llvm/tools/llvm-reduce/deltas/ReduceInstructions.cpp

   1 //===- ReduceArguments.cpp - Specialized Delta Pass -----------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file implements a function which calls the Generic Delta pass in order
  10 // to reduce uninteresting Arguments from defined functions.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "ReduceInstructions.h"
  15
  16 using namespace llvm;
  17
  18 /// Removes out-of-chunk arguments from functions, and modifies their calls
  19 /// accordingly. It also removes allocations of out-of-chunk arguments.
  20 static void extractInstrFromModule(Oracle &O, Module &Program) {
  21   std::vector<Instruction *> InitInstToKeep;
  22
  23   for (auto &F : Program)
  24     for (auto &BB : F) {
  25       // Removing the terminator would make the block invalid. Only iterate over
  26       // instructions before the terminator.
  27       InitInstToKeep.push_back(BB.getTerminator());
  28       for (auto &Inst : make_range(BB.begin(), std::prev(BB.end())))
  29         if (O.shouldKeep())
  30           InitInstToKeep.push_back(&Inst);
  31     }
  32
  33   // We create a vector first, then convert it to a set, so that we don't have
  34   // to pay the cost of rebalancing the set frequently if the order we insert
  35   // the elements doesn't match the order they should appear inside the set.
  36   std::set<Instruction *> InstToKeep(InitInstToKeep.begin(),
  37                                      InitInstToKeep.end());
  38
  39   std::vector<Instruction *> InstToDelete;
  40   for (auto &F : Program)
  41     for (auto &BB : F)
  42       for (auto &Inst : BB)
  43         if (!InstToKeep.count(&Inst)) {
  44           Inst.replaceAllUsesWith(UndefValue::get(Inst.getType()));
  45           InstToDelete.push_back(&Inst);
  46         }
  47
  48   for (auto &I : InstToDelete)
  49     I->eraseFromParent();
  50 }
  51
  52 void llvm::reduceInstructionsDeltaPass(TestRunner &Test) {
  53   outs() << "*** Reducing Instructions...\n";
  54   runDeltaPass(Test, extractInstrFromModule);
  55 }