1 //===- InstCombineLoadStoreAlloca.cpp -------------------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements the visit functions for load, store and alloca.
12 //===----------------------------------------------------------------------===//
14 #include "InstCombine.h"
15 #include "llvm/IntrinsicInst.h"
16 #include "llvm/Analysis/Loads.h"
17 #include "llvm/Target/TargetData.h"
18 #include "llvm/Transforms/Utils/BasicBlockUtils.h"
19 #include "llvm/Transforms/Utils/Local.h"
20 #include "llvm/ADT/Statistic.h"
23 STATISTIC(NumDeadStore, "Number of dead stores eliminated");
25 Instruction *InstCombiner::visitAllocaInst(AllocaInst &AI) {
26 // Ensure that the alloca array size argument has type intptr_t, so that
27 // any casting is exposed early.
29 const Type *IntPtrTy = TD->getIntPtrType(AI.getContext());
30 if (AI.getArraySize()->getType() != IntPtrTy) {
31 Value *V = Builder->CreateIntCast(AI.getArraySize(),
38 // Convert: alloca Ty, C - where C is a constant != 1 into: alloca [C x Ty], 1
39 if (AI.isArrayAllocation()) { // Check C != 1
40 if (const ConstantInt *C = dyn_cast<ConstantInt>(AI.getArraySize())) {
42 ArrayType::get(AI.getAllocatedType(), C->getZExtValue());
43 assert(isa<AllocaInst>(AI) && "Unknown type of allocation inst!");
44 AllocaInst *New = Builder->CreateAlloca(NewTy, 0, AI.getName());
45 New->setAlignment(AI.getAlignment());
47 // Scan to the end of the allocation instructions, to skip over a block of
48 // allocas if possible...also skip interleaved debug info
50 BasicBlock::iterator It = New;
51 while (isa<AllocaInst>(*It) || isa<DbgInfoIntrinsic>(*It)) ++It;
53 // Now that I is pointing to the first non-allocation-inst in the block,
54 // insert our getelementptr instruction...
56 Value *NullIdx =Constant::getNullValue(Type::getInt32Ty(AI.getContext()));
60 Value *V = GetElementPtrInst::CreateInBounds(New, Idx, Idx + 2,
61 New->getName()+".sub", It);
63 // Now make everything use the getelementptr instead of the original
65 return ReplaceInstUsesWith(AI, V);
66 } else if (isa<UndefValue>(AI.getArraySize())) {
67 return ReplaceInstUsesWith(AI, Constant::getNullValue(AI.getType()));
71 if (TD && isa<AllocaInst>(AI) && AI.getAllocatedType()->isSized()) {
72 // If alloca'ing a zero byte object, replace the alloca with a null pointer.
73 // Note that we only do this for alloca's, because malloc should allocate
74 // and return a unique pointer, even for a zero byte allocation.
75 if (TD->getTypeAllocSize(AI.getAllocatedType()) == 0)
76 return ReplaceInstUsesWith(AI, Constant::getNullValue(AI.getType()));
78 // If the alignment is 0 (unspecified), assign it the preferred alignment.
79 if (AI.getAlignment() == 0)
80 AI.setAlignment(TD->getPrefTypeAlignment(AI.getAllocatedType()));
87 /// InstCombineLoadCast - Fold 'load (cast P)' -> cast (load P)' when possible.
88 static Instruction *InstCombineLoadCast(InstCombiner &IC, LoadInst &LI,
89 const TargetData *TD) {
90 User *CI = cast<User>(LI.getOperand(0));
91 Value *CastOp = CI->getOperand(0);
93 const PointerType *DestTy = cast<PointerType>(CI->getType());
94 const Type *DestPTy = DestTy->getElementType();
95 if (const PointerType *SrcTy = dyn_cast<PointerType>(CastOp->getType())) {
97 // If the address spaces don't match, don't eliminate the cast.
