[PATCH] [X86][AVX2] Missing AVX2 memory folding instructions

[Simon Pilgrim]

In http://reviews.llvm.org/D7492#120487, @mkuper wrote:

> What bothers me a bit is that all of the pre-existing broadcast instructions have TB_NO_REVERSE, and the new ones don't.
>  Unfortunately I can't remember *why* they have TB_NO_REVERSE.


I believe its because the VBROADCASTS{SD}rr register instructions were an AVX2 addition while the VBROADCASTS{SD}rm memory instructions were available from AVX1 - so it prevents unfolding from introducing an illegal instruction on AVX1 targets. The VPBROADCAST instructions are all AVX2 instructions so don't need an equivalent limitation.

Nadav might be able to confirm?


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  rL LLVM

http://reviews.llvm.org/D7492

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