Check in LLVM r95781.

1 files changed, 349 insertions, 0 deletions

diff --git a/lib/Transforms/InstCombine/InstCombine.h b/lib/Transforms/InstCombine/InstCombine.h
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+++ b/lib/Transforms/InstCombine/InstCombine.h
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+//===- InstCombine.h - Main InstCombine pass definition -------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef INSTCOMBINE_INSTCOMBINE_H
+#define INSTCOMBINE_INSTCOMBINE_H
+
+#include "InstCombineWorklist.h"
+#include "llvm/Pass.h"
+#include "llvm/Analysis/ValueTracking.h"
+#include "llvm/Support/IRBuilder.h"
+#include "llvm/Support/InstVisitor.h"
+#include "llvm/Support/TargetFolder.h"
+
+namespace llvm {
+  class CallSite;
+  class TargetData;
+  class DbgDeclareInst;
+  class MemIntrinsic;
+  class MemSetInst;
+  
+/// SelectPatternFlavor - We can match a variety of different patterns for
+/// select operations.
+enum SelectPatternFlavor {
+  SPF_UNKNOWN = 0,
+  SPF_SMIN, SPF_UMIN,
+  SPF_SMAX, SPF_UMAX
+  //SPF_ABS - TODO.
+};
+  
+/// getComplexity:  Assign a complexity or rank value to LLVM Values...
+///   0 -> undef, 1 -> Const, 2 -> Other, 3 -> Arg, 3 -> Unary, 4 -> OtherInst
+static inline unsigned getComplexity(Value *V) {
+  if (isa<Instruction>(V)) {
+    if (BinaryOperator::isNeg(V) ||
+        BinaryOperator::isFNeg(V) ||
+        BinaryOperator::isNot(V))
+      return 3;
+    return 4;
+  }
+  if (isa<Argument>(V)) return 3;
+  return isa<Constant>(V) ? (isa<UndefValue>(V) ? 0 : 1) : 2;
+}
+
+  
+/// InstCombineIRInserter - This is an IRBuilder insertion helper that works
+/// just like the normal insertion helper, but also adds any new instructions
+/// to the instcombine worklist.
+class VISIBILITY_HIDDEN InstCombineIRInserter 
+    : public IRBuilderDefaultInserter<true> {
+  InstCombineWorklist &Worklist;
+public:
+  InstCombineIRInserter(InstCombineWorklist &WL) : Worklist(WL) {}
+  
+  void InsertHelper(Instruction *I, const Twine &Name,
+                    BasicBlock *BB, BasicBlock::iterator InsertPt) const {
+    IRBuilderDefaultInserter<true>::InsertHelper(I, Name, BB, InsertPt);
+    Worklist.Add(I);
+  }
+};
+  
+/// InstCombiner - The -instcombine pass.
+class VISIBILITY_HIDDEN InstCombiner
+                             : public FunctionPass,
+                               public InstVisitor<InstCombiner, Instruction*> {
+  TargetData *TD;
+  bool MustPreserveLCSSA;
+  bool MadeIRChange;
+public:
+  /// Worklist - All of the instructions that need to be simplified.
+  InstCombineWorklist Worklist;
+
+  /// Builder - This is an IRBuilder that automatically inserts new
+  /// instructions into the worklist when they are created.
