[LLVMdev] Possible error in LegalizeDAG

[Eli Friedman]

On Thu, Feb 19, 2009 at 10:35 AM, Villmow, Micah <Micah.Villmow at amd.com> wrote:
> On the hardware that I am targeting, which is not a CPU, I must support
> i8 loads, however the hardware only supports natively 32bit aligned
> loads, therefore I have to read in 4 i8's and unpack them and shift them
> based on the read address.  So any i8 load has a 75% chance of being
> unaligned on my hardware,

Oh, okay, makes sense.

> I've tried setting setLoadXAction to Custom, Legal, Expand and Promote.
> Setting it to Expand does not expand it to
> sign_extend and load but to  extload and sign_extend, but I don't
> support extload either.

I suppose you could consider that a bug.  That said, why is this
difficult to implement?  You can just treat an extload of an i8 as a
load of an i8 and get correct code, no?

-Eli