7886bd7ca5
The -polly-flatten-schedule pass reduces the number of scattering
dimensions in its isl_union_map form to make them easier to understand.
It is not meant to be used in production, only for debugging and
regression tests.
To illustrate, how it can make sets simpler, here is a lifetime set
used computed by the porposed DeLICM pass without flattening:
{ Stmt_reduction_for[0, 4] -> [0, 2, o2, o3] : o2 < 0;
Stmt_reduction_for[0, 4] -> [0, 1, o2, o3] : o2 >= 5;
Stmt_reduction_for[0, 4] -> [0, 1, 4, o3] : o3 > 0;
Stmt_reduction_for[0, i1] -> [0, 1, i1, 1] : 0 <= i1 <= 3;
Stmt_reduction_for[0, 4] -> [0, 2, 0, o3] : o3 <= 0 }
And here the same lifetime for a semantically identical one-dimensional
schedule:
{ Stmt_reduction_for[0, i1] -> [2 + 3i1] : 0 <= i1 <= 4 }
Differential Revision: https://reviews.llvm.org/D24310
llvm-svn: 280948
109 lines
3.4 KiB
C++
109 lines
3.4 KiB
C++
//===------ FlattenSchedule.cpp --------------------------------*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// Try to reduce the number of scatter dimension. Useful to make isl_union_map
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// schedules more understandable. This is only intended for debugging and
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// unittests, not for production use.
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//
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//===----------------------------------------------------------------------===//
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#include "polly/FlattenSchedule.h"
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#include "polly/FlattenAlgo.h"
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#include "polly/ScopInfo.h"
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#include "polly/ScopPass.h"
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#define DEBUG_TYPE "polly-flatten-schedule"
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using namespace polly;
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using namespace llvm;
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namespace {
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/// Print a schedule to @p OS.
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///
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/// Prints the schedule for each statements on a new line.
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void printSchedule(raw_ostream &OS, NonowningIslPtr<isl_union_map> Schedule,
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int indent) {
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foreachElt(Schedule, [&OS, indent](IslPtr<isl_map> Map) {
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OS.indent(indent) << Map << "\n";
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});
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}
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/// Flatten the schedule stored in an polly::Scop.
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class FlattenSchedule : public ScopPass {
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private:
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FlattenSchedule(const FlattenSchedule &) = delete;
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const FlattenSchedule &operator=(const FlattenSchedule &) = delete;
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std::shared_ptr<isl_ctx> IslCtx;
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IslPtr<isl_union_map> OldSchedule;
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public:
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static char ID;
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explicit FlattenSchedule() : ScopPass(ID) {}
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virtual void getAnalysisUsage(AnalysisUsage &AU) const override {
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AU.addRequiredTransitive<ScopInfoRegionPass>();
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AU.setPreservesAll();
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}
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virtual bool runOnScop(Scop &S) override {
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// Keep a reference to isl_ctx to ensure that it is not freed before we free
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// OldSchedule.
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IslCtx = S.getSharedIslCtx();
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DEBUG(dbgs() << "Going to flatten old schedule:\n");
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OldSchedule = give(S.getSchedule());
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DEBUG(printSchedule(dbgs(), OldSchedule, 2));
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auto Domains = give(S.getDomains());
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auto RestrictedOldSchedule = give(
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isl_union_map_intersect_domain(OldSchedule.copy(), Domains.copy()));
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DEBUG(dbgs() << "Old schedule with domains:\n");
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DEBUG(printSchedule(dbgs(), RestrictedOldSchedule, 2));
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auto NewSchedule = flattenSchedule(RestrictedOldSchedule);
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DEBUG(dbgs() << "Flattened new schedule:\n");
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DEBUG(printSchedule(dbgs(), NewSchedule, 2));
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NewSchedule =
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give(isl_union_map_gist_domain(NewSchedule.take(), Domains.take()));
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DEBUG(dbgs() << "Gisted, flattened new schedule:\n");
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DEBUG(printSchedule(dbgs(), NewSchedule, 2));
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S.setSchedule(NewSchedule.take());
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return false;
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}
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virtual void printScop(raw_ostream &OS, Scop &S) const override {
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OS << "Schedule before flattening {\n";
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printSchedule(OS, OldSchedule, 4);
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OS << "}\n\n";
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OS << "Schedule after flattening {\n";
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printSchedule(OS, give(S.getSchedule()), 4);
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OS << "}\n";
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}
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virtual void releaseMemory() override {
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OldSchedule = nullptr;
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IslCtx.reset();
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}
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};
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char FlattenSchedule::ID;
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} // anonymous namespace
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Pass *polly::createFlattenSchedulePass() { return new FlattenSchedule(); }
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INITIALIZE_PASS_BEGIN(FlattenSchedule, "polly-flatten-schedule",
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"Polly - Flatten schedule", false, false)
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INITIALIZE_PASS_END(FlattenSchedule, "polly-flatten-schedule",
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"Polly - Flatten schedule", false, false)
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