[PATCH] Introduce TV_INITIALIZE_RTL

[Jeff Law]

On 05/14/2015 10:29 AM, David Malcolm wrote:
> Before this patch, jit.dg/test-benchmark.c at optlevel 0, 100 iterations
> showed "rest of compilation" as taking a significant chunk of time:
>
> rest of compilation     :   1.53 (64%) usr   0.06 (32%) sys   1.60 (27%) wall    1388 kB ( 6%) ggc
>
> This turned out to be almost entirely spent inside initialize_rtl; adding a
> TV_INITIALIZE_RTL for this indicates this cost clearly:
>
> initialize rtl          :   1.46 (61%) usr   0.01 ( 5%) sys   1.42 (24%) wall    1156 kB ( 5%) ggc
> rest of compilation     :   0.05 ( 2%) usr   0.00 ( 0%) sys   0.00 ( 0%) wall     232 kB ( 1%) ggc
>
> I'm experimenting with a followup patch to amortize this away by making RTL
> initialization a one-time deal, but in the meantime, this patch adds
> accounting for it.
>
> OK for trunk? (assuming bootstrap and testing)
>
> gcc/ChangeLog:
> 	* timevar.def (TV_INITIALIZE_RTL): New.
> 	* toplev.c (initialize_rtl): Use an auto_timevar to account this
> 	function's time to TV_INITIALIZE_RTL.
We should done this a long time ago -- initialization/startup items are 
a real issue.

OK.

jeff