selftests: riscv: fix v_exec_initval_nolibc.c

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>
Link: https://lore.kernel.org/r/20250306-fix-v_exec_initval_nolibc-v2-1-97f9dc8a7faf@iencinas.com
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>

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 (file)
--- 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;                                             \
        }                                                                       \
 })