MemCpyOptimizer.cpp revision 5a7aeaa01904b9b0adf256108f302f8961295754
1a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson//===- MemCpyOptimizer.cpp - Optimize use of memcpy and friends -----------===// 2a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson// 3a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson// The LLVM Compiler Infrastructure 4a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson// 5a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson// This file is distributed under the University of Illinois Open Source 6a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson// License. See LICENSE.TXT for details. 7a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson// 8a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson//===----------------------------------------------------------------------===// 9a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson// 10a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson// This pass performs various transformations related to eliminating memcpy 11a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson// calls, or transforming sets of stores into memset's. 12a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson// 13a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson//===----------------------------------------------------------------------===// 14a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 15a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson#define DEBUG_TYPE "memcpyopt" 16a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson#include "llvm/Transforms/Scalar.h" 17a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson#include "llvm/IntrinsicInst.h" 18a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson#include "llvm/Instructions.h" 19fa5cbd6d0fbda23fd669c8718e07b19001b2d21aOwen Anderson#include "llvm/LLVMContext.h" 20a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson#include "llvm/ADT/SmallVector.h" 21a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson#include "llvm/ADT/Statistic.h" 22a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson#include "llvm/Analysis/Dominators.h" 23a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson#include "llvm/Analysis/AliasAnalysis.h" 24a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson#include "llvm/Analysis/MemoryDependenceAnalysis.h" 25a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson#include "llvm/Support/Debug.h" 26a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson#include "llvm/Support/GetElementPtrTypeIterator.h" 27bdff548e4dd577a72094d57b282de4e765643b96Chris Lattner#include "llvm/Support/raw_ostream.h" 28a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson#include "llvm/Target/TargetData.h" 29a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson#include <list> 30a723d1e48f4a261512c28845c53eda569fa5218cOwen Andersonusing namespace llvm; 31a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 32a723d1e48f4a261512c28845c53eda569fa5218cOwen AndersonSTATISTIC(NumMemCpyInstr, "Number of memcpy instructions deleted"); 33a723d1e48f4a261512c28845c53eda569fa5218cOwen AndersonSTATISTIC(NumMemSetInfer, "Number of memsets inferred"); 3405cd03b33559732f8ed55e5ff7554fd06d59eb6aDuncan SandsSTATISTIC(NumMoveToCpy, "Number of memmoves converted to memcpy"); 35a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 36a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson/// isBytewiseValue - If the specified value can be set by repeating the same 37a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson/// byte in memory, return the i8 value that it is represented with. This is 38a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson/// true for all i8 values obviously, but is also true for i32 0, i32 -1, 39a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson/// i16 0xF0F0, double 0.0 etc. If the value can't be handled with a repeated 40a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson/// byte store (e.g. i16 0x1234), return null. 41cf0fe8d813727383d630055bb9d1cde21b00b7e7Chris Lattnerstatic Value *isBytewiseValue(Value *V) { 42cf0fe8d813727383d630055bb9d1cde21b00b7e7Chris Lattner LLVMContext &Context = V->getContext(); 43cf0fe8d813727383d630055bb9d1cde21b00b7e7Chris Lattner 44a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // All byte-wide stores are splatable, even of arbitrary variables. 45b0bc6c361da9009e8414efde317d9bbff755f6c0Duncan Sands if (V->getType()->isIntegerTy(8)) return V; 46a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 47a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // Constant float and double values can be handled as integer values if the 48a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // corresponding integer value is "byteable". An important case is 0.0. 49a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson if (ConstantFP *CFP = dyn_cast<ConstantFP>(V)) { 50cf0fe8d813727383d630055bb9d1cde21b00b7e7Chris Lattner if (CFP->getType()->isFloatTy()) 511d0be15f89cb5056e20e2d24faa8d6afb1573bcaOwen Anderson V = ConstantExpr::getBitCast(CFP, Type::getInt32Ty(Context)); 52cf0fe8d813727383d630055bb9d1cde21b00b7e7Chris Lattner if (CFP->getType()->isDoubleTy()) 531d0be15f89cb5056e20e2d24faa8d6afb1573bcaOwen Anderson V = ConstantExpr::getBitCast(CFP, Type::getInt64Ty(Context)); 54a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // Don't handle long double formats, which have strange constraints. 55a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson } 56a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 57a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // We can handle constant integers that are power of two in size and a 58a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // multiple of 8 bits. 59a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) { 60a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson unsigned Width = CI->getBitWidth(); 61a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson if (isPowerOf2_32(Width) && Width > 8) { 62a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // We can handle this value if the recursive binary decomposition is the 63a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // same at all levels. 64a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson APInt Val = CI->getValue(); 65a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson APInt Val2; 66a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson while (Val.getBitWidth() != 8) { 67a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson unsigned NextWidth = Val.getBitWidth()/2; 68a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson Val2 = Val.lshr(NextWidth); 69a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson Val2.trunc(Val.getBitWidth()/2); 70a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson Val.trunc(Val.getBitWidth()/2); 71a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 72a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // If the top/bottom halves aren't the same, reject it. 73a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson if (Val != Val2) 74a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson return 0; 75a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson } 76eed707b1e6097aac2bb6b3d47271f6300ace7f2eOwen Anderson return ConstantInt::get(Context, Val); 77a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson } 78a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson } 79a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 80a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // Conceptually, we could handle things like: 81a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // %a = zext i8 %X to i16 82a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // %b = shl i16 %a, 8 83a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // %c = or i16 %a, %b 84a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // but until there is an example that actually needs this, it doesn't seem 85a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // worth worrying about. 86a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson return 0; 87a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson} 88a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 89a723d1e48f4a261512c28845c53eda569fa5218cOwen Andersonstatic int64_t GetOffsetFromIndex(const GetElementPtrInst *GEP, unsigned Idx, 90a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson bool &VariableIdxFound, TargetData &TD) { 91a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // Skip over the first indices. 92a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson gep_type_iterator GTI = gep_type_begin(GEP); 93a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson for (unsigned i = 1; i != Idx; ++i, ++GTI) 94a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson /*skip along*/; 95a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 96a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // Compute the offset implied by the rest of the indices. 97a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson int64_t Offset = 0; 98a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson for (unsigned i = Idx, e = GEP->getNumOperands(); i != e; ++i, ++GTI) { 99a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson ConstantInt *OpC = dyn_cast<ConstantInt>(GEP->getOperand(i)); 100a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson if (OpC == 0) 101a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson return VariableIdxFound = true; 102a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson if (OpC->isZero()) continue; // No offset. 103a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 104a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // Handle struct indices, which add their field offset to the pointer. 