98 if (DestTy->getAddressSpace() != SrcTy->getAddressSpace())
101 const Type *SrcPTy = SrcTy->getElementType();
103 if (DestPTy->isIntegerTy() || DestPTy->isPointerTy() ||
104 DestPTy->isVectorTy()) {
105 // If the source is an array, the code below will not succeed. Check to
106 // see if a trivial 'gep P, 0, 0' will help matters. Only do this for
108 if (const ArrayType *ASrcTy = dyn_cast<ArrayType>(SrcPTy))
109 if (Constant *CSrc = dyn_cast<Constant>(CastOp))
110 if (ASrcTy->getNumElements() != 0) {
112 Idxs[0] = Constant::getNullValue(Type::getInt32Ty(LI.getContext()));
114 CastOp = ConstantExpr::getGetElementPtr(CSrc, Idxs, 2);
115 SrcTy = cast<PointerType>(CastOp->getType());
116 SrcPTy = SrcTy->getElementType();
119 if (IC.getTargetData() &&
120 (SrcPTy->isIntegerTy() || SrcPTy->isPointerTy() ||
121 SrcPTy->isVectorTy()) &&
122 // Do not allow turning this into a load of an integer, which is then
123 // casted to a pointer, this pessimizes pointer analysis a lot.
124 (SrcPTy->isPointerTy() == LI.getType()->isPointerTy()) &&
125 IC.getTargetData()->getTypeSizeInBits(SrcPTy) ==
126 IC.getTargetData()->getTypeSizeInBits(DestPTy)) {
128 // Okay, we are casting from one integer or pointer type to another of
129 // the same size. Instead of casting the pointer before the load, cast
130 // the result of the loaded value.
132 IC.Builder->CreateLoad(CastOp, LI.isVolatile(), CI->getName());
133 NewLoad->setAlignment(LI.getAlignment());
134 // Now cast the result of the load.
135 return new BitCastInst(NewLoad, LI.getType());
142 Instruction *InstCombiner::visitLoadInst(LoadInst &LI) {
143 Value *Op = LI.getOperand(0);
145 // Attempt to improve the alignment.
147 unsigned KnownAlign =
148 getOrEnforceKnownAlignment(Op, TD->getPrefTypeAlignment(LI.getType()),TD);
149 unsigned LoadAlign = LI.getAlignment();
150 unsigned EffectiveLoadAlign = LoadAlign != 0 ? LoadAlign :
151 TD->getABITypeAlignment(LI.getType());
153 if (KnownAlign > EffectiveLoadAlign)
154 LI.setAlignment(KnownAlign);
155 else if (LoadAlign == 0)
156 LI.setAlignment(EffectiveLoadAlign);
159 // load (cast X) --> cast (load X) iff safe.
160 if (isa<CastInst>(Op))
161 if (Instruction *Res = InstCombineLoadCast(*this, LI, TD))
164 // None of the following transforms are legal for volatile loads.
165 if (LI.isVolatile()) return 0;
167 // Do really simple store-to-load forwarding and load CSE, to catch cases
168 // where there are several consecutive memory accesses to the same location,
169 // separated by a few arithmetic operations.
170 BasicBlock::iterator BBI = &LI;
171 if (Value *AvailableVal = FindAvailableLoadedValue(Op, LI.getParent(), BBI,6))
172 return ReplaceInstUsesWith(LI, AvailableVal);
174 // load(gep null, ...) -> unreachable
175 if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(Op)) {
176 const Value *GEPI0 = GEPI->getOperand(0);
177 // TODO: Consider a target hook for valid address spaces for this xform.
178 if (isa<ConstantPointerNull>(GEPI0) && GEPI->getPointerAddressSpace() == 0){
179 // Insert a new store to null instruction before the load to indicate
180 // that this code is not reachable. We do this instead of inserting
181 // an unreachable instruction directly because we cannot modify the
183 new StoreInst(UndefValue::get(LI.getType()),
184 Constant::getNullValue(Op->getType()), &LI);
185 return ReplaceInstUsesWith(LI, UndefValue::get(LI.getType()));
189 // load null/undef -> unreachable
190 // TODO: Consider a target hook for valid address spaces for this xform.
191 if (isa<UndefValue>(Op) ||
192 (isa<ConstantPointerNull>(Op) && LI.getPointerAddressSpace() == 0)) {
193 // Insert a new store to null instruction before the load to indicate that
194 // this code is not reachable. We do this instead of inserting an
195 // unreachable instruction directly because we cannot modify the CFG.
