diff options
| -rw-r--r-- | arch/s390/include/asm/bitops.h | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/arch/s390/include/asm/bitops.h b/arch/s390/include/asm/bitops.h index 9bc70acbac9e..ac94672db817 100644 --- a/arch/s390/include/asm/bitops.h +++ b/arch/s390/include/asm/bitops.h @@ -132,9 +132,10 @@ static inline bool test_bit_inv(unsigned long nr, */ static __always_inline unsigned char __flogr(unsigned long word) { - if (__builtin_constant_p(word)) { - unsigned long bit = 0; + unsigned long bit; + if (__builtin_constant_p(word)) { + bit = 0; if (!word) return 64; if (!(word & 0xffffffff00000000UL)) { @@ -169,7 +170,14 @@ static __always_inline unsigned char __flogr(unsigned long word) asm volatile( " flogr %[rp],%[rp]\n" : [rp] "+d" (rp.pair) : : "cc"); - return rp.even & 127; + bit = rp.even; + /* + * The result of the flogr instruction is a value in the range + * of 0..64. Let the compiler know that the AND operation can + * be optimized away. + */ + __assume(bit <= 64); + return bit & 127; } } |