[PATCH] op_helper: fix some compile warnings

[Pan Nengyuan]

We got the following compile-time warnings(gcc7.3):
/mnt/sdb//qemu/target/rx/op_helper.c: In function ‘helper_scmpu’:
/mnt/sdb/qemu/target/rx/op_helper.c:213:24: error: ‘tmp1’ may be used 
uninitialized in this function [-Werror=maybe-uninitialized]
     env->psw_c = (tmp0 >= tmp1);
                  ~~~~~~^~~~~~~~
/mnt/sdb/qemu/target/rx/op_helper.c:213:24: error: ‘tmp0’ may be used 
uninitialized in this function [-Werror=maybe-uninitialized]
/mnt/sdb/qemu/target/rx/op_helper.c: In function ‘helper_suntil’:
/mnt/sdb/qemu/target/rx/op_helper.c:299:23: error: ‘tmp’ may be used 
uninitialized in this function [-Werror=maybe-uninitialized]
     env->psw_c = (tmp <= env->regs[2]);
                  ~~~~~^~~~~~~~~~~~~~~~
/mnt/sdb/qemu/target/rx/op_helper.c: In function ‘helper_swhile’:
/mnt/sdb/qemu/target/rx/op_helper.c:318:23: error: ‘tmp’ may be used 
uninitialized in this function [-Werror=maybe-uninitialized]
     env->psw_c = (tmp <= env->regs[2]);

Actually, it looks like a false-positive because it will enter the body of 
while loop and init it for the first time.
Let's change 'while' to 'do .. while' to avoid it.

Reported-by: Euler Robot <euler.ro...@huawei.com>
Signed-off-by: Pan Nengyuan <pannengy...@huawei.com>
---
 target/rx/op_helper.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/target/rx/op_helper.c b/target/rx/op_helper.c
index f89d294f2b..b612ab1da8 100644
--- a/target/rx/op_helper.c
+++ b/target/rx/op_helper.c
@@ -201,14 +201,14 @@ void helper_scmpu(CPURXState *env)
     if (env->regs[3] == 0) {
         return;
     }
-    while (env->regs[3] != 0) {
+    do {
         tmp0 = cpu_ldub_data_ra(env, env->regs[1]++, GETPC());
         tmp1 = cpu_ldub_data_ra(env, env->regs[2]++, GETPC());
         env->regs[3]--;
         if (tmp0 != tmp1 || tmp0 == '\0') {
             break;
         }
-    }
+    } while (env->regs[3] != 0);
     env->psw_z = tmp0 - tmp1;
     env->psw_c = (tmp0 >= tmp1);
 }
@@ -287,14 +287,14 @@ void helper_suntil(CPURXState *env, uint32_t sz)
     if (env->regs[3] == 0) {
         return ;
     }
-    while (env->regs[3] != 0) {
+    do {
         tmp = cpu_ldufn[sz](env, env->regs[1], GETPC());
         env->regs[1] += 1 << sz;
         env->regs[3]--;
         if (tmp == env->regs[2]) {
             break;
         }
-    }
+    } while (env->regs[3] != 0);
     env->psw_z = tmp - env->regs[2];
     env->psw_c = (tmp <= env->regs[2]);
 }
@@ -306,14 +306,14 @@ void helper_swhile(CPURXState *env, uint32_t sz)
     if (env->regs[3] == 0) {
         return ;
     }
-    while (env->regs[3] != 0) {
+    do {
         tmp = cpu_ldufn[sz](env, env->regs[1], GETPC());
         env->regs[1] += 1 << sz;
         env->regs[3]--;
         if (tmp != env->regs[2]) {
             break;
         }
-    }
+    } while (env->regs[3] != 0);
     env->psw_z = env->regs[3];
     env->psw_c = (tmp <= env->regs[2]);
 }
-- 
2.18.2