Coverage Report

Created: 2019-07-24 05:18

/Users/buildslave/jenkins/workspace/clang-stage2-coverage-R/llvm/include/llvm/Transforms/Scalar/LoopUnrollPass.h
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//===- LoopUnrollPass.h -----------------------------------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_TRANSFORMS_SCALAR_LOOPUNROLLPASS_H
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#define LLVM_TRANSFORMS_SCALAR_LOOPUNROLLPASS_H
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#include "llvm/ADT/Optional.h"
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#include "llvm/Analysis/LoopAnalysisManager.h"
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#include "llvm/IR/PassManager.h"
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namespace llvm {
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extern cl::opt<bool> ForgetSCEVInLoopUnroll;
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class Function;
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class Loop;
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class LPMUpdater;
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/// Loop unroll pass that only does full loop unrolling.
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class LoopFullUnrollPass : public PassInfoMixin<LoopFullUnrollPass> {
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  const int OptLevel;
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  /// If false, use a cost model to determine whether unrolling of a loop is
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  /// profitable. If true, only loops that explicitly request unrolling via
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  /// metadata are considered. All other loops are skipped.
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  const bool OnlyWhenForced;
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  /// If true, forget all loops when unrolling. If false, forget top-most loop
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  /// of the currently processed loops, which removes one entry at a time from
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  /// the internal SCEV records. For large loops, the former is faster.
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  const bool ForgetSCEV;
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public:
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  explicit LoopFullUnrollPass(int OptLevel = 2, bool OnlyWhenForced = false,
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                              bool ForgetSCEV = false)
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      : OptLevel(OptLevel), OnlyWhenForced(OnlyWhenForced),
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        ForgetSCEV(ForgetSCEV) {}
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  PreservedAnalyses run(Loop &L, LoopAnalysisManager &AM,
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                        LoopStandardAnalysisResults &AR, LPMUpdater &U);
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};
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/// A set of parameters used to control various transforms performed by the
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/// LoopUnroll pass. Each of the boolean parameters can be set to:
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///      true - enabling the transformation.
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///      false - disabling the transformation.
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///      None - relying on a global default.
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///
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/// There is also OptLevel parameter, which is used for additional loop unroll
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/// tuning.
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///
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/// Intended use is to create a default object, modify parameters with
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/// additional setters and then pass it to LoopUnrollPass.
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///
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struct LoopUnrollOptions {
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  Optional<bool> AllowPartial;
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  Optional<bool> AllowPeeling;
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  Optional<bool> AllowRuntime;
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  Optional<bool> AllowUpperBound;
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  int OptLevel;
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  /// If false, use a cost model to determine whether unrolling of a loop is
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  /// profitable. If true, only loops that explicitly request unrolling via
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  /// metadata are considered. All other loops are skipped.
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  bool OnlyWhenForced;
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  /// If true, forget all loops when unrolling. If false, forget top-most loop
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  /// of the currently processed loops, which removes one entry at a time from
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  /// the internal SCEV records. For large loops, the former is faster.
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  const bool ForgetSCEV;
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  LoopUnrollOptions(int OptLevel = 2, bool OnlyWhenForced = false,
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                    bool ForgetSCEV = false)
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      : OptLevel(OptLevel), OnlyWhenForced(OnlyWhenForced),
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        ForgetSCEV(ForgetSCEV) {}
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  /// Enables or disables partial unrolling. When disabled only full unrolling
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  /// is allowed.
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  LoopUnrollOptions &setPartial(bool Partial) {
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    AllowPartial = Partial;
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    return *this;
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  }
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  /// Enables or disables unrolling of loops with runtime trip count.
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  LoopUnrollOptions &setRuntime(bool Runtime) {
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    AllowRuntime = Runtime;
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    return *this;
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  }
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  /// Enables or disables loop peeling.
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  LoopUnrollOptions &setPeeling(bool Peeling) {
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    AllowPeeling = Peeling;
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    return *this;
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  }
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  /// Enables or disables the use of trip count upper bound
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  /// in loop unrolling.
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  LoopUnrollOptions &setUpperBound(bool UpperBound) {
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    AllowUpperBound = UpperBound;
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    return *this;
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  }
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  // Sets "optimization level" tuning parameter for loop unrolling.
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  LoopUnrollOptions &setOptLevel(int O) {
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    OptLevel = O;
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    return *this;
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  }
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};
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/// Loop unroll pass that will support both full and partial unrolling.
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/// It is a function pass to have access to function and module analyses.
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/// It will also put loops into canonical form (simplified and LCSSA).
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class LoopUnrollPass : public PassInfoMixin<LoopUnrollPass> {
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  LoopUnrollOptions UnrollOpts;
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public:
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  /// This uses the target information (or flags) to control the thresholds for
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  /// different unrolling stategies but supports all of them.
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  explicit LoopUnrollPass(LoopUnrollOptions UnrollOpts = {})
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      : UnrollOpts(UnrollOpts) {}
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  PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
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};
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} // end namespace llvm
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#endif // LLVM_TRANSFORMS_SCALAR_LOOPUNROLLPASS_H