Re: [PATCH] tests/tcg/s390x: Fix mvc, mvo and pack tests with Clang

[David Hildenbrand]

On 01.03.22 10:39, Thomas Huth wrote:
> These instructions use addressing with a "base address", meaning
> that if register r0 is used, it is always treated as zero, no matter
> what value is stored in the register. So we have to make sure not
> to use register r0 for these instructions in our tests. There was
> no problem with GCC so far since it seems to always pick other
> registers by default, but Clang likes to chose register r0, too,
> so we have to use the "a" constraint to make sure that it does
> not pick r0 here.
> 
> Signed-off-by: Thomas Huth <thuth@redhat.com>
> ---
>  tests/tcg/s390x/mvc.c  | 4 ++--
>  tests/tcg/s390x/mvo.c  | 4 ++--
>  tests/tcg/s390x/pack.c | 2 +-
>  3 files changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/tests/tcg/s390x/mvc.c b/tests/tcg/s390x/mvc.c
> index aa552d52e5..7ae4c44550 100644
> --- a/tests/tcg/s390x/mvc.c
> +++ b/tests/tcg/s390x/mvc.c
> @@ -20,8 +20,8 @@ static inline void mvc_256(const char *dst, const char *src)
>      asm volatile (
>          "    mvc 0(256,%[dst]),0(%[src])\n"
>          :
> -        : [dst] "d" (dst),
> -          [src] "d" (src)
> +        : [dst] "a" (dst),
> +          [src] "a" (src)
>          : "memory");
>  }
>  
> diff --git a/tests/tcg/s390x/mvo.c b/tests/tcg/s390x/mvo.c
> index 5546fe2a97..0c3ecdde2e 100644
> --- a/tests/tcg/s390x/mvo.c
> +++ b/tests/tcg/s390x/mvo.c
> @@ -11,8 +11,8 @@ int main(void)
>      asm volatile (
>          "    mvo 0(4,%[dest]),0(3,%[src])\n"
>          :
> -        : [dest] "d" (dest + 1),
> -          [src] "d" (src + 1)
> +        : [dest] "a" (dest + 1),
> +          [src] "a" (src + 1)
>          : "memory");
>  
>      for (i = 0; i < sizeof(expected); i++) {
> diff --git a/tests/tcg/s390x/pack.c b/tests/tcg/s390x/pack.c
> index 4be36f29a7..55e7e214e8 100644
> --- a/tests/tcg/s390x/pack.c
> +++ b/tests/tcg/s390x/pack.c
> @@ -9,7 +9,7 @@ int main(void)
>      asm volatile(
>          "    pack 2(4,%[data]),2(4,%[data])\n"
>          :
> -        : [data] "r" (&data[0])
> +        : [data] "a" (&data[0])
>          : "memory");
>      for (i = 0; i < 8; i++) {
>          if (data[i] != exp[i]) {

Reviewed-by: David Hildenbrand <david@redhat.com>

-- 
Thanks,

David / dhildenb