nir: stop gcc warning about uninitialised variables

Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
diff --git a/src/compiler/nir/nir_opt_if.c b/src/compiler/nir/nir_opt_if.c
index a804ee9..ec66175 100644
--- a/src/compiler/nir/nir_opt_if.c
+++ b/src/compiler/nir/nir_opt_if.c
@@ -120,7 +120,7 @@
    /* We already know we have exactly one continue */
    assert(exec_list_length(&cond_phi->srcs) == 2);
 
-   uint32_t entry_val, continue_val;
+   uint32_t entry_val = 0, continue_val = 0;
    nir_foreach_phi_src(src, cond_phi) {
       assert(src->src.is_ssa);
       nir_const_value *const_src = nir_src_as_const_value(src->src);