[Mesa-dev] [PATCH] nir/builder: Cast array indices in build_deref_follower

[Jason Ekstrand]

There's no guarantee when build_deref_follower is called that the two
derefs have the same bit size destination.  Insert a cast on the array
index in case we have differing bit sizes.  While we're here, insert
some asserts in build_deref_array and build_deref_ptr_as_array.  The
validator will catch violations here but they're easier to debug if we
catch them while building.

Cc: Karol Herbst <kherbst at redhat.com>
---
 src/compiler/nir/nir_builder.h | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/compiler/nir/nir_builder.h b/src/compiler/nir/nir_builder.h
index 253ca5941cb..b9f27831b36 100644
--- a/src/compiler/nir/nir_builder.h
+++ b/src/compiler/nir/nir_builder.h
@@ -803,6 +803,8 @@ nir_build_deref_array(nir_builder *build, nir_deref_instr *parent,
           glsl_type_is_matrix(parent->type) ||
           glsl_type_is_vector(parent->type));
 
+   assert(index->bit_size == parent->dest.ssa.bit_size);
+
    nir_deref_instr *deref =
       nir_deref_instr_create(build->shader, nir_deref_type_array);
 
@@ -828,6 +830,8 @@ nir_build_deref_ptr_as_array(nir_builder *build, nir_deref_instr *parent,
           parent->deref_type == nir_deref_type_ptr_as_array ||
           parent->deref_type == nir_deref_type_cast);
 
+   assert(index->bit_size == parent->dest.ssa.bit_size);
+
    nir_deref_instr *deref =
       nir_deref_instr_create(build->shader, nir_deref_type_ptr_as_array);
 
@@ -944,7 +948,9 @@ nir_build_deref_follower(nir_builder *b, nir_deref_instr *parent,
 
       if (leader->deref_type == nir_deref_type_array) {
          assert(leader->arr.index.is_ssa);
-         return nir_build_deref_array(b, parent, leader->arr.index.ssa);
+         nir_ssa_def *index = nir_i2i(b, leader->arr.index.ssa,
+                                         parent->dest.ssa.bit_size);
+         return nir_build_deref_array(b, parent, index);
       } else {
          return nir_build_deref_array_wildcard(b, parent);
       }
-- 
2.20.1