105a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson if (const StructType *STy = dyn_cast<StructType>(*GTI)) { 106a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson Offset += TD.getStructLayout(STy)->getElementOffset(OpC->getZExtValue()); 107a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson continue; 108a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson } 109a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 110a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // Otherwise, we have a sequential type like an array or vector. Multiply 111a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // the index by the ElementSize. 112777d2306b36816a53bc1ae1244c0dc7d998ae691Duncan Sands uint64_t Size = TD.getTypeAllocSize(GTI.getIndexedType()); 113a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson Offset += Size*OpC->getSExtValue(); 114a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson } 115a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 116a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson return Offset; 117a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson} 118a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 119a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson/// IsPointerOffset - Return true if Ptr1 is provably equal to Ptr2 plus a 120a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson/// constant offset, and return that constant offset. For example, Ptr1 might 121a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson/// be &A[42], and Ptr2 might be &A[40]. In this case offset would be -8. 122a723d1e48f4a261512c28845c53eda569fa5218cOwen Andersonstatic bool IsPointerOffset(Value *Ptr1, Value *Ptr2, int64_t &Offset, 123a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson TargetData &TD) { 124a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // Right now we handle the case when Ptr1/Ptr2 are both GEPs with an identical 125a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // base. After that base, they may have some number of common (and 126a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // potentially variable) indices. After that they handle some constant 127a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // offset, which determines their offset from each other. At this point, we 128a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // handle no other case. 129a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson GetElementPtrInst *GEP1 = dyn_cast<GetElementPtrInst>(Ptr1); 130a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson GetElementPtrInst *GEP2 = dyn_cast<GetElementPtrInst>(Ptr2); 131a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson if (!GEP1 || !GEP2 || GEP1->getOperand(0) != GEP2->getOperand(0)) 132a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson return false; 133a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 134a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // Skip any common indices and track the GEP types. 135a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson unsigned Idx = 1; 136a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson for (; Idx != GEP1->getNumOperands() && Idx != GEP2->getNumOperands(); ++Idx) 137a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson if (GEP1->getOperand(Idx) != GEP2->getOperand(Idx)) 138a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson break; 139a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 140a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson bool VariableIdxFound = false; 141a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson int64_t Offset1 = GetOffsetFromIndex(GEP1, Idx, VariableIdxFound, TD); 142a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson int64_t Offset2 = GetOffsetFromIndex(GEP2, Idx, VariableIdxFound, TD); 143a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson if (VariableIdxFound) return false; 144a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 145a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson Offset = Offset2-Offset1; 146a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson return true; 147a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson} 148a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 149a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 150a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson/// MemsetRange - Represents a range of memset'd bytes with the ByteVal value. 151a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson/// This allows us to analyze stores like: 152a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson/// store 0 -> P+1 153a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson/// store 0 -> P+0 154a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson/// store 0 -> P+3 155a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson/// store 0 -> P+2 156a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson/// which sometimes happens with stores to arrays of structs etc. When we see 157a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson/// the first store, we make a range [1, 2). The second store extends the range 158a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson/// to [0, 2). The third makes a new range [2, 3). The fourth store joins the 159a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson/// two ranges into [0, 3) which is memset'able. 160a723d1e48f4a261512c28845c53eda569fa5218cOwen Andersonnamespace { 161a723d1e48f4a261512c28845c53eda569fa5218cOwen Andersonstruct MemsetRange { 162a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // Start/End - A semi range that describes the span that this range covers. 163a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // The range is closed at the start and open at the end: [Start, End). 164a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson int64_t Start, End; 165a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 166a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson /// StartPtr - The getelementptr instruction that points to the start of the 167a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson /// range. 168a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson Value *StartPtr; 169a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 170a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson /// Alignment - The known alignment of the first store. 171a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson unsigned Alignment; 172a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 173a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson /// TheStores - The actual stores that make up this range. 174a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson SmallVector<StoreInst*, 16> TheStores; 175a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 176a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson bool isProfitableToUseMemset(const TargetData &TD) const; 177a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 178a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson}; 179a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson} // end anon namespace 180a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 181a723d1e48f4a261512c28845c53eda569fa5218cOwen Andersonbool MemsetRange::isProfitableToUseMemset(const TargetData &TD) const { 182a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // If we found more than 8 stores to merge or 64 bytes, use memset. 183a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson if (TheStores.size() >= 8 || End-Start >= 64) return true; 184a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 185a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // Assume that the code generator is capable of merging pairs of stores 186a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // together if it wants to. 187a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson if (TheStores.size() <= 2) return false; 188a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 189a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // If we have fewer than 8 stores, it can still be worthwhile to do this. 190a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // For example, merging 4 i8 stores into an i32 store is useful almost always. 191a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // However, merging 2 32-bit stores isn't useful on a 32-bit architecture (the 192a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // memset will be split into 2 32-bit stores anyway) and doing so can 193a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // pessimize the llvm optimizer. 