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-rw-r--r--share/mk/bsd.cpu.mk21
1 files changed, 21 insertions, 0 deletions
diff --git a/share/mk/bsd.cpu.mk b/share/mk/bsd.cpu.mk
index 6ba87cc..7d776bc 100644
--- a/share/mk/bsd.cpu.mk
+++ b/share/mk/bsd.cpu.mk
@@ -282,6 +282,27 @@ _CPUCFLAGS += -mfloat-abi=softfp
CFLAGS += ${_CPUCFLAGS}
.endif
+#
+# Prohibit the compiler from emitting SIMD instructions.
+# These flags are added to CFLAGS in areas where the extra context-switch
+# cost outweighs the advantages of SIMD instructions.
+#
+# gcc:
+# Setting -mno-mmx implies -mno-3dnow
+# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3 and -mfpmath=387
+#
+# clang:
+# Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa
+# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and
+# -mno-sse42
+# (-mfpmath= is not supported)
+#
+.if ${MACHINE_CPUARCH} == "i386" || ${MACHINE_CPUARCH} == "amd64"
+CFLAGS_NO_SIMD.clang= -mno-avx
+CFLAGS_NO_SIMD= -mno-mmx -mno-sse
+.endif
+CFLAGS_NO_SIMD += ${CFLAGS_NO_SIMD.${COMPILER_TYPE}}
+
# Add in any architecture-specific CFLAGS.
# These come from make.conf or the command line or the environment.
CFLAGS += ${CFLAGS.${MACHINE_ARCH}}
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