On 12/04/2014 01:54 AM, Richard Biener wrote: > Apart from what Joseph already said using 'sizetype' in the middle-end > for sizes and offsets is really really deep-rooted into the compiler. > What you see above is one aspect - POINTER_PLUS_EXPR offsets > are forced to have sizetype type. But you'd also see it in the inability > to create larger than sizetype objects (DECL_SIZE_UNITs type). > > So for the middle-end part I'd suggest you make sure that sizetype > covers the largest pointer-mode precision your target offers. That of course > doesn't fix what Joseph pointed out - that the user will still run into issues > when writing C programs or when using the C runtime (I suppose TR 18037 > doesn't specify alternate memcpy for different address spaces?)
I'd prefer it if the middle-end were more flexible about what types it allows for the offset of POINTER_PLUS_EXPR. E.g. any integer type of an appropriate mode. I'd expect the right answer is to match targetm.addr_space.address_mode rather than .pointer_mode, so that any extension, if necessary, is already exposed to the optimizers. But I suppose it's also possible that might pessimize things for these weird targets... r~
