From d41c19052b32c747b6baf7399bdb7447a9f88810 Mon Sep 17 00:00:00 2001
From: Matthias Braun <matze@braunis.de>
Date: Tue, 24 Jan 2012 17:47:36 +0100
Subject: [PATCH] simplify splitting for double-width values

We regard them as "constraints" now, so the existing code inserts splits
for these nodes. This simplifies the code as we don't have to check for
already existing Permutations anymore.
---
 ir/be/bechordal.c | 68 +----------------------------------------------
 ir/be/beinsn.c    |  4 +--
 2 files changed, 3 insertions(+), 69 deletions(-)

diff --git a/ir/be/bechordal.c b/ir/be/bechordal.c
index 1dcc8db80..221974288 100644
--- a/ir/be/bechordal.c
+++ b/ir/be/bechordal.c
@@ -196,7 +196,7 @@ static ir_node *handle_constraints(be_chordal_alloc_env_t *alloc_env,
 	 * Perms inserted before the constraint handling phase are considered to be
 	 * correctly precolored. These Perms arise during the ABI handling phase.
 	 */
-	if (!insn->has_constraints)
+	if (!insn->has_constraints || is_Phi(irn))
 		goto end;
 
 	n_regs      = env->cls->n_regs;
@@ -380,69 +380,6 @@ end:
 	return res;
 }
 
-static unsigned check_alignment_constraints(ir_node *node)
-{
-	const arch_register_req_t *req = arch_get_irn_register_req(node);
-	return /* req->type == arch_register_req_type_aligned
-		|| */ req->width > 1;
-}
-
-
-static ir_node *handle_split(be_chordal_alloc_env_t *alloc_env,
-                             ir_node *irn)
-{
-	ir_node *perm = NULL;
-	be_chordal_env_t *env  = alloc_env->chordal_env;
-	void *base             = obstack_base(env->obst);
-	be_insn_t *insn        = chordal_scan_insn(env, irn);
-	ir_node *res           = insn->next_insn;
-
-	/*
-	 * Perms are inserted later before constrained instruction.
-     * So, this function does not split here.
-	 */
-	if (!insn->has_constraints) {
-		ir_node *value;
-		unsigned has_alignment_constraints = 0;
-		const arch_register_class_t *cls = env->cls;
-
-		be_foreach_definition (irn, cls, value,
-							   has_alignment_constraints
-							   |= check_alignment_constraints(value);
-			);
-
-		if (has_alignment_constraints) {
-			/*
-			 * Make the Perm, recompute liveness and re-scan the insn since the
-			 * in operands are now the Projs of the Perm.
-			 */
-			perm = insert_Perm_after(env->irg, env->cls, sched_prev(insn->irn));
-			if(perm != NULL) {
-				DBG((dbg, LEVEL_2, "\tsplit before %+F with node %+F\n", irn, perm));
-			}
-		}
-	}
-
-	obstack_free(env->obst, base);
-	return res;
-}
-
-/**
- * Add split points before operations that have pairing constraints.
- * handle_split() inserts Perm nodes which perm
- * over all values live at the constrained node right in front
- * of the constrained node.
- */
-static void split(ir_node *bl, void *data)
-{
-	be_chordal_alloc_env_t *env    = (be_chordal_alloc_env_t*)data;
-	ir_node                *irn;
-
-	for (irn = sched_first(bl); !sched_is_end(irn);) {
-		irn = handle_split(env, irn);
-	}
-}
-
 /**
  * Handle constraint nodes in each basic block.
  * handle_constraints() inserts Perm nodes which perm
@@ -581,9 +518,6 @@ void be_ra_chordal_color(be_chordal_env_t *chordal_env)
 
 	be_timer_push(T_SPLIT);
 
-	/* Add split points before operations that have pairing constraints */
-	dom_tree_walk_irg(irg, split, NULL, &env);
-
 	if (chordal_env->opts->dump_flags & BE_CH_DUMP_SPLIT) {
 		snprintf(buf, sizeof(buf), "%s-split", chordal_env->cls->name);
 		dump_ir_graph(chordal_env->irg, buf);
diff --git a/ir/be/beinsn.c b/ir/be/beinsn.c
index 2f7a29009..ed44d42d3 100644
--- a/ir/be/beinsn.c
+++ b/ir/be/beinsn.c
@@ -75,7 +75,7 @@ be_insn_t *be_scan_insn(const be_insn_env_t *env, ir_node *irn)
 				o.irn             = irn;
 				o.pos             = -(get_Proj_proj(p) + 1);
 				o.partner         = NULL;
-				o.has_constraints = arch_register_req_is(o.req, limited);
+				o.has_constraints = arch_register_req_is(o.req, limited) | (o.req->width > 1);
 				obstack_grow(obst, &o, sizeof(o));
 				insn->n_ops++;
 				insn->out_constraints |= o.has_constraints;
@@ -89,7 +89,7 @@ be_insn_t *be_scan_insn(const be_insn_env_t *env, ir_node *irn)
 		o.irn     = irn;
 		o.pos     = -1;
 		o.partner = NULL;
-		o.has_constraints = arch_register_req_is(o.req, limited);
+		o.has_constraints = arch_register_req_is(o.req, limited) | (o.req->width > 1);
 		obstack_grow(obst, &o, sizeof(o));
 		insn->n_ops++;
 		insn->out_constraints |= o.has_constraints;
-- 
2.20.1