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Re: [PATCH] Account for prologue spills in reg_pressure scheduling


Hi Maxim,

Maxim Kuvyrkov wrote:
>  Thanks, benchmarking results are welcome!  AArch64 doesn't use reg_pressure
> scheduling by default.  Use "-fsched-pressure
> --param=sched-pressure-algorithm=2" to enable same thing as on ARM.  I would
> imagine C++ and Fortran floating-point code to be most affected.

On aarch64 I only see perf improvements with your patch: no perf degradations on
all the tests that I have run.

base0: r216447, -O3
base1: r216447, -O3 -fsched-pressure --param=sched-pressure-algorithm=2
patch: r216447 + your patch, -O3 -fsched-pressure --param=sched-pressure-algorithm=2

patch vs. base1 is only an improvement.

base1 vs. base0 has a few good improvements, and some small degradations: your
patch improves the perf for one of the degradations to the point it is better
now with -fsched-pressure --param=sched-pressure-algorithm=2 than at -O3.

Could we turn on "-fsched-pressure --param=sched-pressure-algorithm=2" by
default for aarch64?

Thanks,
Sebastian


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