4.5-stable review patch. If anyone has any objections, please let me know.
------------------ From: Vineet Gupta <[email protected]> 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 <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- arch/arc/include/asm/bitops.h | 15 --------------- 1 file changed, 15 deletions(-) --- a/arch/arc/include/asm/bitops.h +++ b/arch/arc/include/asm/bitops.h @@ -35,21 +35,6 @@ static inline void op##_bit(unsigned lon \ 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__( \
