 control flow paths.  Find the merge point.
  Node *region = phi_root->in(0);
  if( region->req() != 3 ) return NULL;
  if( phi_root->req() != 3 ) return NULL;

  // Next up is the true/false control bits
  Node *iff = region->in(1);
  if( !iff ) return NULL;
  Node *ift = region->in(2);
  if( !ift ) return NULL;
  if( iff->Opcode() == Op_IfFalse &&
      ift->Opcode() == Op_IfTrue ) {
  } else if( iff->Opcode() == Op_IfTrue &&
	     ift->Opcode() == Op_IfFalse ) {
    chs = 1-chs;		// Test is reversed
  } else return NULL;		// Not from same IF
  Node *fif = iff->in(0);
  if( ift->in(0) != fif ) return NULL;	// Not from same IF

  // Roll up the predicate chain; get the Bool, CmpX
  BoolNode *bol = fif->in(1)->is_Bool();
  if (bol == NULL) return NULL;   // test is dead (constant true or false)
  switch( bol->_test._test ) {
  case BoolTest::lt: 			   break;
  case BoolTest::le:                       break;
  case BoolTest::gt: 	      chs = 1-chs; break;
  case BoolTest::ge:          chs = 1-chs; break;
  case BoolTest::eq: abs = 0;              break; // Not an ABS function
  case BoolTest::ne: abs = 0; chs = 1-chs; break; // Not an ABS function
  }

  // Test is next
  Node *cmp = bol->in(1);
  const Type *tzero = NULL;
  switch( cmp->Opcode() ) {
  case Op_CmpF:    tzero = TypeF::ZERO; typ = 1; break; // Float ABS
  case Op_CmpD:    tzero = TypeD::ZERO; typ = 2; break; // Double ABS
  default: return NULL;
  }

  // Left of float is value being ABS'd, right is a zero
  Node *x = cmp->in(1);
  if( phase->type(cmp->in(2)) != tzero ) return NULL;

  // Next get the 2 pieces being selected, one is the original value
  // and the other is the negated value.
  Node *neg_x = phi_root->in(2);
  if( phi_root->in(1) == x ) {
  } else if( phi_root->in(2) == x ) {
    chs = 1-chs;
    neg_x = phi_root->in(1);
  }
  // Check negated value for really negating
  int negop = neg_x->Opcode();
  if( tzero == TypeF::ZERO ) {
    // Allow either NegF(x) or SubF(0,X) and fail out for all others
    if( !(negop == Op_NegF && neg_x->in(1) == x ) &&
        !(negop == Op_SubF && neg_x->in(2) == x && phase->type(neg_x->in(1)) == tzero ) )
      return NULL;
  } else {
    // Allow either NegD(x) or SubD(0,X) and fail out for all others
    if( !(negop == Op_NegD && neg_x->in(1) == x ) &&
        !(negop == Op_SubD && neg_x->in(2) == x && phase->type(neg_x->in(1)) == tzero ) )
      return NULL;
  }

  // Yeah-ha!  A Hit!  Now emit either: abs or nothing, then
  // a chs or nothing, of type float or double
  if( abs ) {			// Doing ABS, or doing ID function
    if( typ == 1 ) x = new (2) AbsFNode(x);
    else           x = new (2) AbsDNode(x);
    if( chs )      x = phase->transform(x); // transform all "new" interior nodes
  }
  if( chs ) {			// Simply negating result?
    if( typ == 1 ) x = new (2) NegFNode(x);
    else           x = new (2) NegDNode(x);
  }

  return x;
}
Exemple #5
0
//------------------------------split_if---------------------------------------
// Look for places where we merge constants, then test on the merged value.
// If the IF test will be constant folded on the path with the constant, we
// win by splitting the IF to before the merge point.
static Node* split_if(IfNode *iff, PhaseIterGVN *igvn) {
  // I could be a lot more general here, but I'm trying to squeeze this
  // in before the Christmas '98 break so I'm gonna be kinda restrictive
  // on the patterns I accept.  CNC

