Assert correct values in APInt constructor

If the uint64_t constructor is used, assert that the value is
actuall a signed or unsigned N-bit integer depending on whether
the isSigned flag is set.

Currently, we allow values to be silently truncated, which is
a constant source of subtle bugs -- a particularly common mistake
is to create -1 values without setting the isSigned flag, which
will work fine for all common bit widths (<= 64-bit) and miscompile
for larger integers.

Author: nikic

llvm/lib/Analysis/ConstantFolding.cpp

@@ -3600,8 +3600,9 @@ ConstantFoldScalarFrexpCall(Constant *Op, Type *IntTy) {
 
   // The exponent is an "unspecified value" for inf/nan. We use zero to avoid
   // using undef.
-  Constant *Result1 = FrexpMant.isFinite() ? ConstantInt::get(IntTy, FrexpExp)
-                                           : ConstantInt::getNullValue(IntTy);
+  Constant *Result1 = FrexpMant.isFinite()
+                          ? ConstantInt::getSigned(IntTy, FrexpExp)
+                          : ConstantInt::getNullValue(IntTy);
   return {Result0, Result1};
 }
 

llvm/lib/Analysis/MemoryBuiltins.cpp

@@ -670,7 +670,7 @@ Value *llvm::lowerObjectSizeCall(
   if (!MustSucceed)
     return nullptr;
 
-  return ConstantInt::get(ResultType, MaxVal ? -1ULL : 0);
+  return ConstantInt::get(ResultType, MaxVal ? -1ULL : 0, true);
 }
 
 STATISTIC(ObjectVisitorArgument,

llvm/lib/Analysis/ScalarEvolution.cpp

@@ -1455,7 +1455,7 @@ bool ScalarEvolution::proveNoWrapByVaryingStart(const SCEV *Start,
 
   APInt StartAI = StartC->getAPInt();
 
-  for (unsigned Delta : {-2, -1, 1, 2}) {
+  for (int Delta : {-2, -1, 1, 2}) {
     const SCEV *PreStart = getConstant(StartAI - Delta);
 
     FoldingSetNodeID ID;
@@ -1470,7 +1470,7 @@ bool ScalarEvolution::proveNoWrapByVaryingStart(const SCEV *Start,
     // Give up if we don't already have the add recurrence we need because
     // actually constructing an add recurrence is relatively expensive.
     if (PreAR && PreAR->getNoWrapFlags(WrapType)) {  // proves (2)
-      const SCEV *DeltaS = getConstant(StartC->getType(), Delta);
+      const SCEV *DeltaS = getConstant(StartC->getType(), Delta, true);
       ICmpInst::Predicate Pred = ICmpInst::BAD_ICMP_PREDICATE;
       const SCEV *Limit = ExtendOpTraits<ExtendOpTy>::getOverflowLimitForStep(
           DeltaS, &Pred, this);

llvm/lib/Analysis/ValueTracking.cpp

@@ -8719,7 +8719,7 @@ static void setLimitForFPToI(const Instruction *I, APInt &Lower, APInt &Upper) {
   if (!I->getOperand(0)->getType()->getScalarType()->isHalfTy())
     return;
   if (isa<FPToSIInst>(I) && BitWidth >= 17) {
-    Lower = APInt(BitWidth, -65504);
+    Lower = APInt(BitWidth, -65504, true);
     Upper = APInt(BitWidth, 65505);
   }
 

llvm/lib/Bitcode/Reader/BitcodeReader.cpp

@@ -3023,7 +3023,7 @@ Error BitcodeReader::parseConstants() {
     case bitc::CST_CODE_INTEGER:   // INTEGER: [intval]
       if (!CurTy->isIntegerTy() || Record.empty())
         return error("Invalid integer const record");
-      V = ConstantInt::get(CurTy, decodeSignRotatedValue(Record[0]));
+      V = ConstantInt::getSigned(CurTy, decodeSignRotatedValue(Record[0]));
       break;
     case bitc::CST_CODE_WIDE_INTEGER: {// WIDE_INTEGER: [n x intval]
       if (!CurTy->isIntegerTy() || Record.empty())

llvm/lib/CodeGen/CodeGenPrepare.cpp

@@ -1584,7 +1584,7 @@ static bool matchUAddWithOverflowConstantEdgeCases(CmpInst *Cmp,
   if (Pred == ICmpInst::ICMP_EQ && match(B, m_AllOnes()))
     B = ConstantInt::get(B->getType(), 1);
   else if (Pred == ICmpInst::ICMP_NE && match(B, m_ZeroInt()))
-    B = ConstantInt::get(B->getType(), -1);
+    B = Constant::getAllOnesValue(B->getType());
   else
     return false;
 

llvm/lib/CodeGen/ExpandMemCmp.cpp

@@ -537,7 +537,7 @@ void MemCmpExpansion::emitMemCmpResultBlock() {
                                   ResBlock.PhiSrc2);
 