194a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // 195a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // Since we don't have perfect knowledge here, make some assumptions: assume 196a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // the maximum GPR width is the same size as the pointer size and assume that 197a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // this width can be stored. If so, check to see whether we will end up 198a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // actually reducing the number of stores used. 199a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson unsigned Bytes = unsigned(End-Start); 200a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson unsigned NumPointerStores = Bytes/TD.getPointerSize(); 201a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 202a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // Assume the remaining bytes if any are done a byte at a time. 203a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson unsigned NumByteStores = Bytes - NumPointerStores*TD.getPointerSize(); 204a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 205a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // If we will reduce the # stores (according to this heuristic), do the 206a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // transformation. This encourages merging 4 x i8 -> i32 and 2 x i16 -> i32 207a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // etc. 208a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson return TheStores.size() > NumPointerStores+NumByteStores; 209a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson} 210a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 211a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 212a723d1e48f4a261512c28845c53eda569fa5218cOwen Andersonnamespace { 213a723d1e48f4a261512c28845c53eda569fa5218cOwen Andersonclass MemsetRanges { 214a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson /// Ranges - A sorted list of the memset ranges. We use std::list here 215a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson /// because each element is relatively large and expensive to copy. 216a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson std::list<MemsetRange> Ranges; 217a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson typedef std::list<MemsetRange>::iterator range_iterator; 218a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson TargetData &TD; 219a723d1e48f4a261512c28845c53eda569fa5218cOwen Andersonpublic: 220a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson MemsetRanges(TargetData &td) : TD(td) {} 221a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 222a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson typedef std::list<MemsetRange>::const_iterator const_iterator; 223a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson const_iterator begin() const { return Ranges.begin(); } 224a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson const_iterator end() const { return Ranges.end(); } 225a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson bool empty() const { return Ranges.empty(); } 226a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 227a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson void addStore(int64_t OffsetFromFirst, StoreInst *SI); 228a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson}; 229a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 230a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson} // end anon namespace 231a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 232a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 233a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson/// addStore - Add a new store to the MemsetRanges data structure. This adds a 234a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson/// new range for the specified store at the specified offset, merging into 235a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson/// existing ranges as appropriate. 236a723d1e48f4a261512c28845c53eda569fa5218cOwen Andersonvoid MemsetRanges::addStore(int64_t Start, StoreInst *SI) { 237a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson int64_t End = Start+TD.getTypeStoreSize(SI->getOperand(0)->getType()); 238a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 239a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // Do a linear search of the ranges to see if this can be joined and/or to 240a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // find the insertion point in the list. We keep the ranges sorted for 241a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // simplicity here. This is a linear search of a linked list, which is ugly, 242a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // however the number of ranges is limited, so this won't get crazy slow. 243a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson range_iterator I = Ranges.begin(), E = Ranges.end(); 244a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 245a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson while (I != E && Start > I->End) 246a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson ++I; 247a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 248a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // We now know that I == E, in which case we didn't find anything to merge 249a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // with, or that Start <= I->End. If End < I->Start or I == E, then we need 250a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // to insert a new range. Handle this now. 251a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson if (I == E || End < I->Start) { 252a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson MemsetRange &R = *Ranges.insert(I, MemsetRange()); 253a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson R.Start = Start; 254a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson R.End = End; 255a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson R.StartPtr = SI->getPointerOperand(); 256a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson R.Alignment = SI->getAlignment(); 257a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson R.TheStores.push_back(SI); 258a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson return; 259a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson } 260a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 261a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // This store overlaps with I, add it. 262a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson I->TheStores.push_back(SI); 263a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 264a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // At this point, we may have an interval that completely contains our store. 265a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // If so, just add it to the interval and return. 266a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson if (I->Start <= Start && I->End >= End) 267a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson return; 268a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 269a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // Now we know that Start <= I->End and End >= I->Start so the range overlaps 270a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // but is not entirely contained within the range. 271a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 272a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // See if the range extends the start of the range. In this case, it couldn't 273a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // possibly cause it to join the prior range, because otherwise we would have 274a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // stopped on *it*. 275a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson if (Start < I->Start) { 276a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson I->Start = Start; 277a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson I->StartPtr = SI->getPointerOperand(); 278264d245851173bbace9281a2378a6cc51162b030Dan Gohman I->Alignment = SI->getAlignment(); 279a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson } 280a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 281a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // Now we know that Start <= I->End and Start >= I->Start (so the startpoint 282a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // is in or right at the end of I), and that End >= I->Start. Extend I out to 283a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // End. 284a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson if (End > I->End) { 285a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson I->End = End; 2869c0f146d50ccc3ba780d4854b8e14422430013efNick Lewycky range_iterator NextI = I; 287a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson while (++NextI != E && End >= NextI->Start) { 288a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // Merge the range in. 289a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson I->TheStores.append(NextI->TheStores.begin(), NextI->TheStores.end()); 290a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson if (NextI->End > I->End) 291a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson I->End = NextI->End; 292a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson Ranges.erase(NextI); 293a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson NextI = I; 294a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson } 295a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson } 296a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson} 297a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 298a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson//===----------------------------------------------------------------------===// 299a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson// MemCpyOpt Pass 300a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson//===----------------------------------------------------------------------===// 301a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 302a723d1e48f4a261512c28845c53eda569fa5218cOwen Andersonnamespace { 3033e8b6631e67e01e4960a7ba4668a50c596607473Chris Lattner class MemCpyOpt : public FunctionPass { 304a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson bool runOnFunction(Function &F); 305a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson public: 306a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson static char ID; // Pass identification, replacement for typeid 307081c34b725980f995be9080eaec24cd3dfaaf065Owen Anderson MemCpyOpt() : FunctionPass(ID) { 308081c34b725980f995be9080eaec24cd3dfaaf065Owen Anderson initializeMemCpyOptPass(*PassRegistry::getPassRegistry()); 309081c34b725980f995be9080eaec24cd3dfaaf065Owen Anderson } 310a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 311a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson private: 312a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // This transformation requires dominator postdominator info 313a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson