[Clfs-dev] EGLIBC x86 is special?

[William Harrington]

On Jul 12, 2013, at 12:14 PM, Andrew Bradford wrote:

> OK, but when setting -march= to i386, i486, or i686 isn't the goal to
> not support a processor that's older?

-march is set to $CLFS_TARGET32

-mtune generic I think is there so as to not upset testsuite outcomes.  
I read throughout the whole thread and ran across that if I recall  
correctly.

Also when i686 is used wtih mtune, it also means generic so mtune=i686  
would also mean mtune=generic:

 From the GCC documentation:

‘i686’
When used with -march, the Pentium Pro instruction set is used, so the  
code runs on all i686 family chips. When used with -mtune, it has the  
same meaning as ‘generic’.


We could leave out mtune altogether as march implies mtune. This is  
not the same for i486, i586, pentium, pentium-mmx.

{E,}GLIBC's default optimizations are as follows:

# Default flags to pass the C compiler.
ifndef default_cflags
ifeq ($(release),stable)
default_cflags := -g -O2
else
default_cflags := -g -O
endif
endif

So yes I think we could remove those from the CFLAGS line. We should  
stick with the defaults and let the user decide their own optimizations.

Sincerely,

William Harrington


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