spirv: Ignore ArrayStride in OpPtrAccessChain for Workgroup

From OpPtrAccessChain description in the SPIR-V spec (1.4 rev 1):

    For objects in the Uniform, StorageBuffer, or PushConstant storage
    classes, the element’s address or location is calculated using a
    stride, which will be the Base-type’s Array Stride when the Base
    type is decorated with ArrayStride. For all other objects, the
    implementation will calculate the element’s address or location.

For non-CL shaders the driver should layout the Workgroup storage
class, so override any explicitly set ArrayStride in the shader.  This
currently fixes only the lower_workgroup_access_to_offsets case, which
is used by anv.

Reviewed-by: Juan A. Suarez <[email protected]>
(cherry picked from commit 050eb6389a8867e6173644fbb6b2d13ad0db454b)

1 files changed, 6 insertions, 4 deletions

diff --git a/src/compiler/spirv/spirv_to_nir.c b/src/compiler/spirv/spirv_to_nir.c
index 5e91f8815e8..98df7a87e94 100644
--- a/src/compiler/spirv/spirv_to_nir.c
+++ b/src/compiler/spirv/spirv_to_nir.c
@@ -1422,15 +1422,17 @@ vtn_handle_type(struct vtn_builder *b, SpvOp opcode,
             default:
                break;
             }
-         }
-
-         if (storage_class == SpvStorageClassWorkgroup &&
-             b->options->lower_workgroup_access_to_offsets) {
+         } else if (storage_class == SpvStorageClassWorkgroup &&
+                    b->options->lower_workgroup_access_to_offsets) {
+            /* Workgroup is laid out by the implementation. */
             uint32_t size, align;
             val->type->deref = vtn_type_layout_std430(b, val->type->deref,
                                                       &size, &align);
             val->type->length = size;
             val->type->align = align;
+
+            /* Override any ArrayStride previously set. */
+            val->type->stride = size;
          }
       }
       break;