[Mesa-dev] [PATCH] nvc0/ir: fix predication when the surface format doesn't mismatch

[Ilia Mirkin]

On Fri, May 20, 2016 at 11:03 AM, Samuel Pitoiset
<samuel.pitoiset at gmail.com> wrote:
> Initially to make sure the format doesn't mismatch and won't produce
> out-of-bounds access, we checked that both formats have exactly the same
> number of bytes. But this is actually wrong because the format specified
> in the shader might be smaller. While we are at it, add the predicate
> only when the number of components is not 0 instead of checking the
> blocksize.

Can you explain? I believe the format in shader has to match the
format of the bound image.

Separately, perhaps only do this check for reads/atomics, and not
writes? (Since for writes, we don't really care, since the hw does
it.)

>
> This fixes serious rendering issues in the UE4 demos (tested with
> realistic and reflections).
>
> Signed-off-by: Samuel Pitoiset <samuel.pitoiset at gmail.com>
> ---
>  src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nvc0.cpp | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nvc0.cpp b/src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nvc0.cpp
> index a1823a0..90578f5 100644
> --- a/src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nvc0.cpp
> +++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nvc0.cpp
> @@ -1839,9 +1839,9 @@ NVC0LoweringPass::processSurfaceCoordsNVE4(TexInstruction *su)
>        int blockwidth = format->bits[0] + format->bits[1] +
>                         format->bits[2] + format->bits[3];
>
> -      if (blockwidth >= 8) {
> +      if (format->components != 0) {
>           // make sure that the format doesn't mismatch
> -         bld.mkCmp(OP_SET_OR, CC_NE, TYPE_U32, pred1->getDef(0),
> +         bld.mkCmp(OP_SET_OR, CC_GT, TYPE_U32, pred1->getDef(0),
>                     TYPE_U32, bld.loadImm(NULL, blockwidth / 8),
>                     loadSuInfo32(ind, base + NVE4_SU_INFO_BSIZE),
>                     pred1->getDef(0));
> --
> 2.8.2
>
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