[Bug target/57796] AVX2 gather vectorization: code bloat and reduction of performance

[vincenzo.innocente at cern dot ch]

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