src/share/vm/opto/reg_split.cpp

*** 525,534 ****
--- 525,535 ----
        }
  
        // Initialize needs_phi and needs_split
        bool needs_phi = false;
        bool needs_split = false;
+       bool has_phi = false;
        // Walk the predecessor blocks to check inputs for that live range
        // Grab predecessor block header
        n1 = b->pred(1);
        // Grab the appropriate reaching def info for inpidx
        pred = _cfg._bbs[n1->_idx];
*** 568,579 ****
            n3 = n2;
            u3 = u2;
          }
        }  // End for all potential Phi inputs
  
-       // If a phi is needed, check for it
-       if( needs_phi ) {
          // check block for appropriate phinode & update edges
          for( insidx = 1; insidx <= b->end_idx(); insidx++ ) {
            n1 = b->_nodes[insidx];
            // bail if this is not a phi
            phi = n1->is_Phi() ? n1->as_Phi() : NULL;
--- 569,578 ----
*** 585,599 ****
--- 584,602 ----
          }
          // must be looking at a phi
          if( Find_id(n1) == lidxs.at(slidx) ) {
            // found the necessary phi
            needs_phi = false;
+           has_phi = true;
            // initialize the Reaches entry for this LRG
            Reachblock[slidx] = phi;
            break;
          }  // end if found correct phi
        }  // end for all phi's
+ 
+       // If a phi is needed or exist, check for it
+       if( needs_phi || has_phi ) {
          // add new phinode if one not already found
          if( needs_phi ) {
            // create a new phi node and insert it into the block
            // type is taken from left over pointer to a predecessor
            assert(n3,"No non-NULL reaching DEF for a Phi");
*** 661,671 ****
      // locations.
  
      // Memoize any DOWN reaching definitions for use as DEBUG info
      for( insidx = 0; insidx < spill_cnt; insidx++ ) {
        debug_defs[insidx] = (UPblock[insidx]) ? NULL : Reachblock[insidx];
!       if( UPblock[insidx] )     // Memoize UP decision at block start
          UP_entry[insidx]->set( b->_pre_order );
      }
  
      //----------Walk Instructions in the Block and Split----------
      // For all non-phi instructions in the block
--- 664,674 ----
      // locations.
  
      // Memoize any DOWN reaching definitions for use as DEBUG info
      for( insidx = 0; insidx < spill_cnt; insidx++ ) {
        debug_defs[insidx] = (UPblock[insidx]) ? NULL : Reachblock[insidx];
!       if( UPblock[insidx] )     // Memorize UP decision at block start
          UP_entry[insidx]->set( b->_pre_order );
      }
  
      //----------Walk Instructions in the Block and Split----------
      // For all non-phi instructions in the block
*** 693,703 ****
                    break;
                  u = n->in(i);   // Else record it
                }
              }
              assert( u, "at least 1 valid input expected" );
!             if( i >= cnt ) {    // Didn't find 2+ unique inputs?
                n->replace_by(u); // Then replace with unique input
                n->disconnect_inputs(NULL);
                b->_nodes.remove(insidx);
                insidx--;
                b->_ihrp_index--;
--- 696,707 ----
                    break;
                  u = n->in(i);   // Else record it
                }
              }
              assert( u, "at least 1 valid input expected" );
!             if( i >= cnt ) {    // Found one unique input
!               assert(Find_id(n) == Find_id(u), "should be the same lrg");
                n->replace_by(u); // Then replace with unique input
                n->disconnect_inputs(NULL);
                b->_nodes.remove(insidx);
                insidx--;
                b->_ihrp_index--;