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-rw-r--r--lib/Analysis/ConstantFolding.cpp124
1 files changed, 74 insertions, 50 deletions
diff --git a/lib/Analysis/ConstantFolding.cpp b/lib/Analysis/ConstantFolding.cpp
index eb3e2c6..fd8f2ae 100644
--- a/lib/Analysis/ConstantFolding.cpp
+++ b/lib/Analysis/ConstantFolding.cpp
@@ -47,15 +47,16 @@ using namespace llvm;
// Constant Folding internal helper functions
//===----------------------------------------------------------------------===//
-/// FoldBitCast - Constant fold bitcast, symbolically evaluating it with
-/// DataLayout. This always returns a non-null constant, but it may be a
+/// Constant fold bitcast, symbolically evaluating it with DataLayout.
+/// This always returns a non-null constant, but it may be a
/// ConstantExpr if unfoldable.
static Constant *FoldBitCast(Constant *C, Type *DestTy,
const DataLayout &TD) {
// Catch the obvious splat cases.
if (C->isNullValue() && !DestTy->isX86_MMXTy())
return Constant::getNullValue(DestTy);
- if (C->isAllOnesValue() && !DestTy->isX86_MMXTy())
+ if (C->isAllOnesValue() && !DestTy->isX86_MMXTy() &&
+ !DestTy->isPtrOrPtrVectorTy()) // Don't get ones for ptr types!
return Constant::getAllOnesValue(DestTy);
// Handle a vector->integer cast.
@@ -197,7 +198,7 @@ static Constant *FoldBitCast(Constant *C, Type *DestTy,
// Handle: bitcast (<2 x i64> <i64 0, i64 1> to <4 x i32>)
unsigned Ratio = NumDstElt/NumSrcElt;
- unsigned DstBitSize = DstEltTy->getPrimitiveSizeInBits();
+ unsigned DstBitSize = TD.getTypeSizeInBits(DstEltTy);
// Loop over each source value, expanding into multiple results.
for (unsigned i = 0; i != NumSrcElt; ++i) {
@@ -213,6 +214,15 @@ static Constant *FoldBitCast(Constant *C, Type *DestTy,
ConstantInt::get(Src->getType(), ShiftAmt));
ShiftAmt += isLittleEndian ? DstBitSize : -DstBitSize;
+ // Truncate the element to an integer with the same pointer size and
+ // convert the element back to a pointer using a inttoptr.
+ if (DstEltTy->isPointerTy()) {
+ IntegerType *DstIntTy = Type::getIntNTy(C->getContext(), DstBitSize);
+ Constant *CE = ConstantExpr::getTrunc(Elt, DstIntTy);
+ Result.push_back(ConstantExpr::getIntToPtr(CE, DstEltTy));
+ continue;
+ }
+
// Truncate and remember this piece.
Result.push_back(ConstantExpr::getTrunc(Elt, DstEltTy));
}
@@ -222,9 +232,8 @@ static Constant *FoldBitCast(Constant *C, Type *DestTy,
}
-/// IsConstantOffsetFromGlobal - If this constant is actually a constant offset
-/// from a global, return the global and the constant. Because of
-/// constantexprs, this function is recursive.
+/// If this constant is a constant offset from a global, return the global and
+/// the constant. Because of constantexprs, this function is recursive.
static bool IsConstantOffsetFromGlobal(Constant *C, GlobalValue *&GV,
APInt &Offset, const DataLayout &TD) {
// Trivial case, constant is the global.
@@ -240,7 +249,8 @@ static bool IsConstantOffsetFromGlobal(Constant *C, GlobalValue *&GV,
// Look through ptr->int and ptr->ptr casts.
if (CE->getOpcode() == Instruction::PtrToInt ||
- CE->getOpcode() == Instruction::BitCast)
+ CE->getOpcode() == Instruction::BitCast ||
+ CE->getOpcode() == Instruction::AddrSpaceCast)
return IsConstantOffsetFromGlobal(CE->getOperand(0), GV, Offset, TD);
// i32* getelementptr ([5 x i32]* @a, i32 0, i32 5)
@@ -263,10 +273,10 @@ static bool IsConstantOffsetFromGlobal(Constant *C, GlobalValue *&GV,
return true;
}
-/// ReadDataFromGlobal - Recursive helper to read bits out of global. C is the
-/// constant being copied out of. ByteOffset is an offset into C. CurPtr is the
-/// pointer to copy results into and BytesLeft is the number of bytes left in
-/// the CurPtr buffer. TD is the target data.
