added reg pressure statitics

ir/be/bemain.c

@@ -55,6 +55,7 @@
 #include "bessadestr.h"
 #include "beabi.h"
 #include "belower.h"
+#include "bestat.h"
 
 #define DUMP_INITIAL    (1 << 0)
 #define DUMP_ABI        (1 << 1)
@@ -338,6 +339,9 @@ static void be_main_loop(FILE *file_handle)
 		/* Verify the schedule */
 		sched_verify_irg(irg);
 
+		/* do some statistics */
+		be_do_stat_reg_pressure(&birg);
+
 		/* Do register allocation */
 		arch_code_generator_before_ra(birg.cg);
 		ra->allocate(&birg);

ir/be/bestat.c

+#include "irnode_t.h"
+#include "irprintf.h"
+#include "irgwalk.h"
+#include "irhooks.h"
+#include "dbginfo_t.h"
+#include "firmstat.h"
+#include "ident.h"
+
+#include "bestat.h"
+#include "belive_t.h"
+#include "besched.h"
+
+/**
+ * Compare two live entries.
+ */
+static int cmp_irn_live(const void *a, const void *b)
+{
+  const irn_live_t *p = a;
+  const irn_live_t *q = b;
+
+  return !(p->block == q->block && p->irn == q->irn);
+}
+
+/**
+ * Collect reg pressure statistics per block and per class.
+ */
+static void stat_reg_pressure_block(ir_node *block, void *env) {
+	be_irg_t         *birg = env;
+	const arch_env_t *aenv = birg->main_env->arch_env;
+	int i, n = arch_isa_get_n_reg_class(aenv->isa);
+
+	for (i = 0; i < n; i++) {
+		const arch_register_class_t *cls = arch_isa_get_reg_class(aenv->isa, i);
+		ir_node  *irn;
+		pset     *live_nodes = new_pset(cmp_irn_live, 64);
+		int       max_live;
+
+		live_nodes = be_liveness_end_of_block(aenv, cls, block, live_nodes);
+		max_live   = pset_count(live_nodes);
+
+		sched_foreach_reverse(block, irn) {
+			int cnt;
+
+			live_nodes = be_liveness_transfer(aenv, cls, irn, live_nodes);
+			cnt        = pset_count(live_nodes);
+
+			max_live = cnt < max_live ? max_live : cnt;
+		}
+
+		hook_be_block_regpressure(block, birg->irg, max_live, new_id_from_str(cls->name));
+		ir_printf("max regpressure %+F: %d\n", block, max_live);
+	}
+}
+
+void be_do_stat_reg_pressure(be_irg_t *birg) {
+	/* Collect register pressure information for each block */
+	irg_block_walk_graph(birg->irg, stat_reg_pressure_block, NULL, birg);
+}

ir/be/bestat.h

+#ifndef _BESTAT_H_
+#define _BESTAT_H_
+
+#include "be_t.h"
+
+/**
+ * Collects statistics information about register pressure.
+ * @param birg The be irg object containing the irg
+ */
+void be_do_stat_reg_pressure(be_irg_t *birg);
+
+#endif /* _BESTAT_H_ */
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