+  typedef IRBuilder<true, TargetFolder, InstCombineIRInserter> BuilderTy;
+  BuilderTy *Builder;
+      
+  static char ID; // Pass identification, replacement for typeid
+  InstCombiner() : FunctionPass(&ID), TD(0), Builder(0) {}
+
+public:
+  virtual bool runOnFunction(Function &F);
+  
+  bool DoOneIteration(Function &F, unsigned ItNum);
+
+  virtual void getAnalysisUsage(AnalysisUsage &AU) const;
+                                 
+  TargetData *getTargetData() const { return TD; }
+
+  // Visitation implementation - Implement instruction combining for different
+  // instruction types.  The semantics are as follows:
+  // Return Value:
+  //    null        - No change was made
+  //     I          - Change was made, I is still valid, I may be dead though
+  //   otherwise    - Change was made, replace I with returned instruction
+  //
+  Instruction *visitAdd(BinaryOperator &I);
+  Instruction *visitFAdd(BinaryOperator &I);
+  Value *OptimizePointerDifference(Value *LHS, Value *RHS, const Type *Ty);
+  Instruction *visitSub(BinaryOperator &I);
+  Instruction *visitFSub(BinaryOperator &I);
+  Instruction *visitMul(BinaryOperator &I);
+  Instruction *visitFMul(BinaryOperator &I);
+  Instruction *visitURem(BinaryOperator &I);
+  Instruction *visitSRem(BinaryOperator &I);
+  Instruction *visitFRem(BinaryOperator &I);
+  bool SimplifyDivRemOfSelect(BinaryOperator &I);
+  Instruction *commonRemTransforms(BinaryOperator &I);
+  Instruction *commonIRemTransforms(BinaryOperator &I);
+  Instruction *commonDivTransforms(BinaryOperator &I);
+  Instruction *commonIDivTransforms(BinaryOperator &I);
+  Instruction *visitUDiv(BinaryOperator &I);
+  Instruction *visitSDiv(BinaryOperator &I);
+  Instruction *visitFDiv(BinaryOperator &I);
+  Instruction *FoldAndOfICmps(Instruction &I, ICmpInst *LHS, ICmpInst *RHS);
+  Instruction *FoldAndOfFCmps(Instruction &I, FCmpInst *LHS, FCmpInst *RHS);
+  Instruction *visitAnd(BinaryOperator &I);
+  Instruction *FoldOrOfICmps(Instruction &I, ICmpInst *LHS, ICmpInst *RHS);
+  Instruction *FoldOrOfFCmps(Instruction &I, FCmpInst *LHS, FCmpInst *RHS);
+  Instruction *FoldOrWithConstants(BinaryOperator &I, Value *Op,
+                                   Value *A, Value *B, Value *C);
+  Instruction *visitOr (BinaryOperator &I);
+  Instruction *visitXor(BinaryOperator &I);
+  Instruction *visitShl(BinaryOperator &I);
+  Instruction *visitAShr(BinaryOperator &I);
+  Instruction *visitLShr(BinaryOperator &I);
+  Instruction *commonShiftTransforms(BinaryOperator &I);
+  Instruction *FoldFCmp_IntToFP_Cst(FCmpInst &I, Instruction *LHSI,
+                                    Constant *RHSC);
+  Instruction *FoldCmpLoadFromIndexedGlobal(GetElementPtrInst *GEP,
+                                            GlobalVariable *GV, CmpInst &ICI,
+                                            ConstantInt *AndCst = 0);
+  Instruction *visitFCmpInst(FCmpInst &I);
+  Instruction *visitICmpInst(ICmpInst &I);
+  Instruction *visitICmpInstWithCastAndCast(ICmpInst &ICI);
+  Instruction *visitICmpInstWithInstAndIntCst(ICmpInst &ICI,
+                                              Instruction *LHS,
+                                              ConstantInt *RHS);
+  Instruction *FoldICmpDivCst(ICmpInst &ICI, BinaryOperator *DivI,
+                              ConstantInt *DivRHS);
+  Instruction *FoldICmpAddOpCst(ICmpInst &ICI, Value *X, ConstantInt *CI,
+                                ICmpInst::Predicate Pred, Value *TheAdd);
+  Instruction *FoldGEPICmp(GEPOperator *GEPLHS, Value *RHS,
+                           ICmpInst::Predicate Cond, Instruction &I);
+  Instruction *FoldShiftByConstant(Value *Op0, ConstantInt *Op1,
+                                   BinaryOperator &I);
+  Instruction *commonCastTransforms(CastInst &CI);
+  Instruction *commonPointerCastTransforms(CastInst &CI);
+  Instruction *visitTrunc(TruncInst &CI);
+  Instruction *visitZExt(ZExtInst &CI);
+  Instruction *visitSExt(SExtInst &CI);
+  Instruction *visitFPTrunc(FPTruncInst &CI);
+  Instruction *visitFPExt(CastInst &CI);
+  Instruction *visitFPToUI(FPToUIInst &FI);
+  Instruction *visitFPToSI(FPToSIInst &FI);
+  Instruction *visitUIToFP(CastInst &CI);
+  Instruction *visitSIToFP(CastInst &CI);
+  Instruction *visitPtrToInt(PtrToIntInst &CI);
+  Instruction *visitIntToPtr(IntToPtrInst &CI);
+  Instruction *visitBitCast(BitCastInst &CI);
