nir: Fix divergence analysis for tessellation input/outputs

The load_per_vertex_{input,output} intrinsics simply mean that they're
reading an arrayed input/output, which have one element per invocation.
Most accesses to those use gl_InvocationID as the subscript.  However,
it's totally possible to read any element of the array.  For example,
an evaluation shader might read gl_in[2].gl_Position, or a control
shader might read output[0].

For threads processing a single patch, an input/output load is
convergent if and only if both sources (the per-vertex-array subscript
and the offset) are convergent.  For threads processing multiple
patches, we continued to mark them divergent.

Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Acked-by: Daniel Schürmann <daniel@schuermann.dev>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5613>
This commit is contained in:
Kenneth Graunke
2020-05-05 11:03:12 -07:00
committed by Marge Bot
parent 8278a46b26
commit 6a5fb31fef

View File

@@ -145,6 +145,16 @@ visit_intrinsic(nir_intrinsic_instr *instr, struct divergence_state *state)
else
is_divergent = true;
break;
case nir_intrinsic_load_per_vertex_input:
is_divergent = instr->src[0].ssa->divergent ||
instr->src[1].ssa->divergent;
if (stage == MESA_SHADER_TESS_CTRL)
is_divergent |= !(options & nir_divergence_single_patch_per_tcs_subgroup);
if (stage == MESA_SHADER_TESS_EVAL)
is_divergent |= !(options & nir_divergence_single_patch_per_tes_subgroup);
else
is_divergent = true;
break;
case nir_intrinsic_load_input_vertex:
is_divergent = instr->src[1].ssa->divergent;
assert(stage == MESA_SHADER_FRAGMENT);
@@ -158,6 +168,12 @@ visit_intrinsic(nir_intrinsic_instr *instr, struct divergence_state *state)
else
is_divergent = true;
break;
case nir_intrinsic_load_per_vertex_output:
assert(stage == MESA_SHADER_TESS_CTRL);
is_divergent = instr->src[0].ssa->divergent ||
instr->src[1].ssa->divergent ||
!(options & nir_divergence_single_patch_per_tcs_subgroup);
break;
case nir_intrinsic_load_layer_id:
case nir_intrinsic_load_front_face:
assert(stage == MESA_SHADER_FRAGMENT);
@@ -302,8 +318,6 @@ visit_intrinsic(nir_intrinsic_instr *instr, struct divergence_state *state)
case nir_intrinsic_load_sample_pos:
case nir_intrinsic_load_vertex_id_zero_base:
case nir_intrinsic_load_vertex_id:
case nir_intrinsic_load_per_vertex_input:
case nir_intrinsic_load_per_vertex_output:
case nir_intrinsic_load_instance_id:
case nir_intrinsic_load_invocation_id:
case nir_intrinsic_load_local_invocation_id: