1 //===- InstCombineCasts.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 cast operations.
12 //===----------------------------------------------------------------------===//
14 #include "InstCombine.h"
15 #include "llvm/Target/TargetData.h"
16 #include "llvm/Support/PatternMatch.h"
18 using namespace PatternMatch;
20 /// DecomposeSimpleLinearExpr - Analyze 'Val', seeing if it is a simple linear
21 /// expression. If so, decompose it, returning some value X, such that Val is
24 static Value *DecomposeSimpleLinearExpr(Value *Val, unsigned &Scale,
26 assert(Val->getType()->isInteger(32) && "Unexpected allocation size type!");
27 if (ConstantInt *CI = dyn_cast<ConstantInt>(Val)) {
28 Offset = CI->getZExtValue();
30 return ConstantInt::get(Type::getInt32Ty(Val->getContext()), 0);
33 if (BinaryOperator *I = dyn_cast<BinaryOperator>(Val)) {
34 if (ConstantInt *RHS = dyn_cast<ConstantInt>(I->getOperand(1))) {
35 if (I->getOpcode() == Instruction::Shl) {
36 // This is a value scaled by '1 << the shift amt'.
37 Scale = 1U << RHS->getZExtValue();
39 return I->getOperand(0);
42 if (I->getOpcode() == Instruction::Mul) {
43 // This value is scaled by 'RHS'.
44 Scale = RHS->getZExtValue();
46 return I->getOperand(0);
49 if (I->getOpcode() == Instruction::Add) {
50 // We have X+C. Check to see if we really have (X*C2)+C1,
51 // where C1 is divisible by C2.
54 DecomposeSimpleLinearExpr(I->getOperand(0), SubScale, Offset);
55 Offset += RHS->getZExtValue();
62 // Otherwise, we can't look past this.
68 /// PromoteCastOfAllocation - If we find a cast of an allocation instruction,
69 /// try to eliminate the cast by moving the type information into the alloc.
70 Instruction *InstCombiner::PromoteCastOfAllocation(BitCastInst &CI,
72 // This requires TargetData to get the alloca alignment and size information.
75 const PointerType *PTy = cast<PointerType>(CI.getType());
77 BuilderTy AllocaBuilder(*Builder);
78 AllocaBuilder.SetInsertPoint(AI.getParent(), &AI);
80 // Get the type really allocated and the type casted to.
81 const Type *AllocElTy = AI.getAllocatedType();
82 const Type *CastElTy = PTy->getElementType();
83 if (!AllocElTy->isSized() || !CastElTy->isSized()) return 0;
85 unsigned AllocElTyAlign = TD->getABITypeAlignment(AllocElTy);
86 unsigned CastElTyAlign = TD->getABITypeAlignment(CastElTy);
87 if (CastElTyAlign < AllocElTyAlign) return 0;
89 // If the allocation has multiple uses, only promote it if we are strictly
90 // increasing the alignment of the resultant allocation. If we keep it the
91 // same, we open the door to infinite loops of various kinds. (A reference
92 // from a dbg.declare doesn't count as a use for this purpose.)
93 if (!AI.hasOneUse() && !hasOneUsePlusDeclare(&AI) &&
94 CastElTyAlign == AllocElTyAlign) return 0;
96 uint64_t AllocElTySize = TD->getTypeAllocSize(AllocElTy);
97 uint64_t CastElTySize = TD->getTypeAllocSize(CastElTy);
98 if (CastElTySize == 0 || AllocElTySize == 0) return 0;
100 // See if we can satisfy the modulus by pulling a scale out of the array
102 unsigned ArraySizeScale;
104 Value *NumElements = // See if the array size is a decomposable linear expr.
105 DecomposeSimpleLinearExpr(AI.getOperand(0), ArraySizeScale, ArrayOffset);
107 // If we can now satisfy the modulus, by using a non-1 scale, we really can
109 if ((AllocElTySize*ArraySizeScale) % CastElTySize != 0 ||
110 (AllocElTySize*ArrayOffset ) % CastElTySize != 0) return 0;
112 unsigned Scale = (AllocElTySize*ArraySizeScale)/CastElTySize;
117 Amt = ConstantInt::get(Type::getInt32Ty(CI.getContext()), Scale);
118 // Insert before the alloca, not before the cast.
119 Amt = AllocaBuilder.CreateMul(Amt, NumElements, "tmp");
122 if (int Offset = (AllocElTySize*ArrayOffset)/CastElTySize) {
123 Value *Off = ConstantInt::get(Type::getInt32Ty(CI.getContext()),
125 Amt = AllocaBuilder.CreateAdd(Amt, Off, "tmp");
128 AllocaInst *New = AllocaBuilder.CreateAlloca(CastElTy, Amt);
129 New->setAlignment(AI.getAlignment());
132 // If the allocation has one real use plus a dbg.declare, just remove the
134 if (DbgDeclareInst *DI = hasOneUsePlusDeclare(&AI)) {
135 EraseInstFromFunction(*(Instruction*)DI);
137 // If the allocation has multiple real uses, insert a cast and change all
138 // things that used it to use the new cast. This will also hack on CI, but it
140 else if (!AI.hasOneUse()) {
141 // New is the allocation instruction, pointer typed. AI is the original
142 // allocation instruction, also pointer typed. Thus, cast to use is BitCast.
143 Value *NewCast = AllocaBuilder.CreateBitCast(New, AI.getType(), "tmpcast");
144 AI.replaceAllUsesWith(NewCast);
146 return ReplaceInstUsesWith(CI, New);
150 /// CanEvaluateInDifferentType - Return true if we can take the specified value
151 /// and return it as type Ty without inserting any new casts and without
152 /// changing the computed value. This is used by code that tries to decide
153 /// whether promoting or shrinking integer operations to wider or smaller types
154 /// will allow us to eliminate a truncate or extend.
156 /// This is a truncation operation if Ty is smaller than V->getType(), or an
157 /// extension operation if Ty is larger.
159 /// If CastOpc is a truncation, then Ty will be a type smaller than V. We
160 /// should return true if trunc(V) can be computed by computing V in the smaller
161 /// type. If V is an instruction, then trunc(inst(x,y)) can be computed as
162 /// inst(trunc(x),trunc(y)), which only makes sense if x and y can be
163 /// efficiently truncated.
165 /// If CastOpc is a sext or zext, we are asking if the low bits of the value can
166 /// bit computed in a larger type, which is then and'd or sext_in_reg'd to get
167 /// the final result.
