[Mesa-dev] [PATCH 18/23] i965: Add a brw->scalar_gs flag controlled by INTEL_SCALAR_GS=1.

[Kenneth Graunke]

This patch introduces a brw->scalar_gs flag, similar to brw->scalar_vs,
which controls whether or not to use SIMD8 geometry shaders.

For now, we control it via a new environment variable, INTEL_SCALAR_GS.
This provides a convenient way to try it out.

Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
---
 src/mesa/drivers/dri/i965/brw_shader.cpp | 8 ++++++++
 src/mesa/drivers/dri/i965/brw_shader.h   | 1 +
 2 files changed, 9 insertions(+)

diff --git a/src/mesa/drivers/dri/i965/brw_shader.cpp b/src/mesa/drivers/dri/i965/brw_shader.cpp
index 60300bc..dd83a60 100644
--- a/src/mesa/drivers/dri/i965/brw_shader.cpp
+++ b/src/mesa/drivers/dri/i965/brw_shader.cpp
@@ -87,6 +87,9 @@ brw_compiler_create(void *mem_ctx, const struct brw_device_info *devinfo)
    if (devinfo->gen >= 8 && !(INTEL_DEBUG & DEBUG_VEC4VS))
       compiler->scalar_vs = true;
 
+   if (devinfo->gen >= 8 && brw_env_var_as_boolean("INTEL_SCALAR_GS", false))
+      compiler->scalar_gs = true;
+
    nir_shader_compiler_options *nir_options =
       rzalloc(compiler, nir_shader_compiler_options);
    nir_options->native_integers = true;
@@ -127,6 +130,9 @@ brw_compiler_create(void *mem_ctx, const struct brw_device_info *devinfo)
       case MESA_SHADER_VERTEX:
          is_scalar = compiler->scalar_vs;
          break;
+      case MESA_SHADER_GEOMETRY:
+         is_scalar = compiler->scalar_gs;
+         break;
       default:
          is_scalar = false;
          break;
@@ -199,6 +205,8 @@ is_scalar_shader_stage(struct brw_context *brw, int stage)
    case MESA_SHADER_FRAGMENT:
    case MESA_SHADER_COMPUTE:
       return true;
+   case MESA_SHADER_GEOMETRY:
+      return brw->intelScreen->compiler->scalar_gs;
    case MESA_SHADER_VERTEX:
       return brw->intelScreen->compiler->scalar_vs;
    default:
diff --git a/src/mesa/drivers/dri/i965/brw_shader.h b/src/mesa/drivers/dri/i965/brw_shader.h
index ccccf4d..fd087dd 100644
--- a/src/mesa/drivers/dri/i965/brw_shader.h
+++ b/src/mesa/drivers/dri/i965/brw_shader.h
@@ -92,6 +92,7 @@ struct brw_compiler {
    void (*shader_perf_log)(void *, const char *str, ...) PRINTFLIKE(2, 3);
 
    bool scalar_vs;
+   bool scalar_gs;
    struct gl_shader_compiler_options glsl_compiler_options[MESA_SHADER_STAGES];
 };
 
-- 
2.5.3