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. SimplifyCFGPass()38 SimplifyCFGPass() 39 : SimplifyCFGPass(SimplifyCFGOptions() 40 .forwardSwitchCondToPhi(false) 41 .convertSwitchToLookupTable(false) 42 .needCanonicalLoops(true) 43 .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 56