|a ee376c913d .||7 months ago|
|README.md||7 months ago|
|cpuorakle.awk||7 months ago|
Obtain some safe cpu flags for use in Gentoo. I've added it to 3 Gentoo wiki pages as well.
# The script used to fit into 1 line at the beginning chmod +x cpuorakle.awk gcc '-###' -march=native -x c - 2>&1 | ./cpuorakle.awk
CPU_FLAGS_X86="... sse2 mcx16 sse3 mmxext 3dnow msahf 3dnowext mlzcnt sse4a mabm popcnt sse " CFLAGS="... --param l1-cache-size=64 -march=amdfam10 --param l1-cache-line-size=64 --param l2-cache-size=512 "
mmx, -O2, -pipe are included in vanilla make.conf
I'm not sure how stable avx* flags are since I don't have intel cpu. This along with the following quote is the reason not to include them in first place.
GCC depresses SSEx instructions when -mavx is used. Instead, it generates new AVX instructions or AVX equivalence for all SSEx instructions when needed.
Quoting one person:
your sample output contains lots of faults regarding the CPU_FLAGS_X86="" line. It should only contain CPU Flags which also exist as USE-Flags.
Some other programs will detect avx512* cpu instructions that doesn't exist as CPU_FLAGS_X86 USE flags at this point. Including those existing cpu instructions as CPU_FLAGS_X86 USE flags won't break the system. In case they are added upstream, all users that have included them in their configs will be able to leverage them.