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"
13 //===----------------------------------------------------------------------===//
14 // Local constant propogation...
17 // doConstantPropogation - Constant prop a specific instruction. Returns true
18 // and potentially moves the iterator if constant propogation was performed.
20 bool doConstantPropogation(BasicBlock::iterator &I);
22 // ConstantFoldTerminator - If a terminator instruction is predicated on a
23 // constant value, convert it into an unconditional branch to the constant
24 // destination. This is a nontrivial operation because the successors of this
25 // basic block must have their PHI nodes updated.
27 bool ConstantFoldTerminator(BasicBlock *BB);
30 //===----------------------------------------------------------------------===//
31 // Local dead code elimination...
34 // isInstructionTriviallyDead - Return true if the result produced by the
35 // instruction is not used, and the instruction has no side effects.
37 bool isInstructionTriviallyDead(Instruction *I);
40 // dceInstruction - Inspect the instruction at *BBI and figure out if it
41 // isTriviallyDead. If so, remove the instruction and update the iterator to
42 // point to the instruction that immediately succeeded the original instruction.
44 bool dceInstruction(BasicBlock::iterator &BBI);
47 //===----------------------------------------------------------------------===//
48 // Control Flow Graph Restructuring...
51 // SimplifyCFG - This function is used to do simplification of a CFG. For
52 // example, it adjusts branches to branches to eliminate the extra hop, it
53 // eliminates unreachable basic blocks, and does other "peephole" optimization
54 // of the CFG. It returns true if a modification was made, possibly deleting
55 // the basic block that was pointed to.
57 // WARNING: The entry node of a method may not be simplified.
59 bool SimplifyCFG(BasicBlock *BB);