How can I force float->double promotion for argument passing on PPC?

[Franz Sirl]

Hi,

it turns out that the implementation of the PPC SYSV ABI in gcc still contains
a bug, float parameters passed on the stack are currently not promoted to
double. as specified in the ABI.

It seems using PROMOTE_MODE is not quite right here? I only want the promotion
if the args are passed on the stack.

Any ideas on how to tackle that?

Franz.