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//===-- Local.h - Functions to perform local transformations -----*- C++ -*--=//
//
// This family of functions perform various local transformations to the
// program.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_TRANSFORMS_UTILS_LOCAL_H
#define LLVM_TRANSFORMS_UTILS_LOCAL_H
#include "llvm/Function.h"
#include "llvm/BasicBlock.h"
//===----------------------------------------------------------------------===//
// Local constant propogation...
//
// doConstantPropogation - Constant prop a specific instruction. Returns true
// and potentially moves the iterator if constant propogation was performed.
//
bool doConstantPropogation(BasicBlock::iterator &I);
// ConstantFoldTerminator - If a terminator instruction is predicated on a
// constant value, convert it into an unconditional branch to the constant
// destination. This is a nontrivial operation because the successors of this
// basic block must have their PHI nodes updated.
//
bool ConstantFoldTerminator(BasicBlock *BB);
//===----------------------------------------------------------------------===//
// Local dead code elimination...
//
// isInstructionTriviallyDead - Return true if the result produced by the
// instruction is not used, and the instruction has no side effects.
//
bool isInstructionTriviallyDead(Instruction *I);
// dceInstruction - Inspect the instruction at *BBI and figure out if it
// isTriviallyDead. If so, remove the instruction and update the iterator to
// point to the instruction that immediately succeeded the original instruction.
//
bool dceInstruction(BasicBlock::iterator &BBI);
//===----------------------------------------------------------------------===//
// Control Flow Graph Restructuring...
//
// SimplifyCFG - This function is used to do simplification of a CFG. For
// example, it adjusts branches to branches to eliminate the extra hop, it
// eliminates unreachable basic blocks, and does other "peephole" optimization
// of the CFG. It returns true if a modification was made, and returns an
// iterator that designates the first element remaining after the block that
// was deleted.
//
// WARNING: The entry node of a method may not be simplified.
//
bool SimplifyCFG(Function::iterator &BBIt);
#endif
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