return Insert(Folder.CreateIntCast(VC, DestTy, isSigned), Name);
return Insert(CastInst::CreateIntegerCast(V, DestTy, isSigned), Name);
}
+
+ Value *CreateBitOrPointerCast(Value *V, Type *DestTy,
+ const Twine &Name = "") {
+ if (V->getType() == DestTy)
+ return V;
+ if (V->getType()->isPointerTy() && DestTy->isIntegerTy())
+ return CreatePtrToInt(V, DestTy, Name);
+ if (V->getType()->isIntegerTy() && DestTy->isPointerTy())
+ return CreateIntToPtr(V, DestTy, Name);
+
+ return CreateBitCast(V, DestTy, Name);
+ }
private:
// \brief Provided to resolve 'CreateIntCast(Ptr, Ptr, "...")', giving a
// compile time error, instead of converting the string to bool for the
Instruction *InsertBefore = 0 ///< Place to insert the instruction
);
+ /// @brief Create a BitCast, a PtrToInt, or an IntToPTr cast instruction.
+ ///
+ /// If the value is a pointer type and the destination an integer type,
+ /// creates a PtrToInt cast. If the value is an integer type and the
+ /// destination a pointer type, creates an IntToPtr cast. Otherwise, creates
+ /// a bitcast.
+ static CastInst *CreateBitOrPointerCast(
+ Value *S, ///< The pointer value to be casted (operand 0)
+ Type *Ty, ///< The type to which cast should be made
+ const Twine &Name = "", ///< Name for the instruction
+ Instruction *InsertBefore = 0 ///< Place to insert the instruction
+ );
+
/// @brief Create a ZExt, BitCast, or Trunc for int -> int casts.
static CastInst *CreateIntegerCast(
Value *S, ///< The pointer value to be casted (operand 0)
Type *DestTy ///< The Type to which the value should be cast.
);
+ /// @brief Check whether a bitcast, inttoptr, or ptrtoint cast between these
+ /// types is valid and a no-op.
+ ///
+ /// This ensures that any pointer<->integer cast has enough bits in the
+ /// integer and any other cast is a bitcast.
+ static bool isBitOrNoopPointerCastable(
+ Type *SrcTy, ///< The Type from which the value should be cast.
+ Type *DestTy, ///< The Type to which the value should be cast.
+ const DataLayout *Layout = 0 ///< Optional DataLayout.
+ );
+
/// Returns the opcode necessary to cast Val into Ty using usual casting
/// rules.
/// @brief Infer the opcode for cast operand and type
Type *AccessTy = cast<PointerType>(Ptr->getType())->getElementType();
- // If we're using alias analysis to disambiguate get the size of *Ptr.
- uint64_t AccessSize = AA ? AA->getTypeStoreSize(AccessTy) : 0;
+ // Try to get the DataLayout for this module. This may be null, in which case
+ // the optimizations will be limited.
+ const DataLayout *DL = ScanBB->getDataLayout();
+
+ // Try to get the store size for the type.
+ uint64_t AccessSize = DL ? DL->getTypeStoreSize(AccessTy)
+ : AA ? AA->getTypeStoreSize(AccessTy) : 0;
Value *StrippedPtr = Ptr->stripPointerCasts();
if (LoadInst *LI = dyn_cast<LoadInst>(Inst))
if (AreEquivalentAddressValues(
LI->getPointerOperand()->stripPointerCasts(), StrippedPtr) &&
- CastInst::isBitCastable(LI->getType(), AccessTy)) {
+ CastInst::isBitOrNoopPointerCastable(LI->getType(), AccessTy, DL)) {
if (AATags)
LI->getAAMetadata(*AATags);
return LI;
// (This is true even if the store is volatile or atomic, although
// those cases are unlikely.)
