target/arm: Remove unnecessary gen_io_end() calls

Since commit ba3e7926691ed3 it has been unnecessary for target code
to call gen_io_end() after an IO instruction in icount mode; it is
sufficient to call gen_io_start() before it and to force the end of
the TB.

Many now-unnecessary calls to gen_io_end() were removed in commit
9e9b10c6491153b, but some were missed or accidentally added later.
Remove unneeded calls from the arm target:

 * the call in the handling of exception-return-via-LDM is
   unnecessary, and the code is already forcing end-of-TB
 * the call in the VFP access check code is more complicated:
   we weren't ending the TB, so we need to add the code to
   force that by setting DISAS_UPDATE
 * the doc comment for ARM_CP_IO doesn't need to mention
   gen_io_end() any more

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>
Message-id: 20200619170324.12093-1-peter.maydell@linaro.org

1 files changed, 0 insertions, 3 deletions

diff --git a/target/arm/translate.c b/target/arm/translate.c
index 408fb7a492..795964da1f 100644
--- a/target/arm/translate.c
+++ b/target/arm/translate.c
@@ -7785,9 +7785,6 @@ static bool do_ldm(DisasContext *s, arg_ldst_block *a, int min_n)
             gen_io_start();
         }
         gen_helper_cpsr_write_eret(cpu_env, tmp);
-        if (tb_cflags(s->base.tb) & CF_USE_ICOUNT) {
-            gen_io_end();
-        }
         tcg_temp_free_i32(tmp);
         /* Must exit loop to check un-masked IRQs */
         s->base.is_jmp = DISAS_EXIT;