From: Rasmus Villemoes <[email protected]> Date: Fri, 23 Jan 2015 12:06:52 +0100
> The code 'if (foo & X) foo &= ~X;' is semantically equivalent to > simply 'foo &= ~X;', but gcc generates about four instructions for the > former, one for the latter. Similarly, if X consists of a single bit, > 'if (!(foo & X)) X |= X;' can be replaced by 'foo |= X;'. > > In the atl2 case, gcc does know how to merge the new adjacent > operations, so altogether this gives a nice little code size > reduction of about 80 bytes. > > Signed-off-by: Rasmus Villemoes <[email protected]> I agree with the feedback given that these open-coded sequences should be replaced with the appropriate PCI helpers instead of edited further. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
