Hi!
On Fri, Dec 20, 2019 at 02:34:05PM +0800, Jiufu Guo wrote:
> Previously, limited unrolling was enabled at O2 for powerpc in r278034. At
> that
> time, -fweb and -frename-registers were not enabled together with
> -funroll-loops
> even for -O3. After that, we notice there are some performance degradation on
> SPEC2006fp which caused by without web and rnreg.
And 2017 was fine on all tests. Annoying :-(
> This patch enable -fweb
> and -frename-registers for -O3 to align original behavior before r278034.
Okay. Hopefully we can find a way to determine in what circumstances web
and rnreg help instead of hurt, but until then, the old behaviour is
certainly the safe choice.
> --- a/gcc/testsuite/gcc.dg/torture/stackalign/builtin-return-1.c
> +++ b/gcc/testsuite/gcc.dg/torture/stackalign/builtin-return-1.c
> @@ -2,6 +2,7 @@
> /* Originator: Andrew Church <gcczi...@achurch.org> */
> /* { dg-do run } */
> /* { dg-require-effective-target untyped_assembly } */
> +/* { dg-additional-options "-fno-rename-registers" { target { powerpc*-*-* }
> } } */
What is this for? What happens without it?
The rs6000/ parts are okay for trunk. Thanks!
Segher
