Re: LTO remapping/deduction of machine modes of types/decls

[Richard Biener <rguenther@suse.de>]

On Mon, 2 Jan 2017, Jakub Jelinek wrote:

> On Mon, Jan 02, 2017 at 09:49:55PM +0300, Alexander Monakov wrote:
> > On Mon, 2 Jan 2017, Jakub Jelinek wrote:
> > > If the host has long double the same as double, sure, PTX can use its native
> > > DFmode even for long double.  But otherwise, the storage must be
> > > transferable between accelerator and host.
> > 
> > Hm, sorry, the 'must' is not obvious to me: is it known that the OpenMP ARB
> > would find only this implementation behavior acceptable?
> 
> long double is not non-mappable type in the spec, so it is supposed to work.
> The implementation may choose not to offload whenever it sees long
> double/__float128/_Float128/_Float128x etc.
> 
> > Apart from floating-point types, are there other situations where modes carry
> > information not deducible from the rest of the tree node?
> 
> Dunno about fixed types, partial ints etc., but it is mostly floating point
> types, sure.

Mostly floats I guess.  But just to say it would be very nice to have
enough information in the trees so layout_type can re-construct the
mode.  It already does for 99% of the types...  (just grep for
SET_TYPE_MODE).

Richard.