intel/compiler: Be more conservative about subgroup sizes in GL

The rules for gl_SubgroupSize in Vulkan require that it be a constant
that can be queried through the API.  However, all GL requires is that
it's a uniform.  Instead of always claiming that the subgroup size in
the shader is 32 in GL like we have to do for Vulkan, claim 8 for
geometry stages, the maximum for fragment shaders, and the actual size
for compute.

Reviewed-by: Caio Marcelo de Oliveira Filho <[email protected]>

1 files changed, 4 insertions, 2 deletions

diff --git a/src/intel/compiler/brw_fs.cpp b/src/intel/compiler/brw_fs.cpp
index 30e04ddc318..4ab50aad11f 100644
--- a/src/intel/compiler/brw_fs.cpp
+++ b/src/intel/compiler/brw_fs.cpp
@@ -7967,7 +7967,9 @@ brw_compile_fs(const struct brw_compiler *compiler, void *log_data,
 {
    const struct gen_device_info *devinfo = compiler->devinfo;
 
-   brw_nir_apply_key(shader, compiler, &key->base, true);
+   unsigned max_subgroup_size = unlikely(INTEL_DEBUG & DEBUG_DO32) ? 32 : 16;
+
+   brw_nir_apply_key(shader, compiler, &key->base, max_subgroup_size, true);
    brw_nir_lower_fs_inputs(shader, devinfo, key);
    brw_nir_lower_fs_outputs(shader);
 
@@ -8228,7 +8230,7 @@ compile_cs_to_nir(const struct brw_compiler *compiler,
                   unsigned dispatch_width)
 {
    nir_shader *shader = nir_shader_clone(mem_ctx, src_shader);
-   brw_nir_apply_key(shader, compiler, &key->base, true);
+   brw_nir_apply_key(shader, compiler, &key->base, dispatch_width, true);
 
    NIR_PASS_V(shader, brw_nir_lower_cs_intrinsics, dispatch_width);