virtual void getAnalysisUsage(AnalysisUsage &AU) const { 314a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson AU.setPreservesCFG(); 315a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson AU.addRequired<DominatorTree>(); 316a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson AU.addRequired<MemoryDependenceAnalysis>(); 317a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson AU.addRequired<AliasAnalysis>(); 318a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson AU.addPreserved<AliasAnalysis>(); 319a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson AU.addPreserved<MemoryDependenceAnalysis>(); 320a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson } 321a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 322a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // Helper fuctions 32361c6ba85715fdcb66f746678879984151f1e5485Chris Lattner bool processStore(StoreInst *SI, BasicBlock::iterator &BBI); 32461c6ba85715fdcb66f746678879984151f1e5485Chris Lattner bool processMemCpy(MemCpyInst *M); 325f41eaacee4a4a2d4339dd553626d98c73650c8c7Chris Lattner bool processMemMove(MemMoveInst *M); 3266549121c660dfd18361cd3daf6c766bee80d3097Owen Anderson bool performCallSlotOptzn(Instruction *cpy, Value *cpyDst, Value *cpySrc, 3276549121c660dfd18361cd3daf6c766bee80d3097Owen Anderson uint64_t cpyLen, CallInst *C); 32843f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner bool processMemCpyMemCpyDependence(MemCpyInst *M, MemCpyInst *MDep, 32943f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner uint64_t MSize); 330a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson bool iterateOnFunction(Function &F); 331a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson }; 332a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 333a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson char MemCpyOpt::ID = 0; 334a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson} 335a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 336a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson// createMemCpyOptPass - The public interface to this file... 337a723d1e48f4a261512c28845c53eda569fa5218cOwen AndersonFunctionPass *llvm::createMemCpyOptPass() { return new MemCpyOpt(); } 338a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 3392ab36d350293c77fc8941ce1023e4899df7e3a82Owen AndersonINITIALIZE_PASS_BEGIN(MemCpyOpt, "memcpyopt", "MemCpy Optimization", 3402ab36d350293c77fc8941ce1023e4899df7e3a82Owen Anderson false, false) 3412ab36d350293c77fc8941ce1023e4899df7e3a82Owen AndersonINITIALIZE_PASS_DEPENDENCY(DominatorTree) 3422ab36d350293c77fc8941ce1023e4899df7e3a82Owen AndersonINITIALIZE_PASS_DEPENDENCY(MemoryDependenceAnalysis) 3432ab36d350293c77fc8941ce1023e4899df7e3a82Owen AndersonINITIALIZE_AG_DEPENDENCY(AliasAnalysis) 3442ab36d350293c77fc8941ce1023e4899df7e3a82Owen AndersonINITIALIZE_PASS_END(MemCpyOpt, "memcpyopt", "MemCpy Optimization", 3452ab36d350293c77fc8941ce1023e4899df7e3a82Owen Anderson false, false) 346a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 347a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson/// processStore - When GVN is scanning forward over instructions, we look for 348a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson/// some other patterns to fold away. In particular, this looks for stores to 349a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson/// neighboring locations of memory. If it sees enough consequtive ones 350a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson/// (currently 4) it attempts to merge them together into a memcpy/memset. 35161c6ba85715fdcb66f746678879984151f1e5485Chris Lattnerbool MemCpyOpt::processStore(StoreInst *SI, BasicBlock::iterator &BBI) { 352a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson if (SI->isVolatile()) return false; 353a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 3546549121c660dfd18361cd3daf6c766bee80d3097Owen Anderson TargetData *TD = getAnalysisIfAvailable<TargetData>(); 3556549121c660dfd18361cd3daf6c766bee80d3097Owen Anderson if (!TD) return false; 3566549121c660dfd18361cd3daf6c766bee80d3097Owen Anderson 3576549121c660dfd18361cd3daf6c766bee80d3097Owen Anderson // Detect cases where we're performing call slot forwarding, but 3586549121c660dfd18361cd3daf6c766bee80d3097Owen Anderson // happen to be using a load-store pair to implement it, rather than 3596549121c660dfd18361cd3daf6c766bee80d3097Owen Anderson // a memcpy. 3606549121c660dfd18361cd3daf6c766bee80d3097Owen Anderson if (LoadInst *LI = dyn_cast<LoadInst>(SI->getOperand(0))) { 3616549121c660dfd18361cd3daf6c766bee80d3097Owen Anderson if (!LI->isVolatile() && LI->hasOneUse()) { 3626549121c660dfd18361cd3daf6c766bee80d3097Owen Anderson MemoryDependenceAnalysis &MD = getAnalysis<MemoryDependenceAnalysis>(); 3636549121c660dfd18361cd3daf6c766bee80d3097Owen Anderson 3646549121c660dfd18361cd3daf6c766bee80d3097Owen Anderson MemDepResult dep = MD.getDependency(LI); 3656549121c660dfd18361cd3daf6c766bee80d3097Owen Anderson CallInst *C = 0; 3666549121c660dfd18361cd3daf6c766bee80d3097Owen Anderson if (dep.isClobber() && !isa<MemCpyInst>(dep.getInst())) 3676549121c660dfd18361cd3daf6c766bee80d3097Owen Anderson C = dyn_cast<CallInst>(dep.getInst()); 3686549121c660dfd18361cd3daf6c766bee80d3097Owen Anderson 3696549121c660dfd18361cd3daf6c766bee80d3097Owen Anderson if (C) { 3706549121c660dfd18361cd3daf6c766bee80d3097Owen Anderson bool changed = performCallSlotOptzn(LI, 3716549121c660dfd18361cd3daf6c766bee80d3097Owen Anderson SI->getPointerOperand()->stripPointerCasts(), 3726549121c660dfd18361cd3daf6c766bee80d3097Owen Anderson LI->getPointerOperand()->stripPointerCasts(), 3736549121c660dfd18361cd3daf6c766bee80d3097Owen Anderson TD->getTypeStoreSize(SI->getOperand(0)->getType()), C); 3746549121c660dfd18361cd3daf6c766bee80d3097Owen Anderson if (changed) { 3756549121c660dfd18361cd3daf6c766bee80d3097Owen Anderson MD.removeInstruction(SI); 3766549121c660dfd18361cd3daf6c766bee80d3097Owen Anderson SI->eraseFromParent(); 3776549121c660dfd18361cd3daf6c766bee80d3097Owen Anderson LI->eraseFromParent(); 3786549121c660dfd18361cd3daf6c766bee80d3097Owen Anderson ++NumMemCpyInstr; 3796549121c660dfd18361cd3daf6c766bee80d3097Owen Anderson return true; 3806549121c660dfd18361cd3daf6c766bee80d3097Owen Anderson } 3816549121c660dfd18361cd3daf6c766bee80d3097Owen Anderson } 3826549121c660dfd18361cd3daf6c766bee80d3097Owen Anderson } 3836549121c660dfd18361cd3daf6c766bee80d3097Owen Anderson } 3846549121c660dfd18361cd3daf6c766bee80d3097Owen Anderson 385ff1e98c72ae5f2aa805112925fd5c06049aa8e79Chris Lattner LLVMContext &Context = SI->getContext(); 386ff1e98c72ae5f2aa805112925fd5c06049aa8e79Chris Lattner 387a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // There are two cases that are interesting for this code to handle: memcpy 388a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // and memset. Right now we only handle memset. 389a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 390a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // Ensure that the value being stored is something that can be memset'able a 391a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // byte at a time like "0" or "-1" or any width, as well as things like 392a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // 0xA0A0A0A0 and 0.0. 393cf0fe8d813727383d630055bb9d1cde21b00b7e7Chris Lattner Value *ByteVal = isBytewiseValue(SI->getOperand(0)); 394a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson if (!ByteVal) 395a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson return false; 396a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 397a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson AliasAnalysis &AA = getAnalysis<AliasAnalysis>(); 398a195b7ffd6612a331751c7b6042d5cd921ee586cDan Gohman Module *M = SI->getParent()->getParent()->getParent(); 399a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 400a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // Okay, so we now have a single store that can be splatable. Scan to find 401a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // all subsequent stores of the same value to offset from the same pointer. 402a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // Join these together into ranges, so we can decide whether contiguous blocks 403a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // are stored. 4048942f9bb9f8bfb0d113db6d4a1ae7203dcf4510aDan Gohman MemsetRanges Ranges(*TD); 405a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 406a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson Value *StartPtr = SI->getPointerOperand(); 407a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 408a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson BasicBlock::iterator BI = SI; 409a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson for (++BI; !isa<TerminatorInst>(BI); ++BI) { 410a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson if (isa<CallInst>(BI) || isa<InvokeInst>(BI)) { 411a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // If the call is readnone, ignore it, otherwise bail out. We don't even 412a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // allow readonly here because we don't want something like: 413a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // A[1] = 2; strlen(A); A[2] = 2; -> memcpy(A, ...); strlen(A). 