lower_dw: do not guess modes anymore, let backends specify single word modes

ir/be/ia32/ia32_intrinsics.c

@@ -300,9 +300,13 @@ static ir_entity *ia32_create_intrinsic_fkt(ir_type *method, const ir_op *op,
 void ia32_lower64(void)
 {
 	/* perform doubleword lowering */
+	ir_mode *word_unsigned = ia32_reg_classes[CLASS_ia32_gp].mode;
+	ir_mode *word_signed   = find_signed_mode(word_unsigned);
 	lwrdw_param_t lower_dw_params = {
 		ia32_create_intrinsic_fkt,
 		NULL,
+		word_unsigned,
+		word_signed,
 		64,    /* doubleword size */
 		be_is_big_endian(),
 	};

ir/be/sparc/sparc_lower64.c

@@ -12,6 +12,7 @@
 #include "panic.h"
 #include "sparc_nodes_attr.h"
 #include "gen_sparc_new_nodes.h"
+#include "gen_sparc_regalloc_if.h"
 #include "lower_dw.h"
 #include "ircons_t.h"
 
@@ -124,9 +125,13 @@ static ir_entity *create_64_intrinsic_fkt(ir_type *method, const ir_op *op,
 
 void sparc_lower_64bit(void)
 {
+	ir_mode *word_unsigned = sparc_reg_classes[CLASS_sparc_gp].mode;
+	ir_mode *word_signed   = find_signed_mode(word_unsigned);
 	lwrdw_param_t lower_dw_params = {
 		create_64_intrinsic_fkt,
 		NULL,
+		word_unsigned,
+		word_signed,
 		64,    /* doubleword size */
 		be_is_big_endian(),
 	};

ir/lower/lower_dw.h

@@ -42,6 +42,8 @@ typedef ir_entity *(create_intrinsic_fkt)(ir_type *method, const ir_op *op,
 typedef struct lwrdw_param_t {
 	create_intrinsic_fkt *create_intrinsic; /**< callback that creates the intrinsic entity */
 	void                 *ctx;              /**< context parameter for the creator function */
+	ir_mode              *word_unsigned;    /**< mode for unsigned word */
+	ir_mode              *word_signed;      /**< mode for signed word */
 	unsigned short        doubleword_size;  /**< bitsize of the doubleword mode */
 	bool                  big_endian:1;     /**< target is big endian if true,
 											     else little endian */