> -----Original Message-----
> From: Richard Sandiford <richard.sandif...@arm.com>
> Sent: Friday, July 26, 2024 10:24 AM
> To: Tamar Christina <tamar.christ...@arm.com>
> Cc: gcc-patches@gcc.gnu.org; nd <n...@arm.com>; Richard Earnshaw
> <richard.earns...@arm.com>; Marcus Shawcroft
> <marcus.shawcr...@arm.com>; ktkac...@gcc.gnu.org
> Subject: Re: [PATCH]AArch64: check for vector mode in get_mask_mode
> [PR116074]
>
> Tamar Christina <tamar.christ...@arm.com> writes:
> > Hi All,
> >
> > For historical reasons AArch64 has TI mode vector types but does not
> > consider
> > TImode a vector mode.
> >
> > What's happening in the PR is that get_vectype_for_scalar_type is returning
> > vector(1) TImode for a TImode scalar. This then fails when we call
> > targetm.vectorize.get_mask_mode (vecmode).exists (&) on the TYPE_MODE.
> >
> > I've checked other usages of get_mask_mode and none of them have anything
> that
> > would prevent this same issue from happening. It only happens that normally
> > the vectorizer rejects the vector(1) type early, but in this case we get
> > further because the COND_EXPR hasn't been analyzed yet for a type.
> >
> > I believe get_mask_mode shouldn't fault, and so this adds the check for
> > vector
> > mode in the hook and returns nothing if it's not. I did not add this to the
> > generic function because I believe this is an AArch64 quirk.
>
> Feels to me like the problem is higher up. The hook says:
>
> Return the mode to use for a vector mask that holds one boolean
> result for each element of vector mode @var{mode}. ...
>
> So the caller is breaking the interface if it is passing a non-vector mode.
But my point is that it's AArch64 that creates a vector type from a non-vector
mode.
I can easily fix my own call site. But it's weird that AArch64 has a TYPE_MODE
(vectorype) != VECTOR_MODE.
So I still think this is an AArch64 bug.
Tamar
>
> Thanks,
> Richard
>
> >
> > Bootstrapped Regtested on aarch64-none-linux-gnu and no issues.
> >
> > Ok for master?
> >
> > Thanks,
> > Tamar
> >
> > gcc/ChangeLog:
> >
> > PR target/116074
> > * config/aarch64/aarch64.cc (aarch64_get_mask_mode): Check vector
> mode.
> >
> > gcc/testsuite/ChangeLog:
> >
> > PR target/116074
> > * g++.target/aarch64/pr116074.C: New test.
> >
> > ---
> >
> > diff --git a/gcc/config/aarch64/aarch64.cc b/gcc/config/aarch64/aarch64.cc
> > index
> 355ab97891cf0a7d487fa4c69ae23a5f75897851..045ac0e09b0eaa14935db392
> 4798402c9dd1947c 100644
> > --- a/gcc/config/aarch64/aarch64.cc
> > +++ b/gcc/config/aarch64/aarch64.cc
> > @@ -1870,6 +1870,9 @@ aarch64_sve_pred_mode (machine_mode mode)
> > static opt_machine_mode
> > aarch64_get_mask_mode (machine_mode mode)
> > {
> > + if (!VECTOR_MODE_P (mode))
> > + return opt_machine_mode ();
> > +
> > unsigned int vec_flags = aarch64_classify_vector_mode (mode);
> > if (vec_flags & VEC_SVE_DATA)
> > return aarch64_sve_pred_mode (mode);
> > diff --git a/gcc/testsuite/g++.target/aarch64/pr116074.C
> b/gcc/testsuite/g++.target/aarch64/pr116074.C
> > new file mode 100644
> > index
> 0000000000000000000000000000000000000000..54cf561510c460499a816a
> b6a84603fc20a5f1e5
> > --- /dev/null
> > +++ b/gcc/testsuite/g++.target/aarch64/pr116074.C
> > @@ -0,0 +1,24 @@
> > +/* { dg-do compile } */
> > +/* { dg-additional-options "-O3" } */
> > +
> > +int m[40];
> > +
> > +template <typename k> struct j {
> > + int length;
> > + k *e;
> > + void operator[](int) {
> > + if (length)
> > + __builtin___memcpy_chk(m, m+3, sizeof (k), -1);
> > + }
> > +};
> > +
> > +j<j<int>> o;
> > +
> > +int *q;
> > +
> > +void ao(int i) {
> > + for (; i > 0; i--) {
> > + o[1];
> > + *q = 1;
> > + }
> > +}
