Re: [PATCH ath-next] ath9k: eeprom: alias vpdTableI onto vpdTableL to shrink stack frame

[Toke Høiland-Jørgensen]

Rosen Penev <rosenp@xxxxxxxxx> writes:

> vpdTableL, vpdTableR, and vpdTableI are never live simultaneously.
> vpdTableL and vpdTableR are consumed during the frequency-interpolation
> step that writes vpdTableI; after the if/else they are never read
> again.  Reuse vpdTableL for the interpolated result (what was
> vpdTableI), reducing the stack frame by one 256-byte array.
>
> The read-via-write in the else branch is safe: ath9k_hw_interpolate()
> receives vpdTableL[i][j] by value as a function argument before the
> return value is written back to vpdTableL[i][j].
>
> Stack frame size change (x86_64, clang):
>   before: 0x440 (1088 B)
>   after:  0x330 (816 B)

Huh? These are static variables, how is this affecting stack usage?
I assume this is against your previous (broken) patch?

Anyway, adding this kind of aliasing to fix a problem that you
introduced by changing working code with no real benefit is not an
improvement. I'm OK with fixing actual bugs, but this is just mindless
churn...

-Toke