1 //===-- FunctionLoweringInfo.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 implements routines for translating functions from LLVM IR into
13 //===----------------------------------------------------------------------===//
15 #include "llvm/CodeGen/FunctionLoweringInfo.h"
16 #include "llvm/ADT/PostOrderIterator.h"
17 #include "llvm/CodeGen/Analysis.h"
18 #include "llvm/CodeGen/MachineFrameInfo.h"
19 #include "llvm/CodeGen/MachineFunction.h"
20 #include "llvm/CodeGen/MachineInstrBuilder.h"
21 #include "llvm/CodeGen/MachineModuleInfo.h"
22 #include "llvm/CodeGen/MachineRegisterInfo.h"
23 #include "llvm/CodeGen/WinEHFuncInfo.h"
24 #include "llvm/IR/DataLayout.h"
25 #include "llvm/IR/DebugInfo.h"
26 #include "llvm/IR/DerivedTypes.h"
27 #include "llvm/IR/Function.h"
28 #include "llvm/IR/Instructions.h"
29 #include "llvm/IR/IntrinsicInst.h"
30 #include "llvm/IR/LLVMContext.h"
31 #include "llvm/IR/Module.h"
32 #include "llvm/Support/Debug.h"
33 #include "llvm/Support/ErrorHandling.h"
34 #include "llvm/Support/MathExtras.h"
35 #include "llvm/Support/raw_ostream.h"
36 #include "llvm/Target/TargetFrameLowering.h"
37 #include "llvm/Target/TargetInstrInfo.h"
38 #include "llvm/Target/TargetLowering.h"
39 #include "llvm/Target/TargetOptions.h"
40 #include "llvm/Target/TargetRegisterInfo.h"
41 #include "llvm/Target/TargetSubtargetInfo.h"
45 #define DEBUG_TYPE "function-lowering-info"
47 /// isUsedOutsideOfDefiningBlock - Return true if this instruction is used by
48 /// PHI nodes or outside of the basic block that defines it, or used by a
49 /// switch or atomic instruction, which may expand to multiple basic blocks.
50 static bool isUsedOutsideOfDefiningBlock(const Instruction *I) {
51 if (I->use_empty()) return false;
52 if (isa<PHINode>(I)) return true;
53 const BasicBlock *BB = I->getParent();
54 for (const User *U : I->users())
55 if (cast<Instruction>(U)->getParent() != BB || isa<PHINode>(U))
61 static ISD::NodeType getPreferredExtendForValue(const Value *V) {
62 // For the users of the source value being used for compare instruction, if
63 // the number of signed predicate is greater than unsigned predicate, we
64 // prefer to use SIGN_EXTEND.
66 // With this optimization, we would be able to reduce some redundant sign or
67 // zero extension instruction, and eventually more machine CSE opportunities
69 ISD::NodeType ExtendKind = ISD::ANY_EXTEND;
70 unsigned NumOfSigned = 0, NumOfUnsigned = 0;
71 for (const User *U : V->users()) {
72 if (const auto *CI = dyn_cast<CmpInst>(U)) {
73 NumOfSigned += CI->isSigned();
74 NumOfUnsigned += CI->isUnsigned();
77 if (NumOfSigned > NumOfUnsigned)
78 ExtendKind = ISD::SIGN_EXTEND;
83 void FunctionLoweringInfo::set(const Function &fn, MachineFunction &mf,
87 TLI = MF->getSubtarget().getTargetLowering();
88 RegInfo = &MF->getRegInfo();
89 MachineModuleInfo &MMI = MF->getMMI();
91 // Check whether the function can return without sret-demotion.
92 SmallVector<ISD::OutputArg, 4> Outs;
93 GetReturnInfo(Fn->getReturnType(), Fn->getAttributes(), Outs, *TLI,
95 CanLowerReturn = TLI->CanLowerReturn(Fn->getCallingConv(), *MF,
96 Fn->isVarArg(), Outs, Fn->getContext());
98 // Initialize the mapping of values to registers. This is only set up for
99 // instruction values that are used outside of the block that defines
101 Function::const_iterator BB = Fn->begin(), EB = Fn->end();
102 for (; BB != EB; ++BB)
103 for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
105 if (const AllocaInst *AI = dyn_cast<AllocaInst>(I)) {
106 // Static allocas can be folded into the initial stack frame adjustment.
