diff --git a/src/compiler/nir/nir.c b/src/compiler/nir/nir.c
index 60d5d24a707..678c523e115 100644
--- a/src/compiler/nir/nir.c
+++ b/src/compiler/nir/nir.c
@@ -3353,8 +3353,11 @@ nir_intrinsic_copy_const_indices(nir_intrinsic_instr *dst, nir_intrinsic_instr *
       /* require that dst instruction also uses the same const_index[]: */
       assert(dst_info->index_map[i] > 0);
 
-      dst->const_index[dst_info->index_map[i] - 1] =
-         src->const_index[src_info->index_map[i] - 1];
+      unsigned size = nir_intrinsic_index_size(i);
+
+      memcpy(&dst->const_index[dst_info->index_map[i] - 1],
+             &src->const_index[src_info->index_map[i] - 1],
+             sizeof(dst->const_index[0]) * size);
    }
 }
 
diff --git a/src/compiler/nir/nir_intrinsics_indices_h.py b/src/compiler/nir/nir_intrinsics_indices_h.py
index 6b5b47a737a..63fac4b1dfc 100644
--- a/src/compiler/nir/nir_intrinsics_indices_h.py
+++ b/src/compiler/nir/nir_intrinsics_indices_h.py
@@ -73,6 +73,19 @@ nir_intrinsic_has_${name}(const nir_intrinsic_instr *instr)
 }
 % endfor
 
+static inline unsigned
+nir_intrinsic_index_size(nir_intrinsic_index_flag index)
+{
+   switch (index) {
+% for index in INTR_INDICES:
+% if index.size != 1:
+   case ${"NIR_INTRINSIC_" + index.name.upper()}: return ${index.size};
+% endif
+% endfor
+   default: return 1;
+   }
+}
+
 #endif /* _NIR_INTRINSICS_INDICES_ */
 """