polly/lib/Transform/FlattenSchedule.cpp

   1 //===------ FlattenSchedule.cpp --------------------------------*- C++ -*-===//
   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 // Try to reduce the number of scatter dimension. Useful to make isl_union_map
  10 // schedules more understandable. This is only intended for debugging and
  11 // unittests, not for production use.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "polly/FlattenSchedule.h"
  16 #include "polly/FlattenAlgo.h"
  17 #include "polly/ScopInfo.h"
  18 #include "polly/ScopPass.h"
  19 #include "polly/Support/ISLOStream.h"
  20 #include "polly/Support/ISLTools.h"
  21 #include "polly/Support/PollyDebug.h"
  22 #define DEBUG_TYPE "polly-flatten-schedule"
  23
  24 using namespace polly;
  25 using namespace llvm;
  26
  27 namespace {
  28
  29 /// Print a schedule to @p OS.
  30 ///
  31 /// Prints the schedule for each statements on a new line.
  32 void printSchedule(raw_ostream &OS, const isl::union_map &Schedule,
  33                    int indent) {
  34   for (isl::map Map : Schedule.get_map_list())
  35     OS.indent(indent) << Map << "\n";
  36 }
  37
  38 /// Flatten the schedule stored in an polly::Scop.
  39 class FlattenSchedule final : public ScopPass {
  40 private:
  41   FlattenSchedule(const FlattenSchedule &) = delete;
  42   const FlattenSchedule &operator=(const FlattenSchedule &) = delete;
  43
  44   std::shared_ptr<isl_ctx> IslCtx;
  45   isl::union_map OldSchedule;
  46
  47 public:
  48   static char ID;
  49   explicit FlattenSchedule() : ScopPass(ID) {}
  50
  51   void getAnalysisUsage(AnalysisUsage &AU) const override {
  52     AU.addRequiredTransitive<ScopInfoRegionPass>();
  53     AU.setPreservesAll();
  54   }
  55
  56   bool runOnScop(Scop &S) override {
  57     // Keep a reference to isl_ctx to ensure that it is not freed before we free
  58     // OldSchedule.
  59     IslCtx = S.getSharedIslCtx();
  60
  61     POLLY_DEBUG(dbgs() << "Going to flatten old schedule:\n");
  62     OldSchedule = S.getSchedule();
  63     POLLY_DEBUG(printSchedule(dbgs(), OldSchedule, 2));
  64
  65     auto Domains = S.getDomains();
  66     auto RestrictedOldSchedule = OldSchedule.intersect_domain(Domains);
  67     POLLY_DEBUG(dbgs() << "Old schedule with domains:\n");
  68     POLLY_DEBUG(printSchedule(dbgs(), RestrictedOldSchedule, 2));
  69
  70     auto NewSchedule = flattenSchedule(RestrictedOldSchedule);
  71
  72     POLLY_DEBUG(dbgs() << "Flattened new schedule:\n");
  73     POLLY_DEBUG(printSchedule(dbgs(), NewSchedule, 2));
  74
  75     NewSchedule = NewSchedule.gist_domain(Domains);
  76     POLLY_DEBUG(dbgs() << "Gisted, flattened new schedule:\n");
  77     POLLY_DEBUG(printSchedule(dbgs(), NewSchedule, 2));
  78
  79     S.setSchedule(NewSchedule);
  80     return false;
  81   }
  82
  83   void printScop(raw_ostream &OS, Scop &S) const override {
  84     OS << "Schedule before flattening {\n";
  85     printSchedule(OS, OldSchedule, 4);
  86     OS << "}\n\n";
  87
  88     OS << "Schedule after flattening {\n";
  89     printSchedule(OS, S.getSchedule(), 4);
  90     OS << "}\n";
  91   }
  92
  93   void releaseMemory() override {
  94     OldSchedule = {};
  95     IslCtx.reset();
  96   }
  97 };
  98
  99 char FlattenSchedule::ID;
 100
 101 /// Print result from FlattenSchedule.
 102 class FlattenSchedulePrinterLegacyPass final : public ScopPass {
 103 public:
 104   static char ID;
 105
 106   FlattenSchedulePrinterLegacyPass()
 107       : FlattenSchedulePrinterLegacyPass(outs()) {}
 108   explicit FlattenSchedulePrinterLegacyPass(llvm::raw_ostream &OS)
 109       : ScopPass(ID), OS(OS) {}
 110
 111   bool runOnScop(Scop &S) override {
 112     FlattenSchedule &P = getAnalysis<FlattenSchedule>();
 113
 114     OS << "Printing analysis '" << P.getPassName() << "' for region: '"
 115        << S.getRegion().getNameStr() << "' in function '"
 116        << S.getFunction().getName() << "':\n";
 117     P.printScop(OS, S);
 118
 119     return false;
 120   }
 121
 122   void getAnalysisUsage(AnalysisUsage &AU) const override {
 123     ScopPass::getAnalysisUsage(AU);
 124     AU.addRequired<FlattenSchedule>();
 125     AU.setPreservesAll();
 126   }
 127
 128 private:
 129   llvm::raw_ostream &OS;
 130 };
 131
 132 char FlattenSchedulePrinterLegacyPass::ID = 0;
 133 } // anonymous namespace
 134
 135 Pass *polly::createFlattenSchedulePass() { return new FlattenSchedule(); }
 136
 137 Pass *polly::createFlattenSchedulePrinterLegacyPass(llvm::raw_ostream &OS) {
 138   return new FlattenSchedulePrinterLegacyPass(OS);
 139 }
 140
 141 INITIALIZE_PASS_BEGIN(FlattenSchedule, "polly-flatten-schedule",
 142                       "Polly - Flatten schedule", false, false)
 143 INITIALIZE_PASS_END(FlattenSchedule, "polly-flatten-schedule",
 144                     "Polly - Flatten schedule", false, false)
 145
 146 INITIALIZE_PASS_BEGIN(FlattenSchedulePrinterLegacyPass,
 147                       "polly-print-flatten-schedule",
 148                       "Polly - Print flattened schedule", false, false)
 149 INITIALIZE_PASS_DEPENDENCY(FlattenSchedule)
 150 INITIALIZE_PASS_END(FlattenSchedulePrinterLegacyPass,
 151                     "polly-print-flatten-schedule",
 152                     "Polly - Print flattened schedule", false, false)