-march specifies which ISA to use. -mtune specifies which cpu-type to
optimize instruction ordering for, but not which ISA to use. There are
times when it may make sense to specify mtune=generic and use a more
specific march, such as core2, but the opposite makes little sense at
all: use cpu-type specific ISA, but order the instructions
generically. While the -mtune is implied by -march, gcc does not verify
it is using -mtune=core2 with:
gcc -Q -march=core2 --help=target
Explicitly specify -mtune=core2 to be sure.
Add a comment header describing the CPUs targeted by this tune file.
Signed-off-by: Darren Hart <dvh...@linux.intel.com>
Cc: Richard Purdie <richard.pur...@intel.com>
Cc: Paul Eggleton <paul.eggle...@intel.com>
Cc: Tom Zanussi <tom.zanu...@intel.com>
Cc: Nitin Kamble <nitin.a.kam...@intel.com>
Cc: Mark Hatle <mark.ha...@windriver.com>
Cc: Bruce Ashfield <bruce.ashfi...@windriver.com>
---
meta/conf/machine/include/tune-core2.inc | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/meta/conf/machine/include/tune-core2.inc
b/meta/conf/machine/include/tune-core2.inc
index 85b6924..3b25197 100644
--- a/meta/conf/machine/include/tune-core2.inc
+++ b/meta/conf/machine/include/tune-core2.inc
@@ -1,10 +1,18 @@
+# Settings for the GCC(1) cpu-type "core2":
+#
+# Intel Core2 CPU with 64-bit extensions, MMX, SSE, SSE2, SSE3 and SSSE3
+# instruction set support.
+#
+# This tune is recommended for the Intel Core 2 CPU family, including Conroe,
+# Merom and beyond, as well as the first Atom CPUs, Diamondville, and beyond.
+#
DEFAULTTUNE ?= "core2"
require conf/machine/include/tune-i586.inc
# Extra tune features
TUNEVALID[core2] = "Enable core2 specific processor optimizations"
-TUNE_CCARGS .= "${@bb.utils.contains("TUNE_FEATURES", "core2", " -march=core2
-msse3 -mtune=generic -mfpmath=sse", "", d)}"
+TUNE_CCARGS .= "${@bb.utils.contains("TUNE_FEATURES", "core2", " -march=core2
-mtune=core2 -msse3 -mfpmath=sse", "", d)}"
# Extra tune selections
AVAILTUNES += "core2"
--
1.7.9.5
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