Messages in this thread | | | Date | Wed, 20 May 2015 12:36:44 -0700 | From | Dmitry Torokhov <> | Subject | Re: [PATCH] Input:evdev - Fix to avoid the execution of same instruction in every iteration of for loop. |
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Hi Shailendra,
On Thu, May 21, 2015 at 12:35:46AM +0530, Shailendra Verma wrote: > Here in for loop the instruction "len / sizeof(compat_long_t)" is used > as a terminating condition which is executing (being computed) in every > iteration of for loop. Below is the armv7-a architecture assembly code with > similar for loop having the same instruction in condition.Note that the > instruction "lsr r3, r3, #2" i.e Logical Shift Right on behalf of > "len / sizeof(compat_long_t)" is getting executed every time the loop > iterates.
No, it is not. We compile kernel with -O2 and compiler is smart enough to optimize such constructs.
Thanks.
-- Dmitry
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