  // Look for a compare of a constant and a merged value
  Node *i1 = iff->in(1);
  if( !i1->is_Bool() ) return NULL;
  BoolNode *b = i1->as_Bool();
  Node *cmp = b->in(1);
  if( !cmp->is_Cmp() ) return NULL;
  i1 = cmp->in(1);
  if( i1 == NULL || !i1->is_Phi() ) return NULL;
  PhiNode *phi = i1->as_Phi();
  if( phi->is_copy() ) return NULL;
  Node *con2 = cmp->in(2);
  if( !con2->is_Con() ) return NULL;
  // See that the merge point contains some constants
  Node *con1=NULL;
  uint i4;
  for( i4 = 1; i4 < phi->req(); i4++ ) {
    con1 = phi->in(i4);
    if( !con1 ) return NULL;    // Do not optimize partially collapsed merges
    if( con1->is_Con() ) break; // Found a constant
    // Also allow null-vs-not-null checks
    const TypePtr *tp = igvn->type(con1)->isa_ptr();
    if( tp && tp->_ptr == TypePtr::NotNull )
      break;
  }
  if( i4 >= phi->req() ) return NULL; // Found no constants

  igvn->C->set_has_split_ifs(true); // Has chance for split-if

  // Make sure that the compare can be constant folded away
  Node *cmp2 = cmp->clone();
  cmp2->set_req(1,con1);
  cmp2->set_req(2,con2);
  const Type *t = cmp2->Value(igvn);
  // This compare is dead, so whack it!
  igvn->remove_dead_node(cmp2);
  if( !t->singleton() ) return NULL;

  // No intervening control, like a simple Call
  Node *r = iff->in(0);
  if( !r->is_Region() ) return NULL;
  if( phi->region() != r ) return NULL;
  // No other users of the cmp/bool
  if (b->outcnt() != 1 || cmp->outcnt() != 1) {
    //tty->print_cr("many users of cmp/bool");
    return NULL;
  }

  // Make sure we can determine where all the uses of merged values go
  for (DUIterator_Fast jmax, j = r->fast_outs(jmax); j < jmax; j++) {
    Node* u = r->fast_out(j);
    if( u == r ) continue;
    if( u == iff ) continue;
    if( u->outcnt() == 0 ) continue; // use is dead & ignorable
    if( !u->is_Phi() ) {
      /*
      if( u->is_Start() ) {
        tty->print_cr("Region has inlined start use");
      } else {
        tty->print_cr("Region has odd use");
        u->dump(2);
      }*/
      return NULL;
    }
    if( u != phi ) {
      // CNC - do not allow any other merged value
      //tty->print_cr("Merging another value");
      //u->dump(2);
      return NULL;
    }
    // Make sure we can account for all Phi uses
    for (DUIterator_Fast kmax, k = u->fast_outs(kmax); k < kmax; k++) {
      Node* v = u->fast_out(k); // User of the phi
      // CNC - Allow only really simple patterns.
      // In particular I disallow AddP of the Phi, a fairly common pattern
      if( v == cmp ) continue;  // The compare is OK
      if( (v->is_ConstraintCast()) &&
          v->in(0)->in(0) == iff )
        continue;               // CastPP/II of the IfNode is OK
      // Disabled following code because I cannot tell if exactly one
      // path dominates without a real dominator check. CNC 9/9/1999
      //uint vop = v->Opcode();
      //if( vop == Op_Phi ) {     // Phi from another merge point might be OK
      //  Node *r = v->in(0);     // Get controlling point
      //  if( !r ) return NULL;   // Degraded to a copy
      //  // Find exactly one path in (either True or False doms, but not IFF)
      //  int cnt = 0;
      //  for( uint i = 1; i < r->req(); i++ )
      //    if( r->in(i) && r->in(i)->in(0) == iff )
      //      cnt++;
      //  if( cnt == 1 ) continue; // Exactly one of True or False guards Phi
      //}
      if( !v->is_Call() ) {
        /*
        if( v->Opcode() == Op_AddP ) {
          tty->print_cr("Phi has AddP use");
        } else if( v->Opcode() == Op_CastPP ) {
          tty->print_cr("Phi has CastPP use");
        } else if( v->Opcode() == Op_CastII ) {
          tty->print_cr("Phi has CastII use");
        } else {
          tty->print_cr("Phi has use I cant be bothered with");
        }
        */
      }
      return NULL;

      /* CNC - Cut out all the fancy acceptance tests
      // Can we clone this use when doing the transformation?
      // If all uses are from Phis at this merge or constants, then YES.
      if( !v->in(0) && v != cmp ) {
        tty->print_cr("Phi has free-floating use");
        v->dump(2);
        return NULL;
      }
      for( uint l = 1; l < v->req(); l++ ) {
        if( (!v->in(l)->is_Phi() || v->in(l)->in(0) != r) &&
            !v->in(l)->is_Con() ) {
          tty->print_cr("Phi has use");
          v->dump(2);
          return NULL;
        } // End of if Phi-use input is neither Phi nor Constant
      } // End of for all inputs to Phi-use
      */
    } // End of for all uses of Phi
  } // End of for all uses of Region

  // Only do this if the IF node is in a sane state
  if (iff->outcnt() != 2)
    return NULL;

  // Got a hit!  Do the Mondo Hack!
  //
  //ABC  a1c   def   ghi            B     1     e     h   A C   a c   d f   g i
  // R - Phi - Phi - Phi            Rc - Phi - Phi - Phi   Rx - Phi - Phi - Phi
  //     cmp - 2                         cmp - 2               cmp - 2
  //       bool                            bool_c                bool_x
  //       if                               if_c                  if_x
  //      T  F                              T  F                  T  F
  // ..s..    ..t ..                   ..s..    ..t..        ..s..    ..t..
  //
  // Split the paths coming into the merge point into 2 separate groups of
  // merges.  On the left will be all the paths feeding constants into the
  // Cmp's Phi.  On the right will be the remaining paths.  The Cmp's Phi
  // will fold up into a constant; this will let the Cmp fold up as well as
  // all the control flow.  Below the original IF we have 2 control
  // dependent regions, 's' and 't'.  Now we will merge the two paths
  // just prior to 's' and 't' from the two IFs.  At least 1 path (and quite
  // likely 2 or more) will promptly constant fold away.
  PhaseGVN *phase = igvn;

  // Make a region merging constants and a region merging the rest
  uint req_c = 0;
  Node* predicate_proj = NULL;
  for (uint ii = 1; ii < r->req(); ii++) {
    if (phi->in(ii) == con1) {
      req_c++;
    }
    Node* proj = PhaseIdealLoop::find_predicate(r->in(ii));
    if (proj != NULL) {
      assert(predicate_proj == NULL, "only one predicate entry expected");
      predicate_proj = proj;
    }
  }
  Node* predicate_c = NULL;
  Node* predicate_x = NULL;
  bool counted_loop = r->is_CountedLoop();

  Node *region_c = new (igvn->C, req_c + 1) RegionNode(req_c + 1);
  Node *phi_c    = con1;
  uint  len      = r->req();
  Node *region_x = new (igvn->C, len - req_c) RegionNode(len - req_c);
  Node *phi_x    = PhiNode::make_blank(region_x, phi);
  for (uint i = 1, i_c = 1, i_x = 1; i < len; i++) {
    if (phi->in(i) == con1) {
      region_c->init_req( i_c++, r  ->in(i) );
      if (r->in(i) == predicate_proj)
        predicate_c = predicate_proj;
    } else {
      region_x->init_req( i_x,   r  ->in(i) );
      phi_x   ->init_req( i_x++, phi->in(i) );
      if (r->in(i) == predicate_proj)
        predicate_x = predicate_proj;
    }
  }
  if (predicate_c != NULL && (req_c > 1)) {
    assert(predicate_x == NULL, "only one predicate entry expected");
    predicate_c = NULL; // Do not clone predicate below merge point
  }
  if (predicate_x != NULL && ((len - req_c) > 2)) {
    assert(predicate_c == NULL, "only one predicate entry expected");
    predicate_x = NULL; // Do not clone predicate below merge point
  }

  // Register the new RegionNodes but do not transform them.  Cannot
  // transform until the entire Region/Phi conglomerate has been hacked
  // as a single huge transform.
  igvn->register_new_node_with_optimizer( region_c );
  igvn->register_new_node_with_optimizer( region_x );
  // Prevent the untimely death of phi_x.  Currently he has no uses.  He is
  // about to get one.  If this only use goes away, then phi_x will look dead.
  // However, he will be picking up some more uses down below.
  Node *hook = new (igvn->C, 4) Node(4);
  hook->init_req(0, phi_x);
  hook->init_req(1, phi_c);
  phi_x = phase->transform( phi_x );

  // Make the compare
  Node *cmp_c = phase->makecon(t);
  Node *cmp_x = cmp->clone();
  cmp_x->set_req(1,phi_x);
  cmp_x->set_req(2,con2);
  cmp_x = phase->transform(cmp_x);
  // Make the bool
  Node *b_c = phase->transform(new (igvn->C, 2) BoolNode(cmp_c,b->_test._test));
  Node *b_x = phase->transform(new (igvn->C, 2) BoolNode(cmp_x,b->_test._test));
  // Make the IfNode
  IfNode *iff_c = new (igvn->C, 2) IfNode(region_c,b_c,iff->_prob,iff->_fcnt);
  igvn->set_type_bottom(iff_c);
  igvn->_worklist.push(iff_c);
  hook->init_req(2, iff_c);

  IfNode *iff_x = new (igvn->C, 2) IfNode(region_x,b_x,iff->_prob, iff->_fcnt);
  igvn->set_type_bottom(iff_x);
  igvn->_worklist.push(iff_x);
  hook->init_req(3, iff_x);