107 if (AI->isStaticAlloca()) {
108 const ConstantInt *CUI = cast<ConstantInt>(AI->getArraySize());
109 Type *Ty = AI->getAllocatedType();
110 uint64_t TySize = MF->getDataLayout().getTypeAllocSize(Ty);
112 std::max((unsigned)MF->getDataLayout().getPrefTypeAlignment(Ty),
115 TySize *= CUI->getZExtValue(); // Get total allocated size.
116 if (TySize == 0) TySize = 1; // Don't create zero-sized stack objects.
118 StaticAllocaMap[AI] =
119 MF->getFrameInfo()->CreateStackObject(TySize, Align, false, AI);
123 std::max((unsigned)MF->getDataLayout().getPrefTypeAlignment(
124 AI->getAllocatedType()),
126 unsigned StackAlign =
127 MF->getSubtarget().getFrameLowering()->getStackAlignment();
128 if (Align <= StackAlign)
130 // Inform the Frame Information that we have variable-sized objects.
131 MF->getFrameInfo()->CreateVariableSizedObject(Align ? Align : 1, AI);
135 // Look for inline asm that clobbers the SP register.
136 if (isa<CallInst>(I) || isa<InvokeInst>(I)) {
137 ImmutableCallSite CS(&*I);
138 if (isa<InlineAsm>(CS.getCalledValue())) {
139 unsigned SP = TLI->getStackPointerRegisterToSaveRestore();
140 const TargetRegisterInfo *TRI = MF->getSubtarget().getRegisterInfo();
141 std::vector<TargetLowering::AsmOperandInfo> Ops =
142 TLI->ParseConstraints(Fn->getParent()->getDataLayout(), TRI, CS);
143 for (size_t I = 0, E = Ops.size(); I != E; ++I) {
144 TargetLowering::AsmOperandInfo &Op = Ops[I];
145 if (Op.Type == InlineAsm::isClobber) {
146 // Clobbers don't have SDValue operands, hence SDValue().
147 TLI->ComputeConstraintToUse(Op, SDValue(), DAG);
148 std::pair<unsigned, const TargetRegisterClass *> PhysReg =
149 TLI->getRegForInlineAsmConstraint(TRI, Op.ConstraintCode,
151 if (PhysReg.first == SP)
152 MF->getFrameInfo()->setHasOpaqueSPAdjustment(true);
158 // Look for calls to the @llvm.va_start intrinsic. We can omit some
159 // prologue boilerplate for variadic functions that don't examine their
161 if (const auto *II = dyn_cast<IntrinsicInst>(I)) {
162 if (II->getIntrinsicID() == Intrinsic::vastart)
163 MF->getFrameInfo()->setHasVAStart(true);
166 // If we have a musttail call in a variadic funciton, we need to ensure we
167 // forward implicit register parameters.
168 if (const auto *CI = dyn_cast<CallInst>(I)) {
169 if (CI->isMustTailCall() && Fn->isVarArg())
170 MF->getFrameInfo()->setHasMustTailInVarArgFunc(true);
173 // Mark values used outside their block as exported, by allocating
174 // a virtual register for them.
175 if (isUsedOutsideOfDefiningBlock(&*I))
176 if (!isa<AllocaInst>(I) || !StaticAllocaMap.count(cast<AllocaInst>(I)))
177 InitializeRegForValue(&*I);
179 // Collect llvm.dbg.declare information. This is done now instead of
180 // during the initial isel pass through the IR so that it is done
181 // in a predictable order.
182 if (const DbgDeclareInst *DI = dyn_cast<DbgDeclareInst>(I)) {
183 assert(DI->getVariable() && "Missing variable");
184 assert(DI->getDebugLoc() && "Missing location");
185 if (MMI.hasDebugInfo()) {
186 // Don't handle byval struct arguments or VLAs, for example.
187 // Non-byval arguments are handled here (they refer to the stack
188 // temporary alloca at this point).
189 const Value *Address = DI->getAddress();
191 if (const BitCastInst *BCI = dyn_cast<BitCastInst>(Address))
192 Address = BCI->getOperand(0);
193 if (const AllocaInst *AI = dyn_cast<AllocaInst>(Address)) {
194 DenseMap<const AllocaInst *, int>::iterator SI =
195 StaticAllocaMap.find(AI);
196 if (SI != StaticAllocaMap.end()) { // Check for VLAs.
