PATCH: PR target/34001: Incorrect x86 fastcall behavior

[Mark Mitchell]

Richard Guenther wrote:

>> But it isn't clear if it applies to structure/union. We tested all MS
>> compilers we have and verified that the above doesn't apply to
>> structure/union.  To make fastcall compatible with MS compilers, we
>> should only put scalar arguments in ECX and EDX.
> 
> This would be an ABI change from previous releases.  Regardless of
> whether we want to do this, an entry for the 4.3 changes document
> should be added.

I would suggest that this be done only on Windows, if it's for MS
compatibility.  Unless the code before is actually broken, why should
make a incompatible ABI change?  At least, we should add a switch.

-- 
Mark Mitchell
CodeSourcery
mark@codesourcery.com
(650) 331-3385 x713