168 static bool CanEvaluateInDifferentType(Value *V, const Type *Ty,
169 unsigned CastOpc, int &NumCastsRemoved) {
170 // We can always evaluate constants in another type.
171 if (isa<Constant>(V))
174 Instruction *I = dyn_cast<Instruction>(V);
175 if (!I) return false;
177 const Type *OrigTy = V->getType();
179 // If this is an extension or truncate, we can often eliminate it.
180 if (isa<TruncInst>(I) || isa<ZExtInst>(I) || isa<SExtInst>(I)) {
181 // If this is a cast from the destination type, we can trivially eliminate
182 // it, and this will remove a cast overall.
183 if (I->getOperand(0)->getType() == Ty) {
184 // If the first operand is itself a cast, and is eliminable, do not count
185 // this as an eliminable cast. We would prefer to eliminate those two
187 if (!isa<CastInst>(I->getOperand(0)) && I->hasOneUse())
193 // We can't extend or shrink something that has multiple uses: doing so would
194 // require duplicating the instruction in general, which isn't profitable.
195 if (!I->hasOneUse()) return false;
197 unsigned Opc = I->getOpcode();
199 case Instruction::Add:
200 case Instruction::Sub:
201 case Instruction::Mul:
202 case Instruction::And:
203 case Instruction::Or:
204 case Instruction::Xor:
205 // These operators can all arbitrarily be extended or truncated.
206 return CanEvaluateInDifferentType(I->getOperand(0), Ty, CastOpc,
208 CanEvaluateInDifferentType(I->getOperand(1), Ty, CastOpc,
211 case Instruction::UDiv:
212 case Instruction::URem: {
213 // UDiv and URem can be truncated if all the truncated bits are zero.
214 uint32_t OrigBitWidth = OrigTy->getScalarSizeInBits();
215 uint32_t BitWidth = Ty->getScalarSizeInBits();
216 if (BitWidth < OrigBitWidth) {
217 APInt Mask = APInt::getHighBitsSet(OrigBitWidth, OrigBitWidth-BitWidth);
218 if (MaskedValueIsZero(I->getOperand(0), Mask) &&
219 MaskedValueIsZero(I->getOperand(1), Mask)) {
220 return CanEvaluateInDifferentType(I->getOperand(0), Ty, CastOpc,
222 CanEvaluateInDifferentType(I->getOperand(1), Ty, CastOpc,
228 case Instruction::Shl:
229 // If we are truncating the result of this SHL, and if it's a shift of a
230 // constant amount, we can always perform a SHL in a smaller type.
231 if (ConstantInt *CI = dyn_cast<ConstantInt>(I->getOperand(1))) {
232 uint32_t BitWidth = Ty->getScalarSizeInBits();
233 if (BitWidth < OrigTy->getScalarSizeInBits() &&
234 CI->getLimitedValue(BitWidth) < BitWidth)
235 return CanEvaluateInDifferentType(I->getOperand(0), Ty, CastOpc,
239 case Instruction::LShr:
240 // If this is a truncate of a logical shr, we can truncate it to a smaller
241 // lshr iff we know that the bits we would otherwise be shifting in are
243 if (ConstantInt *CI = dyn_cast<ConstantInt>(I->getOperand(1))) {
244 uint32_t OrigBitWidth = OrigTy->getScalarSizeInBits();
245 uint32_t BitWidth = Ty->getScalarSizeInBits();
246 if (BitWidth < OrigBitWidth &&
247 MaskedValueIsZero(I->getOperand(0),
248 APInt::getHighBitsSet(OrigBitWidth, OrigBitWidth-BitWidth)) &&
249 CI->getLimitedValue(BitWidth) < BitWidth) {
250 return CanEvaluateInDifferentType(I->getOperand(0), Ty, CastOpc,
255 case Instruction::ZExt:
256 case Instruction::SExt:
257 case Instruction::Trunc:
258 // If this is the same kind of case as our original (e.g. zext+zext), we
259 // can safely replace it. Note that replacing it does not reduce the number
260 // of casts in the input.
264 // sext (zext ty1), ty2 -> zext ty2
265 if (CastOpc == Instruction::SExt && Opc == Instruction::ZExt)
268 case Instruction::Select: {
269 SelectInst *SI = cast<SelectInst>(I);
270 return CanEvaluateInDifferentType(SI->getTrueValue(), Ty, CastOpc,
272 CanEvaluateInDifferentType(SI->getFalseValue(), Ty, CastOpc,
275 case Instruction::PHI: {
276 // We can change a phi if we can change all operands. Note that we never
277 // get into trouble with cyclic PHIs here because we only consider
278 // instructions with a single use.
279 PHINode *PN = cast<PHINode>(I);
280 for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
281 if (!CanEvaluateInDifferentType(PN->getIncomingValue(i), Ty, CastOpc,
287 // TODO: Can handle more cases here.
294 /// EvaluateInDifferentType - Given an expression that
295 /// CanEvaluateInDifferentType returns true for, actually insert the code to
296 /// evaluate the expression.
297 Value *InstCombiner::EvaluateInDifferentType(Value *V, const Type *Ty,
299 if (Constant *C = dyn_cast<Constant>(V))
300 return ConstantExpr::getIntegerCast(C, Ty, isSigned /*Sext or ZExt*/);
302 // Otherwise, it must be an instruction.
303 Instruction *I = cast<Instruction>(V);
304 Instruction *Res = 0;
305 unsigned Opc = I->getOpcode();
307 case Instruction::Add:
308 case Instruction::Sub:
309 case Instruction::Mul:
310 case Instruction::And:
311 case Instruction::Or:
312 case Instruction::Xor:
313 case Instruction::AShr:
314 case Instruction::LShr:
315 case Instruction::Shl:
316 case Instruction::UDiv:
317 case Instruction::URem: {
318 Value *LHS = EvaluateInDifferentType(I->getOperand(0), Ty, isSigned);
319 Value *RHS = EvaluateInDifferentType(I->getOperand(1), Ty, isSigned);
320 Res = BinaryOperator::Create((Instruction::BinaryOps)Opc, LHS, RHS);
323 case Instruction::Trunc:
324 case Instruction::ZExt:
325 case Instruction::SExt:
326 // If the source type of the cast is the type we're trying for then we can
327 // just return the source. There's no need to insert it because it is not
329 if (I->getOperand(0)->getType() == Ty)
330 return I->getOperand(0);
332 // Otherwise, must be the same type of cast, so just reinsert a new one.
