gcc options when building kernel

[Andrew Chace]

On Mon, 2006-01-30 at 08:27 +1100, Norberto Meijome wrote:
> Hi all,
> I'm rebuilding my kernel and I noticed some gcc (I believe ) options 
> being used that I don't think I set anyway.
> 
> The options are :
> -mno-mmx -mno-3dnow -mno-sse -mno-sse2
> 
> Does this mean that the kernel won't make use of these cpu features, 
> even though they are supported by the cpu (see below)
> 
> Thanks!
> Beto
> 
> ---- MORE INFO ----
> 
> They  seem to appear throughout the kernel build process, for example:
> 
> ---
> cc -O2 -fno-strict-aliasing -pipe -O2 -pipe -march=pentium-m 
> -DAHC_REG_PRETTY_PRINT=1 -Werror -D_KERNEL -DKLD_MODULE -nostdinc -I-   
> -DHAVE_KERNEL_OPTION_HEADERS -include 
> /usr/obj/usr/src/sys/AYIIN/opt_global.h -I. -I@ -I@/contrib/altq 
> -I@/../include -finline-limit=8000 -fno-common -g 
> -I/usr/obj/usr/src/sys/AYIIN -mno-align-long-strings 
> -mpreferred-stack-boundary=2  -mno-mmx -mno-3dnow -mno-sse -mno-sse2 
> -ffreestanding -Wall -Wredundant-decls -Wnested-externs 
> -Wstrict-prototypes  -Wmissing-prototypes -Wpointer-arith -Winline 
> -Wcast-qual  -fformat-extensions -std=c99 -c 
> /usr/src/sys/modules/aic7xxx/ahc/../../../dev/aic7xxx/aic7xxx.c
> 
> cc -O2 -fno-strict-aliasing -pipe -O2 -pipe -march=pentium-m 
> -DAHC_REG_PRETTY_PRINT=1 -Werror -D_KERNEL -DKLD_MODULE -nostdinc -I-   
> -DHAVE_KERNEL_OPTION_HEADERS -include 
> /usr/obj/usr/src/sys/AYIIN/opt_global.h -I. -I@ -I@/contrib/altq 
> -I@/../include -finline-limit=8000 -fno-common -g 
> -I/usr/obj/usr/src/sys/AYIIN -mno-align-long-strings 
> -mpreferred-stack-boundary=2  -mno-mmx -mno-3dnow -mno-sse -mno-sse2 
> -ffreestanding -Wall -Wredundant-decls -Wnested-externs 
> -Wstrict-prototypes  -Wmissing-prototypes -Wpointer-arith -Winline 
> -Wcast-qual  -fformat-extensions -std=c99 -c 
> /usr/src/sys/modules/aic7xxx/ahc/../../../dev/aic7xxx/aic7xxx_93cx6.c
> ---
> 
> from DMESG, my cpu is :
> ---
> CPU: Intel(R) Pentium(R) M processor 1.50GHz (1496.26-MHz 686-class CPU)
>   Origin = "GenuineIntel"  Id = 0x6d6  Stepping = 6
>   
> Features=0xafe9f9bf<FPU,VME,DE,PSE,TSC,MSR,MCE,CX8,SEP,MTRR,PGE,MCA,CMOV,PAT,CLFLUSH,DTS,ACPI,MMX,FXSR,SSE,SSE2,SS,TM,PBE>
>   Features2=0x180<EST,TM2>
> ---
> 
> My /etc/make.conf is:
> -----
> BOOTWAIT=4000
> 
> SUP_UPDATE="YES"
> SUP="/usr/local/bin/cvsup"
> SUPFILE="/usr/local/etc/stable-supfile"
> PORTSSUPFILE="/usr/local/etc/ports-supfile"
> 
> ENABLE_WPA_SUPPLICANT_EAPOL=true
> NO_PROFILE=true
> NO_INET6=true
> NO_PORTSUPDATE=true
> NO_ATM=true
> 
> X_WINDOW_SYSTEM=xorg
> 
> DOC_LANG = en_US.ISO8859-1
> 
> CPUTYPE?=pentium-m
> CFLAGS+= -O2 -pipe
> # added by use.perl 2006-01-24 12:09:58
> PERL_VER=5.8.7
> PERL_VERSION=5.8.7
> 
> WITH_MOZILLA="firefox"
> WITH_FAM_SYSTEM=fam
> ----

I am curious about this as well... I searched the mailing list arhives,
and googled for a bit, but didn't really come up with anything useful.
Anyone have any pointers to the discussion that was mentioned
previously?