[Cbe-oss-dev] [PATCH] force -mno-string option on cell

Segher Boessenkool segher at kernel.crashing.org
Sat Mar 24 03:35:22 EST 2007

> Nack.  If GCC is now putting string instructions even if you don't 
> specify -mstring than we also need this for CONFIG_FSL_BOOKE.  Please 
> fix that up as well.

In the absence of -mstring and -mno-string options,
GCC will default to either on or off based on other
options (CPU model, mostly).  This is good behaviour
since it intends to give you the best code sequences
for whatever CPU you selected (or for a blended CPU
model etc).

This isn't new GCC behaviour at all.

If a specific piece of code really needs to be
generated without string insns, you should set the
option in the CFLAGS for that code only.

I don't know what the issue is for FSL BookE; if those
CPUs cannot run string insns in supervisor mode, then
you should indeed have -mno-string globally -- but that
is not the case AFAICS.


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