196 new StoreInst(UndefValue::get(LI.getType()),
197 Constant::getNullValue(Op->getType()), &LI);
198 return ReplaceInstUsesWith(LI, UndefValue::get(LI.getType()));
201 // Instcombine load (constantexpr_cast global) -> cast (load global)
202 if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Op))
204 if (Instruction *Res = InstCombineLoadCast(*this, LI, TD))
207 if (Op->hasOneUse()) {
208 // Change select and PHI nodes to select values instead of addresses: this
209 // helps alias analysis out a lot, allows many others simplifications, and
210 // exposes redundancy in the code.
212 // Note that we cannot do the transformation unless we know that the
213 // introduced loads cannot trap! Something like this is valid as long as
214 // the condition is always false: load (select bool %C, int* null, int* %G),
215 // but it would not be valid if we transformed it to load from null
218 if (SelectInst *SI = dyn_cast<SelectInst>(Op)) {
219 // load (select (Cond, &V1, &V2)) --> select(Cond, load &V1, load &V2).
220 unsigned Align = LI.getAlignment();
221 if (isSafeToLoadUnconditionally(SI->getOperand(1), SI, Align, TD) &&
222 isSafeToLoadUnconditionally(SI->getOperand(2), SI, Align, TD)) {
223 LoadInst *V1 = Builder->CreateLoad(SI->getOperand(1),
224 SI->getOperand(1)->getName()+".val");
225 LoadInst *V2 = Builder->CreateLoad(SI->getOperand(2),
226 SI->getOperand(2)->getName()+".val");
227 V1->setAlignment(Align);
228 V2->setAlignment(Align);
229 return SelectInst::Create(SI->getCondition(), V1, V2);
232 // load (select (cond, null, P)) -> load P
233 if (Constant *C = dyn_cast<Constant>(SI->getOperand(1)))
234 if (C->isNullValue()) {
235 LI.setOperand(0, SI->getOperand(2));
239 // load (select (cond, P, null)) -> load P
240 if (Constant *C = dyn_cast<Constant>(SI->getOperand(2)))
241 if (C->isNullValue()) {
242 LI.setOperand(0, SI->getOperand(1));
250 /// InstCombineStoreToCast - Fold store V, (cast P) -> store (cast V), P
251 /// when possible. This makes it generally easy to do alias analysis and/or
252 /// SROA/mem2reg of the memory object.
253 static Instruction *InstCombineStoreToCast(InstCombiner &IC, StoreInst &SI) {
254 User *CI = cast<User>(SI.getOperand(1));
255 Value *CastOp = CI->getOperand(0);
257 const Type *DestPTy = cast<PointerType>(CI->getType())->getElementType();
258 const PointerType *SrcTy = dyn_cast<PointerType>(CastOp->getType());
259 if (SrcTy == 0) return 0;
261 const Type *SrcPTy = SrcTy->getElementType();
263 if (!DestPTy->isIntegerTy() && !DestPTy->isPointerTy())
266 /// NewGEPIndices - If SrcPTy is an aggregate type, we can emit a "noop gep"
267 /// to its first element. This allows us to handle things like:
268 /// store i32 xxx, (bitcast {foo*, float}* %P to i32*)
270 SmallVector<Value*, 4> NewGEPIndices;
272 // If the source is an array, the code below will not succeed. Check to
273 // see if a trivial 'gep P, 0, 0' will help matters. Only do this for
275 if (SrcPTy->isArrayTy() || SrcPTy->isStructTy()) {
276 // Index through pointer.
277 Constant *Zero = Constant::getNullValue(Type::getInt32Ty(SI.getContext()));
278 NewGEPIndices.push_back(Zero);
281 if (const StructType *STy = dyn_cast<StructType>(SrcPTy)) {
282 if (!STy->getNumElements()) /* Struct can be empty {} */
284 NewGEPIndices.push_back(Zero);
285 SrcPTy = STy->getElementType(0);
286 } else if (const ArrayType *ATy = dyn_cast<ArrayType>(SrcPTy)) {
287 NewGEPIndices.push_back(Zero);
288 SrcPTy = ATy->getElementType();
294 SrcTy = PointerType::get(SrcPTy, SrcTy->getAddressSpace());
297 if (!SrcPTy->isIntegerTy() && !SrcPTy->isPointerTy())
300 // If the pointers point into different address spaces or if they point to
301 // values with different sizes, we can't do the transformation.
