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Vectorization Flags

To enable vectorization it is important to set specific flags for the compiler. There are also flags for causing the compiler to generate messages on what it did vectorize. Here the most important flags are given.

 

Cray

Arm

GNU

Fujitsu

  Flags
   Pre-23 CPE
CPE 23 and later:
(not applicable for Fortran)
    Traditional mode Clang mode
-Nclang
Optimization -O3 -O3
-O3 or -Ofast -O3 or -Ofast -Kfast -O3
Vectorization -h vector3 Automatic (if -O3 or -O2 flag is set) -mcpu=a64fx -armpl -mcpu=a64fx -KSVE -march=armv8.2-a+sve
Vectorization report -h msgs -Rpass=loop-vectorize -Rpass=loop-vectorize -fopt-info-vec

-Koptmsg=2
-Nlst=t
(creates a *.lst file with optimization information)

Report on missed optimization -h negmsgs -Rpass-analysis=loop-vectorize -Rpass-analysis=loop-vectorize -fopt-info-vec-missed  
OpenMP -h omp -fopenmp -fopenmp -fopenmp -Kopenmp
Debugging -G 2 -ggdb
-ggdb -ggdb -g
Large memory -h pic -mcmodel=large -mcmodel=large -mcmodel=large -mcmodel=large
Module CPE/version CPE/23.02(or newer)
arm-modules/version gcc/version

fujitsu/
compiler/version

  Compiler names
C cc
armclang gcc fcc
C++ CC
armclang++ g++ FCC
Fortran ftn
armflang gfortran frt