[llvm-commits] [llvm] r111568 - in /llvm/trunk: lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp test/Transforms/InstCombine/2010-08-19-StoreNarrowing.ll

[Duncan Sands]

Hi Owen,

> +    // If we can find a power-of-2 prefix (and if the values we're working with
> +    // are themselves POT widths), then we can narrow the store.  We rely on
> +    // later iterations of instcombine to propagate the demanded bits to narrow
> +    // the other computations in the chain.
> +    if (NewWidth<  AndMask.getBitWidth()&&
> +        isPowerOf2_64(AndMask.getBitWidth())) {
> +      const Type *NewType = IntegerType::get(Ptr->getContext(), NewWidth);

is it possible that you do an i4 store here?  That would actually overwrite 8
bits, which would be wrong.

Ciao,

Duncan.