[Mesa-dev] [PATCH 01/13] nir: allow 64 bit shifts

[Jason Ekstrand]

On Wed, Feb 28, 2018 at 1:18 PM, Karol Herbst <kherbst at redhat.com> wrote:

> On Wed, Feb 28, 2018 at 9:46 PM, Jason Ekstrand <jason at jlekstrand.net>
> wrote:
> > I do not think this patch does what you think it does.  The old opcode
> > allowed you to shift any bit size integer by a 32-bit integer.  The new
> > version allows you to shift N bits by N bits.  In particular, you can't
> > shift a 16-bit by a 32-bit value.
> >
> > I'm not sure what the best thing is to do here.  Really, the size of src1
> > doesn't really matter as 8-bit is enough to do any shifting needed for a
> > 64-bit src0.  You can always compose with a u2u32 to get any src1 bit
> size
> > you want.  We picked 32 because it's been the GL default for a long time.
> >
>
> Well the thing is we ended up with a shift in spirv having two 64 bit
> parameters. Maybe we could just put a convert in it for such cases?
>

I think the quick, easy, and correct solution is to make spirv_to_nir
insert a u2u32 if src1 isn't a 32-bit type.

--Jason


> > On Wed, Feb 28, 2018 at 11:51 AM, Rob Clark <robdclark at gmail.com> wrote:
> >>
> >> From: Karol Herbst <kherbst at redhat.com>
> >>
> >> This is a thing for OpenCL kernels.
> >>
> >> Signed-off-by: Rob Clark <robdclark at gmail.com>
> >> ---
> >>  src/compiler/nir/nir_opcodes.py | 6 +++---
> >>  1 file changed, 3 insertions(+), 3 deletions(-)
> >>
> >> diff --git a/src/compiler/nir/nir_opcodes.py
> >> b/src/compiler/nir/nir_opcodes.py
> >> index 278562b2bd1..c4d2c7805eb 100644
> >> --- a/src/compiler/nir/nir_opcodes.py
> >> +++ b/src/compiler/nir/nir_opcodes.py
> >> @@ -479,9 +479,9 @@ binop("seq", tfloat32, commutative, "(src0 == src1)
> ?
> >> 1.0f : 0.0f") # Set on Equ
> >>  binop("sne", tfloat32, commutative, "(src0 != src1) ? 1.0f : 0.0f") #
> Set
> >> on Not Equal
> >>
> >>
> >> -opcode("ishl", 0, tint, [0, 0], [tint, tuint32], "", "src0 << src1")
> >> -opcode("ishr", 0, tint, [0, 0], [tint, tuint32], "", "src0 >> src1")
> >> -opcode("ushr", 0, tuint, [0, 0], [tuint, tuint32], "", "src0 >> src1")
> >> +opcode("ishl", 0, tint, [0, 0], [tint, tuint], "", "src0 << src1")
> >> +opcode("ishr", 0, tint, [0, 0], [tint, tuint], "", "src0 >> src1")
> >> +opcode("ushr", 0, tuint, [0, 0], [tuint, tuint], "", "src0 >> src1")
> >>
> >>  # bitwise logic operators
> >>  #
> >> --
> >> 2.14.3
> >>
> >
>
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