[Mesa-dev] [PATCH] ir_to_mesa: Don't optimize clamp into saturate when target is GL_VERTEX_PROGRAM_ARB

[Thomas Helland]

This addresses the potential issue I was worried about when I worked on
my patch series for expanding get_range that I sent a while back.
With the "the the " in the commit message fixed:

Reviewed-by: Thomas Helland <thomashelland90 at gmail.com>

This conflicts with my series, but I'll need to do some work on it
either way so I'll rebase on top of this once it hits master.

2014-11-27 9:45 GMT+01:00 Abdiel Janulgue <abdiel.janulgue at linux.intel.com>:
> Add the the same restriction as in the previous try_emit_sat when trying
> to optimize clamp. Fixes an infinite loop in swrast where the lowering
> pass unpacks saturate into clamp but the opt_algebraic pass tries to do
> the opposite.
>
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=83463
>
> Tested-by: Vinson Lee <vlee at freedesktop.org>
> Signed-off-by: Abdiel Janulgue <abdiel.janulgue at linux.intel.com>
> ---
>  src/glsl/opt_algebraic.cpp      | 3 ++-
>  src/mesa/main/mtypes.h          | 1 +
>  src/mesa/program/ir_to_mesa.cpp | 3 ++-
>  3 files changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/src/glsl/opt_algebraic.cpp b/src/glsl/opt_algebraic.cpp
> index 430f5cb..62b14dd 100644
> --- a/src/glsl/opt_algebraic.cpp
> +++ b/src/glsl/opt_algebraic.cpp
> @@ -679,7 +679,8 @@ ir_algebraic_visitor::handle_expression(ir_expression *ir)
>
>     case ir_binop_min:
>     case ir_binop_max:
> -      if (ir->type->base_type != GLSL_TYPE_FLOAT)
> +      if (ir->type->base_type != GLSL_TYPE_FLOAT ||
> +         options->EmitNoSat)
>           break;
>
>        /* Replace min(max) operations and its commutative combinations with
> diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
> index 7389baa..199443a 100644
> --- a/src/mesa/main/mtypes.h
> +++ b/src/mesa/main/mtypes.h
> @@ -2990,6 +2990,7 @@ struct gl_shader_compiler_options
>     GLboolean EmitNoMainReturn;            /**< Emit CONT/RET opcodes? */
>     GLboolean EmitNoNoise;                 /**< Emit NOISE opcodes? */
>     GLboolean EmitNoPow;                   /**< Emit POW opcodes? */
> +   GLboolean EmitNoSat;
>     GLboolean LowerClipDistance; /**< Lower gl_ClipDistance from float[8] to vec4[2]? */
>
>     /**
> diff --git a/src/mesa/program/ir_to_mesa.cpp b/src/mesa/program/ir_to_mesa.cpp
> index 5cd9058..44fd315 100644
> --- a/src/mesa/program/ir_to_mesa.cpp
> +++ b/src/mesa/program/ir_to_mesa.cpp
> @@ -2935,7 +2935,7 @@ _mesa_ir_link_shader(struct gl_context *ctx, struct gl_shader_program *prog)
>
>        bool progress;
>        exec_list *ir = prog->_LinkedShaders[i]->ir;
> -      const struct gl_shader_compiler_options *options =
> +      struct gl_shader_compiler_options *options =
>              &ctx->Const.ShaderCompilerOptions[prog->_LinkedShaders[i]->Stage];
>
>        do {
> @@ -2949,6 +2949,7 @@ _mesa_ir_link_shader(struct gl_context *ctx, struct gl_shader_program *prog)
>                                  | ((options->EmitNoPow) ? POW_TO_EXP2 : 0)
>                                  | ((target == GL_VERTEX_PROGRAM_ARB) ? SAT_TO_CLAMP
>                                      : 0)));
> +         options->EmitNoSat = (target == GL_VERTEX_PROGRAM_ARB);
>
>          progress = do_lower_jumps(ir, true, true, options->EmitNoMainReturn, options->EmitNoCont, options->EmitNoLoops) || progress;
>
> --
> 1.9.1
>
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