Re: Pushed: [PATCH v2] vect: Fix vectorized BIT_FIELD_REF for signed bit-fields [PR110557]

[Prathamesh Kulkarni <prathamesh.kulkarni@linaro.org>]

On Mon, 10 Jul 2023 at 16:43, Xi Ruoyao via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> On Mon, 2023-07-10 at 10:33 +0000, Richard Biener wrote:
> > On Fri, 7 Jul 2023, Xi Ruoyao wrote:
> >
> > > If a bit-field is signed and it's wider than the output type, we
> > > must
> > > ensure the extracted result sign-extended.  But this was not handled
> > > correctly.
> > >
> > > For example:
> > >
> > >     int x : 8;
> > >     long y : 55;
> > >     bool z : 1;
> > >
> > > The vectorized extraction of y was:
> > >
> > >     vect__ifc__49.29_110 =
> > >       MEM <vector(2) long unsigned int> [(struct Item
> > > *)vectp_a.27_108];
> > >     vect_patt_38.30_112 =
> > >       vect__ifc__49.29_110 & { 9223372036854775552,
> > > 9223372036854775552 };
> > >     vect_patt_39.31_113 = vect_patt_38.30_112 >> 8;
> > >     vect_patt_40.32_114 =
> > >       VIEW_CONVERT_EXPR<vector(2) long int>(vect_patt_39.31_113);
> > >
> > > This is obviously incorrect.  This pach has implemented it as:
> > >
> > >     vect__ifc__25.16_62 =
> > >       MEM <vector(2) long unsigned int> [(struct Item
> > > *)vectp_a.14_60];
> > >     vect_patt_31.17_63 =
> > >       VIEW_CONVERT_EXPR<vector(2) long int>(vect__ifc__25.16_62);
> > >     vect_patt_32.18_64 = vect_patt_31.17_63 << 1;
> > >     vect_patt_33.19_65 = vect_patt_32.18_64 >> 9;
> >
> > OK.
>
> Pushed r14-2407 and r13-7553.
Hi Xi,
Your commit:
https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=63ae6bc60c0f67fb2791991bf4b6e7e0a907d420,

seems to cause following regressions on arm-linux-gnueabihf:
FAIL: g++.dg/vect/pr110557.cc  -std=c++98 (test for excess errors)
FAIL: g++.dg/vect/pr110557.cc  -std=c++14 (test for excess errors)
FAIL: g++.dg/vect/pr110557.cc  -std=c++17 (test for excess errors)
FAIL: g++.dg/vect/pr110557.cc  -std=c++20 (test for excess errors)

Excess error:
gcc/testsuite/g++.dg/vect/pr110557.cc:12:8: warning: width of
'Item::y' exceeds its type

Thanks,
Prathamesh
>
> --
> Xi Ruoyao <xry111@xry111.site>
> School of Aerospace Science and Technology, Xidian University