Re: [PATCH] counter: Declare counter_priv() to be const

[William Breathitt Gray <william.gray@linaro.org>]

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On Tue, Jul 18, 2023 at 06:20:15PM +0200, Uwe Kleine-König wrote:
> According to the gcc manual functions "whose return value is not
> affected by changes to the observable state of the program and that have
> no observable effects on such state other than to return a value may
> lend themselves to optimizations such as common subexpression
> elimination. Declaring such functions with the 'const' attribute allows
> GCC to avoid emitting some calls in repeated invocations of the function
> with the same argument values."
> 
> counter_priv() is such a function and so can be marked with the const
> function attribute.
> 
> The effect for an arm allyesconfig build according to bloat-o-meter (on
> top of v6.5-rc2) is:
> 
> 	add/remove: 0/1 grow/shrink: 2/14 up/down: 524/-1064 (-540)
> 	Function                                     old     new   delta
> 	rz_mtu3_count_enable_write                   632    1152    +520
> 	stm32_count_enable_write                     372     376      +4
> 	ti_eqep_action_read                          456     452      -4
> 	stm32_lptim_cnt_action_write                 400     392      -8
> 	stm32_lptim_cnt_action_read                  300     288     -12
> 	rz_mtu3_count_write                          296     284     -12
> 	rz_mtu3_count_read                           304     292     -12
> 	rz_mtu3_count_function_read                  212     200     -12
> 	rz_mtu3_count_direction_read                 268     256     -12
> 	rz_mtu3_action_read                          628     616     -12
> 	rz_mtu3_count_function_write                 328     312     -16
> 	ecap_cnt_suspend                             364     340     -24
> 	ecap_cnt_resume                              300     276     -24
> 	rz_mtu3_count_ceiling_write                  596     560     -36
> 	rz_mtu3_count_enable_read                    332     288     -44
> 	rz_mtu3_count_ceiling_read                   384     340     -44
> 	rz_mtu3_initialize_counter                   792       -    -792
> 	Total: Before=60715, After=60175, chg -0.89%
> 
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

Queued for counter-next.

Thanks,

William Breathitt Gray

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