r334208 - [X86] Add back builtins for _mm_slli_si128/_mm_srli_si128 and similar intrinsics.

[Craig Topper via cfe-commits]

Maybe we're checking the range too early. Maybe we need to do it during IR
emission instead of during semantic analysis.

~Craig


On Fri, Jun 8, 2018 at 12:59 AM Martin Storsjö via cfe-commits <
cfe-commits at lists.llvm.org> wrote:

> On Thu, 7 Jun 2018, Craig Topper via cfe-commits wrote:
>
> > Author: ctopper
> > Date: Thu Jun  7 10:28:03 2018
> > New Revision: 334208
> >
> > URL: http://llvm.org/viewvc/llvm-project?rev=334208&view=rev
> > Log:
> > [X86] Add back builtins for  _mm_slli_si128/_mm_srli_si128 and similar
> intrinsics.
> >
> > We still lower them to native shuffle IR, but we do it in CGBuiltin.cpp
> now. This allows us to check the target feature and ensure the immediate
> fits in 8 bits.
>
> FWIW, this change broke building libaom:
> https://bugs.chromium.org/p/aomedia/issues/detail?id=1945
>
> In libaom, there's a macro construct like this:
>
>   #define v256_shr_n_byte(a, n)
>      \
>     ((n) < 16
>      \
>          ? _mm256_alignr_epi8(
>       \
>                _mm256_permute2x128_si256(a, a, _MM_SHUFFLE(2, 0, 0, 1)),
> a, n)  \
>          : ((n) > 16
>       \
>                 ? _mm256_srli_si256(
>       \
>                       _mm256_permute2x128_si256(a, a, _MM_SHUFFLE(2, 0, 0,
> 1)), \
>                       (n)-16)
>      \
>                 : _mm256_permute2x128_si256(a, a, _MM_SHUFFLE(2, 0, 0,
> 1))))
>
> Since this commit, the compilation errors out due to the _mm256_srli_si256
> with invalid range, even though the toplevel ternary operator won't
> actually pick them to be used. Not sure if there's anything to do from the
> clang point of view here, I guess it's a tradeoff between having stricter
> parameter checks for the intrinsics, vs the convenience of piling them up
> in a macro like this in libaom.
>
> // Martin
> _______________________________________________
> cfe-commits mailing list
> cfe-commits at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/cfe-commits/attachments/20180608/8b656a86/attachment.html>