198 MMI.setVariableDbgInfo(DI->getVariable(), DI->getExpression(),
199 FI, DI->getDebugLoc());
206 // Decide the preferred extend type for a value.
207 PreferredExtendType[&*I] = getPreferredExtendForValue(&*I);
210 // Create an initial MachineBasicBlock for each LLVM BasicBlock in F. This
211 // also creates the initial PHI MachineInstrs, though none of the input
212 // operands are populated.
213 for (BB = Fn->begin(); BB != EB; ++BB) {
214 // Don't create MachineBasicBlocks for imaginary EH pad blocks. These blocks
215 // are really data, and no instructions can live here.
217 const Instruction *I = BB->getFirstNonPHI();
218 // If this is a non-landingpad EH pad, mark this function as using
220 // FIXME: SEH catchpads do not create funclets, so we could avoid setting
221 // this in such cases in order to improve frame layout.
222 if (!isa<LandingPadInst>(I)) {
223 MMI.setHasEHFunclets(true);
224 MF->getFrameInfo()->setHasOpaqueSPAdjustment(true);
226 if (isa<CatchEndPadInst>(I) || isa<CleanupEndPadInst>(I)) {
227 assert(&*BB->begin() == I &&
228 "WinEHPrepare failed to remove PHIs from imaginary BBs");
231 if (isa<CatchPadInst>(I) || isa<CleanupPadInst>(I))
232 assert(&*BB->begin() == I && "WinEHPrepare failed to demote PHIs");
235 MachineBasicBlock *MBB = mf.CreateMachineBasicBlock(&*BB);
239 // Transfer the address-taken flag. This is necessary because there could
240 // be multiple MachineBasicBlocks corresponding to one BasicBlock, and only
241 // the first one should be marked.
242 if (BB->hasAddressTaken())
243 MBB->setHasAddressTaken();
245 // Create Machine PHI nodes for LLVM PHI nodes, lowering them as
247 for (BasicBlock::const_iterator I = BB->begin();
248 const PHINode *PN = dyn_cast<PHINode>(I); ++I) {
249 if (PN->use_empty()) continue;
252 if (PN->getType()->isEmptyTy())
255 DebugLoc DL = PN->getDebugLoc();
256 unsigned PHIReg = ValueMap[PN];
257 assert(PHIReg && "PHI node does not have an assigned virtual register!");
259 SmallVector<EVT, 4> ValueVTs;
260 ComputeValueVTs(*TLI, MF->getDataLayout(), PN->getType(), ValueVTs);
261 for (unsigned vti = 0, vte = ValueVTs.size(); vti != vte; ++vti) {
262 EVT VT = ValueVTs[vti];
263 unsigned NumRegisters = TLI->getNumRegisters(Fn->getContext(), VT);
264 const TargetInstrInfo *TII = MF->getSubtarget().getInstrInfo();
265 for (unsigned i = 0; i != NumRegisters; ++i)
266 BuildMI(MBB, DL, TII->get(TargetOpcode::PHI), PHIReg + i);
267 PHIReg += NumRegisters;
272 // Mark landing pad blocks.
273 SmallVector<const LandingPadInst *, 4> LPads;
274 for (BB = Fn->begin(); BB != EB; ++BB) {
275 const Instruction *FNP = BB->getFirstNonPHI();
276 if (BB->isEHPad() && MBBMap.count(&*BB))
277 MBBMap[&*BB]->setIsEHPad();
278 if (const auto *LPI = dyn_cast<LandingPadInst>(FNP))
279 LPads.push_back(LPI);
282 // If this personality uses funclets, we need to do a bit more work.
283 if (!Fn->hasPersonalityFn())
285 EHPersonality Personality = classifyEHPersonality(Fn->getPersonalityFn());
286 if (!isFuncletEHPersonality(Personality))
289 // Calculate state numbers if we haven't already.
