[Nouveau] [PATCH] nouveau: codegen: Take src swizzle into account on loads

[Ilia Mirkin]

That's wrong. The spec for the instruction needs to be clarified...
The current nouveau impl is correct - only the .x of the address
should be loaded, with up to 16 bytes read into the destination.

On Thu, Apr 7, 2016 at 9:27 AM, Hans de Goede <hdegoede at redhat.com> wrote:
> The llvm TGSI backend does things like:
>
> LOAD TEMP[0].y, MEMORY[0].xxxx, TEMP[0].x
>
> Expecting the data at address TEMP[0].x to get loaded to
> TEMP[0].y. Before this commit the data at TEMP[0].x + 4 would be
> loaded instead. This commit fixes this.
>
> Signed-off-by: Hans de Goede <hdegoede at redhat.com>
> ---
>  src/gallium/drivers/nouveau/codegen/nv50_ir_from_tgsi.cpp | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_from_tgsi.cpp b/src/gallium/drivers/nouveau/codegen/nv50_ir_from_tgsi.cpp
> index 557608e..cc51f5a 100644
> --- a/src/gallium/drivers/nouveau/codegen/nv50_ir_from_tgsi.cpp
> +++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_from_tgsi.cpp
> @@ -2279,12 +2279,16 @@ Converter::handleLOAD(Value *dst0[4])
>
>           Value *off = fetchSrc(1, c);
>           Symbol *sym;
> +         uint32_t src0_component_offset = tgsi.getSrc(0).getSwizzle(c) * 4;
> +
>           if (tgsi.getSrc(1).getFile() == TGSI_FILE_IMMEDIATE) {
>              off = NULL;
>              sym = makeSym(tgsi.getSrc(0).getFile(), r, -1, c,
> -                          tgsi.getSrc(1).getValueU32(0, info) + 4 * c);
> +                          tgsi.getSrc(1).getValueU32(0, info) +
> +                          src0_component_offset);
>           } else {
> -            sym = makeSym(tgsi.getSrc(0).getFile(), r, -1, c, 4 * c);
> +            sym = makeSym(tgsi.getSrc(0).getFile(), r, -1, c,
> +                          src0_component_offset);
>           }
>
>           Instruction *ld = mkLoad(TYPE_U32, dst0[c], sym, off);
> --
> 2.7.3
>