if (AreEquivalentAddressValues(StorePtr, StrippedPtr) &&
- CastInst::isBitCastable(SI->getValueOperand()->getType(), AccessTy)) {
+ CastInst::isBitOrNoopPointerCastable(SI->getValueOperand()->getType(),
+ AccessTy, DL)) {
if (AATags)
SI->getAAMetadata(*AATags);
return SI->getOperand(0);
return Create(Instruction::BitCast, S, Ty, Name, InsertBefore);
}
+CastInst *CastInst::CreateBitOrPointerCast(Value *S, Type *Ty,
+ const Twine &Name,
+ Instruction *InsertBefore) {
+ if (S->getType()->isPointerTy() && Ty->isIntegerTy())
+ return Create(Instruction::PtrToInt, S, Ty, Name, InsertBefore);
+ if (S->getType()->isIntegerTy() && Ty->isPointerTy())
+ return Create(Instruction::IntToPtr, S, Ty, Name, InsertBefore);
+
+ return Create(Instruction::BitCast, S, Ty, Name, InsertBefore);
+}
+
CastInst *CastInst::CreateIntegerCast(Value *C, Type *Ty,
bool isSigned, const Twine &Name,
Instruction *InsertBefore) {
return true;
}
+bool CastInst::isBitOrNoopPointerCastable(Type *SrcTy, Type *DestTy,
+ const DataLayout *DL) {
+ if (auto *PtrTy = dyn_cast<PointerType>(SrcTy))
+ if (auto *IntTy = dyn_cast<IntegerType>(DestTy))
+ return DL && IntTy->getBitWidth() == DL->getPointerTypeSizeInBits(PtrTy);
+ if (auto *PtrTy = dyn_cast<PointerType>(DestTy))
+ if (auto *IntTy = dyn_cast<IntegerType>(SrcTy))
+ return DL && IntTy->getBitWidth() == DL->getPointerTypeSizeInBits(PtrTy);
+
+ return isBitCastable(SrcTy, DestTy);
+}
+
// Provide a way to get a "cast" where the cast opcode is inferred from the
// types and size of the operand. This, basically, is a parallel of the
// logic in the castIsValid function below. This axiom should hold:
BasicBlock::iterator BBI = &LI;
if (Value *AvailableVal = FindAvailableLoadedValue(Op, LI.getParent(), BBI,6))
return ReplaceInstUsesWith(
- LI, Builder->CreateBitCast(AvailableVal, LI.getType()));
+ LI, Builder->CreateBitOrPointerCast(AvailableVal, LI.getType(),
+ LI.getName() + ".cast"));
// load(gep null, ...) -> unreachable
if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(Op)) {
// only happen in dead loops.
if (AvailableVal == LI) AvailableVal = UndefValue::get(LI->getType());
if (AvailableVal->getType() != LI->getType())
- AvailableVal = CastInst::Create(CastInst::BitCast, AvailableVal,
- LI->getType(), "", LI);
+ AvailableVal =
+ CastInst::CreateBitOrPointerCast(AvailableVal, LI->getType(), "", LI);
LI->replaceAllUsesWith(AvailableVal);
LI->eraseFromParent();
return true;
// predecessor use the same bitcast.
Value *&PredV = I->second;
if (PredV->getType() != LI->getType())
- PredV = CastInst::Create(CastInst::BitCast, PredV, LI->getType(), "",
- P->getTerminator());
+ PredV = CastInst::CreateBitOrPointerCast(PredV, LI->getType(), "",
+ P->getTerminator());
PN->addIncoming(PredV, I->first);
}
ret i32 %v
}
-declare void @scribble_on_memory(i32*)
+declare void @scribble_on_i32(i32*)
define i32 @test77(i1 %flag, i32* %x) {
; The load here must not be speculated around the select. One side of the
; load does.
; CHECK-LABEL: @test77(
; CHECK: %[[A:.*]] = alloca i32, align 1
-; CHECK: call void @scribble_on_memory(i32* %[[A]])
+; CHECK: call void @scribble_on_i32(i32* %[[A]])
; CHECK: store i32 0, i32* %x
; CHECK: %[[P:.*]] = select i1 %flag, i32* %[[A]], i32* %x
; CHECK: load i32* %[[P]]
%under_aligned = alloca i32, align 1
- call void @scribble_on_memory(i32* %under_aligned)
+ call void @scribble_on_i32(i32* %under_aligned)
store i32 0, i32* %x
%p = select i1 %flag, i32* %under_aligned, i32* %x
%v = load i32* %p
entry:
%x = alloca i32
%y = alloca i32
- call void @scribble_on_memory(i32* %x)
- call void @scribble_on_memory(i32* %y)
+ call void @scribble_on_i32(i32* %x)
+ call void @scribble_on_i32(i32* %y)
%tmp = load i32* %x
store i32 %tmp, i32* %y
%p = select i1 %flag, i32* %x, i32* %y
%y = alloca i32
%x1 = bitcast float* %x to i32*
%y1 = bitcast i32* %y to float*
- call void @scribble_on_memory(i32* %x1)
- call void @scribble_on_memory(i32* %y)
+ call void @scribble_on_i32(i32* %x1)
+ call void @scribble_on_i32(i32* %y)
%tmp = load i32* %x1
store i32 %tmp, i32* %y
%p = select i1 %flag, float* %x, float* %y1
%y = alloca i32
%x1 = bitcast float* %x to i32*
%y1 = bitcast i32* %y to float*
- call void @scribble_on_memory(i32* %x1)
- call void @scribble_on_memory(i32* %y)
+ call void @scribble_on_i32(i32* %x1)
+ call void @scribble_on_i32(i32* %y)
%tmp = load float* %x
store float %tmp, float* %y1
%p = select i1 %flag, i32* %x1, i32* %y
%v = load i32* %p
ret i32 %v
}
+
+declare void @scribble_on_i64(i64*)
+declare void @scribble_on_i128(i128*)
+
+define i8* @test83(i1 %flag) {
+; Test that we can speculate the load around the select even though they use
+; differently typed pointers and requires inttoptr casts.
+; CHECK-LABEL: @test83(
+; CHECK: %[[X:.*]] = alloca i8*
+; CHECK-NEXT: %[[Y:.*]] = alloca i8*
+; CHECK: %[[V:.*]] = load i64* %[[X]]
+; CHECK-NEXT: %[[C1:.*]] = inttoptr i64 %[[V]] to i8*
+; CHECK-NEXT: store i8* %[[C1]], i8** %[[Y]]
+; CHECK-NEXT: %[[C2:.*]] = inttoptr i64 %[[V]] to i8*
+; CHECK-NEXT: %[[S:.*]] = select i1 %flag, i8* %[[C2]], i8* %[[C1]]
+; CHECK-NEXT: ret i8* %[[S]]
+entry:
+ %x = alloca i8*
+ %y = alloca i64
+ %x1 = bitcast i8** %x to i64*
+ %y1 = bitcast i64* %y to i8**
+ call void @scribble_on_i64(i64* %x1)
+ call void @scribble_on_i64(i64* %y)
+ %tmp = load i64* %x1
+ store i64 %tmp, i64* %y
+ %p = select i1 %flag, i8** %x, i8** %y1
+ %v = load i8** %p
+ ret i8* %v
+}
+
+define i64 @test84(i1 %flag) {
+; Test that we can speculate the load around the select even though they use
+; differently typed pointers and requires a ptrtoint cast.
+; CHECK-LABEL: @test84(
+; CHECK: %[[X:.*]] = alloca i8*
+; CHECK-NEXT: %[[Y:.*]] = alloca i8*
+; CHECK: %[[V:.*]] = load i8** %[[X]]
+; CHECK-NEXT: store i8* %[[V]], i8** %[[Y]]
+; CHECK-NEXT: %[[C:.*]] = ptrtoint i8* %[[V]] to i64
+; CHECK-NEXT: ret i64 %[[C]]
+entry:
+ %x = alloca i8*
+ %y = alloca i64
+ %x1 = bitcast i8** %x to i64*
+ %y1 = bitcast i64* %y to i8**
+ call void @scribble_on_i64(i64* %x1)
+ call void @scribble_on_i64(i64* %y)
+ %tmp = load i8** %x
+ store i8* %tmp, i8** %y1
+ %p = select i1 %flag, i64* %x1, i64* %y
+ %v = load i64* %p
+ ret i64 %v
+}
+
+define i8* @test85(i1 %flag) {
+; Test that we can't speculate the load around the select. The load of the
+; pointer doesn't load all of the stored integer bits. We could fix this, but it
+; would require endianness checks and other nastiness.
+; CHECK-LABEL: @test85(
+; CHECK: %[[T:.*]] = load i128*
+; CHECK-NEXT: store i128 %[[T]], i128*
+; CHECK-NEXT: %[[X:.*]] = load i8**
+; CHECK-NEXT: %[[Y:.*]] = load i8**
+; CHECK-NEXT: %[[V:.*]] = select i1 %flag, i8* %[[X]], i8* %[[Y]]
+; CHECK-NEXT: ret i8* %[[V]]
+entry:
+ %x = alloca [2 x i8*]
+ %y = alloca i128
+ %x1 = bitcast [2 x i8*]* %x to i8**
+ %x2 = bitcast i8** %x1 to i128*
+ %y1 = bitcast i128* %y to i8**
+ call void @scribble_on_i128(i128* %x2)
+ call void @scribble_on_i128(i128* %y)
+ %tmp = load i128* %x2
+ store i128 %tmp, i128* %y
+ %p = select i1 %flag, i8** %x1, i8** %y1
+ %v = load i8** %p
+ ret i8* %v
+}
+
+define i128 @test86(i1 %flag) {
+; Test that we can't speculate the load around the select when the integer size
+; is larger than the pointer size. The store of the pointer doesn't store to all
+; the bits of the integer.
+;
+; CHECK-LABEL: @test86(
+; CHECK: %[[T:.*]] = load i8**
+; CHECK-NEXT: store i8* %[[T]], i8**
+; CHECK-NEXT: %[[X:.*]] = load i128*
+; CHECK-NEXT: %[[Y:.*]] = load i128*
+; CHECK-NEXT: %[[V:.*]] = select i1 %flag, i128 %[[X]], i128 %[[Y]]
+; CHECK-NEXT: ret i128 %[[V]]
+entry:
+ %x = alloca [2 x i8*]
+ %y = alloca i128
+ %x1 = bitcast [2 x i8*]* %x to i8**
+ %x2 = bitcast i8** %x1 to i128*
+ %y1 = bitcast i128* %y to i8**
+ call void @scribble_on_i128(i128* %x2)
+ call void @scribble_on_i128(i128* %y)
+ %tmp = load i8** %x1
+ store i8* %tmp, i8** %y1
+ %p = select i1 %flag, i128* %x2, i128* %y
+ %v = load i128* %p
+ ret i128 %v
+}
projects / llvm / commitdiff