  // Make the true/false arms
  Node *iff_c_t = phase->transform(new (igvn->C, 1) IfTrueNode (iff_c));
  Node *iff_c_f = phase->transform(new (igvn->C, 1) IfFalseNode(iff_c));
  if (predicate_c != NULL) {
    assert(predicate_x == NULL, "only one predicate entry expected");
    // Clone loop predicates to each path
    iff_c_t = igvn->clone_loop_predicates(predicate_c, iff_c_t, !counted_loop);
    iff_c_f = igvn->clone_loop_predicates(predicate_c, iff_c_f, !counted_loop);
  }
  Node *iff_x_t = phase->transform(new (igvn->C, 1) IfTrueNode (iff_x));
  Node *iff_x_f = phase->transform(new (igvn->C, 1) IfFalseNode(iff_x));
  if (predicate_x != NULL) {
    assert(predicate_c == NULL, "only one predicate entry expected");
    // Clone loop predicates to each path
    iff_x_t = igvn->clone_loop_predicates(predicate_x, iff_x_t, !counted_loop);
    iff_x_f = igvn->clone_loop_predicates(predicate_x, iff_x_f, !counted_loop);
  }

  // Merge the TRUE paths
  Node *region_s = new (igvn->C, 3) RegionNode(3);
  igvn->_worklist.push(region_s);
  region_s->init_req(1, iff_c_t);
  region_s->init_req(2, iff_x_t);
  igvn->register_new_node_with_optimizer( region_s );

  // Merge the FALSE paths
  Node *region_f = new (igvn->C, 3) RegionNode(3);
  igvn->_worklist.push(region_f);
  region_f->init_req(1, iff_c_f);
  region_f->init_req(2, iff_x_f);
  igvn->register_new_node_with_optimizer( region_f );

  igvn->hash_delete(cmp);// Remove soon-to-be-dead node from hash table.
  cmp->set_req(1,NULL);  // Whack the inputs to cmp because it will be dead
  cmp->set_req(2,NULL);
  // Check for all uses of the Phi and give them a new home.
  // The 'cmp' got cloned, but CastPP/IIs need to be moved.
  Node *phi_s = NULL;     // do not construct unless needed
  Node *phi_f = NULL;     // do not construct unless needed
  for (DUIterator_Last i2min, i2 = phi->last_outs(i2min); i2 >= i2min; --i2) {
    Node* v = phi->last_out(i2);// User of the phi
    igvn->hash_delete(v);       // Have to fixup other Phi users
    igvn->_worklist.push(v);
    uint vop = v->Opcode();
    Node *proj = NULL;
    if( vop == Op_Phi ) {       // Remote merge point
      Node *r = v->in(0);
      for (uint i3 = 1; i3 < r->req(); i3++)
        if (r->in(i3) && r->in(i3)->in(0) == iff) {
          proj = r->in(i3);
          break;
        }
    } else if( v->is_ConstraintCast() ) {
      proj = v->in(0);          // Controlling projection
    } else {
      assert( 0, "do not know how to handle this guy" );
    }

    Node *proj_path_data, *proj_path_ctrl;
    if( proj->Opcode() == Op_IfTrue ) {
      if( phi_s == NULL ) {
        // Only construct phi_s if needed, otherwise provides
        // interfering use.
        phi_s = PhiNode::make_blank(region_s,phi);
        phi_s->init_req( 1, phi_c );
        phi_s->init_req( 2, phi_x );
        hook->add_req(phi_s);
        phi_s = phase->transform(phi_s);
      }
      proj_path_data = phi_s;
      proj_path_ctrl = region_s;
    } else {
      if( phi_f == NULL ) {
        // Only construct phi_f if needed, otherwise provides
        // interfering use.
        phi_f = PhiNode::make_blank(region_f,phi);
        phi_f->init_req( 1, phi_c );
        phi_f->init_req( 2, phi_x );
        hook->add_req(phi_f);
        phi_f = phase->transform(phi_f);
      }
      proj_path_data = phi_f;
      proj_path_ctrl = region_f;
    }

    // Fixup 'v' for for the split
    if( vop == Op_Phi ) {       // Remote merge point
      uint i;
      for( i = 1; i < v->req(); i++ )
        if( v->in(i) == phi )
          break;
      v->set_req(i, proj_path_data );
    } else if( v->is_ConstraintCast() ) {
      v->set_req(0, proj_path_ctrl );
      v->set_req(1, proj_path_data );
    } else
      ShouldNotReachHere();
  }