+  Instruction *FoldSelectOpOp(SelectInst &SI, Instruction *TI,
+                              Instruction *FI);
+  Instruction *FoldSelectIntoOp(SelectInst &SI, Value*, Value*);
+  Instruction *FoldSPFofSPF(Instruction *Inner, SelectPatternFlavor SPF1,
+                            Value *A, Value *B, Instruction &Outer,
+                            SelectPatternFlavor SPF2, Value *C);
+  Instruction *visitSelectInst(SelectInst &SI);
+  Instruction *visitSelectInstWithICmp(SelectInst &SI, ICmpInst *ICI);
+  Instruction *visitCallInst(CallInst &CI);
+  Instruction *visitInvokeInst(InvokeInst &II);
+
+  Instruction *SliceUpIllegalIntegerPHI(PHINode &PN);
+  Instruction *visitPHINode(PHINode &PN);
+  Instruction *visitGetElementPtrInst(GetElementPtrInst &GEP);
+  Instruction *visitAllocaInst(AllocaInst &AI);
+  Instruction *visitFree(Instruction &FI);
+  Instruction *visitLoadInst(LoadInst &LI);
+  Instruction *visitStoreInst(StoreInst &SI);
+  Instruction *visitBranchInst(BranchInst &BI);
+  Instruction *visitSwitchInst(SwitchInst &SI);
+  Instruction *visitInsertElementInst(InsertElementInst &IE);
+  Instruction *visitExtractElementInst(ExtractElementInst &EI);
+  Instruction *visitShuffleVectorInst(ShuffleVectorInst &SVI);
+  Instruction *visitExtractValueInst(ExtractValueInst &EV);
+
+  // visitInstruction - Specify what to return for unhandled instructions...
+  Instruction *visitInstruction(Instruction &I) { return 0; }
+
+private:
+  bool ShouldChangeType(const Type *From, const Type *To) const;
+  Value *dyn_castNegVal(Value *V) const;
+  Value *dyn_castFNegVal(Value *V) const;
+  const Type *FindElementAtOffset(const Type *Ty, int64_t Offset, 
+                                  SmallVectorImpl<Value*> &NewIndices);
+  Instruction *FoldOpIntoSelect(Instruction &Op, SelectInst *SI);
+                                 
+  /// ValueRequiresCast - Return true if the cast from "V to Ty" actually
+  /// results in any code being generated.  It does not require codegen if V is
+  /// simple enough or if the cast can be folded into other casts.
+  bool ValueRequiresCast(Instruction::CastOps opcode,const Value *V,
+                         const Type *Ty);
+
+  Instruction *visitCallSite(CallSite CS);
+  bool transformConstExprCastCall(CallSite CS);
+  Instruction *transformCallThroughTrampoline(CallSite CS);
+  Instruction *transformZExtICmp(ICmpInst *ICI, Instruction &CI,
+                                 bool DoXform = true);
+  bool WillNotOverflowSignedAdd(Value *LHS, Value *RHS);
+  DbgDeclareInst *hasOneUsePlusDeclare(Value *V);
+  Value *EmitGEPOffset(User *GEP);
+
+public:
+  // InsertNewInstBefore - insert an instruction New before instruction Old
+  // in the program.  Add the new instruction to the worklist.
+  //
+  Instruction *InsertNewInstBefore(Instruction *New, Instruction &Old) {
+    assert(New && New->getParent() == 0 &&
+           "New instruction already inserted into a basic block!");
+    BasicBlock *BB = Old.getParent();
+    BB->getInstList().insert(&Old, New);  // Insert inst
+    Worklist.Add(New);
+    return New;
+  }
+      
+  // ReplaceInstUsesWith - This method is to be used when an instruction is
+  // found to be dead, replacable with another preexisting expression.  Here
+  // we add all uses of I to the worklist, replace all uses of I with the new
+  // value, then return I, so that the inst combiner will know that I was
+  // modified.
+  //
+  Instruction *ReplaceInstUsesWith(Instruction &I, Value *V) {
+    Worklist.AddUsersToWorkList(I);   // Add all modified instrs to worklist.
+    
+    // If we are replacing the instruction with itself, this must be in a
+    // segment of unreachable code, so just clobber the instruction.
+    if (&I == V) 
+      V = UndefValue::get(I.getType());
+      
+    I.replaceAllUsesWith(V);
+    return &I;
+  }
+
+  // EraseInstFromFunction - When dealing with an instruction that has side
+  // effects or produces a void value, we can't rely on DCE to delete the
+  // instruction.  Instead, visit methods should return the value returned by
+  // this function.
+  Instruction *EraseInstFromFunction(Instruction &I) {
+    DEBUG(errs() << "IC: ERASE " << I << '\n');
+
+    assert(I.use_empty() && "Cannot erase instruction that is used!");
+    // Make sure that we reprocess all operands now that we reduced their
+    // use counts.
