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@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@lists.llvm.org > http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits >
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