//===- InstructionCombining.cpp - Combine multiple instructions -----------===//
//
// InstructionCombining - Combine instructions to form fewer, simple
// instructions. This pass does not modify the CFG This pass is where algebraic
// simplification happens.
//
// This pass combines things like:
// %Y = add int 1, %X
// %Z = add int 1, %Y
// into:
// %Z = add int 2, %X
//
// This is a simple worklist driven algorithm.
//
//===----------------------------------------------------------------------===//
#include "llvm/Transforms/Scalar.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/Local.h"
#include "llvm/Instructions.h"
#include "llvm/Pass.h"
#include "llvm/Constants.h"
#include "llvm/ConstantHandling.h"
#include "llvm/DerivedTypes.h"
#include "llvm/GlobalVariable.h"
#include "llvm/Support/InstIterator.h"
#include "llvm/Support/InstVisitor.h"
#include "llvm/Support/CallSite.h"
#include "Support/Statistic.h"
#include <algorithm>
namespace {
Statistic<> NumCombined ("instcombine", "Number of insts combined");
Statistic<> NumConstProp("instcombine", "Number of constant folds");
Statistic<> NumDeadInst ("instcombine", "Number of dead inst eliminated");
class InstCombiner : public FunctionPass,
