[cfe-dev] [LLVMdev] SPIR Portability Discussion

[Villmow, Micah]

> -----Original Message-----
> From: Eli Friedman [mailto:eli.friedman at gmail.com]
> Sent: Wednesday, September 12, 2012 3:22 PM
> To: Villmow, Micah
> Cc: Richard Smith; cfe-dev at cs.uiuc.edu; llvmdev at cs.uiuc.edu
> Subject: Re: [cfe-dev] [LLVMdev] SPIR Portability Discussion
> 
> On Wed, Sep 12, 2012 at 2:58 PM, Villmow, Micah <Micah.Villmow at amd.com>
> wrote:
> > Another factor to consider, with size_t etc as defined in SPIR, is
> the usual
> > arithmetic conversions. For instance (assuming a 64-bit long long),
> > sizeof(int) + 1LL would be signed if size_t is 32 bits wide, and
> would be
> > unsigned if size_t is 64 bits wide. How is this handled?
> >
> > [Villmow, Micah] OpenCL C defines 'int' to be 32bits irrespective of
> the
> > host/device bitness. So this would follow the normal integer
> promotion
> > rules.
> 
> I think you're misunderstanding the issue: the point is, is
> "sizeof(int) + -8LL < 0" true or false?
[Villmow, Micah] Yep, I don't see why this is any different than "4 + -8LL < 0".  OpenCL C, and in turn SPIR, defines sizeof(int) == 4. While this might be a problem in C, this isn't an issue in OpenCL since there is no variance in the sizeof(int) across devices.
> 
> -Eli