On Thu, Aug 17, 2023 at 3:38 AM Andrew Pinski via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> Convert be sinked into a vec_cond if both sides
> fold. Unlike other unary operations, we need to check that we still can handle
> this vec_cond's first operand is the same as the new truth type.
>
> I tried a few different versions of this patch:
> view_convert to the new truth_type but that does not work as we always
> support all vec_cond
> afterwards.
> using expand_vec_cond_expr_p; but that would allow too much.
>
> I also tried to see if view_convert can be handled here but we end up with:
> _3 = VEC_COND_EXPR <_2, { Nan(-1), Nan(-1), Nan(-1), Nan(-1) }, { 0.0,
> 0.0, 0.0, 0.0 }>;
> Which isel does not know how to handle as just being a view_convert from
> `vector(4) <signed-boolean:32>`
> to `vector(4) float` and causes a regression with `g++.target/i386/pr88152.C`
>
> Note, in the case of the SVE testcase, we will sink negate after the convert
> and be able
> to remove a few extra instructions in the end.
> Also with this change gcc.target/aarch64/sve/cond_unary_5.c will now pass.
>
> OK? Bootstrapped and tested on x86_64-linux-gnu and aarch64-linux-gnu.
>
> gcc/ChangeLog:
>
> PR tree-optimization/111006
> PR tree-optimization/110986
> * match.pd: (op(vec_cond(a,b,c))): Handle convert for op.
>
> gcc/testsuite/ChangeLog:
>
> PR tree-optimization/111006
> * gcc.target/aarch64/sve/cond_convert_7.c: New test.
> ---
> gcc/match.pd | 9 ++++++++
> .../gcc.target/aarch64/sve/cond_convert_7.c | 23 +++++++++++++++++++
> 2 files changed, 32 insertions(+)
> create mode 100644 gcc/testsuite/gcc.target/aarch64/sve/cond_convert_7.c
>
> diff --git a/gcc/match.pd b/gcc/match.pd
> index acd2a964917..ca5ab6f289d 100644
> --- a/gcc/match.pd
> +++ b/gcc/match.pd
> @@ -4704,6 +4704,15 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
> (op (vec_cond:s @0 @1 @2))
> (vec_cond @0 (op! @1) (op! @2))))
>
> +/* Sink unary conversions to branches, but only if we do fold both
> + and the target's truth type is the same as we already have. */
> +(for op (convert)
This (for ..) looks unneeded?
Otherwise looks OK.
Thanks,
Richard.
> + (simplify
> + (op (vec_cond:s @0 @1 @2))
> + (if (VECTOR_TYPE_P (type)
> + && types_match (TREE_TYPE (@0), truth_type_for (type)))
> + (vec_cond @0 (op! @1) (op! @2)))))
> +
> /* Sink binary operation to branches, but only if we can fold it. */
> (for op (tcc_comparison plus minus mult bit_and bit_ior bit_xor
> lshift rshift rdiv trunc_div ceil_div floor_div round_div
> diff --git a/gcc/testsuite/gcc.target/aarch64/sve/cond_convert_7.c
> b/gcc/testsuite/gcc.target/aarch64/sve/cond_convert_7.c
> new file mode 100644
> index 00000000000..4bb95b92195
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/aarch64/sve/cond_convert_7.c
> @@ -0,0 +1,23 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -ftree-vectorize -moverride=sve_width=256
> -fdump-tree-optimized" } */
> +
> +/* This is a modified reduced version of cond_unary_5.c */
> +
> +void __attribute__ ((noipa))
> +f0 (unsigned short *__restrict r,
> + int *__restrict a,
> + int *__restrict pred)
> +{
> + for (int i = 0; i < 1024; ++i)
> + {
> + int p = pred[i]?-1:0;
> + r[i] = p ;
> + }
> +}
> +
> +/* { dg-final { scan-assembler-times {\tmov\tz[0-9]+\.h, p[0-7]+/z, #-1} 1 }
> } */
> +/* { dg-final { scan-assembler-not {\tmov\tz[0-9]+\.[hs], p[0-7]+/z, #1} } }
> */
> +
> +/* { dg-final { scan-tree-dump-not "VIEW_CONVERT_EXPR " "optimized" } } */
> +/* { dg-final { scan-tree-dump-not " = -" "optimized" } } */
> +/* { dg-final { scan-tree-dump-not " = \\\(vector" "optimized" } } */
> --
> 2.31.1
>
