use float_arithmetic mode when lowering fabs calls

ir/lower/lower_intrinsics.c

@@ -165,8 +165,17 @@ int i_mapper_abs(ir_node *call)
 	ir_node  *block    = get_nodes_block(call);
 	ir_node  *op       = get_Call_param(call, 0);
 	ir_graph *irg      = get_irn_irg(call);
-	ir_mode  *mode     = get_irn_mode(op);
+	ir_mode  *omode    = get_irn_mode(op);
 	dbg_info *dbg      = get_irn_dbg_info(call);
+	ir_mode  *mode     = omode;
+	if (mode_is_float(mode)) {
+		ir_mode *float_arith = be_get_mode_float_arithmetic();
+		if (float_arith != NULL && mode != float_arith) {
+			mode = float_arith;
+			op   = new_rd_Conv(dbg, block, op, mode);
+		}
+	}
+
 	ir_node  *zero     = new_r_Const(irg, get_mode_null(mode));
 	ir_node  *cmp      = new_rd_Cmp(dbg, block, op, zero, ir_relation_less);
 	ir_node  *minus_op = new_rd_Minus(dbg, block, op, mode);
@@ -179,6 +188,9 @@ int i_mapper_abs(ir_node *call)
 
 	/* construct Mux */
 	mux = new_rd_Mux(dbg, block, cmp, op, minus_op, mode);
+	if (omode != mode) {
+		mux = new_rd_Conv(dbg, block, mux, omode);
+	}
 	DBG_OPT_ALGSIM0(call, mux, FS_OPT_RTS_ABS);
 	replace_call(mux, call, mem, NULL, NULL);
 	return 1;