302 if (!IC.getTargetData() ||
303 SrcTy->getAddressSpace() !=
304 cast<PointerType>(CI->getType())->getAddressSpace() ||
305 IC.getTargetData()->getTypeSizeInBits(SrcPTy) !=
306 IC.getTargetData()->getTypeSizeInBits(DestPTy))
309 // Okay, we are casting from one integer or pointer type to another of
310 // the same size. Instead of casting the pointer before
311 // the store, cast the value to be stored.
313 Value *SIOp0 = SI.getOperand(0);
314 Instruction::CastOps opcode = Instruction::BitCast;
315 const Type* CastSrcTy = SIOp0->getType();
316 const Type* CastDstTy = SrcPTy;
317 if (CastDstTy->isPointerTy()) {
318 if (CastSrcTy->isIntegerTy())
319 opcode = Instruction::IntToPtr;
320 } else if (CastDstTy->isIntegerTy()) {
321 if (SIOp0->getType()->isPointerTy())
322 opcode = Instruction::PtrToInt;
325 // SIOp0 is a pointer to aggregate and this is a store to the first field,
326 // emit a GEP to index into its first field.
327 if (!NewGEPIndices.empty())
328 CastOp = IC.Builder->CreateInBoundsGEP(CastOp, NewGEPIndices.begin(),
329 NewGEPIndices.end());
331 NewCast = IC.Builder->CreateCast(opcode, SIOp0, CastDstTy,
332 SIOp0->getName()+".c");
333 SI.setOperand(0, NewCast);
334 SI.setOperand(1, CastOp);
338 /// equivalentAddressValues - Test if A and B will obviously have the same
339 /// value. This includes recognizing that %t0 and %t1 will have the same
340 /// value in code like this:
341 /// %t0 = getelementptr \@a, 0, 3
342 /// store i32 0, i32* %t0
343 /// %t1 = getelementptr \@a, 0, 3
344 /// %t2 = load i32* %t1
346 static bool equivalentAddressValues(Value *A, Value *B) {
347 // Test if the values are trivially equivalent.
348 if (A == B) return true;
350 // Test if the values come form identical arithmetic instructions.
351 // This uses isIdenticalToWhenDefined instead of isIdenticalTo because
352 // its only used to compare two uses within the same basic block, which
353 // means that they'll always either have the same value or one of them
354 // will have an undefined value.
355 if (isa<BinaryOperator>(A) ||
358 isa<GetElementPtrInst>(A))
359 if (Instruction *BI = dyn_cast<Instruction>(B))
360 if (cast<Instruction>(A)->isIdenticalToWhenDefined(BI))
363 // Otherwise they may not be equivalent.
367 // If this instruction has two uses, one of which is a llvm.dbg.declare,
368 // return the llvm.dbg.declare.
369 DbgDeclareInst *InstCombiner::hasOneUsePlusDeclare(Value *V) {
372 for (Value::use_iterator UI = V->use_begin(), E = V->use_end();
375 if (DbgDeclareInst *DI = dyn_cast<DbgDeclareInst>(U))
377 if (isa<BitCastInst>(U) && U->hasOneUse()) {
378 if (DbgDeclareInst *DI = dyn_cast<DbgDeclareInst>(*U->use_begin()))
385 Instruction *InstCombiner::visitStoreInst(StoreInst &SI) {
386 Value *Val = SI.getOperand(0);
387 Value *Ptr = SI.getOperand(1);
389 // If the RHS is an alloca with a single use, zapify the store, making the
391 // If the RHS is an alloca with a two uses, the other one being a
392 // llvm.dbg.declare, zapify the store and the declare, making the
393 // alloca dead. We must do this to prevent declares from affecting
395 if (!SI.isVolatile()) {
396 if (Ptr->hasOneUse()) {
397 if (isa<AllocaInst>(Ptr))
398 return EraseInstFromFunction(SI);
399 if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Ptr)) {
400 if (isa<AllocaInst>(GEP->getOperand(0))) {
401 if (GEP->getOperand(0)->hasOneUse())
402 return EraseInstFromFunction(SI);
403 if (DbgDeclareInst *DI = hasOneUsePlusDeclare(GEP->getOperand(0))) {
404 EraseInstFromFunction(*DI);
405 return EraseInstFromFunction(SI);
410 if (DbgDeclareInst *DI = hasOneUsePlusDeclare(Ptr)) {
411 EraseInstFromFunction(*DI);
412 return EraseInstFromFunction(SI);
416 // Attempt to improve the alignment.
