[Mesa-dev] [PATCH 11/21] glsl: Store ir_variable::ir_type in 8 bits instead of 32

[Patrick Baggett]

On Wed, May 28, 2014 at 2:17 PM, Ian Romanick <idr at freedesktop.org> wrote:

> On 05/27/2014 08:28 PM, Matt Turner wrote:
> > On Tue, May 27, 2014 at 7:49 PM, Ian Romanick <idr at freedesktop.org>
> wrote:
> >> From: Ian Romanick <ian.d.romanick at intel.com>
> >>
> >> No change in the peak ir_variable memory usage in a trimmed apitrace of
> >> dota2 on 64-bit.
> >>
> >> No change in the peak ir_variable memory usage in a trimmed apitrace of
> >> dota2 on 32-bit.
> >>
> >> Signed-off-by: Ian Romanick <ian.d.romanick at intel.com>
> >> ---
> >>  src/glsl/ir.h | 5 +++--
> >>  1 file changed, 3 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/src/glsl/ir.h b/src/glsl/ir.h
> >> index 7faee74..bc02f6e 100644
> >> --- a/src/glsl/ir.h
> >> +++ b/src/glsl/ir.h
> >> @@ -92,12 +92,13 @@ enum ir_node_type {
> >>   */
> >>  class ir_instruction : public exec_node {
> >>  private:
> >> -   enum ir_node_type ir_type;
> >> +   uint8_t ir_type;
> >>
> >>  public:
> >>     inline enum ir_node_type get_ir_type() const
> >>     {
> >> -      return this->ir_type;
> >> +      STATIC_ASSERT(ir_type_max < 256);
> >> +      return (enum ir_node_type) this->ir_type;
> >>     }
> >>
> >>     /**
> >> --
> >> 1.8.1.4
> >
> > Instead of doing this, you can mark the enum type with the PACKED
> > attribute. I did this in a similar change in i965 already. See
> > http://lists.freedesktop.org/archives/mesa-dev/2014-February/054643.html
> >
> > This way we still get enum type checking and warnings out of switch
> > statements and such.
>
> Hmm... that would mean that patch 10 wouldn't strictly be necessary.
> The disadvantage is that the next patch would need (right?) some changes
> for MSVC, especially on 32-bit.  I think it would need to be
>
> #if sizeof(ir_node_type) < sizeof(void *)
>

I don't think the preprocessor can evaluate sizeof().


> # define PADDING_BYTES (sizeof(void *) - sizeof(ir_node_type))
> #else
> # define PADDING_BYTES sizeof(void *)
> #  if (__GNUC__ >= 3)
> #    error "GCC did us wrong."
> #  endif
> #endif
>
>   uint8_t padding[PADDING_BYTES];
>
> Seems a little sketchy, but might still be better... hmm...
> _______________________________________________
> mesa-dev mailing list
> mesa-dev at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/mesa-dev
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.freedesktop.org/archives/mesa-dev/attachments/20140528/1225ad02/attachment.html>