[Mesa-dev] [PATCH] glsl: Don't convert reductions of ivec to a dot-product

[Kenneth Graunke]

On Tuesday, June 24, 2014 07:15:00 PM Ian Romanick wrote:
> From: Ian Romanick <ian.d.romanick at intel.com>
> 
> Mesa has an optimization that converts expressions like "v.x + v.y + v.z
> + v.w" into dot(v, 1.0).  And therein lies the rub: the other operand to
> the dot-product is always a float... even if the vector is an ivec or
> uvec.  This results in an assertion failure in ir_builder.
> 
> If the base type of the operand is not float, don't try the
> optimization.  Dot-product is not valid on integer data.
> 
> Fixes piglit vs-integer-reduction.shader_test and OpenGL ES conformance
> test ES2-CTS.gtf.GL2Tests.glGetUniform.glGetUniform.
> 
> Signed-off-by: Ian Romanick <ian.d.romanick at intel.com>
> Cc: Matt Turner <mattst88 at gmail.com>
> ---
>  src/glsl/opt_algebraic.cpp | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/src/glsl/opt_algebraic.cpp b/src/glsl/opt_algebraic.cpp
> index 448af6b..ac7514a 100644
> --- a/src/glsl/opt_algebraic.cpp
> +++ b/src/glsl/opt_algebraic.cpp
> @@ -124,7 +124,9 @@ static ir_expression *
>  try_replace_with_dot(ir_expression *expr0, ir_expression *expr1, void 
*mem_ctx)
>  {
>     if (expr0 && expr0->operation == ir_binop_add &&
> -       expr1 && expr1->operation == ir_binop_add) {
> +       expr0->type->is_float() &&
> +       expr1 && expr1->operation == ir_binop_add &&
> +       expr1->type->is_float()) {
>        ir_swizzle *x = expr0->operands[0]->as_swizzle();
>        ir_swizzle *y = expr0->operands[1]->as_swizzle();
>        ir_swizzle *z = expr1->operands[0]->as_swizzle();
> 

Nice catch!

Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>
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