290 WinEHFuncInfo &EHInfo = MMI.getWinEHFuncInfo(&fn);
291 if (Personality == EHPersonality::MSVC_CXX)
292 calculateWinCXXEHStateNumbers(&fn, EHInfo);
293 else if (isAsynchronousEHPersonality(Personality))
294 calculateSEHStateNumbers(&fn, EHInfo);
295 else if (Personality == EHPersonality::CoreCLR)
296 calculateClrEHStateNumbers(&fn, EHInfo);
298 calculateCatchReturnSuccessorColors(&fn, EHInfo);
300 // Map all BB references in the WinEH data to MBBs.
301 for (WinEHTryBlockMapEntry &TBME : EHInfo.TryBlockMap) {
302 for (WinEHHandlerType &H : TBME.HandlerArray) {
303 if (H.CatchObj.Alloca) {
304 assert(StaticAllocaMap.count(H.CatchObj.Alloca));
305 H.CatchObj.FrameIndex = StaticAllocaMap[H.CatchObj.Alloca];
307 H.CatchObj.FrameIndex = INT_MAX;
310 H.Handler = MBBMap[H.Handler.get<const BasicBlock *>()];
313 for (CxxUnwindMapEntry &UME : EHInfo.CxxUnwindMap)
315 UME.Cleanup = MBBMap[UME.Cleanup.get<const BasicBlock *>()];
316 for (SEHUnwindMapEntry &UME : EHInfo.SEHUnwindMap) {
317 const BasicBlock *BB = UME.Handler.get<const BasicBlock *>();
318 UME.Handler = MBBMap[BB];
320 for (ClrEHUnwindMapEntry &CME : EHInfo.ClrEHUnwindMap) {
321 const BasicBlock *BB = CME.Handler.get<const BasicBlock *>();
322 CME.Handler = MBBMap[BB];
325 // If there's an explicit EH registration node on the stack, record its
327 if (EHInfo.EHRegNode && EHInfo.EHRegNode->getParent()->getParent() == Fn) {
328 assert(StaticAllocaMap.count(EHInfo.EHRegNode));
329 EHInfo.EHRegNodeFrameIndex = StaticAllocaMap[EHInfo.EHRegNode];
332 // Copy the state numbers to LandingPadInfo for the current function, which
333 // could be a handler or the parent. This should happen for 32-bit SEH and
335 if (Personality == EHPersonality::MSVC_CXX ||
336 Personality == EHPersonality::MSVC_X86SEH) {
337 for (const LandingPadInst *LP : LPads) {
338 MachineBasicBlock *LPadMBB = MBBMap[LP->getParent()];
339 MMI.addWinEHState(LPadMBB, EHInfo.EHPadStateMap[LP]);
344 /// clear - Clear out all the function-specific state. This returns this
345 /// FunctionLoweringInfo to an empty state, ready to be used for a
346 /// different function.
347 void FunctionLoweringInfo::clear() {
350 StaticAllocaMap.clear();
351 LiveOutRegInfo.clear();
353 ArgDbgValues.clear();
354 ByValArgFrameIndexMap.clear();
356 StatepointStackSlots.clear();
357 StatepointRelocatedValues.clear();
358 PreferredExtendType.clear();
361 /// CreateReg - Allocate a single virtual register for the given type.
362 unsigned FunctionLoweringInfo::CreateReg(MVT VT) {
363 return RegInfo->createVirtualRegister(
364 MF->getSubtarget().getTargetLowering()->getRegClassFor(VT));
367 /// CreateRegs - Allocate the appropriate number of virtual registers of
368 /// the correctly promoted or expanded types. Assign these registers
369 /// consecutive vreg numbers and return the first assigned number.
371 /// In the case that the given value has struct or array type, this function
372 /// will assign registers for each member or element.
374 unsigned FunctionLoweringInfo::CreateRegs(Type *Ty) {
375 const TargetLowering *TLI = MF->getSubtarget().getTargetLowering();
377 SmallVector<EVT, 4> ValueVTs;
378 ComputeValueVTs(*TLI, MF->getDataLayout(), Ty, ValueVTs);
380 unsigned FirstReg = 0;
381 for (unsigned Value = 0, e = ValueVTs.size(); Value != e; ++Value) {
382 EVT ValueVT = ValueVTs[Value];
383 MVT RegisterVT = TLI->getRegisterType(Ty->getContext(), ValueVT);
385 unsigned NumRegs = TLI->getNumRegisters(Ty->getContext(), ValueVT);
386 for (unsigned i = 0; i != NumRegs; ++i) {
387 unsigned R = CreateReg(RegisterVT);
388 if (!FirstReg) FirstReg = R;
394 /// GetLiveOutRegInfo - Gets LiveOutInfo for a register, returning NULL if the
395 /// register is a PHI destination and the PHI's LiveOutInfo is not valid. If
396 /// the register's LiveOutInfo is for a smaller bit width, it is extended to
397 /// the larger bit width by zero extension. The bit width must be no smaller
398 /// than the LiveOutInfo's existing bit width.
