[LLVMdev] Support for per-loop pragma

[Junjie Gu]

Hi Chris,

Thanks. I will see what I can do for this.

Junjie

On Wed, May 19, 2010 at 3:45 PM, Chris Lattner <clattner at apple.com> wrote:
>
> On May 19, 2010, at 2:38 PM, Junjie Gu wrote:
>
>> Many compilers support per-loop pragma, such as loop unrolling (ie
>> #pragma unroll=2).  Is there any LLVM project/effort going on
>> in this area ? What is the expected way for implementing per-loop
>> pragma, or general pragma ?  Suggestions/comments ?
>
> Hi Junjie,
>
> I don't know of anyone working on it, but it seems like a natural application of the metadata support in mainline:
> http://blog.llvm.org/2010/04/extensible-metadata-in-llvm-ir.html
>
> We'd want to tag something, perhaps the backedge branches with metadata, then have the loop canonicalization passes preserve them.
>
> -Chris