Youwei Wang has posted comments on this change.

Change subject: IMPALA-3604: Clean up SSE handling
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Patch Set 1:

(3 comments)

http://gerrit.cloudera.org:8080/#/c/3227/1/be/src/util/sse-util.h
File be/src/util/sse-util.h:

Line 85: /// CPU requirement is raised to at least the targeted instruction set.
> Please do not create empty #if blocks.
Hi Jim. Since this becomes a blank #if block after its internal #error is 
commented out, and the remained comment is contradictory to IMPALA-3604, can I 
remove this entire #if block for I guess it is no longer needed here?


Line 97: static inline __m128i SSE4_cmpestrm(__m128i str1, int len1, __m128i 
str2, int len2) {
> Why did you remove the comment that was here?
Sorry, it seems I removed them by accident.


Line 99:   __asm__ volatile ("pcmpestrm %5, %2, %1"
> Can clang use the intrinsics?
Clang doesn't support __attribute__ for clang version < 3.8. 
(https://godbolt.org/g/PUcrhU) In this case, we have to modify the build 
configuration if we add some SSE4.2 intrinsics here. But this is not allowed. 

So clang itself can use intrinsics. However, due to missing support for the 
__attribute__, we can't use the intrinsics directly here for clang like the GCC 
code.


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Gerrit-MessageType: comment
Gerrit-Change-Id: Id346187f3248922ec2a323548de4bdeaccd7a771
Gerrit-PatchSet: 1
Gerrit-Project: Impala
Gerrit-Branch: cdh5-trunk
Gerrit-Owner: Youwei Wang <[email protected]>
Gerrit-Reviewer: Alex Behm <[email protected]>
Gerrit-Reviewer: Jim Apple <[email protected]>
Gerrit-Reviewer: Mostafa Mokhtar <[email protected]>
Gerrit-Reviewer: Tim Armstrong <[email protected]>
Gerrit-Reviewer: Youwei Wang <[email protected]>
Gerrit-HasComments: Yes

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