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    Subject[PATCH 4.2.y-ckt 161/218] ARC: bitops: Remove non relevant comments
    Date
    4.2.8-ckt7 -stable review patch.  If anyone has any objections, please let me know.

    ---8<------------------------------------------------------------

    From: Vineet Gupta <vgupta@synopsys.com>

    commit 2a41b6dc28dc71c1a3f1622612a26edc58f7561e upstream.

    commit 80f420842ff42 removed the ARC bitops microoptimization but failed
    to prune the comments to same effect

    Fixes: 80f420842ff42 ("ARC: Make ARC bitops "safer" (add anti-optimization)")
    Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
    Signed-off-by: Kamal Mostafa <kamal@canonical.com>
    ---
    arch/arc/include/asm/bitops.h | 15 ---------------
    1 file changed, 15 deletions(-)

    diff --git a/arch/arc/include/asm/bitops.h b/arch/arc/include/asm/bitops.h
    index 57c1f33..0352fb8 100644
    --- a/arch/arc/include/asm/bitops.h
    +++ b/arch/arc/include/asm/bitops.h
    @@ -35,21 +35,6 @@ static inline void op##_bit(unsigned long nr, volatile unsigned long *m)\
    \
    m += nr >> 5; \
    \
    - /* \
    - * ARC ISA micro-optimization: \
    - * \
    - * Instructions dealing with bitpos only consider lower 5 bits \
    - * e.g (x << 33) is handled like (x << 1) by ASL instruction \
    - * (mem pointer still needs adjustment to point to next word) \
    - * \
    - * Hence the masking to clamp @nr arg can be elided in general. \
    - * \
    - * However if @nr is a constant (above assumed in a register), \
    - * and greater than 31, gcc can optimize away (x << 33) to 0, \
    - * as overflow, given the 32-bit ISA. Thus masking needs to be \
    - * done for const @nr, but no code is generated due to gcc \
    - * const prop. \
    - */ \
    nr &= 0x1f; \
    \
    __asm__ __volatile__( \
    --
    2.7.4
    \
     
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