Jim Apple has posted comments on this change.

Change subject: Allow compiler to use SSE3 and SSSE3 instructions.
......................................................................


Patch Set 2:

> > > Aren't these already on by default?  I'm pretty sure impalad
 > ends
 > > > up with SSSE3 instructions.  What's the default -march for our
 > > > toolchain gcc?
 > >
 > > I checked by using an SSE3 Intel Intrisic without adding this
 > > compiler option. It caused the build to fail with "target
 > specific
 > > option mismatch"
 > 
 > SSE3 shouldn't be enabled but SSSE3 might be.  But it might not be.
 > 
 > However, what's the motivation for this change?  Do you see a
 > tangible benefit?  We could do it, but there might be some Impala
 > users out there running on AMD Bulldozer (2011) even though we
 > technically require SSSE3.

The purpose is to make byte shuffles and unaligned 16-byte SIMD loads available 
for use with some of the SIMD optimizations that are being done by the Intel 
contributors.

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Gerrit-MessageType: comment
Gerrit-Change-Id: Ib045e00b5aa71cc6ef16dbda160bfdc7b765158a
Gerrit-PatchSet: 2
Gerrit-Project: Impala
Gerrit-Branch: cdh5-trunk
Gerrit-Owner: Jim Apple <[email protected]>
Gerrit-Reviewer: Dan Hecht <[email protected]>
Gerrit-Reviewer: Jim Apple <[email protected]>
Gerrit-Reviewer: Tim Armstrong <[email protected]>
Gerrit-HasComments: No

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