+    if (I.getNumOperands() < 8) {
+      for (User::op_iterator i = I.op_begin(), e = I.op_end(); i != e; ++i)
+        if (Instruction *Op = dyn_cast<Instruction>(*i))
+          Worklist.Add(Op);
+    }
+    Worklist.Remove(&I);
+    I.eraseFromParent();
+    MadeIRChange = true;
+    return 0;  // Don't do anything with FI
+  }
+      
+  void ComputeMaskedBits(Value *V, const APInt &Mask, APInt &KnownZero,
+                         APInt &KnownOne, unsigned Depth = 0) const {
+    return llvm::ComputeMaskedBits(V, Mask, KnownZero, KnownOne, TD, Depth);
+  }
+  
+  bool MaskedValueIsZero(Value *V, const APInt &Mask, 
+                         unsigned Depth = 0) const {
+    return llvm::MaskedValueIsZero(V, Mask, TD, Depth);
+  }
+  unsigned ComputeNumSignBits(Value *Op, unsigned Depth = 0) const {
+    return llvm::ComputeNumSignBits(Op, TD, Depth);
+  }
+
+private:
+
+  /// SimplifyCommutative - This performs a few simplifications for 
+  /// commutative operators.
+  bool SimplifyCommutative(BinaryOperator &I);
+
+  /// SimplifyDemandedUseBits - Attempts to replace V with a simpler value
+  /// based on the demanded bits.
+  Value *SimplifyDemandedUseBits(Value *V, APInt DemandedMask, 
+                                 APInt& KnownZero, APInt& KnownOne,
+                                 unsigned Depth);
+  bool SimplifyDemandedBits(Use &U, APInt DemandedMask, 
+                            APInt& KnownZero, APInt& KnownOne,
+                            unsigned Depth=0);
+      
+  /// SimplifyDemandedInstructionBits - Inst is an integer instruction that
+  /// SimplifyDemandedBits knows about.  See if the instruction has any
+  /// properties that allow us to simplify its operands.
+  bool SimplifyDemandedInstructionBits(Instruction &Inst);
+      
+  Value *SimplifyDemandedVectorElts(Value *V, APInt DemandedElts,
+                                    APInt& UndefElts, unsigned Depth = 0);
+    
+  // FoldOpIntoPhi - Given a binary operator, cast instruction, or select
+  // which has a PHI node as operand #0, see if we can fold the instruction
+  // into the PHI (which is only possible if all operands to the PHI are
+  // constants).
+  //
+  // If AllowAggressive is true, FoldOpIntoPhi will allow certain transforms
+  // that would normally be unprofitable because they strongly encourage jump
+  // threading.
+  Instruction *FoldOpIntoPhi(Instruction &I, bool AllowAggressive = false);
+
+  // FoldPHIArgOpIntoPHI - If all operands to a PHI node are the same "unary"
+  // operator and they all are only used by the PHI, PHI together their
+  // inputs, and do the operation once, to the result of the PHI.
+  Instruction *FoldPHIArgOpIntoPHI(PHINode &PN);
+  Instruction *FoldPHIArgBinOpIntoPHI(PHINode &PN);
+  Instruction *FoldPHIArgGEPIntoPHI(PHINode &PN);
+  Instruction *FoldPHIArgLoadIntoPHI(PHINode &PN);
+
+  
+  Instruction *OptAndOp(Instruction *Op, ConstantInt *OpRHS,
+                        ConstantInt *AndRHS, BinaryOperator &TheAnd);
+  
+  Value *FoldLogicalPlusAnd(Value *LHS, Value *RHS, ConstantInt *Mask,
+                            bool isSub, Instruction &I);
+  Instruction *InsertRangeTest(Value *V, Constant *Lo, Constant *Hi,
+                               bool isSigned, bool Inside, Instruction &IB);
+  Instruction *PromoteCastOfAllocation(BitCastInst &CI, AllocaInst &AI);
+  Instruction *MatchBSwap(BinaryOperator &I);
+  bool SimplifyStoreAtEndOfBlock(StoreInst &SI);
+  Instruction *SimplifyMemTransfer(MemIntrinsic *MI);
+  Instruction *SimplifyMemSet(MemSetInst *MI);
+
+
+  Value *EvaluateInDifferentType(Value *V, const Type *Ty, bool isSigned);
+
+  unsigned GetOrEnforceKnownAlignment(Value *V,
+                                      unsigned PrefAlign = 0);
+
+};
+
+      
+  
+} // end namespace llvm.
+
+#endif