[opaque pointer types] [NFC] Add an explicit type argument to ConstantFoldLoadFromConstPtr.

[dblaikie]

Looks OK

lib/Analysis/ConstantFolding.cpp

488

Presumably this could be getElementType (since SrcPtrTy is already a PointerType) - but in either case this is a stop-gap and will eventually be removed/migrated?

[mjacob]

include/llvm/Analysis/ConstantFolding.h

98

It's not clear which type Ty refers to.

[eddyb]

lib/Analysis/ConstantFolding.cpp

488

I've been using getPointerElementType everywhere so it matches my local setup where PointerType::getPointerElementType is the only method used everywhere (the one on Value is gone and PointerType::getElementType is deprecated).

include/llvm/Analysis/ConstantFolding.h

 /// \brief Attempt to constant fold an extractelement instruction with the
 /// specified operands and indices.  The constant result is returned if
 /// successful; if not, null is returned.
 Constant *ConstantFoldExtractElementInstruction(Constant *Val, Constant *Idx);
 
 /// ConstantFoldLoadFromConstPtr - Return the value that a load from C would
 /// produce if it is constant and determinable.  If this is not determinable,
 /// return null.
-Constant *ConstantFoldLoadFromConstPtr(Constant *C, const DataLayout &DL);
+Constant *ConstantFoldLoadFromConstPtr(Constant *C, Type *Ty, const DataLayout &DL);
 
 /// ConstantFoldLoadThroughGEPConstantExpr - Given a constant and a
 /// getelementptr constantexpr, return the constant value being addressed by the
 /// constant expression, or null if something is funny and we can't decide.
 Constant *ConstantFoldLoadThroughGEPConstantExpr(Constant *C, ConstantExpr *CE);
 
 /// ConstantFoldLoadThroughGEPIndices - Given a constant and getelementptr
 /// indices (with an *implied* zero pointer index that is not in the list),

lib/Analysis/ConstantFolding.cpp

if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
     }
   }
 
   // Otherwise, unknown initializer type.
   return false;
 }
 
 static Constant *FoldReinterpretLoadFromConstPtr(Constant *C,
+                                                 Type *LoadTy,
                                                  const DataLayout &DL) {
   PointerType *PTy = cast<PointerType>(C->getType());
-  Type *LoadTy = PTy->getElementType();
   IntegerType *IntType = dyn_cast<IntegerType>(LoadTy);
 
   // If this isn't an integer load we can't fold it directly.
   if (!IntType) {
     unsigned AS = PTy->getAddressSpace();
 
     // If this is a float/double load, we can try folding it as an int32/64 load
     // and then bitcast the result.  This can be useful for union cases.  Note
     // that address spaces don't matter here since we're not going to result in
     // an actual new load.
     Type *MapTy;
     if (LoadTy->isHalfTy())
-      MapTy = Type::getInt16PtrTy(C->getContext(), AS);
+      MapTy = Type::getInt16Ty(C->getContext());
     else if (LoadTy->isFloatTy())
-      MapTy = Type::getInt32PtrTy(C->getContext(), AS);
+      MapTy = Type::getInt32Ty(C->getContext());
     else if (LoadTy->isDoubleTy())
-      MapTy = Type::getInt64PtrTy(C->getContext(), AS);
+      MapTy = Type::getInt64Ty(C->getContext());
     else if (LoadTy->isVectorTy()) {
-      MapTy = PointerType::getIntNPtrTy(C->getContext(),
-                                        DL.getTypeAllocSizeInBits(LoadTy), AS);
+      MapTy = PointerType::getIntNTy(C->getContext(),
+                                     DL.getTypeAllocSizeInBits(LoadTy));
     } else
       return nullptr;
 
