[U-Boot] [PATCH 7/7] GCC4.6: Squash warning in cmd_mem.c
Simon Glass
sjg at chromium.org
Mon Sep 26 21:01:16 CEST 2011
Hi Marek,
On Mon, Sep 26, 2011 at 11:34 AM, Marek Vasut <marek.vasut at gmail.com> wrote:
> On Monday, September 26, 2011 08:29:22 PM Simon Glass wrote:
>> Hi Merek,
>>
>> On Mon, Sep 26, 2011 at 11:24 AM, Marek Vasut <marek.vasut at gmail.com> wrote:
>> > On Monday, September 26, 2011 08:05:43 PM Simon Glass wrote:
>> >> Hi Marek,
>> >>
>> >> On Sun, Sep 25, 2011 at 5:26 PM, Marek Vasut <marek.vasut at gmail.com> wrote:
>> >> > cmd_mem.c: In function ‘do_mem_loop’:
>> >> > cmd_mem.c:474:25: warning: variable ‘junk’ set but not used
>> >> > [-Wunused-but-set-variable]
>> >> >
>> >> > The assigned variable can be removed because the pointers are volatile
>> >> > so accesses to their addresses are always generated.
>> >> >
>> >> > Signed-off-by: Marek Vasut <marek.vasut at gmail.com>
>> >> > ---
>> >> > common/cmd_mem.c | 8 ++++----
>> >> > 1 files changed, 4 insertions(+), 4 deletions(-)
>> >> >
>> >> > diff --git a/common/cmd_mem.c b/common/cmd_mem.c
>> >> > index 4daa1b3..e84cc4e 100644
>> >> > --- a/common/cmd_mem.c
>> >> > +++ b/common/cmd_mem.c
>> >> > @@ -471,7 +471,7 @@ int do_mem_base (cmd_tbl_t *cmdtp, int flag, int
>> >> > argc, char * const argv[])
>> >> >
>> >> > int do_mem_loop (cmd_tbl_t *cmdtp, int flag, int argc, char * const
>> >> > argv[]) {
>> >> > - ulong addr, length, i, junk;
>> >> > + ulong addr, length, i;
>> >> > int size;
>> >> > volatile uint *longp;
>> >> > volatile ushort *shortp;
>> >> > @@ -518,7 +518,7 @@ int do_mem_loop (cmd_tbl_t *cmdtp, int flag, int
>> >> > argc, char * const argv[]) longp = (uint *)addr;
>> >> > i = length;
>> >> > while (i-- > 0)
>> >> > - junk = *longp++;
>> >> > + *longp++;
>> >> > }
>> >> > }
>> >> > if (size == 2) {
>> >> > @@ -526,14 +526,14 @@ int do_mem_loop (cmd_tbl_t *cmdtp, int flag, int
>> >> > argc, char * const argv[]) shortp = (ushort *)addr;
>> >> > i = length;
>> >> > while (i-- > 0)
>> >> > - junk = *shortp++;
>> >> > + *shortp++;
>> >> > }
>> >> > }
>> >> > for (;;) {
>> >> > cp = (u_char *)addr;
>> >> > i = length;
>> >> > while (i-- > 0)
>> >> > - junk = *cp++;
>> >> > + *cp++;
>> >> > }
>> >> > }
>> >>
>> >> I checked the ARM assembler output and it looks fine.
>> >>
>> >> Acked-by: Simon Glass <sjg at chromium.org>
>> >>
>> >> Re the 'length == 1' case (above your patch) site, it is assigning to
>> >> 'i' here. Could/should we remove that assignment also?
>> >
>> > The loop below depends on that ... ?
>>
>> Which loop? It doesn't look like the value of i is used?
>
> i = length;
> while (i-- > 0)
>
> This loop
The assignment to i I was referring to is here:
if (length == 1) {
if (size == 4) {
longp = (uint *)addr;
for (;;)
i = *longp;
^^^ this line
}
if (size == 2) {
shortp = (ushort *)addr;
for (;;)
i = *shortp;
^^^ this line
}
cp = (u_char *)addr;
for (;;)
i = *cp;
^^^ this line
}
I was wondering if we need to assign to i? The output code appears
unchanged with my compiler if the 'i =' is removed.
Regards,
Simon
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