399 const FunctionLoweringInfo::LiveOutInfo *
400 FunctionLoweringInfo::GetLiveOutRegInfo(unsigned Reg, unsigned BitWidth) {
401 if (!LiveOutRegInfo.inBounds(Reg))
404 LiveOutInfo *LOI = &LiveOutRegInfo[Reg];
408 if (BitWidth > LOI->KnownZero.getBitWidth()) {
409 LOI->NumSignBits = 1;
410 LOI->KnownZero = LOI->KnownZero.zextOrTrunc(BitWidth);
411 LOI->KnownOne = LOI->KnownOne.zextOrTrunc(BitWidth);
417 /// ComputePHILiveOutRegInfo - Compute LiveOutInfo for a PHI's destination
418 /// register based on the LiveOutInfo of its operands.
419 void FunctionLoweringInfo::ComputePHILiveOutRegInfo(const PHINode *PN) {
420 Type *Ty = PN->getType();
421 if (!Ty->isIntegerTy() || Ty->isVectorTy())
424 SmallVector<EVT, 1> ValueVTs;
425 ComputeValueVTs(*TLI, MF->getDataLayout(), Ty, ValueVTs);
426 assert(ValueVTs.size() == 1 &&
427 "PHIs with non-vector integer types should have a single VT.");
428 EVT IntVT = ValueVTs[0];
430 if (TLI->getNumRegisters(PN->getContext(), IntVT) != 1)
432 IntVT = TLI->getTypeToTransformTo(PN->getContext(), IntVT);
433 unsigned BitWidth = IntVT.getSizeInBits();
435 unsigned DestReg = ValueMap[PN];
436 if (!TargetRegisterInfo::isVirtualRegister(DestReg))
438 LiveOutRegInfo.grow(DestReg);
439 LiveOutInfo &DestLOI = LiveOutRegInfo[DestReg];
441 Value *V = PN->getIncomingValue(0);
442 if (isa<UndefValue>(V) || isa<ConstantExpr>(V)) {
443 DestLOI.NumSignBits = 1;
444 APInt Zero(BitWidth, 0);
445 DestLOI.KnownZero = Zero;
446 DestLOI.KnownOne = Zero;
450 if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
451 APInt Val = CI->getValue().zextOrTrunc(BitWidth);
452 DestLOI.NumSignBits = Val.getNumSignBits();
453 DestLOI.KnownZero = ~Val;
454 DestLOI.KnownOne = Val;
456 assert(ValueMap.count(V) && "V should have been placed in ValueMap when its"
457 "CopyToReg node was created.");
458 unsigned SrcReg = ValueMap[V];
459 if (!TargetRegisterInfo::isVirtualRegister(SrcReg)) {
460 DestLOI.IsValid = false;
463 const LiveOutInfo *SrcLOI = GetLiveOutRegInfo(SrcReg, BitWidth);
465 DestLOI.IsValid = false;
471 assert(DestLOI.KnownZero.getBitWidth() == BitWidth &&
472 DestLOI.KnownOne.getBitWidth() == BitWidth &&
473 "Masks should have the same bit width as the type.");
475 for (unsigned i = 1, e = PN->getNumIncomingValues(); i != e; ++i) {
476 Value *V = PN->getIncomingValue(i);
477 if (isa<UndefValue>(V) || isa<ConstantExpr>(V)) {
478 DestLOI.NumSignBits = 1;
479 APInt Zero(BitWidth, 0);
480 DestLOI.KnownZero = Zero;
481 DestLOI.KnownOne = Zero;
485 if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
486 APInt Val = CI->getValue().zextOrTrunc(BitWidth);
487 DestLOI.NumSignBits = std::min(DestLOI.NumSignBits, Val.getNumSignBits());
488 DestLOI.KnownZero &= ~Val;
489 DestLOI.KnownOne &= Val;
493 assert(ValueMap.count(V) && "V should have been placed in ValueMap when "
494 "its CopyToReg node was created.");
495 unsigned SrcReg = ValueMap[V];
496 if (!TargetRegisterInfo::isVirtualRegister(SrcReg)) {
497 DestLOI.IsValid = false;
500 const LiveOutInfo *SrcLOI = GetLiveOutRegInfo(SrcReg, BitWidth);
502 DestLOI.IsValid = false;
505 DestLOI.NumSignBits = std::min(DestLOI.NumSignBits, SrcLOI->NumSignBits);
506 DestLOI.KnownZero &= SrcLOI->KnownZero;
507 DestLOI.KnownOne &= SrcLOI->KnownOne;
511 /// setArgumentFrameIndex - Record frame index for the byval
512 /// argument. This overrides previous frame index entry for this argument,
514 void FunctionLoweringInfo::setArgumentFrameIndex(const Argument *A,
516 ByValArgFrameIndexMap[A] = FI;
519 /// getArgumentFrameIndex - Get frame index for the byval argument.