333 Res = CastInst::Create(cast<CastInst>(I)->getOpcode(), I->getOperand(0),Ty);
335 case Instruction::Select: {
336 Value *True = EvaluateInDifferentType(I->getOperand(1), Ty, isSigned);
337 Value *False = EvaluateInDifferentType(I->getOperand(2), Ty, isSigned);
338 Res = SelectInst::Create(I->getOperand(0), True, False);
341 case Instruction::PHI: {
342 PHINode *OPN = cast<PHINode>(I);
343 PHINode *NPN = PHINode::Create(Ty);
344 for (unsigned i = 0, e = OPN->getNumIncomingValues(); i != e; ++i) {
345 Value *V =EvaluateInDifferentType(OPN->getIncomingValue(i), Ty, isSigned);
346 NPN->addIncoming(V, OPN->getIncomingBlock(i));
352 // TODO: Can handle more cases here.
353 llvm_unreachable("Unreachable!");
358 return InsertNewInstBefore(Res, *I);
362 /// This function is a wrapper around CastInst::isEliminableCastPair. It
363 /// simply extracts arguments and returns what that function returns.
364 static Instruction::CastOps
365 isEliminableCastPair(
366 const CastInst *CI, ///< The first cast instruction
367 unsigned opcode, ///< The opcode of the second cast instruction
368 const Type *DstTy, ///< The target type for the second cast instruction
369 TargetData *TD ///< The target data for pointer size
372 const Type *SrcTy = CI->getOperand(0)->getType(); // A from above
373 const Type *MidTy = CI->getType(); // B from above
375 // Get the opcodes of the two Cast instructions
376 Instruction::CastOps firstOp = Instruction::CastOps(CI->getOpcode());
377 Instruction::CastOps secondOp = Instruction::CastOps(opcode);
379 unsigned Res = CastInst::isEliminableCastPair(firstOp, secondOp, SrcTy, MidTy,
381 TD ? TD->getIntPtrType(CI->getContext()) : 0);
383 // We don't want to form an inttoptr or ptrtoint that converts to an integer
384 // type that differs from the pointer size.
385 if ((Res == Instruction::IntToPtr &&
386 (!TD || SrcTy != TD->getIntPtrType(CI->getContext()))) ||
387 (Res == Instruction::PtrToInt &&
388 (!TD || DstTy != TD->getIntPtrType(CI->getContext()))))
391 return Instruction::CastOps(Res);
394 /// ValueRequiresCast - Return true if the cast from "V to Ty" actually results
395 /// in any code being generated. It does not require codegen if V is simple
396 /// enough or if the cast can be folded into other casts.
397 bool InstCombiner::ValueRequiresCast(Instruction::CastOps opcode,const Value *V,
399 if (V->getType() == Ty || isa<Constant>(V)) return false;
401 // If this is another cast that can be eliminated, it isn't codegen either.
402 if (const CastInst *CI = dyn_cast<CastInst>(V))
403 if (isEliminableCastPair(CI, opcode, Ty, TD))
409 /// @brief Implement the transforms common to all CastInst visitors.
410 Instruction *InstCombiner::commonCastTransforms(CastInst &CI) {
411 Value *Src = CI.getOperand(0);
413 // Many cases of "cast of a cast" are eliminable. If it's eliminable we just
415 if (CastInst *CSrc = dyn_cast<CastInst>(Src)) { // A->B->C cast
416 if (Instruction::CastOps opc =
417 isEliminableCastPair(CSrc, CI.getOpcode(), CI.getType(), TD)) {
418 // The first cast (CSrc) is eliminable so we need to fix up or replace
419 // the second cast (CI). CSrc will then have a good chance of being dead.
420 return CastInst::Create(opc, CSrc->getOperand(0), CI.getType());
424 // If we are casting a select then fold the cast into the select
425 if (SelectInst *SI = dyn_cast<SelectInst>(Src))
426 if (Instruction *NV = FoldOpIntoSelect(CI, SI))
429 // If we are casting a PHI then fold the cast into the PHI
430 if (isa<PHINode>(Src)) {
431 // We don't do this if this would create a PHI node with an illegal type if
432 // it is currently legal.
433 if (!isa<IntegerType>(Src->getType()) ||
434 !isa<IntegerType>(CI.getType()) ||
435 ShouldChangeType(CI.getType(), Src->getType()))
436 if (Instruction *NV = FoldOpIntoPhi(CI))
443 /// commonIntCastTransforms - This function implements the common transforms
444 /// for trunc, zext, and sext.
445 Instruction *InstCombiner::commonIntCastTransforms(CastInst &CI) {
446 if (Instruction *Result = commonCastTransforms(CI))
449 // See if we can simplify any instructions used by the LHS whose sole
450 // purpose is to compute bits we don't care about.
451 if (SimplifyDemandedInstructionBits(CI))
454 // If the source isn't an instruction or has more than one use then we
455 // can't do anything more.
456 Instruction *Src = dyn_cast<Instruction>(CI.getOperand(0));
457 if (!Src || !Src->hasOneUse())
460 // Check to see if we can eliminate the cast by changing the entire
461 // computation chain to do the computation in the result type.
462 const Type *SrcTy = Src->getType();
463 const Type *DestTy = CI.getType();
465 // Only do this if the dest type is a simple type, don't convert the
466 // expression tree to something weird like i93 unless the source is also
468 if (!isa<VectorType>(DestTy) && !ShouldChangeType(SrcTy, DestTy))
471 // Attempt to propagate the cast into the instruction for int->int casts.
472 int NumCastsRemoved = 0;
473 if (!CanEvaluateInDifferentType(Src, DestTy, CI.getOpcode(), NumCastsRemoved))
476 switch (CI.getOpcode()) {
477 default: assert(0 && "not an integer cast");
478 case Instruction::Trunc:
479 // If this cast is a truncate, evaluting in a different type always
480 // eliminates the cast, so it is always a win.
482 case Instruction::ZExt:
483 // If this is a zero-extension, we need to do an AND to maintain the clear
484 // top-part of the computation, so we require that the input have eliminated
485 // at least one cast.
486 if (NumCastsRemoved < 1)
489 case Instruction::SExt:
490 // If this is a sign extension, we insert two new shifts (to do the
491 // extension) so we require that two casts have been eliminated.
