Simon Pilgrim 02b7bb4769 [X86][SSE] Avoid vector byte shuffles with zero by using pshufb to create zeros
pshufb can shuffle in zero bytes as well as bytes from a source vector - we can use this to avoid having to shuffle 2 vectors and ORing the result when the used inputs from a vector are all zeroable.

Differential Revision: http://reviews.llvm.org/D6878

llvm-svn: 225551
2015-01-09 22:03:19 +00:00
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2014-12-30 03:24:14 +00:00
2015-01-08 16:11:18 +00:00
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