diff --git a/src/compiler/nir/nir_builder.c b/src/compiler/nir/nir_builder.c
index 8a93394730f..3e2a64ec976 100644
--- a/src/compiler/nir/nir_builder.c
+++ b/src/compiler/nir/nir_builder.c
@@ -379,6 +379,22 @@ nir_builder_instr_insert(nir_builder *build, nir_instr *instr)
    build->cursor = nir_after_instr(instr);
 }
 
+void
+nir_builder_instr_insert_at_top(nir_builder *build, nir_instr *instr)
+{
+   nir_cursor top = nir_before_impl(build->impl);
+   const bool at_top = build->cursor.block != NULL &&
+                       nir_cursors_equal(build->cursor, top);
+
+   nir_instr_insert(top, instr);
+
+   if (build->update_divergence)
+      nir_update_instr_divergence(build->shader, instr);
+
+   if (at_top)
+      build->cursor = nir_after_instr(instr);
+}
+
 void
 nir_builder_cf_insert(nir_builder *build, nir_cf_node *cf)
 {
diff --git a/src/compiler/nir/nir_builder.h b/src/compiler/nir/nir_builder.h
index 661c70d8f16..0fbad8e0fdb 100644
--- a/src/compiler/nir/nir_builder.h
+++ b/src/compiler/nir/nir_builder.h
@@ -182,6 +182,7 @@ nir_shader_intrinsics_pass(nir_shader *shader,
 }
 
 void nir_builder_instr_insert(nir_builder *build, nir_instr *instr);
+void nir_builder_instr_insert_at_top(nir_builder *build, nir_instr *instr);
 
 static inline nir_instr *
 nir_builder_last_instr(nir_builder *build)
@@ -250,9 +251,7 @@ nir_undef(nir_builder *build, unsigned num_components, unsigned bit_size)
    if (!undef)
       return NULL;
 
-   nir_instr_insert(nir_before_impl(build->impl), &undef->instr);
-   if (build->update_divergence)
-      nir_update_instr_divergence(build->shader, &undef->instr);
+   nir_builder_instr_insert_at_top(build, &undef->instr);
 
    return &undef->def;
 }
@@ -1832,7 +1831,7 @@ nir_decl_reg(nir_builder *b, unsigned num_components, unsigned bit_size,
    nir_intrinsic_set_divergent(decl, true);
    nir_def_init(&decl->instr, &decl->def, 1, 32);
 
-   nir_instr_insert(nir_before_impl(b->impl), &decl->instr);
+   nir_builder_instr_insert_at_top(b, &decl->instr);
 
    return &decl->def;
 }