Jim Apple has posted comments on this change.

Change subject: IMPALA-2809: Improve ByteSwap with builtin function or SSE or 
AVX2.
......................................................................


Patch Set 5:

(2 comments)

http://gerrit.cloudera.org:8080/#/c/3081/5/be/src/util/bit-util.inline.h
File be/src/util/bit-util.inline.h:

Line 139: __attribute__((target("sse4.2")))
I just realized that I'm not sure if we can use __attribute__((target... and 
Intel intrinsics. See sse-util.h for the reason why:


    #ifndef IR_COMPILE
    /// When compiling to native code (i.e. not IR), we cannot use the -msse4.2 
compiler                                                                        
                                                                                
   
    /// flag.  Otherwise, the compiler will emit SSE 4.2 instructions outside 
of the runtime                                                                  
                                                                                
     
    /// SSE 4.2 checks and Impala will crash on CPUs that don't support SSE 4.2 
                                                                                
                                                                                
   
    /// (IMPALA-1399/1646).  The compiler intrinsics cannot be used without 
-msse4.2, so we                                                                 
                                                                                
       
    /// define our own implementations of the intrinsics instead.


Line 174:   static const FuncPointer SIMDFuncTable[2] = {ByteSwapSSE_Unit, 
ByteSwapAVX2_Unit};
> Hi Jim. If you don't mind, I just want to make sure that you suggest to mak
Sorry, I meant an actual template parameter.


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Gerrit-MessageType: comment
Gerrit-Change-Id: I392ed5a8d5683f30f161282c228c1aedd7b648c1
Gerrit-PatchSet: 5
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: Marcel Kornacker <[email protected]>
Gerrit-Reviewer: Mostafa Mokhtar <[email protected]>
Gerrit-Reviewer: Tim Armstrong <[email protected]>
Gerrit-Reviewer: Youwei Wang <[email protected]>
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