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de95c380c7
a more sane approach to AVX2 support. Fundamentally, there is no useful way to lower integer vectors in AVX. None. We always end up with a VINSERTF128 in the end, so we might as well eagerly switch to the floating point domain and do everything there. This cleans up lots of weird and unlikely to be correct differences between integer and floating point shuffles when we only have AVX1. The other nice consequence is that by doing things this way we will make it much easier to write the integer lowering routines as we won't need to duplicate the logic to check for AVX vs. AVX2 in each one -- if we actually try to lower a 256-bit vector as an integer vector, we have AVX2 and can rely on it. I think this will make the code much simpler and more comprehensible. Currently, I've disabled *all* support for AVX2 so that we always fall back to AVX. This keeps everything working rather than asserting. That will go away with the subsequent series of patches that provide a baseline AVX2 implementation. Please note, I'm going to implement AVX2 *without access to hardware*. That means I cannot correctness test this path. I will be relying on those with access to AVX2 hardware to do correctness testing and fix bugs here, but as a courtesy I'm trying to sketch out the framework for the new-style vector shuffle lowering in the context of the AVX2 ISA. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218228 91177308-0d34-0410-b5e6-96231b3b80d8
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