diff --git a/src/compiler/nir/nir.c b/src/compiler/nir/nir.c
index acedb0536ab..693d119671b 100644
--- a/src/compiler/nir/nir.c
+++ b/src/compiler/nir/nir.c
@@ -371,6 +371,7 @@ nir_function_impl_create_bare(nir_shader *shader)
    exec_list_make_empty(&impl->locals);
    impl->reg_alloc = 0;
    impl->ssa_alloc = 0;
+   impl->num_blocks = 0;
    impl->valid_metadata = nir_metadata_none;
    impl->structured = true;
 
diff --git a/src/compiler/nir/nir_validate.c b/src/compiler/nir/nir_validate.c
index b974bc9f46d..fe50e291c70 100644
--- a/src/compiler/nir/nir_validate.c
+++ b/src/compiler/nir/nir_validate.c
@@ -1517,6 +1517,7 @@ validate_function_impl(nir_function_impl *impl, validate_state *state)
                                     sizeof(BITSET_WORD));
 
    _mesa_set_clear(state->blocks, NULL);
+   _mesa_set_resize(state->blocks, impl->num_blocks);
    collect_blocks(&impl->body, state);
    _mesa_set_add(state->blocks, impl->end_block);
    validate_assert(state, !exec_list_is_empty(&impl->body));