This is the mail archive of the gcc-patches@gcc.gnu.org mailing list for the GCC project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: [PATCH] combine: Allow combining two insns to two insns


On Wed, 1 Aug 2018 at 11:40, Segher Boessenkool
<segher@kernel.crashing.org> wrote:
>
> On Wed, Aug 01, 2018 at 10:27:31AM +0200, Christophe Lyon wrote:
> > On Tue, 31 Jul 2018 at 15:57, Segher Boessenkool
> > <segher@kernel.crashing.org> wrote:
> > > On Tue, Jul 31, 2018 at 02:34:06PM +0200, Christophe Lyon wrote:
> > > > Since this was committed, I've noticed regressions
> > > > on aarch64:
> > > > FAIL: gcc.dg/zero_bits_compound-1.c scan-assembler-not \\(and:
> > >
> > > This went from
> > >         and     w0, w0, 255
> > >         lsl     w1, w0, 8
> > >         orr     w0, w1, w0, lsl 20
> > >         ret
> > > to
> > >         and     w1, w0, 255
> > >         ubfiz   w0, w0, 8, 8
> > >         orr     w0, w0, w1, lsl 20
> > >         ret
> > > so it's neither an improvement nor a regression, just different code.
> > > The testcase wants no ANDs in the RTL.
> >
> > I didn't try to manually regenerate the code before and after the patch,
> > but if there was "and     w0, w0, 255" before the patch, why did the test pass?
>
> It wasn't an AND in RTL (it was a ZERO_EXTEND).
>

Indeed, I missed the -dP in the options.

> > > > on arm-none-linux-gnueabi
> > > > FAIL: gfortran.dg/actual_array_constructor_1.f90   -O1  execution test
> > >
> > > That sounds bad.  Open a PR, maybe?
> > >
> > I've just filed PR86771
>
> Thanks.
>
>
> Segher


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]