[PATCH] Removing unnecessary addrspacecasts from non-generic address spaces to the generic address space

[Philip Reames]

A key point here is that not all targets will have a "generic" address 
space.  This is a new concept which is bring introduced and needs to be 
defined carefully.

Philip

On 03/31/2014 02:08 PM, Jingyue Wu wrote:
> Hi Matt,
>
> I actually think it should go to lib/Transforms/InstCombine when it 
> gets generalized. Also, TTI would need to expose which address space 
> is generic and whether such optimization would benefit at all.
>
> Jingyue
>
>
> On Mon, Mar 31, 2014 at 2:00 PM, Matt Arsenault 
> <Matthew.Arsenault at amd.com <mailto:Matthew.Arsenault at amd.com>> wrote:
>
>
>       This looks like it doesn't handle vectors of pointers, although
>     that's probably not very important.
>
>       I don't see anything tying this to NVPTX except the use of 0 for
>     generic. Where should this go when generalized? Put it in
>     lib/CodeGen and add getGenericAddressSpace() to TTI?
>
>
>     ================
>     Comment at: lib/Target/NVPTX/NVPTXFavorNonGenericAddrSpaces.cpp:67-72
>     @@ +66,8 @@
>     +
>     +  Value *Src = Cast->getOperand(0);
>     +  PointerType *SrcTy = cast<PointerType>(Src->getType());
>     +  PointerType *DestTy = cast<PointerType>(Cast->getType());
>     +  // We cannot remove the addrspacecast if the element type changes.
>     +  if (SrcTy->getElementType() != DestTy->getElementType())
>     +    return false;
>     +
>     ----------------
>     If the element type changes, you can still do it, but you'll need
>     to do the bitcast separately. I had a patch a while ago
>     (http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20131118/195642.html)
>     to canonicalize to splitting the bitcast and addrspacecast into
>     separate operations. It might be better to handle it that way than
>     trying to figure it out here.
>
>
>     http://llvm-reviews.chandlerc.com/D3235
>
>
>
>
> _______________________________________________
> llvm-commits mailing list
> llvm-commits at cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20140331/8415897e/attachment.html>