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