http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57927
Bug ID: 57927
Summary: -march=core-avx2 different than -march=native on
INTEL Haswell (i7-4700K)
Product: gcc
Version: 4.9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: vincenzo.innocente at cern dot ch
for instance
mkdir scimark2TMP
cd scimark2TMP
wget http://math.nist.gov/scimark2/scimark2_1c.zip .
unzip scimark2_1c.zip
c++ -S LU.c -O3 -march=native -o LU.native -v
c++ -S LU.c -O3 -march=core-avx2 -o LU.avx2 -v
diff LU.native LU.avx2
if you run the benchmark
gcc -O3 -march=core-avx2 *.c -lm; ./a.out 5
gcc -O3 -march=native *.c -lm; ./a.out 5
"core-avx2" is better than "native"
