On Sat, May 25, 2024 at 4:45 PM Feng Xue OS <f...@os.amperecomputing.com> wrote:
>
> Some utility functions (such as vect_look_through_possible_promotion) that are
> to find out certain kind of direct or indirect definition SSA for a value, may
> return the original one of the SSA, not its pattern representative SSA, even
> pattern is involved. For example,
>
> a = (T1) patt_b;
> patt_b = (T2) c; // b = ...
> patt_c = not-a-cast; // c = ...
>
> Given 'a', the mentioned function will return 'c', instead of 'patt_c'. This
> subtlety would make some pattern recog code that is unaware of it mis-use the
> original instead of the new pattern statement, which is inconsistent wth
> processing logic of the pattern formation pass. This patch corrects the issue
> by forcing another utility function (vect_get_internal_def) return the pattern
> statement information to caller by default.
>
> Regression test on x86-64 and aarch64.
>
> Feng
> --
> gcc/
> PR tree-optimization/115060
> * tree-vect-patterns.h (vect_get_internal_def): Add a new parameter
> for_vectorize.
> (vect_widened_op_tree): Call vect_get_internal_def instead of look_def
> to get statement information.
> (vect_recog_widen_abd_pattern): No need to call
> vect_stmt_to_vectorize.
> ---
> gcc/tree-vect-patterns.cc | 16 +++++++++++-----
> 1 file changed, 11 insertions(+), 5 deletions(-)
>
> diff --git a/gcc/tree-vect-patterns.cc b/gcc/tree-vect-patterns.cc
> index a313dc64643..fa35bf26372 100644
> --- a/gcc/tree-vect-patterns.cc
> +++ b/gcc/tree-vect-patterns.cc
> @@ -258,15 +258,21 @@ vect_element_precision (unsigned int precision)
> }
>
> /* If OP is defined by a statement that's being considered for vectorization,
> - return information about that statement, otherwise return NULL. */
> + return information about that statement, otherwise return NULL.
> + FOR_VECTORIZE is used to specify whether original or vectorization
> + representative (if have) statement information is returned. */
>
> static stmt_vec_info
> -vect_get_internal_def (vec_info *vinfo, tree op)
> +vect_get_internal_def (vec_info *vinfo, tree op, bool for_vectorize = true)
I'm probably blind - but you nowhere pass 'false' and I think returning the
pattern stmt is the correct behavior always.
OK with omitting the new parameter.
> {
> stmt_vec_info def_stmt_info = vinfo->lookup_def (op);
> if (def_stmt_info
> && STMT_VINFO_DEF_TYPE (def_stmt_info) == vect_internal_def)
> - return def_stmt_info;
> + {
> + if (for_vectorize)
> + def_stmt_info = vect_stmt_to_vectorize (def_stmt_info);
> + return def_stmt_info;
> + }
> return NULL;
> }
>
> @@ -655,7 +661,8 @@ vect_widened_op_tree (vec_info *vinfo, stmt_vec_info
> stmt_info, tree_code code,
>
> /* Recursively process the definition of the operand. */
> stmt_vec_info def_stmt_info
> - = vinfo->lookup_def (this_unprom->op);
> + = vect_get_internal_def (vinfo, this_unprom->op);
> +
> nops = vect_widened_op_tree (vinfo, def_stmt_info, code,
> widened_code, shift_p, max_nops,
> this_unprom, common_type,
> @@ -1739,7 +1746,6 @@ vect_recog_widen_abd_pattern (vec_info *vinfo,
> stmt_vec_info stmt_vinfo,
> if (!abd_pattern_vinfo)
> return NULL;
>
> - abd_pattern_vinfo = vect_stmt_to_vectorize (abd_pattern_vinfo);
> gcall *abd_stmt = dyn_cast <gcall *> (STMT_VINFO_STMT (abd_pattern_vinfo));
> if (!abd_stmt