+/// Recursive helper to read bits out of global. C is the constant being copied
+/// out of. ByteOffset is an offset into C. CurPtr is the pointer to copy
+/// results into and BytesLeft is the number of bytes left in
+/// the CurPtr buffer. TD is the target data.
static bool ReadDataFromGlobal(Constant *C, uint64_t ByteOffset,
unsigned char *CurPtr, unsigned BytesLeft,
const DataLayout &TD) {
@@ -517,9 +527,8 @@ static Constant *ConstantFoldLoadThroughBitcast(ConstantExpr *CE,
return nullptr;
}
-/// ConstantFoldLoadFromConstPtr - Return the value that a load from C would
-/// produce if it is constant and determinable. If this is not determinable,
-/// return null.
+/// 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,
const DataLayout *TD) {
// First, try the easy cases:
@@ -609,7 +618,7 @@ static Constant *ConstantFoldLoadInst(const LoadInst *LI, const DataLayout *TD){
return nullptr;
}
-/// SymbolicallyEvaluateBinop - One of Op0/Op1 is a constant expression.
+/// 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.
@@ -666,9 +675,8 @@ static Constant *SymbolicallyEvaluateBinop(unsigned Opc, Constant *Op0,
return nullptr;
}
-/// CastGEPIndices - If array indices are not pointer-sized integers,
-/// explicitly cast them so that they aren't implicitly casted by the
-/// getelementptr.
+/// If array indices are not pointer-sized integers, explicitly cast them so
+/// that they aren't implicitly casted by the getelementptr.
static Constant *CastGEPIndices(ArrayRef<Constant *> Ops,
Type *ResultTy, const DataLayout *TD,
const TargetLibraryInfo *TLI) {
@@ -723,8 +731,7 @@ static Constant* StripPtrCastKeepAS(Constant* Ptr) {
return Ptr;
}
-/// SymbolicallyEvaluateGEP - If we can symbolically evaluate the specified GEP
-/// constant expression, do so.
+/// If we can symbolically evaluate the GEP constant expression, do so.
static Constant *SymbolicallyEvaluateGEP(ArrayRef<Constant *> Ops,
Type *ResultTy, const DataLayout *TD,
const TargetLibraryInfo *TLI) {
@@ -886,7 +893,7 @@ static Constant *SymbolicallyEvaluateGEP(ArrayRef<Constant *> Ops,
// Constant Folding public APIs
//===----------------------------------------------------------------------===//
-/// ConstantFoldInstruction - Try to constant fold the specified instruction.
+/// Try to constant fold the specified instruction.
/// If successful, the constant result is returned, if not, null is returned.
/// Note that this fails if not all of the operands are constant. Otherwise,
/// this function can only fail when attempting to fold instructions like loads
@@ -966,7 +973,7 @@ Constant *llvm::ConstantFoldInstruction(Instruction *I,
static Constant *
ConstantFoldConstantExpressionImpl(const ConstantExpr *CE, const DataLayout *TD,
const TargetLibraryInfo *TLI,
- SmallPtrSet<ConstantExpr *, 4> &FoldedOps) {
+ SmallPtrSetImpl<ConstantExpr *> &FoldedOps) {
SmallVector<Constant *, 8> Ops;
for (User::const_op_iterator i = CE->op_begin(), e = CE->op_end(); i != e;
++i) {
@@ -974,7 +981,7 @@ ConstantFoldConstantExpressionImpl(const ConstantExpr *CE, const DataLayout *TD,
// Recursively fold the ConstantExpr's operands. If we have already folded
// a ConstantExpr, we don't have to process it again.
