Enabling -frename-registers?

[Bernd Schmidt]

On 05/04/2016 11:05 AM, Alan Modra wrote:
> I agree it's good to find these things..  Another nasty bug to add to
> the list is complete breakage of gccgo on powerpc64le.  I see register
> renaming around the prologue call to __morestack, which trashes
> function arguments.

How does this come about, is there something incorrect about the RTL 
representation of __morestack?


Bernd