414a292b2f49f1557f234e9fa987da690c6d24118e5Gabor Greif if (AA.getModRefBehavior(CallSite(BI)) == 415a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson AliasAnalysis::DoesNotAccessMemory) 416a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson continue; 417a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 418a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // TODO: If this is a memset, try to join it in. 419a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 420a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson break; 421a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson } else if (isa<VAArgInst>(BI) || isa<LoadInst>(BI)) 422a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson break; 423a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 424a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // If this is a non-store instruction it is fine, ignore it. 425a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson StoreInst *NextStore = dyn_cast<StoreInst>(BI); 426a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson if (NextStore == 0) continue; 427a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 428a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // If this is a store, see if we can merge it in. 429a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson if (NextStore->isVolatile()) break; 430a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 431a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // Check to see if this stored value is of the same byte-splattable value. 432cf0fe8d813727383d630055bb9d1cde21b00b7e7Chris Lattner if (ByteVal != isBytewiseValue(NextStore->getOperand(0))) 433a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson break; 434a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 435a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // Check to see if this store is to a constant offset from the start ptr. 436a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson int64_t Offset; 4378942f9bb9f8bfb0d113db6d4a1ae7203dcf4510aDan Gohman if (!IsPointerOffset(StartPtr, NextStore->getPointerOperand(), Offset, *TD)) 438a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson break; 439a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 440a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson Ranges.addStore(Offset, NextStore); 441a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson } 442a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 443a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // If we have no ranges, then we just had a single store with nothing that 444a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // could be merged in. This is a very common case of course. 445a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson if (Ranges.empty()) 446a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson return false; 447a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 448a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // If we had at least one store that could be merged in, add the starting 449a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // store as well. We try to avoid this unless there is at least something 450a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // interesting as a small compile-time optimization. 451a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson Ranges.addStore(0, SI); 452a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 453a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 454a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // Now that we have full information about ranges, loop over the ranges and 455a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // emit memset's for anything big enough to be worthwhile. 456a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson bool MadeChange = false; 457a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson for (MemsetRanges::const_iterator I = Ranges.begin(), E = Ranges.end(); 458a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson I != E; ++I) { 459a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson const MemsetRange &Range = *I; 460a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 461a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson if (Range.TheStores.size() == 1) continue; 462a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 463a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // If it is profitable to lower this range to memset, do so now. 4648942f9bb9f8bfb0d113db6d4a1ae7203dcf4510aDan Gohman if (!Range.isProfitableToUseMemset(*TD)) 465a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson continue; 466a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 467a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // Otherwise, we do want to transform this! Create a new memset. We put 468a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // the memset right before the first instruction that isn't part of this 469a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // memset block. This ensure that the memset is dominated by any addressing 470a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // instruction needed by the start of the block. 471a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson BasicBlock::iterator InsertPt = BI; 47220adc9dc4650313f017b27d9818eb2176238113dMon P Wang 473a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // Get the starting pointer of the block. 474a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson StartPtr = Range.StartPtr; 47520adc9dc4650313f017b27d9818eb2176238113dMon P Wang 47620adc9dc4650313f017b27d9818eb2176238113dMon P Wang // Determine alignment 47720adc9dc4650313f017b27d9818eb2176238113dMon P Wang unsigned Alignment = Range.Alignment; 47820adc9dc4650313f017b27d9818eb2176238113dMon P Wang if (Alignment == 0) { 47920adc9dc4650313f017b27d9818eb2176238113dMon P Wang const Type *EltType = 48020adc9dc4650313f017b27d9818eb2176238113dMon P Wang cast<PointerType>(StartPtr->getType())->getElementType(); 48120adc9dc4650313f017b27d9818eb2176238113dMon P Wang Alignment = TD->getABITypeAlignment(EltType); 48220adc9dc4650313f017b27d9818eb2176238113dMon P Wang } 48320adc9dc4650313f017b27d9818eb2176238113dMon P Wang 484a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // Cast the start ptr to be i8* as memset requires. 48520adc9dc4650313f017b27d9818eb2176238113dMon P Wang const PointerType* StartPTy = cast<PointerType>(StartPtr->getType()); 48620adc9dc4650313f017b27d9818eb2176238113dMon P Wang const PointerType *i8Ptr = Type::getInt8PtrTy(Context, 48720adc9dc4650313f017b27d9818eb2176238113dMon P Wang StartPTy->getAddressSpace()); 48820adc9dc4650313f017b27d9818eb2176238113dMon P Wang if (StartPTy!= i8Ptr) 489460f656475738d1a95a6be95346908ce1597df25Daniel Dunbar StartPtr = new BitCastInst(StartPtr, i8Ptr, StartPtr->getName(), 490a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson InsertPt); 49120adc9dc4650313f017b27d9818eb2176238113dMon P Wang 492a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson Value *Ops[] = { 493a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson StartPtr, ByteVal, // Start, value 494e922c0201916e0b980ab3cfe91e1413e68d55647Owen Anderson // size 495ff1e98c72ae5f2aa805112925fd5c06049aa8e79Chris Lattner ConstantInt::get(Type::getInt64Ty(Context), Range.End-Range.Start), 496e922c0201916e0b980ab3cfe91e1413e68d55647Owen Anderson // align 49720adc9dc4650313f017b27d9818eb2176238113dMon P Wang ConstantInt::get(Type::getInt32Ty(Context), Alignment), 49820adc9dc4650313f017b27d9818eb2176238113dMon P Wang // volatile 49920adc9dc4650313f017b27d9818eb2176238113dMon P Wang ConstantInt::get(Type::getInt1Ty(Context), 0), 500a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson }; 50120adc9dc4650313f017b27d9818eb2176238113dMon P Wang const Type *Tys[] = { Ops[0]->getType(), Ops[2]->getType() }; 50220adc9dc4650313f017b27d9818eb2176238113dMon P Wang 50320adc9dc4650313f017b27d9818eb2176238113dMon P Wang Function *MemSetF = Intrinsic::getDeclaration(M, Intrinsic::memset, Tys, 2); 50420adc9dc4650313f017b27d9818eb2176238113dMon P Wang 50520adc9dc4650313f017b27d9818eb2176238113dMon P Wang Value *C = CallInst::Create(MemSetF, Ops, Ops+5, "", InsertPt); 506cb33fd17cce475a1d47b2695e311b6934ad0ef86David Greene DEBUG(dbgs() << "Replace stores:\n"; 507a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson for (unsigned i = 0, e = Range.TheStores.size(); i != e; ++i) 508cb33fd17cce475a1d47b2695e311b6934ad0ef86David Greene dbgs() << *Range.TheStores[i]; 509cb33fd17cce475a1d47b2695e311b6934ad0ef86David Greene dbgs() << "With: " << *C); C=C; 510a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 511a8bd65835be9e1ce07f5006e92625ec4e9fa387aOwen Anderson // Don't invalidate the iterator 512a8bd65835be9e1ce07f5006e92625ec4e9fa387aOwen Anderson BBI = BI; 513a8bd65835be9e1ce07f5006e92625ec4e9fa387aOwen Anderson 514a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // Zap all the stores. 515ff1e98c72ae5f2aa805112925fd5c06049aa8e79Chris Lattner for (SmallVector<StoreInst*, 16>::const_iterator 516ff1e98c72ae5f2aa805112925fd5c06049aa8e79Chris Lattner SI = Range.TheStores.begin(), 517a8bd65835be9e1ce07f5006e92625ec4e9fa387aOwen Anderson SE = Range.TheStores.end(); SI != SE; ++SI) 518a8bd65835be9e1ce07f5006e92625ec4e9fa387aOwen Anderson (*SI)->eraseFromParent(); 519a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson ++NumMemSetInfer; 520a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson MadeChange = true; 521a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson } 522a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 523a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson return MadeChange; 524a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson} 525a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 526a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 527a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson/// performCallSlotOptzn - takes a memcpy and a call that it depends on, 528a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson/// and checks for the possibility of a call slot optimization by having 529a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson/// the call write its result directly into the destination of the memcpy. 