if (ConstantExpr *NewCE = dyn_cast<ConstantExpr>(NewC)) {
- if (FoldedOps.insert(NewCE))
+ if (FoldedOps.insert(NewCE).second)
NewC = ConstantFoldConstantExpressionImpl(NewCE, TD, TLI, FoldedOps);
}
Ops.push_back(NewC);
@@ -986,7 +993,7 @@ ConstantFoldConstantExpressionImpl(const ConstantExpr *CE, const DataLayout *TD,
return ConstantFoldInstOperands(CE->getOpcode(), CE->getType(), Ops, TD, TLI);
}
-/// ConstantFoldConstantExpression - Attempt to fold the constant expression
+/// Attempt to fold the constant expression
/// using the specified DataLayout. If successful, the constant result is
/// result is returned, if not, null is returned.
Constant *llvm::ConstantFoldConstantExpression(const ConstantExpr *CE,
@@ -996,7 +1003,7 @@ Constant *llvm::ConstantFoldConstantExpression(const ConstantExpr *CE,
return ConstantFoldConstantExpressionImpl(CE, TD, TLI, FoldedOps);
}
-/// ConstantFoldInstOperands - Attempt to constant fold an instruction with the
+/// Attempt to constant fold an instruction with the
/// specified opcode and operands. If successful, the constant result is
/// returned, if not, null is returned. Note that this function can fail when
/// attempting to fold instructions like loads and stores, which have no
@@ -1101,10 +1108,9 @@ Constant *llvm::ConstantFoldInstOperands(unsigned Opcode, Type *DestTy,
}
}
-/// ConstantFoldCompareInstOperands - Attempt to constant fold a compare
+/// Attempt to constant fold a compare
/// instruction (icmp/fcmp) with the specified operands. If it fails, it
/// returns a constant expression of the specified operands.
-///
Constant *llvm::ConstantFoldCompareInstOperands(unsigned Predicate,
Constant *Ops0, Constant *Ops1,
const DataLayout *TD,
@@ -1191,9 +1197,9 @@ Constant *llvm::ConstantFoldCompareInstOperands(unsigned Predicate,
}
-/// 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.
+/// 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 *llvm::ConstantFoldLoadThroughGEPConstantExpr(Constant *C,
ConstantExpr *CE) {
if (!CE->getOperand(1)->isNullValue())
@@ -1209,10 +1215,9 @@ Constant *llvm::ConstantFoldLoadThroughGEPConstantExpr(Constant *C,
return C;
}
-/// ConstantFoldLoadThroughGEPIndices - Given a constant and getelementptr
-/// indices (with an *implied* zero pointer index that is not in the list),
-/// return the constant value being addressed by a virtual load, or null if
-/// something is funny and we can't decide.
+/// Given a constant and getelementptr indices (with an *implied* zero pointer
+/// index that is not in the list), return the constant value being addressed by
+/// a virtual load, or null if something is funny and we can't decide.
Constant *llvm::ConstantFoldLoadThroughGEPIndices(Constant *C,
ArrayRef<Constant*> Indices) {
// Loop over all of the operands, tracking down which value we are
@@ -1230,11 +1235,12 @@ Constant *llvm::ConstantFoldLoadThroughGEPIndices(Constant *C,
// Constant Folding for Calls
//
-/// canConstantFoldCallTo - Return true if its even possible to fold a call to
-/// the specified function.
+/// Return true if it's even possible to fold a call to the specified function.
bool llvm::canConstantFoldCallTo(const Function *F) {
switch (F->getIntrinsicID()) {
case Intrinsic::fabs:
+ case Intrinsic::minnum:
+ case Intrinsic::maxnum:
case Intrinsic::log:
case Intrinsic::log2:
case Intrinsic::log10:
@@ -1320,7 +1326,7 @@ static Constant *GetConstantFoldFPValue(double V, Type *Ty) {
}
namespace {
-/// llvm_fenv_clearexcept - Clear the floating-point exception state.