   Value *Res =
-      Builder.CreateSelect(Cmp, ConstantInt::get(Builder.getInt32Ty(), -1),
+      Builder.CreateSelect(Cmp, Constant::getAllOnesValue(Builder.getInt32Ty()),
                            ConstantInt::get(Builder.getInt32Ty(), 1));
 
   PhiRes->addIncoming(Res, ResBlock.BB);

llvm/lib/Transforms/IPO/WholeProgramDevirt.cpp

@@ -1615,17 +1615,20 @@ Constant *DevirtModule::importConstant(VTableSlot Slot, ArrayRef<uint64_t> Args,
   if (GV->hasMetadata(LLVMContext::MD_absolute_symbol))
     return C;
 
-  auto SetAbsRange = [&](uint64_t Min, uint64_t Max) {
+  auto SetAbsRange = [&](const APInt &Min, const APInt &Max) {
     auto *MinC = ConstantAsMetadata::get(ConstantInt::get(IntPtrTy, Min));
     auto *MaxC = ConstantAsMetadata::get(ConstantInt::get(IntPtrTy, Max));
     GV->setMetadata(LLVMContext::MD_absolute_symbol,
                     MDNode::get(M.getContext(), {MinC, MaxC}));
   };
   unsigned AbsWidth = IntTy->getBitWidth();
-  if (AbsWidth == IntPtrTy->getBitWidth())
-    SetAbsRange(~0ull, ~0ull); // Full set.
+  unsigned IntPtrWidth = IntPtrTy->getBitWidth();
+  if (AbsWidth == IntPtrWidth)
+    // Full set.
+    SetAbsRange(APInt::getAllOnes(IntPtrWidth), APInt::getAllOnes(IntPtrWidth));
   else
-    SetAbsRange(0, 1ull << AbsWidth);
+    SetAbsRange(APInt::getZero(IntPtrWidth),
+                APInt::getOneBitSet(IntPtrWidth, AbsWidth));
   return C;
 }
 
@@ -1832,7 +1835,7 @@ bool DevirtModule::tryVirtualConstProp(
     }
 
     // Rewrite each call to a load from OffsetByte/OffsetBit.
-    Constant *ByteConst = ConstantInt::get(Int32Ty, OffsetByte);
+    Constant *ByteConst = ConstantInt::get(Int32Ty, OffsetByte, true);
     Constant *BitConst = ConstantInt::get(Int8Ty, 1ULL << OffsetBit);
     applyVirtualConstProp(CSByConstantArg.second,
                           TargetsForSlot[0].Fn->getName(), ByteConst, BitConst);

llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp

@@ -306,8 +306,8 @@ Instruction *InstCombinerImpl::SimplifyAnyMemSet(AnyMemSetInst *MI) {
     Dest = Builder.CreateBitCast(Dest, NewDstPtrTy);
 
     // Extract the fill value and store.
-    const uint64_t Fill = FillC->getZExtValue()*0x0101010101010101ULL;
-    Constant *FillVal = ConstantInt::get(ITy, Fill);
+    Constant *FillVal = ConstantInt::get(
+        MI->getContext(), APInt::getSplat(Len * 8, FillC->getValue()));
     StoreInst *S = Builder.CreateStore(FillVal, Dest, MI->isVolatile());
     S->copyMetadata(*MI, LLVMContext::MD_DIAssignID);
     for (auto *DAI : at::getAssignmentMarkers(S)) {

llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp

@@ -305,7 +305,7 @@ Instruction *InstCombinerImpl::foldCmpLoadFromIndexedGlobal(
       DL.getTypeAllocSize(Init->getType()->getArrayElementType());
   auto MaskIdx = [&](Value *Idx) {
     if (!GEP->isInBounds() && llvm::countr_zero(ElementSize) != 0) {
-      Value *Mask = ConstantInt::get(Idx->getType(), -1);
+      Value *Mask = Constant::getAllOnesValue(Idx->getType());
       Mask = Builder.CreateLShr(Mask, llvm::countr_zero(ElementSize));
       Idx = Builder.CreateAnd(Idx, Mask);
     }