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       1             : //===- SimplifyCFG.h - Simplify and canonicalize the CFG --------*- C++ -*-===//
       2             : //
       3             : //                     The LLVM Compiler Infrastructure
       4             : //
       5             : // This file is distributed under the University of Illinois Open Source
       6             : // License. See LICENSE.TXT for details.
       7             : //
       8             : //===----------------------------------------------------------------------===//
       9             : /// \file
      10             : /// This file provides the interface for the pass responsible for both
      11             : /// simplifying and canonicalizing the CFG.
      12             : ///
      13             : //===----------------------------------------------------------------------===//
      14             : 
      15             : #ifndef LLVM_TRANSFORMS_SCALAR_SIMPLIFYCFG_H
      16             : #define LLVM_TRANSFORMS_SCALAR_SIMPLIFYCFG_H
      17             : 
      18             : #include "llvm/Transforms/Utils/Local.h"
      19             : #include "llvm/IR/Function.h"
      20             : #include "llvm/IR/PassManager.h"
      21             : 
      22             : namespace llvm {
      23             : 
      24             : /// A pass to simplify and canonicalize the CFG of a function.
      25             : ///
      26             : /// This pass iteratively simplifies the entire CFG of a function. It may change
      27             : /// or remove control flow to put the CFG into a canonical form expected by
      28             : /// other passes of the mid-level optimizer. Depending on the specified options,
      29             : /// it may further optimize control-flow to create non-canonical forms.
      30             : class SimplifyCFGPass : public PassInfoMixin<SimplifyCFGPass> {
      31             :   SimplifyCFGOptions Options;
      32             : 
      33             : public:
      34             :   /// The default constructor sets the pass options to create canonical IR,
      35             :   /// rather than optimal IR. That is, by default we bypass transformations that
      36             :   /// are likely to improve performance but make analysis for other passes more
      37             :   /// difficult.
      38             :   SimplifyCFGPass()
      39         547 :       : SimplifyCFGPass(SimplifyCFGOptions()
      40             :                             .forwardSwitchCondToPhi(false)
      41             :                             .convertSwitchToLookupTable(false)
      42             :                             .needCanonicalLoops(true)
      43         547 :                             .sinkCommonInsts(false)) {}
      44             : 
      45             : 
      46             :   /// Construct a pass with optional optimizations.
      47             :   SimplifyCFGPass(const SimplifyCFGOptions &PassOptions);
      48             : 
      49             :   /// Run the pass over the function.
      50             :   PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
      51             : };
      52             : 
      53             : }
      54             : 
      55             : #endif