Re: default compilation flags for AMD64
On 6/25/06, Dimitris Lampridis <dlampridis@gmail.com> wrote:
Hi everybody,
Hi
I was wondering if anyone can inform me of the default compilation flags for
AMD64 when compiling and installing debian source packages. I suppose there
is such a thing (there should be an -march=k8 or -mtune by default, no? ), on
top of which every package possibly adds its own?
when compiling pcre for example, the compiler is invoked as:
x86_64-linux-gnu-gcc -c -Wall -g -O2 -I. -I. -DSUPPORT_UTF8
-DSUPPORT_UCP -DPOSIX_MALLOC_THRESHOLD=10 ./pcre_try_flipped.c -fPIC
-DPIC -o .libs/pcre_try_flipped.o
But since we are compiling on amd64, the default should be k8, I mean
the default for gcc, right?
Have a look at the head of the asm output from:
x86_64-linux-gnu-gcc -Wall -g -O2 -I. -I. -DSUPPORT_UTF8
-DSUPPORT_UCP -DPOSIX_MALLOC_THRESHOLD=10 -S ./pcre_version.c
-fverbose-asm
# options passed: -I. -I. -DSUPPORT_UTF8 -DSUPPORT_UCP
# -DPOSIX_MALLOC_THRESHOLD=10 -mtune=k8 -auxbase -g -O2 -Wall -fverbose-asm
Also further down the line, there is a -m64.
IIRC I compiled once a program with -march=k8, and without it, and
they were identical.
I wonder what the default -march is. However since we are generating
64-bit code, it can't be anything lower than a k8, right?
If I am wrong, please somebody tell me :)
PS: My gentoo alter-ego has taken control over me, shoot me before its too
late :)
Take a look at sf.net/projects/debtoo
Cheers,
Edwin
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