include/llvm/Transforms/Scalar/SimplifyCFG.h

   1 //===- SimplifyCFG.h - Simplify and canonicalize the CFG --------*- 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 /// \file
   9 /// This file provides the interface for the pass responsible for both
  10 /// simplifying and canonicalizing the CFG.
  11 ///
  12 //===----------------------------------------------------------------------===//
  13
  14 #ifndef LLVM_TRANSFORMS_SCALAR_SIMPLIFYCFG_H
  15 #define LLVM_TRANSFORMS_SCALAR_SIMPLIFYCFG_H
  16
  17 #include "llvm/Transforms/Utils/Local.h"
  18 #include "llvm/IR/Function.h"
  19 #include "llvm/IR/PassManager.h"
  20
  21 namespace llvm {
  22
  23 /// A pass to simplify and canonicalize the CFG of a function.
  24 ///
  25 /// This pass iteratively simplifies the entire CFG of a function. It may change
  26 /// or remove control flow to put the CFG into a canonical form expected by
  27 /// other passes of the mid-level optimizer. Depending on the specified options,
  28 /// it may further optimize control-flow to create non-canonical forms.
  29 class SimplifyCFGPass : public PassInfoMixin<SimplifyCFGPass> {
  30   SimplifyCFGOptions Options;
  31
  32 public:
  33   /// The default constructor sets the pass options to create canonical IR,
  34   /// rather than optimal IR. That is, by default we bypass transformations that
  35   /// are likely to improve performance but make analysis for other passes more
  36   /// difficult.
  37   SimplifyCFGPass()
  38       : SimplifyCFGPass(SimplifyCFGOptions()
  39                             .forwardSwitchCondToPhi(false)
  40                             .convertSwitchToLookupTable(false)
  41                             .needCanonicalLoops(true)
  42                             .sinkCommonInsts(false)) {}
  43
  44
  45   /// Construct a pass with optional optimizations.
  46   SimplifyCFGPass(const SimplifyCFGOptions &PassOptions);
  47
  48   /// Run the pass over the function.
  49   PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
  50 };
  51
  52 }
  53
  54 #endif