1 //===-- Local.h - Functions to perform local transformations -----*- C++ -*--=//
3 // This family of functions perform various local transformations to the
6 //===----------------------------------------------------------------------===//
8 #ifndef LLVM_TRANSFORMS_UTILS_LOCAL_H
9 #define LLVM_TRANSFORMS_UTILS_LOCAL_H
11 #include "llvm/Function.h"
14 //===----------------------------------------------------------------------===//
15 // Local constant propagation...
18 /// doConstantPropagation - Constant prop a specific instruction. Returns true
19 /// and potentially moves the iterator if constant propagation was performed.
21 bool doConstantPropagation(BasicBlock::iterator &I);
23 /// ConstantFoldTerminator - If a terminator instruction is predicated on a
24 /// constant value, convert it into an unconditional branch to the constant
25 /// destination. This is a nontrivial operation because the successors of this
26 /// basic block must have their PHI nodes updated.
28 bool ConstantFoldTerminator(BasicBlock *BB);
31 //===----------------------------------------------------------------------===//
32 // Local dead code elimination...
35 /// isInstructionTriviallyDead - Return true if the result produced by the
36 /// instruction is not used, and the instruction has no side effects.
38 bool isInstructionTriviallyDead(Instruction *I);
41 /// dceInstruction - Inspect the instruction at *BBI and figure out if it
42 /// isTriviallyDead. If so, remove the instruction and update the iterator to
43 /// point to the instruction that immediately succeeded the original
46 bool dceInstruction(BasicBlock::iterator &BBI);
49 //===----------------------------------------------------------------------===//
50 // Control Flow Graph Restructuring...
53 /// SimplifyCFG - This function is used to do simplification of a CFG. For
54 /// example, it adjusts branches to branches to eliminate the extra hop, it
55 /// eliminates unreachable basic blocks, and does other "peephole" optimization
56 /// of the CFG. It returns true if a modification was made, possibly deleting
57 /// the basic block that was pointed to.
59 /// WARNING: The entry node of a method may not be simplified.
61 bool SimplifyCFG(BasicBlock *BB);