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[Bug target/57796] AVX2 gather vectorization: code bloat and reduction of performance
- From: "vincenzo.innocente at cern dot ch" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Tue, 28 Mar 2017 17:04:59 +0000
- Subject: [Bug target/57796] AVX2 gather vectorization: code bloat and reduction of performance
- Auto-submitted: auto-generated
- References: <bug-57796-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=57796
--- Comment #10 from vincenzo Innocente <vincenzo.innocente at cern dot ch> ---
added a self contained "benchmark"
on my machine
[innocent@vinavx3 ctest]$ c++ -Ofast -Wall SparseOnly.c -march=native ; time
./a.out
0.496u 0.000s 0:00.49 100.0% 0+0k 0+0io 0pf+0w
[innocent@vinavx3 ctest]$ c++ -O2 -Wall SparseOnly.c -march=native ; time
./a.out
0.411u 0.000s 0:00.41 100.0% 0+0k 0+0io 0pf+0w
[innocent@vinavx3 ctest]$ c++ -O3 -Wall SparseOnly.c -march=native ; time
./a.out
0.413u 0.000s 0:00.41 100.0% 0+0k 0+0io 0pf+0w