[Mesa-dev] [PATCH] nir/gather_info: Handle double inputs in set_io_mask

[Jason Ekstrand]

It's a little sketchy to put the logic in set_io_mask but due to a
detail of the GLSL spec, it's safe to check for 64-bit without knowing
the full access chain.  This fixes a bug where try_mask_partial_io
succeeded at marking a portion of the input as used but then we came
along and marked the whole thing in double_inputs_read.  By putting it
in set_io_mask, we get the correct flagging even for partial reads.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=103241
Cc: mesa-stable at lists.freedesktop.org
Cc: Timothy Arceri <tarceri at itsqueeze.com>
Cc: Alejandro Piñeiro <apinheiro at igalia.com>
---
 src/compiler/nir/nir_gather_info.c | 28 +++++++++++++++++-----------
 1 file changed, 17 insertions(+), 11 deletions(-)

diff --git a/src/compiler/nir/nir_gather_info.c b/src/compiler/nir/nir_gather_info.c
index 9469396..bab37f3 100644
--- a/src/compiler/nir/nir_gather_info.c
+++ b/src/compiler/nir/nir_gather_info.c
@@ -54,6 +54,23 @@ set_io_mask(nir_shader *shader, nir_variable *var, int offset, int len,
          else
             shader->info.inputs_read |= bitfield;
 
+         /* From the GLSL 4.60 spec, section 4.3.4 "Input Variables":
+          *
+          *    It is a compile-time error to declare a vertex shader input
+          *    containing any of the  following:
+          *
+          *     - A Boolean type (bool, bvec2, bvec3, bvec4)
+          *     - An opaque type
+          *     - A structure
+          *
+          * Therefore, when looking for 64-bit attributes, we need only
+          * consider arrays of vectors.
+          */
+         if (shader->info.stage == MESA_SHADER_VERTEX &&
+             glsl_type_is_dual_slot(glsl_without_array(var->type))) {
+            shader->info.double_inputs_read |= bitfield;
+         }
+
          if (shader->info.stage == MESA_SHADER_FRAGMENT) {
             shader->info.fs.uses_sample_qualifier |= var->data.sample;
          }
@@ -226,17 +243,6 @@ gather_intrinsic_info(nir_intrinsic_instr *instr, nir_shader *shader)
 
          if (!try_mask_partial_io(shader, instr->variables[0], is_output_read))
             mark_whole_variable(shader, var, is_output_read);
-
-         /* We need to track which input_reads bits correspond to a
-          * dvec3/dvec4 input attribute */
-         if (shader->info.stage == MESA_SHADER_VERTEX &&
-             var->data.mode == nir_var_shader_in &&
-             glsl_type_is_dual_slot(glsl_without_array(var->type))) {
-            for (uint i = 0; i < glsl_count_attribute_slots(var->type, false); i++) {
-               int idx = var->data.location + i;
-               shader->info.double_inputs_read |= BITFIELD64_BIT(idx);
-            }
-         }
       }
       break;
    }
-- 
2.5.0.400.gff86faf