+/// Clear the floating-point exception state.
static inline void llvm_fenv_clearexcept() {
#if defined(HAVE_FENV_H) && HAVE_DECL_FE_ALL_EXCEPT
feclearexcept(FE_ALL_EXCEPT);
@@ -1328,7 +1334,7 @@ static inline void llvm_fenv_clearexcept() {
errno = 0;
}
-/// llvm_fenv_testexcept - Test if a floating-point exception was raised.
+/// Test if a floating-point exception was raised.
static inline bool llvm_fenv_testexcept() {
int errno_val = errno;
if (errno_val == ERANGE || errno_val == EDOM)
@@ -1365,14 +1371,13 @@ static Constant *ConstantFoldBinaryFP(double (*NativeFP)(double, double),
return GetConstantFoldFPValue(V, Ty);
}
-/// ConstantFoldConvertToInt - Attempt to an SSE floating point to integer
-/// conversion of a constant floating point. If roundTowardZero is false, the
-/// default IEEE rounding is used (toward nearest, ties to even). This matches
-/// the behavior of the non-truncating SSE instructions in the default rounding
-/// mode. The desired integer type Ty is used to select how many bits are
-/// available for the result. Returns null if the conversion cannot be
-/// performed, otherwise returns the Constant value resulting from the
-/// conversion.
+/// Attempt to fold an SSE floating point to integer conversion of a constant
+/// floating point. If roundTowardZero is false, the default IEEE rounding is
+/// used (toward nearest, ties to even). This matches the behavior of the
+/// non-truncating SSE instructions in the default rounding mode. The desired
+/// integer type Ty is used to select how many bits are available for the
+/// result. Returns null if the conversion cannot be performed, otherwise
+/// returns the Constant value resulting from the conversion.
static Constant *ConstantFoldConvertToInt(const APFloat &Val,
bool roundTowardZero, Type *Ty) {
// All of these conversion intrinsics form an integer of at most 64bits.
@@ -1519,8 +1524,14 @@ static Constant *ConstantFoldScalarCall(StringRef Name, unsigned IntrinsicID,
(Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy())) {
if (V >= -0.0)
return ConstantFoldFP(sqrt, V, Ty);
- else // Undefined
- return Constant::getNullValue(Ty);
+ else {
+ // Unlike the sqrt definitions in C/C++, POSIX, and IEEE-754 - which
+ // all guarantee or favor returning NaN - the square root of a
+ // negative number is not defined for the LLVM sqrt intrinsic.
+ // This is because the intrinsic should only be emitted in place of
+ // libm's sqrt function when using "no-nans-fp-math".
+ return UndefValue::get(Ty);
+ }
}
break;
case 's':
@@ -1626,6 +1637,19 @@ static Constant *ConstantFoldScalarCall(StringRef Name, unsigned IntrinsicID,
V1.copySign(V2);
return ConstantFP::get(Ty->getContext(), V1);
}
+
+ if (IntrinsicID == Intrinsic::minnum) {
+ const APFloat &C1 = Op1->getValueAPF();
+ const APFloat &C2 = Op2->getValueAPF();
+ return ConstantFP::get(Ty->getContext(), minnum(C1, C2));
+ }
+
+ if (IntrinsicID == Intrinsic::maxnum) {
+ const APFloat &C1 = Op1->getValueAPF();
+ const APFloat &C2 = Op2->getValueAPF();
+ return ConstantFP::get(Ty->getContext(), maxnum(C1, C2));
+ }
+
if (!TLI)
return nullptr;
if (Name == "pow" && TLI->has(LibFunc::pow))
@@ -1761,7 +1785,7 @@ static Constant *ConstantFoldVectorCall(StringRef Name, unsigned IntrinsicID,
return ConstantVector::get(Result);
}
-/// ConstantFoldCall - Attempt to constant fold a call to the specified function
+/// Attempt to constant fold a call to the specified function
/// with the specified arguments, returning null if unsuccessful.
Constant *
llvm::ConstantFoldCall(Function *F, ArrayRef<Constant *> Operands,
generated by cgit v1.1 at 2024-05-21 05:11:13 +0000