  // Now replace the original iff's True/False with region_s/region_t.
  // This makes the original iff go dead.
  for (DUIterator_Last i3min, i3 = iff->last_outs(i3min); i3 >= i3min; --i3) {
    Node* p = iff->last_out(i3);
    assert( p->Opcode() == Op_IfTrue || p->Opcode() == Op_IfFalse, "" );
    Node *u = (p->Opcode() == Op_IfTrue) ? region_s : region_f;
    // Replace p with u
    igvn->add_users_to_worklist(p);
    for (DUIterator_Last lmin, l = p->last_outs(lmin); l >= lmin;) {
      Node* x = p->last_out(l);
      igvn->hash_delete(x);
      uint uses_found = 0;
      for( uint j = 0; j < x->req(); j++ ) {
        if( x->in(j) == p ) {
          x->set_req(j, u);
          uses_found++;
        }
      }
      l -= uses_found;    // we deleted 1 or more copies of this edge
    }
    igvn->remove_dead_node(p);
  }

  // Force the original merge dead
  igvn->hash_delete(r);
  // First, remove region's dead users.
  for (DUIterator_Last lmin, l = r->last_outs(lmin); l >= lmin;) {
    Node* u = r->last_out(l);
    if( u == r ) {
      r->set_req(0, NULL);
    } else {
      assert(u->outcnt() == 0, "only dead users");
      igvn->remove_dead_node(u);
    }
    l -= 1;
  }
  igvn->remove_dead_node(r);

  // Now remove the bogus extra edges used to keep things alive
  igvn->remove_dead_node( hook );

  // Must return either the original node (now dead) or a new node
  // (Do not return a top here, since that would break the uniqueness of top.)
  return new (igvn->C, 1) ConINode(TypeInt::ZERO);
}
Exemple #6
0
//------------------------------is_range_check---------------------------------
// Return 0 if not a range check.  Return 1 if a range check and set index and
// offset.  Return 2 if we had to negate the test.  Index is NULL if the check
// is versus a constant.
int IfNode::is_range_check(Node* &range, Node* &index, jint &offset) {
  Node* b = in(1);
  if (b == NULL || !b->is_Bool())  return 0;
  BoolNode* bn = b->as_Bool();
  Node* cmp = bn->in(1);
  if (cmp == NULL)  return 0;
  if (cmp->Opcode() != Op_CmpU)  return 0;

  Node* l = cmp->in(1);
  Node* r = cmp->in(2);
  int flip_test = 1;
  if (bn->_test._test == BoolTest::le) {
    l = cmp->in(2);
    r = cmp->in(1);
    flip_test = 2;
  } else if (bn->_test._test != BoolTest::lt) {
    return 0;
  }
  if (l->is_top())  return 0;   // Top input means dead test
  if (r->Opcode() != Op_LoadRange)  return 0;

  // We have recognized one of these forms:
  //  Flip 1:  If (Bool[<] CmpU(l, LoadRange)) ...
  //  Flip 2:  If (Bool[<=] CmpU(LoadRange, l)) ...

  // Make sure it's a real range check by requiring an uncommon trap
  // along the OOB path.  Otherwise, it's possible that the user wrote
  // something which optimized to look like a range check but behaves
  // in some other way.
  Node* iftrap = proj_out(flip_test == 2 ? true : false);
  bool found_trap = false;
  if (iftrap != NULL) {
    Node* u = iftrap->unique_ctrl_out();
    if (u != NULL) {
      // It could be a merge point (Region) for uncommon trap.
      if (u->is_Region()) {
        Node* c = u->unique_ctrl_out();
        if (c != NULL) {
          iftrap = u;
          u = c;
        }
      }
      if (u->in(0) == iftrap && u->is_CallStaticJava()) {
        int req = u->as_CallStaticJava()->uncommon_trap_request();
        if (Deoptimization::trap_request_reason(req) ==
            Deoptimization::Reason_range_check) {
          found_trap = true;
        }
      }
    }
  }
  if (!found_trap)  return 0;   // sorry, no cigar

  // Look for index+offset form
  Node* ind = l;
  jint  off = 0;
  if (l->is_top()) {
    return 0;
  } else if (l->is_Add()) {
    if ((off = l->in(1)->find_int_con(0)) != 0) {
      ind = l->in(2);
    } else if ((off = l->in(2)->find_int_con(0)) != 0) {
      ind = l->in(1);
    }
  } else if ((off = l->find_int_con(-1)) >= 0) {
    // constant offset with no variable index
    ind = NULL;
  } else {
    // variable index with no constant offset (or dead negative index)
    off = 0;
  }

  // Return all the values:
  index  = ind;
  offset = off;
  range  = r;
  return flip_test;
}