[llvm-commits] [llvm] r77460 - /llvm/trunk/docs/LangRef.html

[Dan Gohman]

On Aug 18, 2009, at 10:38 AM, Duncan Sands wrote:


> Hi Dan,
>
>
>> Add one-past-the-end language to the inbounds keyword.
>>
>
> is this useful for LLVM?  Also, I hear that C has a rule like this
> for arrays, however I think in that case the address of the array
> element one off the end is valid, but that may in fact be many
> bytes off the end if the array element is large.  It's not clear
> from your wording whether you mean one byte off the end is ok,
> or something closer to C.

The one-past-the-end rule is entirely motivated by the need to
support C, and programming models that lower to C-like semantics.
 From my reading of the standard, only one byte of address space
is required to satisfy C's one-past-the-end rule.

If I've misinterpreted the standard, or if there are programming
models which require more than one byte and which could be
accommodated by a reasonable change, I'm interested in hearing
about it.

Dan