5306549121c660dfd18361cd3daf6c766bee80d3097Owen Andersonbool MemCpyOpt::performCallSlotOptzn(Instruction *cpy, 5316549121c660dfd18361cd3daf6c766bee80d3097Owen Anderson Value *cpyDest, Value *cpySrc, 5326549121c660dfd18361cd3daf6c766bee80d3097Owen Anderson uint64_t cpyLen, CallInst *C) { 533a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // The general transformation to keep in mind is 534a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // 535a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // call @func(..., src, ...) 536a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // memcpy(dest, src, ...) 537a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // 538a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // -> 539a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // 540a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // memcpy(dest, src, ...) 541a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // call @func(..., dest, ...) 542a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // 543a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // Since moving the memcpy is technically awkward, we additionally check that 544a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // src only holds uninitialized values at the moment of the call, meaning that 545a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // the memcpy can be discarded rather than moved. 546a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 547a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // Deliberately get the source and destination with bitcasts stripped away, 548a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // because we'll need to do type comparisons based on the underlying type. 5497d3056b16038a6a09c452c0dfcc3c8f4e421506aGabor Greif CallSite CS(C); 550a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 551a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // Require that src be an alloca. This simplifies the reasoning considerably. 55261c6ba85715fdcb66f746678879984151f1e5485Chris Lattner AllocaInst *srcAlloca = dyn_cast<AllocaInst>(cpySrc); 553a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson if (!srcAlloca) 554a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson return false; 555a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 556a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // Check that all of src is copied to dest. 55761c6ba85715fdcb66f746678879984151f1e5485Chris Lattner TargetData *TD = getAnalysisIfAvailable<TargetData>(); 5588942f9bb9f8bfb0d113db6d4a1ae7203dcf4510aDan Gohman if (!TD) return false; 559a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 56061c6ba85715fdcb66f746678879984151f1e5485Chris Lattner ConstantInt *srcArraySize = dyn_cast<ConstantInt>(srcAlloca->getArraySize()); 561a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson if (!srcArraySize) 562a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson return false; 563a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 5648942f9bb9f8bfb0d113db6d4a1ae7203dcf4510aDan Gohman uint64_t srcSize = TD->getTypeAllocSize(srcAlloca->getAllocatedType()) * 565a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson srcArraySize->getZExtValue(); 566a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 5676549121c660dfd18361cd3daf6c766bee80d3097Owen Anderson if (cpyLen < srcSize) 568a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson return false; 569a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 570a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // Check that accessing the first srcSize bytes of dest will not cause a 571a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // trap. Otherwise the transform is invalid since it might cause a trap 572a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // to occur earlier than it otherwise would. 57361c6ba85715fdcb66f746678879984151f1e5485Chris Lattner if (AllocaInst *A = dyn_cast<AllocaInst>(cpyDest)) { 574a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // The destination is an alloca. Check it is larger than srcSize. 57561c6ba85715fdcb66f746678879984151f1e5485Chris Lattner ConstantInt *destArraySize = dyn_cast<ConstantInt>(A->getArraySize()); 576a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson if (!destArraySize) 577a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson return false; 578a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 5798942f9bb9f8bfb0d113db6d4a1ae7203dcf4510aDan Gohman uint64_t destSize = TD->getTypeAllocSize(A->getAllocatedType()) * 580a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson destArraySize->getZExtValue(); 581a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 582a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson if (destSize < srcSize) 583a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson return false; 58461c6ba85715fdcb66f746678879984151f1e5485Chris Lattner } else if (Argument *A = dyn_cast<Argument>(cpyDest)) { 585a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // If the destination is an sret parameter then only accesses that are 586a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // outside of the returned struct type can trap. 587a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson if (!A->hasStructRetAttr()) 588a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson return false; 589a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 59061c6ba85715fdcb66f746678879984151f1e5485Chris Lattner const Type *StructTy = cast<PointerType>(A->getType())->getElementType(); 5918942f9bb9f8bfb0d113db6d4a1ae7203dcf4510aDan Gohman uint64_t destSize = TD->getTypeAllocSize(StructTy); 592a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 593a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson if (destSize < srcSize) 594a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson return false; 595a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson } else { 596a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson return false; 597a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson } 598a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 599a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // Check that src is not accessed except via the call and the memcpy. This 600a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // guarantees that it holds only undefined values when passed in (so the final 601a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // memcpy can be dropped), that it is not read or written between the call and 602a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // the memcpy, and that writing beyond the end of it is undefined. 603a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson SmallVector<User*, 8> srcUseList(srcAlloca->use_begin(), 604a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson srcAlloca->use_end()); 605a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson while (!srcUseList.empty()) { 606321a813c536e2f1f2f05bbe78a7fbf64046f0557Dan Gohman User *UI = srcUseList.pop_back_val(); 607a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 608009e4f760969e3530cc2641a9599e646a20580c2Owen Anderson if (isa<BitCastInst>(UI)) { 609a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson for (User::use_iterator I = UI->use_begin(), E = UI->use_end(); 610a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson I != E; ++I) 611a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson srcUseList.push_back(*I); 61261c6ba85715fdcb66f746678879984151f1e5485Chris Lattner } else if (GetElementPtrInst *G = dyn_cast<GetElementPtrInst>(UI)) { 613009e4f760969e3530cc2641a9599e646a20580c2Owen Anderson if (G->hasAllZeroIndices()) 614009e4f760969e3530cc2641a9599e646a20580c2Owen Anderson for (User::use_iterator I = UI->use_begin(), E = UI->use_end(); 615009e4f760969e3530cc2641a9599e646a20580c2Owen Anderson I != E; ++I) 616009e4f760969e3530cc2641a9599e646a20580c2Owen Anderson srcUseList.push_back(*I); 617009e4f760969e3530cc2641a9599e646a20580c2Owen Anderson else 618009e4f760969e3530cc2641a9599e646a20580c2Owen Anderson return false; 619a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson } else if (UI != C && UI != cpy) { 620a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson return false; 621a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson } 622a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson } 623a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 624a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // Since we're changing the parameter to the callsite, we need to make sure 625a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // that what would be the new parameter dominates the callsite. 62661c6ba85715fdcb66f746678879984151f1e5485Chris Lattner DominatorTree &DT = getAnalysis<DominatorTree>(); 62761c6ba85715fdcb66f746678879984151f1e5485Chris Lattner if (Instruction *cpyDestInst = dyn_cast<Instruction>(cpyDest)) 628a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson if (!DT.dominates(cpyDestInst, C)) 629a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson return false; 630a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 631a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // In addition to knowing that the call does not access src in some 632a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // unexpected manner, for example via a global, which we deduce from 633a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // the use analysis, we also need to know that it does not sneakily 634a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // access dest. We rely on AA to figure this out for us. 63561c6ba85715fdcb66f746678879984151f1e5485Chris Lattner AliasAnalysis &AA = getAnalysis<AliasAnalysis>(); 6366549121c660dfd18361cd3daf6c766bee80d3097Owen Anderson if (AA.getModRefInfo(C, cpyDest, srcSize) != 637a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson AliasAnalysis::NoModRef) 638a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson return false; 639a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 640a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // All the checks have passed, so do the transformation. 