492 if (NumCastsRemoved < 2)
497 DEBUG(errs() << "ICE: EvaluateInDifferentType converting expression type"
498 " to avoid cast: " << CI);
499 Value *Res = EvaluateInDifferentType(Src, DestTy,
500 CI.getOpcode() == Instruction::SExt);
501 assert(Res->getType() == DestTy);
503 uint32_t SrcBitSize = SrcTy->getScalarSizeInBits();
504 uint32_t DestBitSize = DestTy->getScalarSizeInBits();
505 switch (CI.getOpcode()) {
506 default: assert(0 && "Unknown cast type!");
507 case Instruction::Trunc:
508 // Just replace this cast with the result.
509 return ReplaceInstUsesWith(CI, Res);
510 case Instruction::ZExt: {
511 // If the high bits are already zero, just replace this cast with the
513 APInt Mask(APInt::getBitsSet(DestBitSize, SrcBitSize, DestBitSize));
514 if (MaskedValueIsZero(Res, Mask))
515 return ReplaceInstUsesWith(CI, Res);
517 // We need to emit an AND to clear the high bits.
518 Constant *C = ConstantInt::get(CI.getContext(),
519 APInt::getLowBitsSet(DestBitSize, SrcBitSize));
520 return BinaryOperator::CreateAnd(Res, C);
522 case Instruction::SExt: {
523 // If the high bits are already filled with sign bit, just replace this
524 // cast with the result.
525 unsigned NumSignBits = ComputeNumSignBits(Res);
526 if (NumSignBits > (DestBitSize - SrcBitSize))
527 return ReplaceInstUsesWith(CI, Res);
529 // We need to emit a cast to truncate, then a cast to sext.
530 return new SExtInst(Builder->CreateTrunc(Res, Src->getType()), DestTy);
535 Instruction *InstCombiner::visitTrunc(TruncInst &CI) {
536 if (Instruction *Result = commonIntCastTransforms(CI))
539 Value *Src = CI.getOperand(0);
540 const Type *DestTy = CI.getType();
542 // Canonicalize trunc x to i1 -> (icmp ne (and x, 1), 0), likewise for vector.
543 if (DestTy->getScalarSizeInBits() == 1) {
544 Constant *One = ConstantInt::get(Src->getType(), 1);
545 Src = Builder->CreateAnd(Src, One, "tmp");
546 Value *Zero = Constant::getNullValue(Src->getType());
547 return new ICmpInst(ICmpInst::ICMP_NE, Src, Zero);
553 /// transformZExtICmp - Transform (zext icmp) to bitwise / integer operations
554 /// in order to eliminate the icmp.
555 Instruction *InstCombiner::transformZExtICmp(ICmpInst *ICI, Instruction &CI,
557 // If we are just checking for a icmp eq of a single bit and zext'ing it
558 // to an integer, then shift the bit to the appropriate place and then
559 // cast to integer to avoid the comparison.
560 if (ConstantInt *Op1C = dyn_cast<ConstantInt>(ICI->getOperand(1))) {
561 const APInt &Op1CV = Op1C->getValue();
563 // zext (x <s 0) to i32 --> x>>u31 true if signbit set.
564 // zext (x >s -1) to i32 --> (x>>u31)^1 true if signbit clear.
565 if ((ICI->getPredicate() == ICmpInst::ICMP_SLT && Op1CV == 0) ||
566 (ICI->getPredicate() == ICmpInst::ICMP_SGT &&Op1CV.isAllOnesValue())) {
567 if (!DoXform) return ICI;
569 Value *In = ICI->getOperand(0);
570 Value *Sh = ConstantInt::get(In->getType(),
571 In->getType()->getScalarSizeInBits()-1);
572 In = Builder->CreateLShr(In, Sh, In->getName()+".lobit");
573 if (In->getType() != CI.getType())
574 In = Builder->CreateIntCast(In, CI.getType(), false/*ZExt*/, "tmp");
576 if (ICI->getPredicate() == ICmpInst::ICMP_SGT) {
577 Constant *One = ConstantInt::get(In->getType(), 1);
578 In = Builder->CreateXor(In, One, In->getName()+".not");
581 return ReplaceInstUsesWith(CI, In);
586 // zext (X == 0) to i32 --> X^1 iff X has only the low bit set.
587 // zext (X == 0) to i32 --> (X>>1)^1 iff X has only the 2nd bit set.
588 // zext (X == 1) to i32 --> X iff X has only the low bit set.
589 // zext (X == 2) to i32 --> X>>1 iff X has only the 2nd bit set.
590 // zext (X != 0) to i32 --> X iff X has only the low bit set.
591 // zext (X != 0) to i32 --> X>>1 iff X has only the 2nd bit set.
592 // zext (X != 1) to i32 --> X^1 iff X has only the low bit set.
593 // zext (X != 2) to i32 --> (X>>1)^1 iff X has only the 2nd bit set.
594 if ((Op1CV == 0 || Op1CV.isPowerOf2()) &&
595 // This only works for EQ and NE
597 // If Op1C some other power of two, convert:
598 uint32_t BitWidth = Op1C->getType()->getBitWidth();
599 APInt KnownZero(BitWidth, 0), KnownOne(BitWidth, 0);
600 APInt TypeMask(APInt::getAllOnesValue(BitWidth));
601 ComputeMaskedBits(ICI->getOperand(0), TypeMask, KnownZero, KnownOne);
603 APInt KnownZeroMask(~KnownZero);
604 if (KnownZeroMask.isPowerOf2()) { // Exactly 1 possible 1?
605 if (!DoXform) return ICI;
607 bool isNE = ICI->getPredicate() == ICmpInst::ICMP_NE;
608 if (Op1CV != 0 && (Op1CV != KnownZeroMask)) {
609 // (X&4) == 2 --> false
610 // (X&4) != 2 --> true
611 Constant *Res = ConstantInt::get(Type::getInt1Ty(CI.getContext()),
613 Res = ConstantExpr::getZExt(Res, CI.getType());
614 return ReplaceInstUsesWith(CI, Res);
617 uint32_t ShiftAmt = KnownZeroMask.logBase2();
618 Value *In = ICI->getOperand(0);
620 // Perform a logical shr by shiftamt.
621 // Insert the shift to put the result in the low bit.
622 In = Builder->CreateLShr(In, ConstantInt::get(In->getType(),ShiftAmt),
623 In->getName()+".lobit");
626 if ((Op1CV != 0) == isNE) { // Toggle the low bit.
