Re: [PATCH] x86: make use of inc/dec conditional

[Jan Beulich]

>>> Thomas Gleixner <tglx@xxxxxxxxxxxxx> 19.08.09 11:06 >>>
>You still do not tell on which machines the INC/DEC instructions
>should be avoided and why. GCC avoiding it is not a convincing
>argument.

On Pentium4 (Prescott/Nocona) inc/dec not modifying the carry flag cause
an extra instruction dependency on EFLAGS, and hence extra latency in
when the instruction can be scheduled for execution.

Jan

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