https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109176
--- Comment #7 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Jakub Jelinek from comment #5)
> Before veclower2 we had/have
> _7 = ba_5(D) < a_6(D);
> _8 = svnand_b_z (_7, _7, _7);
> _9 = VEC_COND_EXPR <_7, _8, _7>;
> where _7/_8/_9 are all __SVBool_t.
> Before the r11-1445 changes, the VEC_COND_EXPR would be left untouched,
> because
> expand_vec_cond_expr_p (__SVBool_t, __SVBool_t, SSA_NAME) is true on aarch64.
> Now it doesn't, because _7 def_stmt is a comparison, and so
> expand_vec_cond_expr_p (__SVBool_t, VNx16QI, LT_EXPR).
> --- gcc/tree-vect-generic.cc.jj 2023-03-12 22:36:06.356178068 +0100
> +++ gcc/tree-vect-generic.cc 2023-03-20 16:31:03.321831866 +0100
> @@ -1063,6 +1063,12 @@ expand_vector_condition (gimple_stmt_ite
> return true;
> }
>
> + if (!TYPE_VECTOR_SUBPARTS (type).is_constant ()
> + && VECTOR_BOOLEAN_TYPE_P (type)
> + && VECTOR_BOOLEAN_TYPE_P (TREE_TYPE (a))
> + && expand_vec_cond_expr_p (type, TREE_TYPE (a), TREE_CODE (a)))
> + return true;
> +
> /* Handle vector boolean types with bitmasks. If there is a comparison
> and we can expand the comparison into the vector boolean bitmask,
> or otherwise if it is compatible with type, we can transform
> basically restores the behaviour here for the SVE boolean types and makes it
> compile.
> Because otherwise, unless this would be solvable by the AVX512 "Handle
> vector boolean types with bitmasks." code the non-constant vector elts cases
> will always ICE in the following code, int nunits =
> nunits_for_known_piecewise_op (type);
> requires constant TYPE_VECTOR_SUBPARTS and the code really isn't prepared to
> handle anything non-constant.
OK, so expand_vec_cond_expr_p does
bool
expand_vec_cond_expr_p (tree value_type, tree cmp_op_type, enum tree_code code)
{
machine_mode value_mode = TYPE_MODE (value_type);
machine_mode cmp_op_mode = TYPE_MODE (cmp_op_type);
if (VECTOR_BOOLEAN_TYPE_P (cmp_op_type)
&& get_vcond_mask_icode (TYPE_MODE (value_type),
TYPE_MODE (cmp_op_type)) != CODE_FOR_nothing)
return true;
first. I think vector lowering should always check the original 'a'
if it is a mask, like with the following, there's no good reason to
special-case this just for VL vectors
diff --git a/gcc/tree-vect-generic.cc b/gcc/tree-vect-generic.cc
index 519a824ec72..c957c9aa7a9 100644
--- a/gcc/tree-vect-generic.cc
+++ b/gcc/tree-vect-generic.cc
@@ -1040,6 +1040,10 @@ expand_vector_condition (gimple_stmt_iterator *gsi,
bitmap dce_ssa_names)
tree_code code = TREE_CODE (a);
gassign *assign = NULL;
+ if (VECTOR_BOOLEAN_TYPE_P (TREE_TYPE (a))
+ && expand_vec_cond_expr_p (type, TREE_TYPE (a), ERROR_MARK))
+ return true;
+
if (code == SSA_NAME)
{
assign = dyn_cast<gassign *> (SSA_NAME_DEF_STMT (a));
@@ -1053,14 +1057,14 @@ expand_vector_condition (gimple_stmt_iterator *gsi,
bitmap dce_ssa_names)
comp_inner_type = TREE_TYPE (TREE_TYPE (a1));
comp_width = vector_element_bits_tree (TREE_TYPE (a1));
}
- }
- if (expand_vec_cond_expr_p (type, TREE_TYPE (a1), code)
- || (integer_all_onesp (b) && integer_zerop (c)
- && expand_vec_cmp_expr_p (type, TREE_TYPE (a1), code)))
- {
- gcc_assert (TREE_CODE (a) == SSA_NAME || TREE_CODE (a) == VECTOR_CST);
- return true;
+ if (expand_vec_cond_expr_p (type, TREE_TYPE (a1), code)
+ || (integer_all_onesp (b) && integer_zerop (c)
+ && expand_vec_cmp_expr_p (type, TREE_TYPE (a1), code)))
+ {
+ gcc_assert (TREE_CODE (a) == SSA_NAME || TREE_CODE (a) ==
VECTOR_CST);
+ return true;
+ }
}
/* Handle vector boolean types with bitmasks. If there is a comparison