627 Constant *One = ConstantInt::get(In->getType(), 1);
628 In = Builder->CreateXor(In, One, "tmp");
631 if (CI.getType() == In->getType())
632 return ReplaceInstUsesWith(CI, In);
634 return CastInst::CreateIntegerCast(In, CI.getType(), false/*ZExt*/);
639 // icmp ne A, B is equal to xor A, B when A and B only really have one bit.
640 // It is also profitable to transform icmp eq into not(xor(A, B)) because that
641 // may lead to additional simplifications.
642 if (ICI->isEquality() && CI.getType() == ICI->getOperand(0)->getType()) {
643 if (const IntegerType *ITy = dyn_cast<IntegerType>(CI.getType())) {
644 uint32_t BitWidth = ITy->getBitWidth();
645 Value *LHS = ICI->getOperand(0);
646 Value *RHS = ICI->getOperand(1);
648 APInt KnownZeroLHS(BitWidth, 0), KnownOneLHS(BitWidth, 0);
649 APInt KnownZeroRHS(BitWidth, 0), KnownOneRHS(BitWidth, 0);
650 APInt TypeMask(APInt::getAllOnesValue(BitWidth));
651 ComputeMaskedBits(LHS, TypeMask, KnownZeroLHS, KnownOneLHS);
652 ComputeMaskedBits(RHS, TypeMask, KnownZeroRHS, KnownOneRHS);
654 if (KnownZeroLHS == KnownZeroRHS && KnownOneLHS == KnownOneRHS) {
655 APInt KnownBits = KnownZeroLHS | KnownOneLHS;
656 APInt UnknownBit = ~KnownBits;
657 if (UnknownBit.countPopulation() == 1) {
658 if (!DoXform) return ICI;
660 Value *Result = Builder->CreateXor(LHS, RHS);
662 // Mask off any bits that are set and won't be shifted away.
663 if (KnownOneLHS.uge(UnknownBit))
664 Result = Builder->CreateAnd(Result,
665 ConstantInt::get(ITy, UnknownBit));
667 // Shift the bit we're testing down to the lsb.
668 Result = Builder->CreateLShr(
669 Result, ConstantInt::get(ITy, UnknownBit.countTrailingZeros()));
671 if (ICI->getPredicate() == ICmpInst::ICMP_EQ)
672 Result = Builder->CreateXor(Result, ConstantInt::get(ITy, 1));
673 Result->takeName(ICI);
674 return ReplaceInstUsesWith(CI, Result);
683 Instruction *InstCombiner::visitZExt(ZExtInst &CI) {
684 // If one of the common conversion will work, do it.
685 if (Instruction *Result = commonIntCastTransforms(CI))
688 Value *Src = CI.getOperand(0);
690 // If this is a TRUNC followed by a ZEXT then we are dealing with integral
691 // types and if the sizes are just right we can convert this into a logical
692 // 'and' which will be much cheaper than the pair of casts.
693 if (TruncInst *CSrc = dyn_cast<TruncInst>(Src)) { // A->B->C cast
694 // Get the sizes of the types involved. We know that the intermediate type
695 // will be smaller than A or C, but don't know the relation between A and C.
696 Value *A = CSrc->getOperand(0);
697 unsigned SrcSize = A->getType()->getScalarSizeInBits();
698 unsigned MidSize = CSrc->getType()->getScalarSizeInBits();
699 unsigned DstSize = CI.getType()->getScalarSizeInBits();
700 // If we're actually extending zero bits, then if
701 // SrcSize < DstSize: zext(a & mask)
702 // SrcSize == DstSize: a & mask
703 // SrcSize > DstSize: trunc(a) & mask
704 if (SrcSize < DstSize) {
705 APInt AndValue(APInt::getLowBitsSet(SrcSize, MidSize));
706 Constant *AndConst = ConstantInt::get(A->getType(), AndValue);
707 Value *And = Builder->CreateAnd(A, AndConst, CSrc->getName()+".mask");
708 return new ZExtInst(And, CI.getType());
711 if (SrcSize == DstSize) {
712 APInt AndValue(APInt::getLowBitsSet(SrcSize, MidSize));
713 return BinaryOperator::CreateAnd(A, ConstantInt::get(A->getType(),
716 if (SrcSize > DstSize) {
717 Value *Trunc = Builder->CreateTrunc(A, CI.getType(), "tmp");
718 APInt AndValue(APInt::getLowBitsSet(DstSize, MidSize));
719 return BinaryOperator::CreateAnd(Trunc,
720 ConstantInt::get(Trunc->getType(),
725 if (ICmpInst *ICI = dyn_cast<ICmpInst>(Src))
726 return transformZExtICmp(ICI, CI);
728 BinaryOperator *SrcI = dyn_cast<BinaryOperator>(Src);
729 if (SrcI && SrcI->getOpcode() == Instruction::Or) {
730 // zext (or icmp, icmp) --> or (zext icmp), (zext icmp) if at least one
731 // of the (zext icmp) will be transformed.
732 ICmpInst *LHS = dyn_cast<ICmpInst>(SrcI->getOperand(0));
733 ICmpInst *RHS = dyn_cast<ICmpInst>(SrcI->getOperand(1));
734 if (LHS && RHS && LHS->hasOneUse() && RHS->hasOneUse() &&
735 (transformZExtICmp(LHS, CI, false) ||
736 transformZExtICmp(RHS, CI, false))) {
737 Value *LCast = Builder->CreateZExt(LHS, CI.getType(), LHS->getName());
738 Value *RCast = Builder->CreateZExt(RHS, CI.getType(), RHS->getName());
739 return BinaryOperator::Create(Instruction::Or, LCast, RCast);
743 // zext(trunc(t) & C) -> (t & zext(C)).
744 if (SrcI && SrcI->getOpcode() == Instruction::And && SrcI->hasOneUse())
745 if (ConstantInt *C = dyn_cast<ConstantInt>(SrcI->getOperand(1)))
746 if (TruncInst *TI = dyn_cast<TruncInst>(SrcI->getOperand(0))) {
747 Value *TI0 = TI->getOperand(0);
748 if (TI0->getType() == CI.getType())
750 BinaryOperator::CreateAnd(TI0,
751 ConstantExpr::getZExt(C, CI.getType()));
754 // zext((trunc(t) & C) ^ C) -> ((t & zext(C)) ^ zext(C)).
