Re: [PATCH v2] selftests: riscv: fix v_exec_initval_nolibc.c

[Ignacio Encinas Rubio <ignacio@iencinas.com>]

Gentle ping :)

On 6/3/25 20:49, Ignacio Encinas wrote:
> Vector registers are zero initialized by the kernel. Stop accepting
> "all ones" as a clean value.
> 
> Note that this was not working as expected given that
> 	value == 0xff
> can be assumed to be always false by the compiler as value's range is
> [-128, 127]. Both GCC (-Wtype-limits) and clang
> (-Wtautological-constant-out-of-range-compare) warn about this.
> 
> Reviewed-by: Charlie Jenkins <charlie@rivosinc.com>
> Tested-by: Charlie Jenkins <charlie@rivosinc.com>
> Signed-off-by: Ignacio Encinas <ignacio@iencinas.com>
> ---
> Changes in v2:
> 
> Remove code that becomes useless now that the only "clean" value for
> vector registers is 0.
> 
> - Link to v1: https://lore.kernel.org/r/20250305-fix-v_exec_initval_nolibc-v1-1-b87b60e43002@iencinas.com
> ---
>  tools/testing/selftests/riscv/vector/v_exec_initval_nolibc.c | 10 +++-------
>  1 file changed, 3 insertions(+), 7 deletions(-)
> 
> diff --git a/tools/testing/selftests/riscv/vector/v_exec_initval_nolibc.c b/tools/testing/selftests/riscv/vector/v_exec_initval_nolibc.c
> index 35c0812e32de0c82a54f84bd52c4272507121e35..4dde05e45a04122b566cedc36d20b072413b00e2 100644
> --- a/tools/testing/selftests/riscv/vector/v_exec_initval_nolibc.c
> +++ b/tools/testing/selftests/riscv/vector/v_exec_initval_nolibc.c
> @@ -6,7 +6,7 @@
>   * the values. To further ensure consistency, this file is compiled without
>   * libc and without auto-vectorization.
>   *
> - * To be "clean" all values must be either all ones or all zeroes.
> + * To be "clean" all values must be all zeroes.
>   */
>  
>  #define __stringify_1(x...)	#x
> @@ -14,9 +14,8 @@
>  
>  int main(int argc, char **argv)
>  {
> -	char prev_value = 0, value;
> +	char value = 0;
>  	unsigned long vl;
> -	int first = 1;
>  
>  	if (argc > 2 && strcmp(argv[2], "x"))
>  		asm volatile (
> @@ -44,14 +43,11 @@ int main(int argc, char **argv)
>  			"vsrl.vi " __stringify(register) ", " __stringify(register) ", 8\n\t" \
>  			".option pop\n\t"					\
>  			: "=r" (value));					\
> -		if (first) {							\
> -			first = 0;						\
> -		} else if (value != prev_value || !(value == 0x00 || value == 0xff)) { \
> +		if (value != 0x00) {						\
>  			printf("Register " __stringify(register)		\
>  				" values not clean! value: %u\n", value);	\
>  			exit(-1);						\
>  		}								\
> -		prev_value = value;						\
>  	}									\
>  })
>  
> 
> ---
> base-commit: 03d38806a902b36bf364cae8de6f1183c0a35a67
> change-id: 20250301-fix-v_exec_initval_nolibc-498d976c372d
> 
> Best regards,