64112cb36c11564e2a7cf85b4b29bddab5c5fd63cf5Owen Anderson bool changedArgument = false; 642a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson for (unsigned i = 0; i < CS.arg_size(); ++i) 643009e4f760969e3530cc2641a9599e646a20580c2Owen Anderson if (CS.getArgument(i)->stripPointerCasts() == cpySrc) { 644a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson if (cpySrc->getType() != cpyDest->getType()) 6457cbd8a3e92221437048b484d5ef9c0a22d0f8c58Gabor Greif cpyDest = CastInst::CreatePointerCast(cpyDest, cpySrc->getType(), 646a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson cpyDest->getName(), C); 64712cb36c11564e2a7cf85b4b29bddab5c5fd63cf5Owen Anderson changedArgument = true; 64861c6ba85715fdcb66f746678879984151f1e5485Chris Lattner if (CS.getArgument(i)->getType() == cpyDest->getType()) 649009e4f760969e3530cc2641a9599e646a20580c2Owen Anderson CS.setArgument(i, cpyDest); 65061c6ba85715fdcb66f746678879984151f1e5485Chris Lattner else 65161c6ba85715fdcb66f746678879984151f1e5485Chris Lattner CS.setArgument(i, CastInst::CreatePointerCast(cpyDest, 65261c6ba85715fdcb66f746678879984151f1e5485Chris Lattner CS.getArgument(i)->getType(), cpyDest->getName(), C)); 653a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson } 654a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 65512cb36c11564e2a7cf85b4b29bddab5c5fd63cf5Owen Anderson if (!changedArgument) 65612cb36c11564e2a7cf85b4b29bddab5c5fd63cf5Owen Anderson return false; 65712cb36c11564e2a7cf85b4b29bddab5c5fd63cf5Owen Anderson 658a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // Drop any cached information about the call, because we may have changed 659a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // its dependence information by changing its parameter. 66061c6ba85715fdcb66f746678879984151f1e5485Chris Lattner MemoryDependenceAnalysis &MD = getAnalysis<MemoryDependenceAnalysis>(); 6614f8c18c7c757875cfa45383e7cf33d65d2c4d564Chris Lattner MD.removeInstruction(C); 662a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 663a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // Remove the memcpy 664a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson MD.removeInstruction(cpy); 665fe60104ac97f3a8736dcfbfdf9547c7b7cc7b951Dan Gohman ++NumMemCpyInstr; 666a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 667a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson return true; 668a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson} 669a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 67043f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner/// processMemCpyMemCpyDependence - We've found that the (upward scanning) 67143f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner/// memory dependence of memcpy 'M' is the memcpy 'MDep'. Try to simplify M to 67243f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner/// copy from MDep's input if we can. MSize is the size of M's copy. 67343f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner/// 67443f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattnerbool MemCpyOpt::processMemCpyMemCpyDependence(MemCpyInst *M, MemCpyInst *MDep, 67543f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner uint64_t MSize) { 676a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // We can only transforms memcpy's where the dest of one is the source of the 67743f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner // other. 678a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson if (M->getSource() != MDep->getDest()) 679a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson return false; 680a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 681a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // Second, the length of the memcpy's must be the same, or the preceeding one 682a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // must be larger than the following one. 68361c6ba85715fdcb66f746678879984151f1e5485Chris Lattner ConstantInt *C1 = dyn_cast<ConstantInt>(MDep->getLength()); 68443f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner if (!C1) return false; 685a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 686a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson uint64_t DepSize = C1->getValue().getZExtValue(); 687a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 68843f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner if (DepSize < MSize) 689a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson return false; 690a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 6915a7aeaa01904b9b0adf256108f302f8961295754Chris Lattner Intrinsic::ID ResultFn = Intrinsic::memcpy; 6925a7aeaa01904b9b0adf256108f302f8961295754Chris Lattner 6935a7aeaa01904b9b0adf256108f302f8961295754Chris Lattner // If the dest of the second might alias the source of the first, then the 6945a7aeaa01904b9b0adf256108f302f8961295754Chris Lattner // source and dest might overlap. We still want to eliminate the intermediate 6955a7aeaa01904b9b0adf256108f302f8961295754Chris Lattner // value, but we have to generate a memmove instead of memcpy. 69661c6ba85715fdcb66f746678879984151f1e5485Chris Lattner AliasAnalysis &AA = getAnalysis<AliasAnalysis>(); 69712f7085027657957e08aea597b5c9fed44052969Chris Lattner if (!AA.isNoAlias(M->getRawDest(), MSize, MDep->getRawSource(), DepSize)) 6985a7aeaa01904b9b0adf256108f302f8961295754Chris Lattner ResultFn = Intrinsic::memmove; 699a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 700a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson // If all checks passed, then we can transform these memcpy's 701245b7f6ec26a8d27c984da4cceb7cfc27abcba6bChris Lattner const Type *ArgTys[3] = { 702245b7f6ec26a8d27c984da4cceb7cfc27abcba6bChris Lattner M->getRawDest()->getType(), 70343f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner MDep->getRawSource()->getType(), 704245b7f6ec26a8d27c984da4cceb7cfc27abcba6bChris Lattner M->getLength()->getType() 705245b7f6ec26a8d27c984da4cceb7cfc27abcba6bChris Lattner }; 70643f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner Function *MemCpyFun = 70743f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner Intrinsic::getDeclaration(M->getParent()->getParent()->getParent(), 7085a7aeaa01904b9b0adf256108f302f8961295754Chris Lattner ResultFn, ArgTys, 3); 70943f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner 71004fcbf954fef6d9866b5120f406e7401dc9aa29fEric Christopher // Make sure to use the lesser of the alignment of the source and the dest 71104fcbf954fef6d9866b5120f406e7401dc9aa29fEric Christopher // since we're changing where we're reading from, but don't want to increase 71204fcbf954fef6d9866b5120f406e7401dc9aa29fEric Christopher // the alignment past what can be read from or written to. 713c69a00047013a0e2e07ae44c38e013a7d905b10eEric Christopher // TODO: Is this worth it if we're creating a less aligned memcpy? For 714c69a00047013a0e2e07ae44c38e013a7d905b10eEric Christopher // example we could be moving from movaps -> movq on x86. 71504fcbf954fef6d9866b5120f406e7401dc9aa29fEric Christopher unsigned Align = std::min(MDep->getAlignmentCst()->getZExtValue(), 71604fcbf954fef6d9866b5120f406e7401dc9aa29fEric Christopher M->getAlignmentCst()->getZExtValue()); 71704fcbf954fef6d9866b5120f406e7401dc9aa29fEric Christopher LLVMContext &Context = M->getContext(); 71804fcbf954fef6d9866b5120f406e7401dc9aa29fEric Christopher ConstantInt *AlignCI = ConstantInt::get(Type::getInt32Ty(Context), Align); 71920adc9dc4650313f017b27d9818eb2176238113dMon P Wang Value *Args[5] = { 72020adc9dc4650313f017b27d9818eb2176238113dMon P Wang M->getRawDest(), MDep->getRawSource(), M->getLength(), 72104fcbf954fef6d9866b5120f406e7401dc9aa29fEric Christopher AlignCI, M->getVolatileCst() 722dfe964ce8c367248e587f2d9ecc7fac5ee2c6fdcChris Lattner }; 72320adc9dc4650313f017b27d9818eb2176238113dMon P Wang CallInst *C = CallInst::Create(MemCpyFun, Args, Args+5, "", M); 724a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 72543f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner 72643f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner MemoryDependenceAnalysis &MD = getAnalysis<MemoryDependenceAnalysis>(); 72743f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner 72802e9988020acb3e8b0271aa9ebc7c8e770c8a85fOwen Anderson // If C and M don't interfere, then this is a valid transformation. If they 72902e9988020acb3e8b0271aa9ebc7c8e770c8a85fOwen Anderson // did, this would mean that the two sources overlap, which would be bad. 73043f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner MemDepResult dep = MD.getDependency(C); 73143f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner if (dep.isClobber() && dep.getInst() == MDep) { 7324f8c18c7c757875cfa45383e7cf33d65d2c4d564Chris Lattner MD.removeInstruction(M); 733a8bd65835be9e1ce07f5006e92625ec4e9fa387aOwen Anderson M->eraseFromParent(); 734fe60104ac97f3a8736dcfbfdf9547c7b7cc7b951Dan Gohman ++NumMemCpyInstr; 735a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson return true; 736a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson } 737a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 73802e9988020acb3e8b0271aa9ebc7c8e770c8a85fOwen Anderson // Otherwise, there was no point in doing this, so we remove the call we 73902e9988020acb3e8b0271aa9ebc7c8e770c8a85fOwen Anderson // inserted and act like nothing happened. 