755 if (SrcI && SrcI->getOpcode() == Instruction::Xor && SrcI->hasOneUse())
756 if (ConstantInt *C = dyn_cast<ConstantInt>(SrcI->getOperand(1)))
757 if (BinaryOperator *And = dyn_cast<BinaryOperator>(SrcI->getOperand(0)))
758 if (And->getOpcode() == Instruction::And && And->hasOneUse() &&
759 And->getOperand(1) == C)
760 if (TruncInst *TI = dyn_cast<TruncInst>(And->getOperand(0))) {
761 Value *TI0 = TI->getOperand(0);
762 if (TI0->getType() == CI.getType()) {
763 Constant *ZC = ConstantExpr::getZExt(C, CI.getType());
764 Value *NewAnd = Builder->CreateAnd(TI0, ZC, "tmp");
765 return BinaryOperator::CreateXor(NewAnd, ZC);
769 // zext (xor i1 X, true) to i32 --> xor (zext i1 X to i32), 1
771 if (SrcI && SrcI->hasOneUse() && SrcI->getType()->isInteger(1) &&
772 match(SrcI, m_Not(m_Value(X))) &&
773 (!X->hasOneUse() || !isa<CmpInst>(X))) {
774 Value *New = Builder->CreateZExt(X, CI.getType());
775 return BinaryOperator::CreateXor(New, ConstantInt::get(CI.getType(), 1));
781 Instruction *InstCombiner::visitSExt(SExtInst &CI) {
782 if (Instruction *I = commonIntCastTransforms(CI))
785 Value *Src = CI.getOperand(0);
787 // Canonicalize sign-extend from i1 to a select.
788 if (Src->getType()->isInteger(1))
789 return SelectInst::Create(Src,
790 Constant::getAllOnesValue(CI.getType()),
791 Constant::getNullValue(CI.getType()));
793 // See if the value being truncated is already sign extended. If so, just
794 // eliminate the trunc/sext pair.
795 if (Operator::getOpcode(Src) == Instruction::Trunc) {
796 Value *Op = cast<User>(Src)->getOperand(0);
797 unsigned OpBits = Op->getType()->getScalarSizeInBits();
798 unsigned MidBits = Src->getType()->getScalarSizeInBits();
799 unsigned DestBits = CI.getType()->getScalarSizeInBits();
800 unsigned NumSignBits = ComputeNumSignBits(Op);
802 if (OpBits == DestBits) {
803 // Op is i32, Mid is i8, and Dest is i32. If Op has more than 24 sign
804 // bits, it is already ready.
805 if (NumSignBits > DestBits-MidBits)
806 return ReplaceInstUsesWith(CI, Op);
807 } else if (OpBits < DestBits) {
808 // Op is i32, Mid is i8, and Dest is i64. If Op has more than 24 sign
809 // bits, just sext from i32.
810 if (NumSignBits > OpBits-MidBits)
811 return new SExtInst(Op, CI.getType(), "tmp");
813 // Op is i64, Mid is i8, and Dest is i32. If Op has more than 56 sign
814 // bits, just truncate to i32.
815 if (NumSignBits > OpBits-MidBits)
816 return new TruncInst(Op, CI.getType(), "tmp");
820 // If the input is a shl/ashr pair of a same constant, then this is a sign
821 // extension from a smaller value. If we could trust arbitrary bitwidth
822 // integers, we could turn this into a truncate to the smaller bit and then
823 // use a sext for the whole extension. Since we don't, look deeper and check
824 // for a truncate. If the source and dest are the same type, eliminate the
825 // trunc and extend and just do shifts. For example, turn:
826 // %a = trunc i32 %i to i8
828 // %c = ashr i8 %b, 6
829 // %d = sext i8 %c to i32
831 // %a = shl i32 %i, 30
832 // %d = ashr i32 %a, 30
834 ConstantInt *BA = 0, *CA = 0;
835 if (match(Src, m_AShr(m_Shl(m_Value(A), m_ConstantInt(BA)),
836 m_ConstantInt(CA))) &&
837 BA == CA && isa<TruncInst>(A)) {
838 Value *I = cast<TruncInst>(A)->getOperand(0);
839 if (I->getType() == CI.getType()) {
840 unsigned MidSize = Src->getType()->getScalarSizeInBits();
841 unsigned SrcDstSize = CI.getType()->getScalarSizeInBits();
842 unsigned ShAmt = CA->getZExtValue()+SrcDstSize-MidSize;
843 Constant *ShAmtV = ConstantInt::get(CI.getType(), ShAmt);
844 I = Builder->CreateShl(I, ShAmtV, CI.getName());
845 return BinaryOperator::CreateAShr(I, ShAmtV);
853 /// FitsInFPType - Return a Constant* for the specified FP constant if it fits
854 /// in the specified FP type without changing its value.
855 static Constant *FitsInFPType(ConstantFP *CFP, const fltSemantics &Sem) {
857 APFloat F = CFP->getValueAPF();
858 (void)F.convert(Sem, APFloat::rmNearestTiesToEven, &losesInfo);
860 return ConstantFP::get(CFP->getContext(), F);
864 /// LookThroughFPExtensions - If this is an fp extension instruction, look
865 /// through it until we get the source value.
866 static Value *LookThroughFPExtensions(Value *V) {
867 if (Instruction *I = dyn_cast<Instruction>(V))
868 if (I->getOpcode() == Instruction::FPExt)
869 return LookThroughFPExtensions(I->getOperand(0));
871 // If this value is a constant, return the constant in the smallest FP type
872 // that can accurately represent it. This allows us to turn
873 // (float)((double)X+2.0) into x+2.0f.
874 if (ConstantFP *CFP = dyn_cast<ConstantFP>(V)) {
875 if (CFP->getType() == Type::getPPC_FP128Ty(V->getContext()))
876 return V; // No constant folding of this.
877 // See if the value can be truncated to float and then reextended.
878 if (Value *V = FitsInFPType(CFP, APFloat::IEEEsingle))
880 if (CFP->getType()->isDoubleTy())
881 return V; // Won't shrink.
882 if (Value *V = FitsInFPType(CFP, APFloat::IEEEdouble))
884 // Don't try to shrink to various long double types.
890 Instruction *InstCombiner::visitFPTrunc(FPTruncInst &CI) {
891 if (Instruction *I = commonCastTransforms(CI))
894 // If we have fptrunc(fadd (fpextend x), (fpextend y)), where x and y are
895 // smaller than the destination type, we can eliminate the truncate by doing
896 // the add as the smaller type. This applies to fadd/fsub/fmul/fdiv as well
897 // as many builtins (sqrt, etc).
