make compiler more deterministic by sorting Perm inputs

[libfirm] / ir / be / beirgmod.c

diff --git a/ir/be/beirgmod.c b/ir/be/beirgmod.c
index 3270e2c..022561a 100644 (file)
--- a/ir/be/beirgmod.c
+++ b/ir/be/beirgmod.c
@@ -69,6 +69,15 @@
 
 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
 
+static int cmp_node_nr(const void *a, const void *b)
+{
+       ir_node **p1 = (ir_node**)a;
+       ir_node **p2 = (ir_node**)b;
+       long      n1 = get_irn_node_nr(*p1);
+       long      n2 = get_irn_node_nr(*p2);
+       return (n1>n2) - (n1<n2);
+}
+
 /*
   ___                     _     ____
  |_ _|_ __  ___  ___ _ __| |_  |  _ \ ___ _ __ _ __ ___
@@ -110,6 +119,8 @@ ir_node *insert_Perm_after(ir_graph *irg, const arch_register_class_t *cls,
                i++;
        }
        ir_nodeset_destroy(&live);
+       /* make the input order deterministic */
+       qsort(nodes, n, sizeof(nodes[0]), cmp_node_nr);
 
        perm = be_new_Perm(cls, bl, n, nodes);
        sched_add_after(pos, perm);