On Mon, 24 Apr 2023 at 15:02, Richard Sandiford
<richard.sandif...@arm.com> wrote:
>
> Prathamesh Kulkarni <prathamesh.kulka...@linaro.org> writes:
> > gcc/ChangeLog:
> > * tree-ssa-forwprop.cc (is_combined_permutation_identity): Try to
> > simplify two successive VEC_PERM_EXPRs with single operand and same
> > mask, where mask chooses elements in reverse order.
> >
> > gcc/testesuite/ChangeLog:
> > * gcc.target/aarch64/sve/acle/general/rev-1.c: New test.
> >
> > diff --git a/gcc/testsuite/gcc.target/aarch64/sve/acle/general/rev-1.c
> > b/gcc/testsuite/gcc.target/aarch64/sve/acle/general/rev-1.c
> > new file mode 100644
> > index 00000000000..e57ee67d716
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.target/aarch64/sve/acle/general/rev-1.c
> > @@ -0,0 +1,12 @@
> > +/* { dg-do compile } */
> > +/* { dg-options "-O3 -fdump-tree-optimized" } */
> > +
> > +#include <arm_sve.h>
> > +
> > +svint32_t f(svint32_t v)
> > +{
> > + return svrev_s32 (svrev_s32 (v));
> > +}
> > +
> > +/* { dg-final { scan-tree-dump "return v_1\\(D\\)" "optimized" } } */
> > +/* { dg-final { scan-tree-dump-not "VEC_PERM_EXPR" "optimized" } } */
> > diff --git a/gcc/tree-ssa-forwprop.cc b/gcc/tree-ssa-forwprop.cc
> > index 9b567440ba4..61df7efe82c 100644
> > --- a/gcc/tree-ssa-forwprop.cc
> > +++ b/gcc/tree-ssa-forwprop.cc
> > @@ -2541,6 +2541,27 @@ is_combined_permutation_identity (tree mask1, tree
> > mask2)
> >
> > gcc_checking_assert (TREE_CODE (mask1) == VECTOR_CST
> > && TREE_CODE (mask2) == VECTOR_CST);
> > +
> > + /* For VLA masks, check for the following pattern:
> > + v1 = VEC_PERM_EXPR (v0, v0, mask1)
> > + v2 = VEC_PERM_EXPR (v1, v1, mask2)
>
> Maybe blank out the second operands using "...":
>
> v1 = VEC_PERM_EXPR (v0, ..., mask1)
> v2 = VEC_PERM_EXPR (v1, ..., mask2)
>
> to make it clear that they don't matter.
>
> OK with that change, thanks.
Thanks, committed in:
https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=f0eabc52c9a2d3da0bfc201da7a5c1658b76e9a4
Thanks,
Prathamesh
>
> Richard
>
> > + -->
> > + v2 = v0
> > + if mask1 == mask2 == {nelts - 1, nelts - 2, ...}. */
> > +
> > + if (operand_equal_p (mask1, mask2, 0)
> > + && !VECTOR_CST_NELTS (mask1).is_constant ())
> > + {
> > + vec_perm_builder builder;
> > + if (tree_to_vec_perm_builder (&builder, mask1))
> > + {
> > + poly_uint64 nelts = TYPE_VECTOR_SUBPARTS (TREE_TYPE (mask1));
> > + vec_perm_indices sel (builder, 1, nelts);
> > + if (sel.series_p (0, 1, nelts - 1, -1))
> > + return 1;
> > + }
> > + }
> > +
> > mask = fold_ternary (VEC_PERM_EXPR, TREE_TYPE (mask1), mask1, mask1,
> > mask2);
> > if (mask == NULL_TREE || TREE_CODE (mask) != VECTOR_CST)
> > return 0;
