[Mesa-stable] [Mesa-dev] [PATCH 2/2] glsl: Relax ir_quadop_bitfield_insert type restrictions.

[Ilia Mirkin]

On Tue, Jan 5, 2016 at 8:34 AM, Kenneth Graunke <kenneth at whitecape.org> wrote:
> While GLSL restricts bitfieldInsert's offset and bits parameters to
> be scalars, we shouldn't require this in the IR.
>
> In particular, opt_vectorize() tries to combine
>
> result.x = bitfieldInsert(src0.x, src1.x, src2.x, src3.x);
> result.y = bitfieldInsert(src0.y, src1.y, src2.y, src3.y);
> result.z = bitfieldInsert(src0.z, src1.z, src2.z, src3.z);
> result.w = bitfieldInsert(src0.w, src1.w, src2.w, src3.w);
>
> into a single ivec4 bitfieldInsert operation.  This currently breaks,
> because the last two types become ivec4 rather than int.  It seems
> perfectly reasonable to allow this.

Might I recommend also giving this treatment to
ir_triop_bitfield_extract? It seems like it would suffer from the same
failure with opt_vectorize.

>
> i965 lowers ir_quadop_bitfield_insert to ir_binop_bfm and ir_triop_bfi,
> which already lift these restrictions.
>
> (I debated about using is_integer() or base_type == GLSL_TYPE_INT here;
> I ended up relaxing it to allow either int/uint because ir_binop_bfm
> and ir_triop_bfi do that already.)
>
> Fixes assertion failures when compiling Shadow of Mordor vertex shaders
> on i965 in vec4 mode (where OptimizeForAOS enables opt_vectorize()).
>
> Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
> Cc: Matt Turner <mattst88 at gmail.com>
> Cc: mesa-stable at lists.freedesktop.org
> ---
>  src/glsl/ir_validate.cpp | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/src/glsl/ir_validate.cpp b/src/glsl/ir_validate.cpp
> index dcc079c..b5eaaff 100644
> --- a/src/glsl/ir_validate.cpp
> +++ b/src/glsl/ir_validate.cpp
> @@ -661,8 +661,8 @@ ir_validate::visit_leave(ir_expression *ir)
>     case ir_quadop_bitfield_insert:
>        assert(ir->operands[0]->type == ir->type);
>        assert(ir->operands[1]->type == ir->type);
> -      assert(ir->operands[2]->type == glsl_type::int_type);
> -      assert(ir->operands[3]->type == glsl_type::int_type);
> +      assert(ir->operands[2]->type->is_integer());
> +      assert(ir->operands[3]->type->is_integer());
>        break;
>
>     case ir_quadop_vector:
> --
> 2.6.4
>
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