patch: disable string insns on ppc e500

[Aldy Hernandez]

>
> Richard> You should be checking target_flags_explicit here, not 
> target_flags.
>
> 	The PowerPC port adds MASK_MULTIPLE and MASK_STRING to
> target_flags if optimizing for size, so target_flags is the right 
> variable
> to test.  This is not just disabling MASK_STRING set by the user, 
> although
> the user also could set it.

Exactly.

>
> 	Aldy could add a test checking for E500 before enabling
> MASK_STRING when optimizing for size, and separately disable it if not
> explicitly set.  Or test both target_flags and target_flags_explicit.

Not exactly because the CPU is set in eabispe.h's 
SUBSUBTARGET_OVERRIDE_OPTIONS, which isn't defined until the code in 
question.  My check has to come right after SUBSUBTARGET*, or the set 
of MASK_STRING has to come after SUBSUBTARGET*.

Aldy