-    C = FoldBitCast(C, MapTy, DL);
-    if (Constant *Res = FoldReinterpretLoadFromConstPtr(C, DL))
+    C = FoldBitCast(C, MapTy->getPointerTo(AS), DL);
+    if (Constant *Res = FoldReinterpretLoadFromConstPtr(C, MapTy, DL))
       return FoldBitCast(Res, LoadTy, DL);
     return nullptr;
   }
 
   unsigned BytesLoaded = (IntType->getBitWidth() + 7) / 8;
   if (BytesLoaded > 32 || BytesLoaded == 0)
     return nullptr;
 
for (unsigned i = 1; i != BytesLoaded; ++i) {
       ResultVal |= RawBytes[i];
     }
   }
 
   return ConstantInt::get(IntType->getContext(), ResultVal);
 }
 
 static Constant *ConstantFoldLoadThroughBitcast(ConstantExpr *CE,
+                                                Type *DestTy,
                                                 const DataLayout &DL) {
-  auto *DestPtrTy = dyn_cast<PointerType>(CE->getType());
-  if (!DestPtrTy)
+  auto *SrcPtr = CE->getOperand(0);
+  auto *SrcPtrTy = dyn_cast<PointerType>(SrcPtr->getType());
+  if (!SrcPtrTy)
     return nullptr;
-  Type *DestTy = DestPtrTy->getElementType();
+  Type *SrcTy = SrcPtrTy->getPointerElementType();
 
-  Constant *C = ConstantFoldLoadFromConstPtr(CE->getOperand(0), DL);
+  Constant *C = ConstantFoldLoadFromConstPtr(SrcPtr, SrcTy, DL);
   if (!C)
     return nullptr;
 
   do {
     Type *SrcTy = C->getType();
 
     // If the type sizes are the same and a cast is legal, just directly
     // cast the constant.
do {
     C = C->getAggregateElement(0u);
   } while (C);
 
   return nullptr;
 }
 
 /// Return the value that a load from C would produce if it is constant and
 /// determinable. If this is not determinable, return null.
-Constant *llvm::ConstantFoldLoadFromConstPtr(Constant *C,
+Constant *llvm::ConstantFoldLoadFromConstPtr(Constant *C, Type *Ty,
                                              const DataLayout &DL) {
   // First, try the easy cases:
   if (GlobalVariable *GV = dyn_cast<GlobalVariable>(C))
     if (GV->isConstant() && GV->hasDefinitiveInitializer())
       return GV->getInitializer();
 
   if (auto *GA = dyn_cast<GlobalAlias>(C))
     if (GA->getAliasee() && !GA->mayBeOverridden())
-      return ConstantFoldLoadFromConstPtr(GA->getAliasee(), DL);
+      return ConstantFoldLoadFromConstPtr(GA->getAliasee(), Ty, DL);
 
   // If the loaded value isn't a constant expr, we can't handle it.
   ConstantExpr *CE = dyn_cast<ConstantExpr>(C);
   if (!CE)
     return nullptr;
 
   if (CE->getOpcode() == Instruction::GetElementPtr) {
     if (GlobalVariable *GV = dyn_cast<GlobalVariable>(CE->getOperand(0))) {
       if (GV->isConstant() && GV->hasDefinitiveInitializer()) {
         if (Constant *V =
              ConstantFoldLoadThroughGEPConstantExpr(GV->getInitializer(), CE))
           return V;
       }
     }
   }
 
   if (CE->getOpcode() == Instruction::BitCast)
-    if (Constant *LoadedC = ConstantFoldLoadThroughBitcast(CE, DL))
+    if (Constant *LoadedC = ConstantFoldLoadThroughBitcast(CE, Ty, DL))
       return LoadedC;
 
   // Instead of loading constant c string, use corresponding integer value
   // directly if string length is small enough.
   StringRef Str;
   if (getConstantStringInfo(CE, Str) && !Str.empty()) {
     unsigned StrLen = Str.size();
-    Type *Ty = cast<PointerType>(CE->getType())->getElementType();
     unsigned NumBits = Ty->getPrimitiveSizeInBits();
     // Replace load with immediate integer if the result is an integer or fp
     // value.
     if ((NumBits >> 3) == StrLen + 1 && (NumBits & 7) == 0 &&
         (isa<IntegerType>(Ty) || Ty->isFloatingPointTy())) {
       APInt StrVal(NumBits, 0);
       APInt SingleChar(NumBits, 0);
       if (DL.isLittleEndian()) {
if (getConstantStringInfo(CE, Str) && !Str.empty()) {
     }
   }
 
