From 64f5f0cf11fe4a0d4753060e45639604d725652d Mon Sep 17 00:00:00 2001
From: Matthias Braun <matthias.braun@kit.edu>
Date: Mon, 27 Aug 2012 14:50:17 +0200
Subject: [PATCH] move load mode shrinking into ldst phase

Performing it as localopt was hairy as the optimisation dependet on
correct iredges values which were misleading/wrong during construction
of new stuff.
---
 ir/ir/iropt.c    | 20 --------------------
 ir/opt/ldstopt.c | 42 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 42 insertions(+), 20 deletions(-)

diff --git a/ir/ir/iropt.c b/ir/ir/iropt.c
index f9958a141..d37db02cc 100644
--- a/ir/ir/iropt.c
+++ b/ir/ir/iropt.c
@@ -5597,26 +5597,6 @@ static ir_node *transform_node_Conv(ir_node *n)
 		}
 	}
 
-	/* shrink mode of load if possible. */
-	if (is_Proj(a)) {
-		ir_node *pred = get_Proj_pred(a);
-		if (is_Load(pred)) {
-			/* only do it if we are the only user (otherwise the risk is too
-			 * great that we end up with 2 loads instead of one). */
-			ir_graph *irg = get_irn_irg(n);
-			if (edges_activated(irg) && get_irn_n_edges(a) == 1) {
-				ir_mode *load_mode = get_Load_mode(pred);
-				if (!mode_is_float(load_mode) && !mode_is_float(mode) &&
-					get_mode_size_bits(mode) <= get_mode_size_bits(load_mode)
-					&& !be_get_backend_param()->byte_order_big_endian) {
-					set_Load_mode(pred, mode);
-					set_irn_mode(a, mode);
-					return a;
-				}
-			}
-		}
-	}
-
 	return n;
 }
 
diff --git a/ir/opt/ldstopt.c b/ir/opt/ldstopt.c
index ad7e96794..e1c2c719f 100644
--- a/ir/opt/ldstopt.c
+++ b/ir/opt/ldstopt.c
@@ -1487,6 +1487,44 @@ static unsigned optimize_phi(ir_node *phi, walk_env_t *wenv)
 	return res | DF_CHANGED;
 }  /* optimize_phi */
 
+static int optimize_conv_load(ir_node *conv)
+{
+	ir_node *op = get_Conv_op(conv);
+	if (!is_Proj(op))
+		return 0;
+	if (get_irn_n_edges(op) > 1)
+		return 0;
+	/* shrink mode of load if possible. */
+	ir_node *load = get_Proj_pred(op);
+	if (!is_Load(load))
+		return 0;
+
+	/* only do it if we are the only user (otherwise the risk is too
+	 * great that we end up with 2 loads instead of one). */
+	ir_mode *mode      = get_irn_mode(conv);
+	ir_mode *load_mode = get_Load_mode(load);
+	int      bits_diff
+		= get_mode_size_bits(load_mode) - get_mode_size_bits(mode);
+	if (mode_is_float(load_mode) || mode_is_float(mode) || bits_diff < 0)
+	    return 0;
+
+	if (be_get_backend_param()->byte_order_big_endian) {
+		if (bits_diff % 8 != 0)
+			return 0;
+		ir_graph *irg   = get_irn_irg(conv);
+		ir_node  *ptr   = get_Load_ptr(load);
+		ir_mode  *mode  = get_irn_mode(ptr);
+		ir_node  *delta = new_r_Const_long(irg, mode, bits_diff/8);
+		ir_node  *block = get_nodes_block(load);
+		ir_node  *add   = new_r_Add(block, ptr, delta, mode);
+		set_Load_ptr(load, add);
+	}
+	set_Load_mode(load, mode);
+	set_irn_mode(op, mode);
+	exchange(conv, op);
+	return DF_CHANGED;
+}
+
 /**
  * walker, do the optimizations
  */
@@ -1508,6 +1546,10 @@ static void do_load_store_optimize(ir_node *n, void *env)
 		wenv->changes |= optimize_phi(n, wenv);
 		break;
 
+	case iro_Conv:
+		wenv->changes |= optimize_conv_load(n);
+		break;
+
 	default:
 		break;
 	}
-- 
2.20.1