arm-protos.h (arm_modes_tieable_p): Declare.

gcc/
	* config/arm/arm-protos.h (arm_modes_tieable_p): Declare.
	* config/arm/arm.h (MODES_TIEABLE_P): Use it.
	* config/arm/arm.c (arm_modes_tieable_p): New function.  Allow
	NEON vector and structure modes to be tied.

From-SVN: r179355

gcc/ChangeLog

+2011-09-29  Richard Sandiford  <richard.sandiford@linaro.org>
+
+	* config/arm/arm-protos.h (arm_modes_tieable_p): Declare.
+	* config/arm/arm.h (MODES_TIEABLE_P): Use it.
+	* config/arm/arm.c (arm_modes_tieable_p): New function.  Allow
+	NEON vector and structure modes to be tied.
+
 2011-09-29  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
 
 	* graphite-scop-detection.c (make_close_phi_nodes_unique):  New

gcc/config/arm/arm-protos.h

@@ -46,6 +46,7 @@ extern void arm_output_fn_unwind (FILE *, bool);
 extern bool arm_vector_mode_supported_p (enum machine_mode);
 extern bool arm_small_register_classes_for_mode_p (enum machine_mode);
 extern int arm_hard_regno_mode_ok (unsigned int, enum machine_mode);
+extern bool arm_modes_tieable_p (enum machine_mode, enum machine_mode);
 extern int const_ok_for_arm (HOST_WIDE_INT);
 extern int const_ok_for_op (HOST_WIDE_INT, enum rtx_code);
 extern int arm_split_constant (RTX_CODE, enum machine_mode, rtx,

gcc/config/arm/arm.c

@@ -18260,6 +18260,29 @@ arm_hard_regno_mode_ok (unsigned int regno, enum machine_mode mode)
 	  && regno <= LAST_FPA_REGNUM);
 }
 
+/* Implement MODES_TIEABLE_P.  */
+
+bool
+arm_modes_tieable_p (enum machine_mode mode1, enum machine_mode mode2)
+{
+  if (GET_MODE_CLASS (mode1) == GET_MODE_CLASS (mode2))
+    return true;
+
+  /* We specifically want to allow elements of "structure" modes to
+     be tieable to the structure.  This more general condition allows
+     other rarer situations too.  */
+  if (TARGET_NEON
+      && (VALID_NEON_DREG_MODE (mode1)
+	  || VALID_NEON_QREG_MODE (mode1)
+	  || VALID_NEON_STRUCT_MODE (mode1))
+      && (VALID_NEON_DREG_MODE (mode2)
+	  || VALID_NEON_QREG_MODE (mode2)
+	  || VALID_NEON_STRUCT_MODE (mode2)))
+    return true;
+
+  return false;
+}
+
 /* For efficiency and historical reasons LO_REGS, HI_REGS and CC_REGS are
    not used in arm mode.  */
 

gcc/config/arm/arm.h

@@ -975,12 +975,7 @@ extern int arm_arch_thumb_hwdiv;
 #define HARD_REGNO_MODE_OK(REGNO, MODE)					\
   arm_hard_regno_mode_ok ((REGNO), (MODE))
 
-/* Value is 1 if it is a good idea to tie two pseudo registers
-   when one has mode MODE1 and one has mode MODE2.
-   If HARD_REGNO_MODE_OK could produce different values for MODE1 and MODE2,
-   for any hard reg, then this must be 0 for correct output.  */
-#define MODES_TIEABLE_P(MODE1, MODE2)  \
-  (GET_MODE_CLASS (MODE1) == GET_MODE_CLASS (MODE2))
+#define MODES_TIEABLE_P(MODE1, MODE2) arm_modes_tieable_p (MODE1, MODE2)
 
 #define VALID_IWMMXT_REG_MODE(MODE) \
  (arm_vector_mode_supported_p (MODE) || (MODE) == DImode)