   // If this load comes from anywhere in a constant global, and if the global
   // is all undef or zero, we know what it loads.
   if (GlobalVariable *GV =
           dyn_cast<GlobalVariable>(GetUnderlyingObject(CE, DL))) {
     if (GV->isConstant() && GV->hasDefinitiveInitializer()) {
-      Type *ResTy = cast<PointerType>(C->getType())->getElementType();
       if (GV->getInitializer()->isNullValue())
-        return Constant::getNullValue(ResTy);
+        return Constant::getNullValue(Ty);
       if (isa<UndefValue>(GV->getInitializer()))
-        return UndefValue::get(ResTy);
+        return UndefValue::get(Ty);
     }
   }
 
   // Try hard to fold loads from bitcasted strange and non-type-safe things.
-  return FoldReinterpretLoadFromConstPtr(CE, DL);
+  return FoldReinterpretLoadFromConstPtr(CE, Ty, DL);
 }
 
 static Constant *ConstantFoldLoadInst(const LoadInst *LI,
                                       const DataLayout &DL) {
   if (LI->isVolatile()) return nullptr;
 
   if (Constant *C = dyn_cast<Constant>(LI->getOperand(0)))
-    return ConstantFoldLoadFromConstPtr(C, DL);
+    return ConstantFoldLoadFromConstPtr(C, LI->getType(), DL);
 
   return nullptr;
 }
 
 /// One of Op0/Op1 is a constant expression.
 /// Attempt to symbolically evaluate the result of a binary operator merging
 /// these together.  If target data info is available, it is provided as DL,
 /// otherwise DL is null.

lib/Analysis/InstructionSimplify.cpp

if (Constant *CRepOp = dyn_cast<Constant>(RepOp)) {
     // All operands were constants, fold it.
     if (ConstOps.size() == I->getNumOperands()) {
       if (CmpInst *C = dyn_cast<CmpInst>(I))
         return ConstantFoldCompareInstOperands(C->getPredicate(), ConstOps[0],
                                                ConstOps[1], Q.DL, Q.TLI);
 
       if (LoadInst *LI = dyn_cast<LoadInst>(I))
         if (!LI->isVolatile())
-          return ConstantFoldLoadFromConstPtr(ConstOps[0], Q.DL);
+          return ConstantFoldLoadFromConstPtr(ConstOps[0], LI->getType(), Q.DL);
 
       return ConstantFoldInstOperands(I, ConstOps, Q.DL, Q.TLI);
     }
   }
 
   return nullptr;
 }
 

lib/Analysis/ScalarEvolution.cpp

for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) {
     Operands[i] = C;
   }
 
   if (CmpInst *CI = dyn_cast<CmpInst>(I))
     return ConstantFoldCompareInstOperands(CI->getPredicate(), Operands[0],
                                            Operands[1], DL, TLI);
   if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
     if (!LI->isVolatile())
-      return ConstantFoldLoadFromConstPtr(Operands[0], DL);
+      return ConstantFoldLoadFromConstPtr(Operands[0], LI->getType(), DL);
   }
   return ConstantFoldInstOperands(I, Operands, DL, TLI);
 }
 
 
 // If every incoming value to PN except the one for BB is a specific Constant,
 // return that, else return nullptr.
 static Constant *getOtherIncomingValue(PHINode *PN, BasicBlock *BB) {
if (Instruction *I = dyn_cast<Instruction>(SU->getValue())) {
         if (MadeImprovement) {
           Constant *C = nullptr;
           const DataLayout &DL = getDataLayout();
           if (const CmpInst *CI = dyn_cast<CmpInst>(I))
             C = ConstantFoldCompareInstOperands(CI->getPredicate(), Operands[0],
                                                 Operands[1], DL, &TLI);
           else if (const LoadInst *LI = dyn_cast<LoadInst>(I)) {
             if (!LI->isVolatile())
-              C = ConstantFoldLoadFromConstPtr(Operands[0], DL);
+              C = ConstantFoldLoadFromConstPtr(Operands[0], LI->getType(), DL);
           } else
             C = ConstantFoldInstOperands(I, Operands, DL, &TLI);
           if (!C) return V;
           return getSCEV(C);
         }
       }
     }
 

lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp

static SDValue getMemCmpLoad(const Value *PtrVal, MVT LoadVT,
   // Check to see if this load can be trivially constant folded, e.g. if the
   // input is from a string literal.
   if (const Constant *LoadInput = dyn_cast<Constant>(PtrVal)) {
     // Cast pointer to the type we really want to load.
     LoadInput = ConstantExpr::getBitCast(const_cast<Constant *>(LoadInput),
                                          PointerType::getUnqual(LoadTy));
 
     if (const Constant *LoadCst = ConstantFoldLoadFromConstPtr(
-            const_cast<Constant *>(LoadInput), *Builder.DL))
+            const_cast<Constant *>(LoadInput), LoadTy, *Builder.DL))
       return Builder.getValue(LoadCst);
   }
 
   // Otherwise, we have to emit the load.  If the pointer is to unfoldable but
   // still constant memory, the input chain can be the entry node.
   SDValue Root;
   bool ConstantMemory = false;
 

lib/Transforms/Scalar/GVN.cpp

static int AnalyzeLoadFromClobberingMemInst(Type *LoadTy, Value *LoadPtr,
   // offset applied as appropriate.
   Src = ConstantExpr::getBitCast(Src,
                                  Type::getInt8PtrTy(Src->getContext(), AS));
   Constant *OffsetCst =
     ConstantInt::get(Type::getInt64Ty(Src->getContext()), (unsigned)Offset);
   Src = ConstantExpr::getGetElementPtr(Type::getInt8Ty(Src->getContext()), Src,
                                        OffsetCst);
   Src = ConstantExpr::getBitCast(Src, PointerType::get(LoadTy, AS));
-  if (ConstantFoldLoadFromConstPtr(Src, DL))
+  if (ConstantFoldLoadFromConstPtr(Src, LoadTy, DL))
     return Offset;
   return -1;
 }
 
 
 /// This function is called when we have a
 /// memdep query of a load that ends up being a clobbering store.  This means
 /// that the store provides bits used by the load but we the pointers don't
static Value *GetMemInstValueForLoad(MemIntrinsic *SrcInst, unsigned Offset,
   // offset applied as appropriate.
   Src = ConstantExpr::getBitCast(Src,
                                  Type::getInt8PtrTy(Src->getContext(), AS));
   Constant *OffsetCst =
     ConstantInt::get(Type::getInt64Ty(Src->getContext()), (unsigned)Offset);
   Src = ConstantExpr::getGetElementPtr(Type::getInt8Ty(Src->getContext()), Src,
                                        OffsetCst);
   Src = ConstantExpr::getBitCast(Src, PointerType::get(LoadTy, AS));
-  return ConstantFoldLoadFromConstPtr(Src, DL);
+  return ConstantFoldLoadFromConstPtr(Src, LoadTy, DL);
 }
 
 
 /// Given a set of loads specified by ValuesPerBlock,
 /// construct SSA form, allowing us to eliminate LI.  This returns the value
 /// that should be used at LI's definition site.
 static Value *ConstructSSAForLoadSet(LoadInst *LI,
                          SmallVectorImpl<AvailableValueInBlock> &ValuesPerBlock,

lib/Transforms/Scalar/SCCP.cpp

if (!TrackedGlobals.empty()) {
       if (It != TrackedGlobals.end()) {
         mergeInValue(IV, &I, It->second);
         return;
       }
     }
   }
 
   // Transform load from a constant into a constant if possible.
-  if (Constant *C = ConstantFoldLoadFromConstPtr(Ptr, DL)) {
+  if (Constant *C = ConstantFoldLoadFromConstPtr(Ptr, I.getType(), DL)) {
     if (isa<UndefValue>(C))
       return;
     return markConstant(IV, &I, C);
   }
 
   // Otherwise we cannot say for certain what value this load will produce.
   // Bail out.
   markOverdefined(IV, &I);