text: /*
   * Copyright 2004-2018 Cray Inc.
   * Other additional copyright holders may be indicated within.
   *
   * The entirety of this work is licensed under the Apache License,
   * Version 2.0 (the "License"); you may not use this file except
   * in compliance with the License.
   *
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  #include "astutil.h"
  #include "expr.h"
  #include "ForallStmt.h"
  #include "optimizations.h"
  #include "stmt.h"
  #include "LoopStmt.h"
  #include <vector>
  #include <set>
  #include "stlUtil.h"
  
  //
  // Removes gotos where the label immediately follows the goto and
  // unused labels
  //
  void removeUnnecessaryGotos(FnSymbol* fn, bool removeEpilogueLabel) {
    std::vector<BaseAST*> asts;
    std::set<BaseAST*> labels;
    std::set<LoopStmt*> loops;
    std::vector<ForallStmt*> foralls;
    collect_asts(fn, asts);
    for_vector(BaseAST, ast, asts) {
      if (GotoStmt* gotoStmt = toGotoStmt(ast)) {
        DefExpr* def = toDefExpr(gotoStmt->next);
        SymExpr* label = toSymExpr(gotoStmt->label);
        INT_ASSERT(label);
        if (def && def->sym == label->symbol())
          gotoStmt->remove();
        else
          labels.insert(label->symbol());
      } else if (LoopStmt* loop = toLoopStmt(ast)) {
        loops.insert(loop);
      } else if (ForallStmt* forall = toForallStmt(ast)) {
        foralls.push_back(forall);
      }
    }
  
    for_vector(BaseAST, ast2, asts) {
      if (DefExpr* def = toDefExpr(ast2))
        if (LabelSymbol* label = toLabelSymbol(def->sym))
          if (!label->hasFlag(FLAG_EPILOGUE_LABEL) || removeEpilogueLabel)
            if (labels.find(label) == labels.end())
              def->remove();
    }
  
    for_set(LoopStmt, loop, loops) {
      LabelSymbol* breakLabel    = loop->breakLabelGet();
      LabelSymbol* continueLabel = loop->continueLabelGet();
  
      if (breakLabel && isAlive(breakLabel) == false) {
        loop->breakLabelSet(NULL);
      }
  
      if (continueLabel && isAlive(continueLabel) == false) {
        loop->continueLabelSet(NULL);
      }
    }
  
    for_vector(ForallStmt, forall, foralls) {
      if (forall->fContinueLabel && !isAlive(forall->fContinueLabel))
        forall->fContinueLabel = NULL;
      if (forall->fErrorHandlerLabel && !isAlive(forall->fErrorHandlerLabel))
        forall->fErrorHandlerLabel = NULL;
    }
  }
  