Simon Pilgrim 19033384c0 [X86][AVX] Support bit-mask integer shuffles for 256-bit integer vectors
AVX1 doesn't support the shuffling of 256-bit integer vectors. For 32/64-bit elements we get around this by shuffling as float/double but for 8/16-bit elements (assuming they can't widen) we currently just split, shuffle as 128-bit vectors and concatenate the results back.

This patch adds the ability to lower using the bit-mask patterns before defaulting to the splitting behaviour. In some cases this ends up matching what AVX2 would do anyhow or what AVX1 does on the split vectors.

Part 1 of 2

Differential Revision: http://reviews.llvm.org/D17292

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@261081 91177308-0d34-0410-b5e6-96231b3b80d8
2016-02-17 10:37:49 +00:00
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2016-02-16 15:16:00 +00:00