Add comment as follow up to r245712

[oota-llvm.git] / lib / IR / ConstantFold.cpp

diff --git a/lib/IR/ConstantFold.cpp b/lib/IR/ConstantFold.cpp
index 178612c6a3e7234e0fc3eac8f36a3881b8557f44..f63ce9bbf038a1fda1da0a987341727618729f24 100644 (file)
--- a/lib/IR/ConstantFold.cpp
+++ b/lib/IR/ConstantFold.cpp
@@ -1057,8 +1057,7 @@ Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode,
 
           if (GVAlign > 1) {
             unsigned DstWidth = CI2->getType()->getBitWidth();
-            unsigned SrcWidth =
-                std::min(DstWidth, static_cast<unsigned>(Log2_32(GVAlign)));
+            unsigned SrcWidth = std::min(DstWidth, Log2_32(GVAlign));
             APInt BitsNotSet(APInt::getLowBitsSet(DstWidth, SrcWidth));
 
             // If checking bits we know are clear, return zero.
@@ -1998,17 +1997,17 @@ static bool isInBoundsIndices(ArrayRef<IndexTy> Idxs) {
 }
 
 /// \brief Test whether a given ConstantInt is in-range for a SequentialType.
-static bool isIndexInRangeOfSequentialType(const SequentialType *STy,
+static bool isIndexInRangeOfSequentialType(SequentialType *STy,
                                            const ConstantInt *CI) {
-  if (const PointerType *PTy = dyn_cast<PointerType>(STy))
-    // Only handle pointers to sized types, not pointers to functions.
-    return PTy->getElementType()->isSized();
+  // And indicies are valid when indexing along a pointer
+  if (isa<PointerType>(STy))
+    return true;
 
   uint64_t NumElements = 0;
   // Determine the number of elements in our sequential type.
-  if (const ArrayType *ATy = dyn_cast<ArrayType>(STy))
+  if (auto *ATy = dyn_cast<ArrayType>(STy))
     NumElements = ATy->getNumElements();
-  else if (const VectorType *VTy = dyn_cast<VectorType>(STy))
+  else if (auto *VTy = dyn_cast<VectorType>(STy))
     NumElements = VTy->getNumElements();
 
   assert((isa<ArrayType>(STy) || NumElements > 0) &&
@@ -2164,10 +2163,10 @@ static Constant *ConstantFoldGetElementPtrImpl(Type *PointeeTy, Constant *C,
   // Check to see if any array indices are not within the corresponding
   // notional array or vector bounds. If so, try to determine if they can be
   // factored out into preceding dimensions.
-  bool Unknown = false;
   SmallVector<Constant *, 8> NewIdxs;
   Type *Ty = PointeeTy;
   Type *Prev = C->getType();
+  bool Unknown = !isa<ConstantInt>(Idxs[0]);
   for (unsigned i = 1, e = Idxs.size(); i != e;
        Prev = Ty, Ty = cast<CompositeType>(Ty)->getTypeAtIndex(Idxs[i]), ++i) {
     if (ConstantInt *CI = dyn_cast<ConstantInt>(Idxs[i])) {
@@ -2179,7 +2178,7 @@ static Constant *ConstantFoldGetElementPtrImpl(Type *PointeeTy, Constant *C,
             // dimension.
             NewIdxs.resize(Idxs.size());
             uint64_t NumElements = 0;
-            if (const ArrayType *ATy = dyn_cast<ArrayType>(Ty))
+            if (auto *ATy = dyn_cast<ArrayType>(Ty))
               NumElements = ATy->getNumElements();
             else
               NumElements = cast<VectorType>(Ty)->getNumElements();
@@ -2222,7 +2221,7 @@ static Constant *ConstantFoldGetElementPtrImpl(Type *PointeeTy, Constant *C,
   if (!NewIdxs.empty()) {
     for (unsigned i = 0, e = Idxs.size(); i != e; ++i)
       if (!NewIdxs[i]) NewIdxs[i] = cast<Constant>(Idxs[i]);
-    return ConstantExpr::getGetElementPtr(nullptr, C, NewIdxs, inBounds);
+    return ConstantExpr::getGetElementPtr(PointeeTy, C, NewIdxs, inBounds);
   }
 
   // If all indices are known integers and normalized, we can do a simple