418 unsigned KnownAlign =
419 getOrEnforceKnownAlignment(Ptr, TD->getPrefTypeAlignment(Val->getType()),
421 unsigned StoreAlign = SI.getAlignment();
422 unsigned EffectiveStoreAlign = StoreAlign != 0 ? StoreAlign :
423 TD->getABITypeAlignment(Val->getType());
425 if (KnownAlign > EffectiveStoreAlign)
426 SI.setAlignment(KnownAlign);
427 else if (StoreAlign == 0)
428 SI.setAlignment(EffectiveStoreAlign);
431 // Do really simple DSE, to catch cases where there are several consecutive
432 // stores to the same location, separated by a few arithmetic operations. This
433 // situation often occurs with bitfield accesses.
434 BasicBlock::iterator BBI = &SI;
435 for (unsigned ScanInsts = 6; BBI != SI.getParent()->begin() && ScanInsts;
438 // Don't count debug info directives, lest they affect codegen,
439 // and we skip pointer-to-pointer bitcasts, which are NOPs.
440 if (isa<DbgInfoIntrinsic>(BBI) ||
441 (isa<BitCastInst>(BBI) && BBI->getType()->isPointerTy())) {
446 if (StoreInst *PrevSI = dyn_cast<StoreInst>(BBI)) {
447 // Prev store isn't volatile, and stores to the same location?
448 if (!PrevSI->isVolatile() &&equivalentAddressValues(PrevSI->getOperand(1),
452 EraseInstFromFunction(*PrevSI);
458 // If this is a load, we have to stop. However, if the loaded value is from
459 // the pointer we're loading and is producing the pointer we're storing,
460 // then *this* store is dead (X = load P; store X -> P).
461 if (LoadInst *LI = dyn_cast<LoadInst>(BBI)) {
462 if (LI == Val && equivalentAddressValues(LI->getOperand(0), Ptr) &&
464 return EraseInstFromFunction(SI);
466 // Otherwise, this is a load from some other location. Stores before it
471 // Don't skip over loads or things that can modify memory.
472 if (BBI->mayWriteToMemory() || BBI->mayReadFromMemory())
477 if (SI.isVolatile()) return 0; // Don't hack volatile stores.
479 // store X, null -> turns into 'unreachable' in SimplifyCFG
480 if (isa<ConstantPointerNull>(Ptr) && SI.getPointerAddressSpace() == 0) {
481 if (!isa<UndefValue>(Val)) {
482 SI.setOperand(0, UndefValue::get(Val->getType()));
483 if (Instruction *U = dyn_cast<Instruction>(Val))
484 Worklist.Add(U); // Dropped a use.
486 return 0; // Do not modify these!
489 // store undef, Ptr -> noop
490 if (isa<UndefValue>(Val))
491 return EraseInstFromFunction(SI);
493 // If the pointer destination is a cast, see if we can fold the cast into the
495 if (isa<CastInst>(Ptr))
496 if (Instruction *Res = InstCombineStoreToCast(*this, SI))
498 if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Ptr))
500 if (Instruction *Res = InstCombineStoreToCast(*this, SI))
504 // If this store is the last instruction in the basic block (possibly
505 // excepting debug info instructions), and if the block ends with an
506 // unconditional branch, try to move it to the successor block.
510 } while (isa<DbgInfoIntrinsic>(BBI) ||
511 (isa<BitCastInst>(BBI) && BBI->getType()->isPointerTy()));
512 if (BranchInst *BI = dyn_cast<BranchInst>(BBI))
513 if (BI->isUnconditional())
514 if (SimplifyStoreAtEndOfBlock(SI))
515 return 0; // xform done!
520 /// SimplifyStoreAtEndOfBlock - Turn things like:
521 /// if () { *P = v1; } else { *P = v2 }
522 /// into a phi node with a store in the successor.
524 /// Simplify things like:
525 /// *P = v1; if () { *P = v2; }
526 /// into a phi node with a store in the successor.
