[PATCH, rs6000] Do not enable pcrel-opt by default

Segher Boessenkool segher@kernel.crashing.org
Wed Jun 23 14:57:10 GMT 2021


Hi!

On Tue, Jun 22, 2021 at 04:13:36PM -0500, Aaron Sawdey wrote:
> SPEC2017 testing on p10 shows that this optimization does not have a
> positive impact on performance. So we are no longer going to enable it
> by default. The test cases for it needed to be updated so they always
> enable it to test it.

> gcc/
> 	* config/rs6000/rs6000-cpus.def: Take OPTION_MASK_PCREL_OPT out
> 	 of OTHER_POWER10_MASKS so it will not be enabled by default.

Stray space at start of line.

> --- a/gcc/config/rs6000/rs6000-cpus.def
> +++ b/gcc/config/rs6000/rs6000-cpus.def
> @@ -75,9 +75,10 @@
>  				 | OPTION_MASK_P9_VECTOR)
>  
>  /* Flags that need to be turned off if -mno-power10.  */
> +/* PCREL_OPT is now disabled by default so we comment it out here.  */

"Now" is meaningless to future readers ;-)

Please also say *why* it is disabled.

Okay for trunk like that.  Also okay for 11 if it regstraps.  Thanks!


Segher


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