[Bug target/47977] powerpc (-mcpu=8548) Wrong code for double operations in little endian mode
joseph at codesourcery dot com
gcc-bugzilla@gcc.gnu.org
Fri Mar 4 15:35:00 GMT 2011
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.
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