[Bug target/47977] powerpc (-mcpu=8548) Wrong code for double operations in little endian mode

["joseph at codesourcery dot com" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47977

--- Comment #4 from joseph at codesourcery dot com <joseph at codesourcery dot com> 2011-03-04 15:35:20 UTC ---
On Fri, 4 Mar 2011, m.lazzarotto at robox dot it wrote:

> My target is effectively an e500v2.
> I also tried to pass -mabi=spe, with no difference in the output.
> Is using --enable-e500-double compile-time equivalent to use -mdouble-float
> runtime?

It is roughly equivalent to -mfloat-gprs=double - but it may not work 
sensibly except for the e500-specific targets such as powerpc-eabispe.  
And this is only useful with -mabi=spe.  e500v2 should follow the 
soft-float ABI (in particular, double arguments are passed in two GPRs, 
not one; the only time all 64 bits of a GPR are used for argument passing 
or return is for SPE vectors).  Because of the error-prone nature of 
passing all the required options manually, I advise configuring for 
powerpc-eabispe.