528 bool InstCombiner::SimplifyStoreAtEndOfBlock(StoreInst &SI) {
529 BasicBlock *StoreBB = SI.getParent();
531 // Check to see if the successor block has exactly two incoming edges. If
532 // so, see if the other predecessor contains a store to the same location.
533 // if so, insert a PHI node (if needed) and move the stores down.
534 BasicBlock *DestBB = StoreBB->getTerminator()->getSuccessor(0);
536 // Determine whether Dest has exactly two predecessors and, if so, compute
537 // the other predecessor.
538 pred_iterator PI = pred_begin(DestBB);
540 BasicBlock *OtherBB = 0;
545 if (++PI == pred_end(DestBB))
554 if (++PI != pred_end(DestBB))
557 // Bail out if all the relevant blocks aren't distinct (this can happen,
558 // for example, if SI is in an infinite loop)
559 if (StoreBB == DestBB || OtherBB == DestBB)
562 // Verify that the other block ends in a branch and is not otherwise empty.
563 BasicBlock::iterator BBI = OtherBB->getTerminator();
564 BranchInst *OtherBr = dyn_cast<BranchInst>(BBI);
565 if (!OtherBr || BBI == OtherBB->begin())
568 // If the other block ends in an unconditional branch, check for the 'if then
569 // else' case. there is an instruction before the branch.
570 StoreInst *OtherStore = 0;
571 if (OtherBr->isUnconditional()) {
573 // Skip over debugging info.
574 while (isa<DbgInfoIntrinsic>(BBI) ||
575 (isa<BitCastInst>(BBI) && BBI->getType()->isPointerTy())) {
576 if (BBI==OtherBB->begin())
580 // If this isn't a store, isn't a store to the same location, or if the
581 // alignments differ, bail out.
582 OtherStore = dyn_cast<StoreInst>(BBI);
583 if (!OtherStore || OtherStore->getOperand(1) != SI.getOperand(1) ||
584 OtherStore->getAlignment() != SI.getAlignment())
587 // Otherwise, the other block ended with a conditional branch. If one of the
588 // destinations is StoreBB, then we have the if/then case.
589 if (OtherBr->getSuccessor(0) != StoreBB &&
590 OtherBr->getSuccessor(1) != StoreBB)
593 // Okay, we know that OtherBr now goes to Dest and StoreBB, so this is an
594 // if/then triangle. See if there is a store to the same ptr as SI that
597 // Check to see if we find the matching store.
598 if ((OtherStore = dyn_cast<StoreInst>(BBI))) {
599 if (OtherStore->getOperand(1) != SI.getOperand(1) ||
600 OtherStore->getAlignment() != SI.getAlignment())
604 // If we find something that may be using or overwriting the stored
605 // value, or if we run out of instructions, we can't do the xform.
606 if (BBI->mayReadFromMemory() || BBI->mayWriteToMemory() ||
607 BBI == OtherBB->begin())
611 // In order to eliminate the store in OtherBr, we have to
612 // make sure nothing reads or overwrites the stored value in
614 for (BasicBlock::iterator I = StoreBB->begin(); &*I != &SI; ++I) {
615 // FIXME: This should really be AA driven.
616 if (I->mayReadFromMemory() || I->mayWriteToMemory())
621 // Insert a PHI node now if we need it.
622 Value *MergedVal = OtherStore->getOperand(0);
623 if (MergedVal != SI.getOperand(0)) {
624 PHINode *PN = PHINode::Create(MergedVal->getType(), "storemerge");
625 PN->reserveOperandSpace(2);
626 PN->addIncoming(SI.getOperand(0), SI.getParent());
627 PN->addIncoming(OtherStore->getOperand(0), OtherBB);
628 MergedVal = InsertNewInstBefore(PN, DestBB->front());
631 // Advance to a place where it is safe to insert the new store and
633 BBI = DestBB->getFirstNonPHI();
634 InsertNewInstBefore(new StoreInst(MergedVal, SI.getOperand(1),
635 OtherStore->isVolatile(),
636 SI.getAlignment()), *BBI);
638 // Nuke the old stores.
639 EraseInstFromFunction(SI);
640 EraseInstFromFunction(*OtherStore);