Richard Biener via Gcc-patches <gcc-patches@gcc.gnu.org> writes:
> On Wed, Dec 1, 2021 at 11:56 AM Richard Sandiford via Gcc-patches
> <gcc-patches@gcc.gnu.org> wrote:
>>
>> When checking for compatible stmts, vect_build_slp_tree_1 did:
>>
>> && !(STMT_VINFO_GROUPED_ACCESS (stmt_info)
>> && (first_stmt_code == ARRAY_REF
>> || first_stmt_code == BIT_FIELD_REF
>> || first_stmt_code == INDIRECT_REF
>> || first_stmt_code == COMPONENT_REF
>> || first_stmt_code == MEM_REF)))
>>
>> That is, it allowed any rhs_code as long as the first_stmt_code
>> looked valid. This had the effect of allowing IFN_MASK_LOAD
>> to be paired with an earlier non-call code (but didn't allow
>> the reverse).
>>
>> This patch makes the check symmetrical.
>>
>> Still testing on x86_64-linux-gnu. OK if testing passes, or doesn't
>> this seem like the right approach?
>
> It's indeed a too weak comparison of the classification of the first
> and the followup operands, some larger refactoring is probably
> needed to improve here (note how we compare STMT_VINFO_GROUPED_ACCESS
> of the followup against the tree codes of the first stmt but also later
> compare first_stmt_load_p against load_p).
>
> The proposed patch looks reasonable (but then we could drop
> the STMT_VINFO_GROUPED_ACCESS (stmt_info) part of the check?),
Yeah, was wondering about that. Seemed safer to keep it, since without
it we might pair non-memory BIT_FIELD_REFs with other things. I guess
the same goes for the first stmt though, and the mismatch ought to be
caught later anyway.
> so OK.
Thanks,
Richard
> Thanks,
> Richard.
>
>> Richard
>>
>>
>> gcc/
>> PR tree-optimization/103517
>> * tree-vect-slp.c (vect_build_slp_tree_1): When allowing two
>> different component references, check the codes of both them,
>> rather than just the first.
>>
>> gcc/testsuite/
>> PR tree-optimization/103517
>> * gcc.dg/vect/pr103517.c: New test.
>> ---
>> gcc/testsuite/gcc.dg/vect/pr103517.c | 13 +++++++++++++
>> gcc/tree-vect-slp.c | 7 ++++++-
>> 2 files changed, 19 insertions(+), 1 deletion(-)
>> create mode 100644 gcc/testsuite/gcc.dg/vect/pr103517.c
>>
>> diff --git a/gcc/testsuite/gcc.dg/vect/pr103517.c
>> b/gcc/testsuite/gcc.dg/vect/pr103517.c
>> new file mode 100644
>> index 00000000000..de87fc48f84
>> --- /dev/null
>> +++ b/gcc/testsuite/gcc.dg/vect/pr103517.c
>> @@ -0,0 +1,13 @@
>> +/* { dg-do compile } */
>> +/* { dg-additional-options "-march=skylake-avx512" { target x86_64-*-*
>> i?86-*-* } } */
>> +
>> +int a;
>> +short b, c;
>> +extern short d[];
>> +void e() {
>> + for (short f = 1; f < (short)a; f += 2)
>> + if (d[f + 1]) {
>> + b = d[f];
>> + c = d[f + 1];
>> + }
>> +}
>> diff --git a/gcc/tree-vect-slp.c b/gcc/tree-vect-slp.c
>> index 7bff5118bd0..bc22ffeed82 100644
>> --- a/gcc/tree-vect-slp.c
>> +++ b/gcc/tree-vect-slp.c
>> @@ -1121,7 +1121,12 @@ vect_build_slp_tree_1 (vec_info *vinfo, unsigned char
>> *swap,
>> || first_stmt_code == BIT_FIELD_REF
>> || first_stmt_code == INDIRECT_REF
>> || first_stmt_code == COMPONENT_REF
>> - || first_stmt_code == MEM_REF)))
>> + || first_stmt_code == MEM_REF)
>> + && (rhs_code == ARRAY_REF
>> + || rhs_code == BIT_FIELD_REF
>> + || rhs_code == INDIRECT_REF
>> + || rhs_code == COMPONENT_REF
>> + || rhs_code == MEM_REF)))
>> || first_stmt_load_p != load_p
>> || first_stmt_phi_p != phi_p)
>> {
>> --
>> 2.25.1
>>