898 BinaryOperator *OpI = dyn_cast<BinaryOperator>(CI.getOperand(0));
899 if (OpI && OpI->hasOneUse()) {
900 switch (OpI->getOpcode()) {
902 case Instruction::FAdd:
903 case Instruction::FSub:
904 case Instruction::FMul:
905 case Instruction::FDiv:
906 case Instruction::FRem:
907 const Type *SrcTy = OpI->getType();
908 Value *LHSTrunc = LookThroughFPExtensions(OpI->getOperand(0));
909 Value *RHSTrunc = LookThroughFPExtensions(OpI->getOperand(1));
910 if (LHSTrunc->getType() != SrcTy &&
911 RHSTrunc->getType() != SrcTy) {
912 unsigned DstSize = CI.getType()->getScalarSizeInBits();
913 // If the source types were both smaller than the destination type of
914 // the cast, do this xform.
915 if (LHSTrunc->getType()->getScalarSizeInBits() <= DstSize &&
916 RHSTrunc->getType()->getScalarSizeInBits() <= DstSize) {
917 LHSTrunc = Builder->CreateFPExt(LHSTrunc, CI.getType());
918 RHSTrunc = Builder->CreateFPExt(RHSTrunc, CI.getType());
919 return BinaryOperator::Create(OpI->getOpcode(), LHSTrunc, RHSTrunc);
928 Instruction *InstCombiner::visitFPExt(CastInst &CI) {
929 return commonCastTransforms(CI);
932 Instruction *InstCombiner::visitFPToUI(FPToUIInst &FI) {
933 Instruction *OpI = dyn_cast<Instruction>(FI.getOperand(0));
935 return commonCastTransforms(FI);
937 // fptoui(uitofp(X)) --> X
938 // fptoui(sitofp(X)) --> X
939 // This is safe if the intermediate type has enough bits in its mantissa to
940 // accurately represent all values of X. For example, do not do this with
941 // i64->float->i64. This is also safe for sitofp case, because any negative
942 // 'X' value would cause an undefined result for the fptoui.
943 if ((isa<UIToFPInst>(OpI) || isa<SIToFPInst>(OpI)) &&
944 OpI->getOperand(0)->getType() == FI.getType() &&
945 (int)FI.getType()->getScalarSizeInBits() < /*extra bit for sign */
946 OpI->getType()->getFPMantissaWidth())
947 return ReplaceInstUsesWith(FI, OpI->getOperand(0));
949 return commonCastTransforms(FI);
952 Instruction *InstCombiner::visitFPToSI(FPToSIInst &FI) {
953 Instruction *OpI = dyn_cast<Instruction>(FI.getOperand(0));
955 return commonCastTransforms(FI);
957 // fptosi(sitofp(X)) --> X
958 // fptosi(uitofp(X)) --> X
959 // This is safe if the intermediate type has enough bits in its mantissa to
960 // accurately represent all values of X. For example, do not do this with
961 // i64->float->i64. This is also safe for sitofp case, because any negative
962 // 'X' value would cause an undefined result for the fptoui.
963 if ((isa<UIToFPInst>(OpI) || isa<SIToFPInst>(OpI)) &&
964 OpI->getOperand(0)->getType() == FI.getType() &&
965 (int)FI.getType()->getScalarSizeInBits() <=
966 OpI->getType()->getFPMantissaWidth())
967 return ReplaceInstUsesWith(FI, OpI->getOperand(0));
969 return commonCastTransforms(FI);
972 Instruction *InstCombiner::visitUIToFP(CastInst &CI) {
973 return commonCastTransforms(CI);
976 Instruction *InstCombiner::visitSIToFP(CastInst &CI) {
977 return commonCastTransforms(CI);
980 Instruction *InstCombiner::visitIntToPtr(IntToPtrInst &CI) {
981 // If the source integer type is larger than the intptr_t type for
982 // this target, do a trunc to the intptr_t type, then inttoptr of it. This
983 // allows the trunc to be exposed to other transforms. Don't do this for
984 // extending inttoptr's, because we don't know if the target sign or zero
985 // extends to pointers.
986 if (TD && CI.getOperand(0)->getType()->getScalarSizeInBits() >
987 TD->getPointerSizeInBits()) {
988 Value *P = Builder->CreateTrunc(CI.getOperand(0),
989 TD->getIntPtrType(CI.getContext()), "tmp");
990 return new IntToPtrInst(P, CI.getType());
993 if (Instruction *I = commonCastTransforms(CI))
999 /// @brief Implement the transforms for cast of pointer (bitcast/ptrtoint)
1000 Instruction *InstCombiner::commonPointerCastTransforms(CastInst &CI) {
1001 Value *Src = CI.getOperand(0);
1003 if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Src)) {
1004 // If casting the result of a getelementptr instruction with no offset, turn
1005 // this into a cast of the original pointer!
1006 if (GEP->hasAllZeroIndices()) {
1007 // Changing the cast operand is usually not a good idea but it is safe
1008 // here because the pointer operand is being replaced with another
1009 // pointer operand so the opcode doesn't need to change.
1011 CI.setOperand(0, GEP->getOperand(0));
1015 // If the GEP has a single use, and the base pointer is a bitcast, and the
1016 // GEP computes a constant offset, see if we can convert these three
1017 // instructions into fewer. This typically happens with unions and other
1018 // non-type-safe code.
1019 if (TD && GEP->hasOneUse() && isa<BitCastInst>(GEP->getOperand(0)) &&
1020 GEP->hasAllConstantIndices()) {
1021 // We are guaranteed to get a constant from EmitGEPOffset.
1022 ConstantInt *OffsetV = cast<ConstantInt>(EmitGEPOffset(GEP));
1023 int64_t Offset = OffsetV->getSExtValue();
1025 // Get the base pointer input of the bitcast, and the type it points to.
