[PATCH 1/6] target/xtensa: fix uninitialized variable warning

[Chen Qun]

The compiler cannot determine whether the return values of the 
xtensa_operand_is_register(isa, opc, opnd)
 and xtensa_operand_is_visible(isa, opc, opnd) functions are the same.
So,it assumes that 'rf' is not assigned, but it's used.

The compiler showed warning:
target/xtensa/translate.c: In function ‘disas_xtensa_insn’:
target/xtensa/translate.c:985:43: warning: ‘rf’ may be used uninitialized in 
this function [-Wmaybe-uninitialized]
  985 |                     arg[vopnd].num_bits = xtensa_regfile_num_bits(isa, 
rf);
      |                                           
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Add a default value for 'rf' to prevented the warning.

Reported-by: Euler Robot <euler.ro...@huawei.com>
Signed-off-by: Chen Qun <kuhn.chen...@huawei.com>
---
Cc: Max Filippov <jcmvb...@gmail.com>
---
 target/xtensa/translate.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/target/xtensa/translate.c b/target/xtensa/translate.c
index 944a157747..eea851bbe7 100644
--- a/target/xtensa/translate.c
+++ b/target/xtensa/translate.c
@@ -953,7 +953,7 @@ static void disas_xtensa_insn(CPUXtensaState *env, 
DisasContext *dc)
 
         for (opnd = vopnd = 0; opnd < opnds; ++opnd) {
             void **register_file = NULL;
-            xtensa_regfile rf;
+            xtensa_regfile rf = -1;
 
             if (xtensa_operand_is_register(isa, opc, opnd)) {
                 rf = xtensa_operand_regfile(isa, opc, opnd);
-- 
2.27.0