path: root/profiles/arch/x86_64/make.defaults

# We definitely use 64-bit ABI.
ABI_X86="64"
IUSE_IMPLICIT="abi_x86_64"

ARCH="x86_64"
ACCEPT_KEYWORDS="${ARCH} amd64"  # HACK for using Gentoo ebuilds

# -O2           -> Perform second-level optimisations.
#                  Not -Os because most/all x86_64 aren't starved for space.
# -ggdb         -> Generate GDB debugging information.
#                  This is used with splitdebug to make -dbg split packages.
# -march=nocona -> Require a "Nocona" Pentium 4 or newer.
#                  At some point, pending user demand, this may change to core2.
#                  !!!NOTE!!! If that happens, Nocona P4 will no longer work!
# -mtune=core2  -> Tune for Core 2 processors.
#                  Most tuning for Core 2 is applicable to * Bridge and *well,
#                  and makes code more performant on the much larger base of
#                  those machines.
# -fno-omit-... -> Never omit the frame pointer.
#                  This is crucial for proper debugging.
# -mfpmath=sse  -> Use SSE for all floating point math.
#                  Since SSE is always available, this knob ensures that GCC
#                  will take advantage of it over preferring 387 math, which
#                  can drag down performance on modern x86_64.
CFLAGS="-O2 -ggdb -march=nocona -mtune=core2 -fno-omit-frame-pointer -mfpmath=sse"
CXXFLAGS="${CFLAGS}"

ELIBC="musl"

USE="pam threads"