1026 Value *OrigBase = cast<BitCastInst>(GEP->getOperand(0))->getOperand(0);
1027 const Type *GEPIdxTy =
1028 cast<PointerType>(OrigBase->getType())->getElementType();
1029 SmallVector<Value*, 8> NewIndices;
1030 if (FindElementAtOffset(GEPIdxTy, Offset, NewIndices)) {
1031 // If we were able to index down into an element, create the GEP
1032 // and bitcast the result. This eliminates one bitcast, potentially
1034 Value *NGEP = cast<GEPOperator>(GEP)->isInBounds() ?
1035 Builder->CreateInBoundsGEP(OrigBase,
1036 NewIndices.begin(), NewIndices.end()) :
1037 Builder->CreateGEP(OrigBase, NewIndices.begin(), NewIndices.end());
1038 NGEP->takeName(GEP);
1040 if (isa<BitCastInst>(CI))
1041 return new BitCastInst(NGEP, CI.getType());
1042 assert(isa<PtrToIntInst>(CI));
1043 return new PtrToIntInst(NGEP, CI.getType());
1048 return commonCastTransforms(CI);
1051 Instruction *InstCombiner::visitPtrToInt(PtrToIntInst &CI) {
1052 // If the destination integer type is smaller than the intptr_t type for
1053 // this target, do a ptrtoint to intptr_t then do a trunc. This allows the
1054 // trunc to be exposed to other transforms. Don't do this for extending
1055 // ptrtoint's, because we don't know if the target sign or zero extends its
1058 CI.getType()->getScalarSizeInBits() < TD->getPointerSizeInBits()) {
1059 Value *P = Builder->CreatePtrToInt(CI.getOperand(0),
1060 TD->getIntPtrType(CI.getContext()),
1062 return new TruncInst(P, CI.getType());
1065 return commonPointerCastTransforms(CI);
1068 Instruction *InstCombiner::visitBitCast(BitCastInst &CI) {
1069 // If the operands are integer typed then apply the integer transforms,
1070 // otherwise just apply the common ones.
1071 Value *Src = CI.getOperand(0);
1072 const Type *SrcTy = Src->getType();
1073 const Type *DestTy = CI.getType();
1075 // Get rid of casts from one type to the same type. These are useless and can
1076 // be replaced by the operand.
1077 if (DestTy == Src->getType())
1078 return ReplaceInstUsesWith(CI, Src);
1080 if (const PointerType *DstPTy = dyn_cast<PointerType>(DestTy)) {
1081 const PointerType *SrcPTy = cast<PointerType>(SrcTy);
1082 const Type *DstElTy = DstPTy->getElementType();
1083 const Type *SrcElTy = SrcPTy->getElementType();
1085 // If the address spaces don't match, don't eliminate the bitcast, which is
1086 // required for changing types.
1087 if (SrcPTy->getAddressSpace() != DstPTy->getAddressSpace())
1090 // If we are casting a alloca to a pointer to a type of the same
1091 // size, rewrite the allocation instruction to allocate the "right" type.
1092 // There is no need to modify malloc calls because it is their bitcast that
1093 // needs to be cleaned up.
1094 if (AllocaInst *AI = dyn_cast<AllocaInst>(Src))
1095 if (Instruction *V = PromoteCastOfAllocation(CI, *AI))
1098 // If the source and destination are pointers, and this cast is equivalent
1099 // to a getelementptr X, 0, 0, 0... turn it into the appropriate gep.
1100 // This can enhance SROA and other transforms that want type-safe pointers.
1101 Constant *ZeroUInt =
1102 Constant::getNullValue(Type::getInt32Ty(CI.getContext()));
1103 unsigned NumZeros = 0;
1104 while (SrcElTy != DstElTy &&
1105 isa<CompositeType>(SrcElTy) && !isa<PointerType>(SrcElTy) &&
1106 SrcElTy->getNumContainedTypes() /* not "{}" */) {
1107 SrcElTy = cast<CompositeType>(SrcElTy)->getTypeAtIndex(ZeroUInt);
1111 // If we found a path from the src to dest, create the getelementptr now.
1112 if (SrcElTy == DstElTy) {
1113 SmallVector<Value*, 8> Idxs(NumZeros+1, ZeroUInt);
1114 return GetElementPtrInst::CreateInBounds(Src, Idxs.begin(), Idxs.end(),"",
1115 ((Instruction*)NULL));
1119 if (const VectorType *DestVTy = dyn_cast<VectorType>(DestTy)) {
1120 if (DestVTy->getNumElements() == 1 && !isa<VectorType>(SrcTy)) {
1121 Value *Elem = Builder->CreateBitCast(Src, DestVTy->getElementType());
1122 return InsertElementInst::Create(UndefValue::get(DestTy), Elem,
1123 Constant::getNullValue(Type::getInt32Ty(CI.getContext())));
1124 // FIXME: Canonicalize bitcast(insertelement) -> insertelement(bitcast)
1128 if (const VectorType *SrcVTy = dyn_cast<VectorType>(SrcTy)) {
1129 if (SrcVTy->getNumElements() == 1 && !isa<VectorType>(DestTy)) {
1131 Builder->CreateExtractElement(Src,
1132 Constant::getNullValue(Type::getInt32Ty(CI.getContext())));
1133 return CastInst::Create(Instruction::BitCast, Elem, DestTy);
1137 if (ShuffleVectorInst *SVI = dyn_cast<ShuffleVectorInst>(Src)) {
1138 // Okay, we have (bitcast (shuffle ..)). Check to see if this is
1139 // a bitconvert to a vector with the same # elts.
1140 if (SVI->hasOneUse() && isa<VectorType>(DestTy) &&
1141 cast<VectorType>(DestTy)->getNumElements() ==
1142 SVI->getType()->getNumElements() &&
1143 SVI->getType()->getNumElements() ==
1144 cast<VectorType>(SVI->getOperand(0)->getType())->getNumElements()) {
1146 // If either of the operands is a cast from CI.getType(), then
1147 // evaluating the shuffle in the casted destination's type will allow
1148 // us to eliminate at least one cast.
1149 if (((Tmp = dyn_cast<BitCastInst>(SVI->getOperand(0))) &&
1150 Tmp->getOperand(0)->getType() == DestTy) ||
1151 ((Tmp = dyn_cast<BitCastInst>(SVI->getOperand(1))) &&
1152 Tmp->getOperand(0)->getType() == DestTy)) {
1153 Value *LHS = Builder->CreateBitCast(SVI->getOperand(0), DestTy);
1154 Value *RHS = Builder->CreateBitCast(SVI->getOperand(1), DestTy);
1155 // Return a new shuffle vector. Use the same element ID's, as we
1156 // know the vector types match #elts.
1157 return new ShuffleVectorInst(LHS, RHS, SVI->getOperand(2));
1162 if (isa<PointerType>(SrcTy))
1163 return commonPointerCastTransforms(CI);
1164 return commonCastTransforms(CI);