[Bug target/58269] [4.9 Regression] ICE when building libobjc on x86_64-apple-darwin* after revision 201915

["iains at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58269

--- Comment #7 from Iain Sandoe <iains at gcc dot gnu.org> ---
(In reply to tocarip.intel from comment #6)
> -                || (TARGET_SSE && SSE_REGNO_P (regno) &&

> Those changes are not needed. If TARGET_64BIT is fasle all sse registers
> except xmm0-xmm7 should be fixed. Correct fix is 

<snip>

> Looks like this will break ABI. Before we returned true for e. g. xmm10.

indeed, that was worrying me too.

> I couldn't find Darwin ABI to check which behaivor is correct.

The ABI for [x86_64] Darwin *should be* the same as 
"System V Application Binary Interface AMD64 Architecture Processor Supplement
Draft Version 0.99.5"

it is possible that:
(a) GCC has been broken a while and this is just not covered by the test-suite.
(b) the system ABI has deviated from the referenced document.

However - regardless of the doc, the system ABI is effectively defined by
Apple's GCC-4.2.1 (or successor clang, where that is not the system default).

> If we want to keep current behaivor something like 

<snip> 

> Should work.

I will apply your revised patch (and keep the second amendment in reserve) and
do some compat tests to find out what we need to do to be compliant with the
system

thanks for the patch, iain.