[gcc r12-1065] C-SKY: Delete TARGET_CAN_CHANGE_MODE_CLASS, use defualt definition.

[qu <xianmiao@gcc.gnu.org>]

https://gcc.gnu.org/g:5f338210456bf4f142a2da6eb0a01ae8ffecaa88

commit r12-1065-g5f338210456bf4f142a2da6eb0a01ae8ffecaa88
Author: Geng Qi <gengqi@linux.alibaba.com>
Date:   Fri Apr 30 21:02:15 2021 +0800

    C-SKY: Delete TARGET_CAN_CHANGE_MODE_CLASS, use defualt definition.
    
    gcc/ChangeLog:
    
            * config/csky/csky.c (csky_can_change_mode_class): Delete.
            For csky, HF/SF mode use the low bits of VREGS.

Diff:
---
 gcc/config/csky/csky.c | 16 ----------------
 1 file changed, 16 deletions(-)

diff --git a/gcc/config/csky/csky.c b/gcc/config/csky/csky.c
index c0e42a26026..e55821fe2ee 100644
--- a/gcc/config/csky/csky.c
+++ b/gcc/config/csky/csky.c
@@ -608,9 +608,6 @@ csky_default_logical_op_non_short_circuit (void)
 #undef TARGET_MODES_TIEABLE_P
 #define TARGET_MODES_TIEABLE_P csky_modes_tieable_p
 
-#undef TARGET_CAN_CHANGE_MODE_CLASS
-#define TARGET_CAN_CHANGE_MODE_CLASS csky_can_change_mode_class
-
 #undef	TARGET_CONDITIONAL_REGISTER_USAGE
 #define TARGET_CONDITIONAL_REGISTER_USAGE csky_conditional_register_usage
 
@@ -2370,19 +2367,6 @@ csky_modes_tieable_p (machine_mode mode1, machine_mode mode2)
 	   && (mode1 == DFmode || mode2 == DFmode));
 }
 
-/* Implement TARGET_CAN_CHANGE_MODE_CLASS.
-   V_REG registers can't do subreg as all values are reformatted to
-   internal precision.  */
-
-static bool
-csky_can_change_mode_class (machine_mode from,
-			    machine_mode to,
-			    reg_class_t rclass)
-{
-  return (GET_MODE_SIZE (from) == GET_MODE_SIZE (to)
-	  || !reg_classes_intersect_p (V_REGS, rclass));
-}
-
 /* Implement TARGET_CLASS_LIKELY_SPILLED_P.
    We need to define this for MINI_REGS when we only use r0 - r7.
    Otherwise we can end up using r0-r4 for function arguments, and don't