- Split bearch.h correctly into bearch.h and bearch_t.h

[libfirm] / ir / be / bespillbelady.c

diff --git a/ir/be/bespillbelady.c b/ir/be/bespillbelady.c
index b91c645..c5e58b7 100644 (file)
--- a/ir/be/bespillbelady.c
+++ b/ir/be/bespillbelady.c
@@ -9,14 +9,6 @@
 #include "config.h"
 #endif
 
-#ifdef HAVE_ALLOCA_H
-#include <alloca.h>
-#endif
-
-#ifdef HAVE_MALLOC_H
-#include <malloc.h>
-#endif
-
 #include "obst.h"
 #include "set.h"
 #include "pset.h"
@@ -29,9 +21,10 @@
 #include "iredges_t.h"
 #include "ircons_t.h"
 #include "irprintf.h"
+#include "xmalloc.h"
 
 #include "beutil.h"
-#include "bearch.h"
+#include "bearch_t.h"
 #include "bespillbelady.h"
 #include "beuses_t.h"
 #include "besched_t.h"
@@ -673,13 +666,27 @@ next_value:
        }
 }
 
-void be_spill_belady(be_irg_t *birg, const arch_register_class_t *cls) {
+/**
+ * Do spilling for a register class on a graph using the belady heuristic.
+ * In the transformed graph, the register pressure never exceeds the number
+ * of available registers.
+ *
+ * @param birg  The backend graph
+ * @param cls   The register class to spill
+ */
+static void be_spill_belady(be_irg_t *birg, const arch_register_class_t *cls) {
        be_spill_belady_spill_env(birg, cls, NULL);
 }
 
 void be_spill_belady_spill_env(be_irg_t *birg, const arch_register_class_t *cls, spill_env_t *spill_env) {
        belady_env_t env;
        ir_graph *irg = be_get_birg_irg(birg);
+       int n_regs;
+
+       /* some special classes contain only ignore regs, nothing to do then */
+       n_regs = cls->n_regs - be_put_ignore_regs(birg, cls, NULL);
+       if(n_regs == 0)
+               return;
 
        be_invalidate_liveness(birg);
        be_assure_liveness(birg);
@@ -693,7 +700,7 @@ void be_spill_belady_spill_env(be_irg_t *birg, const arch_register_class_t *cls,
        env.arch      = birg->main_env->arch_env;
        env.cls       = cls;
        env.lv        = be_get_birg_liveness(birg);
-       env.n_regs    = env.cls->n_regs - be_put_ignore_regs(birg, cls, NULL);
+       env.n_regs    = n_regs;
        env.ws        = new_workset(&env, &env.ob);
        env.uses      = be_begin_uses(irg, env.lv);
        env.loop_ana  = be_new_loop_pressure(birg);