520 /// If the argument does not have any assigned frame index then 0 is
522 int FunctionLoweringInfo::getArgumentFrameIndex(const Argument *A) {
523 DenseMap<const Argument *, int>::iterator I =
524 ByValArgFrameIndexMap.find(A);
525 if (I != ByValArgFrameIndexMap.end())
527 DEBUG(dbgs() << "Argument does not have assigned frame index!\n");
531 unsigned FunctionLoweringInfo::getCatchPadExceptionPointerVReg(
532 const Value *CPI, const TargetRegisterClass *RC) {
533 MachineRegisterInfo &MRI = MF->getRegInfo();
534 auto I = CatchPadExceptionPointers.insert({CPI, 0});
535 unsigned &VReg = I.first->second;
537 VReg = MRI.createVirtualRegister(RC);
538 assert(VReg && "null vreg in exception pointer table!");
542 /// ComputeUsesVAFloatArgument - Determine if any floating-point values are
543 /// being passed to this variadic function, and set the MachineModuleInfo's
544 /// usesVAFloatArgument flag if so. This flag is used to emit an undefined
545 /// reference to _fltused on Windows, which will link in MSVCRT's
546 /// floating-point support.
547 void llvm::ComputeUsesVAFloatArgument(const CallInst &I,
548 MachineModuleInfo *MMI)
550 FunctionType *FT = cast<FunctionType>(
551 I.getCalledValue()->getType()->getContainedType(0));
552 if (FT->isVarArg() && !MMI->usesVAFloatArgument()) {
553 for (unsigned i = 0, e = I.getNumArgOperands(); i != e; ++i) {
554 Type* T = I.getArgOperand(i)->getType();
555 for (auto i : post_order(T)) {
556 if (i->isFloatingPointTy()) {
557 MMI->setUsesVAFloatArgument(true);
565 /// AddLandingPadInfo - Extract the exception handling information from the
566 /// landingpad instruction and add them to the specified machine module info.
567 void llvm::AddLandingPadInfo(const LandingPadInst &I, MachineModuleInfo &MMI,
568 MachineBasicBlock *MBB) {
569 if (const auto *PF = dyn_cast<Function>(
570 I.getParent()->getParent()->getPersonalityFn()->stripPointerCasts()))
571 MMI.addPersonality(PF);
576 // FIXME: New EH - Add the clauses in reverse order. This isn't 100% correct,
577 // but we need to do it this way because of how the DWARF EH emitter
578 // processes the clauses.
579 for (unsigned i = I.getNumClauses(); i != 0; --i) {
580 Value *Val = I.getClause(i - 1);
581 if (I.isCatch(i - 1)) {
582 MMI.addCatchTypeInfo(MBB,
583 dyn_cast<GlobalValue>(Val->stripPointerCasts()));
585 // Add filters in a list.
586 Constant *CVal = cast<Constant>(Val);
587 SmallVector<const GlobalValue*, 4> FilterList;
588 for (User::op_iterator
589 II = CVal->op_begin(), IE = CVal->op_end(); II != IE; ++II)
590 FilterList.push_back(cast<GlobalValue>((*II)->stripPointerCasts()));
592 MMI.addFilterTypeInfo(MBB, FilterList);