740a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson MD.removeInstruction(C); 741a8bd65835be9e1ce07f5006e92625ec4e9fa387aOwen Anderson C->eraseFromParent(); 74202e9988020acb3e8b0271aa9ebc7c8e770c8a85fOwen Anderson return false; 743a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson} 744a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 74543f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner 74643f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner/// processMemCpy - perform simplification of memcpy's. If we have memcpy A 74743f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner/// which copies X to Y, and memcpy B which copies Y to Z, then we can rewrite 74843f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner/// B to be a memcpy from X to Z (or potentially a memmove, depending on 74943f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner/// circumstances). This allows later passes to remove the first memcpy 75043f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner/// altogether. 75143f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattnerbool MemCpyOpt::processMemCpy(MemCpyInst *M) { 75243f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner MemoryDependenceAnalysis &MD = getAnalysis<MemoryDependenceAnalysis>(); 75343f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner 75443f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner // We can only optimize statically-sized memcpy's. 75543f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner ConstantInt *cpyLen = dyn_cast<ConstantInt>(M->getLength()); 75643f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner if (!cpyLen) return false; 75743f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner 75843f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner // The are two possible optimizations we can do for memcpy: 75943f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner // a) memcpy-memcpy xform which exposes redundance for DSE. 76043f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner // b) call-memcpy xform for return slot optimization. 76143f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner MemDepResult dep = MD.getDependency(M); 76243f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner if (!dep.isClobber()) 76343f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner return false; 76443f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner 76543f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner if (MemCpyInst *MDep = dyn_cast<MemCpyInst>(dep.getInst())) 76643f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner return processMemCpyMemCpyDependence(M, MDep, cpyLen->getZExtValue()); 76743f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner 76843f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner if (CallInst *C = dyn_cast<CallInst>(dep.getInst())) { 76943f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner bool changed = performCallSlotOptzn(M, M->getDest(), M->getSource(), 77043f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner cpyLen->getZExtValue(), C); 77143f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner if (changed) M->eraseFromParent(); 77243f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner return changed; 77343f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner } 77443f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner return false; 77543f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner} 77643f8e43eb2a166f50c3a077040d8bdb24104433aChris Lattner 777f41eaacee4a4a2d4339dd553626d98c73650c8c7Chris Lattner/// processMemMove - Transforms memmove calls to memcpy calls when the src/dst 778f41eaacee4a4a2d4339dd553626d98c73650c8c7Chris Lattner/// are guaranteed not to alias. 779f41eaacee4a4a2d4339dd553626d98c73650c8c7Chris Lattnerbool MemCpyOpt::processMemMove(MemMoveInst *M) { 780f41eaacee4a4a2d4339dd553626d98c73650c8c7Chris Lattner AliasAnalysis &AA = getAnalysis<AliasAnalysis>(); 781f41eaacee4a4a2d4339dd553626d98c73650c8c7Chris Lattner 782f41eaacee4a4a2d4339dd553626d98c73650c8c7Chris Lattner // If the memmove is a constant size, use it for the alias query, this allows 783f41eaacee4a4a2d4339dd553626d98c73650c8c7Chris Lattner // us to optimize things like: memmove(P, P+64, 64); 7843da848bbda62b25c12335998aaa44ab361f0bf15Dan Gohman uint64_t MemMoveSize = AliasAnalysis::UnknownSize; 785f41eaacee4a4a2d4339dd553626d98c73650c8c7Chris Lattner if (ConstantInt *Len = dyn_cast<ConstantInt>(M->getLength())) 786f41eaacee4a4a2d4339dd553626d98c73650c8c7Chris Lattner MemMoveSize = Len->getZExtValue(); 787f41eaacee4a4a2d4339dd553626d98c73650c8c7Chris Lattner 788f41eaacee4a4a2d4339dd553626d98c73650c8c7Chris Lattner // See if the pointers alias. 789f41eaacee4a4a2d4339dd553626d98c73650c8c7Chris Lattner if (AA.alias(M->getRawDest(), MemMoveSize, M->getRawSource(), MemMoveSize) != 790f41eaacee4a4a2d4339dd553626d98c73650c8c7Chris Lattner AliasAnalysis::NoAlias) 791f41eaacee4a4a2d4339dd553626d98c73650c8c7Chris Lattner return false; 792f41eaacee4a4a2d4339dd553626d98c73650c8c7Chris Lattner 793cb33fd17cce475a1d47b2695e311b6934ad0ef86David Greene DEBUG(dbgs() << "MemCpyOpt: Optimizing memmove -> memcpy: " << *M << "\n"); 794f41eaacee4a4a2d4339dd553626d98c73650c8c7Chris Lattner 795f41eaacee4a4a2d4339dd553626d98c73650c8c7Chris Lattner // If not, then we know we can transform this. 796f41eaacee4a4a2d4339dd553626d98c73650c8c7Chris Lattner Module *Mod = M->getParent()->getParent()->getParent(); 79720adc9dc4650313f017b27d9818eb2176238113dMon P Wang const Type *ArgTys[3] = { M->getRawDest()->getType(), 79820adc9dc4650313f017b27d9818eb2176238113dMon P Wang M->getRawSource()->getType(), 79920adc9dc4650313f017b27d9818eb2176238113dMon P Wang M->getLength()->getType() }; 800a399781289092fcdceb58b21174229f4373c4191Gabor Greif M->setCalledFunction(Intrinsic::getDeclaration(Mod, Intrinsic::memcpy, 801a399781289092fcdceb58b21174229f4373c4191Gabor Greif ArgTys, 3)); 80205cd03b33559732f8ed55e5ff7554fd06d59eb6aDuncan Sands 803f41eaacee4a4a2d4339dd553626d98c73650c8c7Chris Lattner // MemDep may have over conservative information about this instruction, just 804f41eaacee4a4a2d4339dd553626d98c73650c8c7Chris Lattner // conservatively flush it from the cache. 805f41eaacee4a4a2d4339dd553626d98c73650c8c7Chris Lattner getAnalysis<MemoryDependenceAnalysis>().removeInstruction(M); 80605cd03b33559732f8ed55e5ff7554fd06d59eb6aDuncan Sands 80705cd03b33559732f8ed55e5ff7554fd06d59eb6aDuncan Sands ++NumMoveToCpy; 808f41eaacee4a4a2d4339dd553626d98c73650c8c7Chris Lattner return true; 809f41eaacee4a4a2d4339dd553626d98c73650c8c7Chris Lattner} 810f41eaacee4a4a2d4339dd553626d98c73650c8c7Chris Lattner 811f41eaacee4a4a2d4339dd553626d98c73650c8c7Chris Lattner 81261c6ba85715fdcb66f746678879984151f1e5485Chris Lattner// MemCpyOpt::iterateOnFunction - Executes one iteration of GVN. 813a723d1e48f4a261512c28845c53eda569fa5218cOwen Andersonbool MemCpyOpt::iterateOnFunction(Function &F) { 81461c6ba85715fdcb66f746678879984151f1e5485Chris Lattner bool MadeChange = false; 815a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 81661c6ba85715fdcb66f746678879984151f1e5485Chris Lattner // Walk all instruction in the function. 817a8bd65835be9e1ce07f5006e92625ec4e9fa387aOwen Anderson for (Function::iterator BB = F.begin(), BBE = F.end(); BB != BBE; ++BB) { 818a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson for (BasicBlock::iterator BI = BB->begin(), BE = BB->end(); 819a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson BI != BE;) { 82061c6ba85715fdcb66f746678879984151f1e5485Chris Lattner // Avoid invalidating the iterator. 82161c6ba85715fdcb66f746678879984151f1e5485Chris Lattner Instruction *I = BI++; 822a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 823a8bd65835be9e1ce07f5006e92625ec4e9fa387aOwen Anderson if (StoreInst *SI = dyn_cast<StoreInst>(I)) 82461c6ba85715fdcb66f746678879984151f1e5485Chris Lattner MadeChange |= processStore(SI, BI); 82561c6ba85715fdcb66f746678879984151f1e5485Chris Lattner else if (MemCpyInst *M = dyn_cast<MemCpyInst>(I)) 82661c6ba85715fdcb66f746678879984151f1e5485Chris Lattner MadeChange |= processMemCpy(M); 827f41eaacee4a4a2d4339dd553626d98c73650c8c7Chris Lattner else if (MemMoveInst *M = dyn_cast<MemMoveInst>(I)) { 828f41eaacee4a4a2d4339dd553626d98c73650c8c7Chris Lattner if (processMemMove(M)) { 829f41eaacee4a4a2d4339dd553626d98c73650c8c7Chris Lattner --BI; // Reprocess the new memcpy. 830f41eaacee4a4a2d4339dd553626d98c73650c8c7Chris Lattner MadeChange = true; 831f41eaacee4a4a2d4339dd553626d98c73650c8c7Chris Lattner } 832f41eaacee4a4a2d4339dd553626d98c73650c8c7Chris Lattner } 833a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson } 834a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson } 835a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson 83661c6ba85715fdcb66f746678879984151f1e5485Chris Lattner return MadeChange; 837a723d1e48f4a261512c28845c53eda569fa5218cOwen Anderson} 83861c6ba85715fdcb66f746678879984151f1e5485Chris Lattner 83961c6ba85715fdcb66f746678879984151f1e5485Chris Lattner// MemCpyOpt::runOnFunction - This is the main transformation entry point for a 84061c6ba85715fdcb66f746678879984151f1e5485Chris Lattner// function. 84161c6ba85715fdcb66f746678879984151f1e5485Chris Lattner// 84261c6ba85715fdcb66f746678879984151f1e5485Chris Lattnerbool MemCpyOpt::runOnFunction(Function &F) { 84361c6ba85715fdcb66f746678879984151f1e5485Chris Lattner bool MadeChange = false; 84461c6ba85715fdcb66f746678879984151f1e5485Chris Lattner while (1) { 84561c6ba85715fdcb66f746678879984151f1e5485Chris Lattner if (!iterateOnFunction(F)) 84661c6ba85715fdcb66f746678879984151f1e5485Chris Lattner break; 84761c6ba85715fdcb66f746678879984151f1e5485Chris Lattner MadeChange = true; 84861c6ba85715fdcb66f746678879984151f1e5485Chris Lattner } 84961c6ba85715fdcb66f746678879984151f1e5485Chris Lattner 85061c6ba85715fdcb66f746678879984151f1e5485Chris Lattner return MadeChange; 85161c6ba85715fdcb66f746678879984151f1e5485Chris Lattner} 85261c6ba85715fdcb66f746678879984151f1e5485Chris Lattner 85361c6ba85715fdcb66f746678879984151f1e5485Chris Lattner 85461c6ba85715fdcb66f746678879984151f1e5485Chris Lattner 855