insert Keeps to assure should_be_different constraint

diff --git a/ir/be/bechordal_main.c b/ir/be/bechordal_main.c
index b423b2c..6767885 100644 (file)
--- a/ir/be/bechordal_main.c
+++ b/ir/be/bechordal_main.c
@@ -266,6 +266,9 @@ static void be_ra_chordal_main(const be_irg_t *bi)
 
        obstack_init(&chordal_env.obst);
 
+       /* add Keeps for should_be_different constrained nodes */
+       lower_nodes_before_ra(&chordal_env);
+
        /* Perform the following for each register class. */
        for(j = 0, m = arch_isa_get_n_reg_class(isa); j < m; ++j) {
                chordal_env.cls          = arch_isa_get_reg_class(isa, j);

diff --git a/ir/be/belower.c b/ir/be/belower.c
index 8064401..b89c357 100644 (file)
--- a/ir/be/belower.c
+++ b/ir/be/belower.c
@@ -463,6 +463,50 @@ static void lower_perm_node(ir_node *irn, void *walk_env) {
 
 
 
+/**
+ * Checks if node has a should_be_different constraint in output
+ * and adds a Keep then to assure the constraint.
+ */
+static void assure_different_constraint(ir_node *irn, lower_env_t *env) {
+       const arch_env_t          *arch_env = env->chord_env->birg->main_env->arch_env;
+       const arch_register_req_t *req;
+       arch_register_req_t        req_temp;
+       ir_node                   *in[2], *keep;
+
+       req = arch_get_register_req(arch_env, &req_temp, irn, -1);
+
+       if (req && arch_register_req_is(req, should_be_different)) {
+               /* We found a should_be_different constraint. */
+               assert(req->other_different && "missing irn for constraint");
+
+               in[0] = irn;
+               in[1] = req->other_different;
+
+               keep = be_new_Keep(req->cls, env->chord_env->birg->irg, get_nodes_block(irn), 2, in);
+               DBG((env->dbg_module, LEVEL_1, "created %+F for %+F to assure should_be_different\n", keep, irn));
+       }
+}
+
+
+
+/**
+ * Calls the corresponding lowering function for the node.
+ *
+ * @param irn      The node to be checked for lowering
+ * @param walk_env The walker environment
+ */
+static void lower_nodes_before_ra_walker(ir_node *irn, void *walk_env) {
+       if (is_Block(irn))
+               return;
+
+       if (mode_is_datab(get_irn_mode(irn)))
+               assure_different_constraint(irn, walk_env);
+
+       return;
+}
+
+
+
 /**
  * Calls the corresponding lowering function for the node.
  *
@@ -484,9 +528,26 @@ static void lower_nodes_after_ra_walker(ir_node *irn, void *walk_env) {
 
 
 
+/**
+ * Walks over all blocks in an irg and performs action need to be
+ * done before register allocation (e.g. add Keeps for should be different constraints).
+ *
+ * @param chord_env The chordal environment containing the irg
+ */
+void lower_nodes_before_ra(be_chordal_env_t *chord_env) {
+       lower_env_t env;
+
+       env.chord_env  = chord_env;
+       env.dbg_module = firm_dbg_register("firm.be.lower");
+
+       irg_walk_blkwise_graph(chord_env->irg, NULL, lower_nodes_before_ra_walker, &env);
+}
+
+
+
 /**
  * Walks over all blocks in an irg and performs lowering need to be
- * done after register allocation (e.g. perm and spill/reload lowering).
+ * done after register allocation (e.g. perm lowering).
  *
  * @param chord_env The chordal environment containing the irg
  * @param do_copy   1 == resolve cycles with a free reg if available

diff --git a/ir/be/belower.h b/ir/be/belower.h
index 06745fd..be4302f 100644 (file)
--- a/ir/be/belower.h
+++ b/ir/be/belower.h
@@ -10,6 +10,7 @@
 
 #include "bechordal.h"
 
+void lower_nodes_before_ra(be_chordal_env_t *chord_env);
 void lower_nodes_after_ra(be_chordal_env_t *chord_env, int do_copy);
 
 #endif /* _BELOWER_H_ */