[Qemu-devel] Re: [PATCH 11/12] ppc: avoid write only variables

[Alexander Graf]

On 08.10.2010, at 23:25, Blue Swirl wrote:

> Compiling with GCC 4.6.0 20100925 produced warnings:
> /src/qemu/target-ppc/op_helper.c: In function 'helper_icbi':
> /src/qemu/target-ppc/op_helper.c:351:14: error: variable 'tmp' set but
> not used [-Werror=unused-but-set-variable]
> /src/qemu/target-ppc/op_helper.c: In function 'do_6xx_tlb':
> /src/qemu/target-ppc/op_helper.c:3805:28: error: variable 'EPN' set
> but not used [-Werror=unused-but-set-variable]
> /src/qemu/target-ppc/op_helper.c: In function 'do_74xx_tlb':
> /src/qemu/target-ppc/op_helper.c:3838:28: error: variable 'EPN' set
> but not used [-Werror=unused-but-set-variable]
> 
> Fix by adding a dummy cast so that the variable is not unused. Delete tmp.
> 
> Signed-off-by: Blue Swirl <address@hidden>
> ---
> target-ppc/op_helper.c |   12 +++++++-----
> 1 files changed, 7 insertions(+), 5 deletions(-)
> 
> diff --git a/target-ppc/op_helper.c b/target-ppc/op_helper.c
> index 45f1655..13502ae 100644
> --- a/target-ppc/op_helper.c
> +++ b/target-ppc/op_helper.c
> @@ -348,15 +348,13 @@ void helper_dcbz_970(target_ulong addr)
> 
> void helper_icbi(target_ulong addr)
> {
> -    uint32_t tmp;
> -
>     addr &= ~(env->dcache_line_size - 1);
>     /* Invalidate one cache line :
>      * PowerPC specification says this is to be treated like a load
>      * (not a fetch) by the MMU. To be sure it will be so,
>      * do the load "by hand".
>      */
> -    tmp = ldl(addr);
> +    ldl(addr);
>     tb_invalidate_page_range(addr, addr + env->icache_line_size);
> }
> 
> @@ -3802,7 +3800,8 @@ void helper_tlbie (target_ulong addr)
> /* PowerPC 602/603 software TLB load instructions helpers */
> static void do_6xx_tlb (target_ulong new_EPN, int is_code)
> {
> -    target_ulong RPN, CMP, EPN;
> +    target_ulong RPN, CMP;
> +    target_ulong EPN;

That one's no longer necessary then, right?

>     int way;
> 
>     RPN = env->spr[SPR_RPA];
> @@ -3814,6 +3813,7 @@ static void do_6xx_tlb (target_ulong new_EPN, int 
> is_code)
>         EPN = env->spr[SPR_DMISS];
>     }
>     way = (env->spr[SPR_SRR1] >> 17) & 1;
> +    (void)EPN; /* avoid a compiler warning */
>     LOG_SWTLB("%s: EPN " TARGET_FMT_lx " " TARGET_FMT_lx " PTE0 " 
> TARGET_FMT_lx
>               " PTE1 " TARGET_FMT_lx " way %d\n", __func__, new_EPN, EPN, CMP,
>               RPN, way);
> @@ -3835,13 +3835,15 @@ void helper_6xx_tlbi (target_ulong EPN)
> /* PowerPC 74xx software TLB load instructions helpers */
> static void do_74xx_tlb (target_ulong new_EPN, int is_code)
> {
> -    target_ulong RPN, CMP, EPN;
> +    target_ulong RPN, CMP;
> +    target_ulong EPN;

Same here.

Alex