on 2024/7/1 22:28, Richard Biener wrote:
> On Mon, Jul 1, 2024 at 8:16 AM Kewen.Lin <li...@linux.ibm.com> wrote:
>>
>> Hi,
>>
>> As PR115659 shows, assuming c = x CMP y, there are some
>> folding chances for patterns r = c ? -1/z : z/0.
>>
>> For r = c ? -1 : z, it can be folded into:
>> - r = c | z (with ior_optab supported)
>> - or r = c ? c : z
>>
>> while for r = c ? z : 0, it can be foled into:
>> - r = c & z (with and_optab supported)
>> - or r = c ? z : c
>>
>> This patch is to teach ISEL to take care of them and also
>> remove the redundant gsi_replace as the caller of function
>> gimple_expand_vec_cond_expr will handle it.
>
> Yeah, not the nicest API ...
>
>> Bootstrapped and regtested on x86_64-redhat-linux and
>> powerpc64{,le}-linux-gnu.
>>
>> Is it ok for trunk?
>
> Minor nit below
>
>> BR,
>> Kewen
>> -----
>> PR tree-optimization/115659
>>
>> gcc/ChangeLog:
>>
>> * gimple-isel.cc (gimple_expand_vec_cond_expr): Add more foldings for
>> patterns x CMP y ? -1 : z and x CMP y ? z : 0.
>> ---
>> gcc/gimple-isel.cc | 48 +++++++++++++++++++++++++++++++++++++++-------
>> 1 file changed, 41 insertions(+), 7 deletions(-)
>>
>> diff --git a/gcc/gimple-isel.cc b/gcc/gimple-isel.cc
>> index 54c1801038b..71af1a8cd97 100644
>> --- a/gcc/gimple-isel.cc
>> +++ b/gcc/gimple-isel.cc
>> @@ -240,16 +240,50 @@ gimple_expand_vec_cond_expr (struct function *fun,
>> gimple_stmt_iterator *gsi,
>> can_compute_op0 = expand_vec_cmp_expr_p (op0a_type, op0_type,
>> tcode);
>>
>> - /* Try to fold x CMP y ? -1 : 0 to x CMP y. */
>> if (can_compute_op0
>> - && integer_minus_onep (op1)
>> - && integer_zerop (op2)
>> && TYPE_MODE (TREE_TYPE (lhs)) == TYPE_MODE (TREE_TYPE (op0)))
>> {
>> - tree conv_op = build1 (VIEW_CONVERT_EXPR, TREE_TYPE (lhs),
>> op0);
>> - gassign *new_stmt = gimple_build_assign (lhs, conv_op);
>> - gsi_replace (gsi, new_stmt, true);
>> - return new_stmt;
>> + /* Assuming c = x CMP y. */
>> + bool op1_minus_onep = integer_minus_onep (op1);
>> + bool op2_zerop = integer_zerop (op2);
>> + tree vtype = TREE_TYPE (lhs);
>> + machine_mode vmode = TYPE_MODE (vtype);
>> + /* Try to fold r = c ? -1 : 0 to r = c. */
>> + if (op1_minus_onep && op2_zerop)
>> + {
>> + tree conv_op = build1 (VIEW_CONVERT_EXPR, vtype, op0);
>> + return gimple_build_assign (lhs, conv_op);
>> + }
>> + /* Try to fold r = c ? -1 : z to r = c | z, or
>> + r = c ? c : z. */
>> + if (op1_minus_onep)
>> + {
>> + tree conv_op = build1 (VIEW_CONVERT_EXPR, vtype, op0);
>> + tree new_op0 = make_ssa_name (vtype);
>> + gassign *new_stmt = gimple_build_assign (new_op0, conv_op);
>> + gsi_insert_seq_before (gsi, new_stmt, GSI_SAME_STMT);
>> + if (optab_handler (ior_optab, vmode) != CODE_FOR_nothing)
>> + /* r = c | z */
>> + return gimple_build_assign (lhs, BIT_IOR_EXPR, new_op0,
>> + op2);
>> + /* r = c ? c : z */
>> + op1 = new_op0;
>
> maybe better call it new_op1 then? Or new_op.
>
>> + }
>> + /* Try to fold r = c ? z : 0 to r = c & z, or
>> + r = c ? z : c. */
>> + else if (op2_zerop)
>> + {
>> + tree conv_op = build1 (VIEW_CONVERT_EXPR, vtype, op0);
>> + tree new_op0 = make_ssa_name (vtype);
>> + gassign *new_stmt = gimple_build_assign (new_op0, conv_op);
>> + gsi_insert_seq_before (gsi, new_stmt, GSI_SAME_STMT);
>> + if (optab_handler (and_optab, vmode) != CODE_FOR_nothing)
>> + /* r = c | z */
>> + return gimple_build_assign (lhs, BIT_AND_EXPR, new_op0,
>> + op1);
>> + /* r = c ? z : c */
>> + op2 = new_op0;
>
> Likewise (new_op2 or also new_op).
>
> OK with that nit fixed.
Thanks Richi, refined with new_op1/new_op2, re-tested well and pushed as
r15-1763.
BR,
Kewen
>
> Thanks,
> Richard.
>
>> + }
>> }
>>
>> /* When the compare has EH we do not want to forward it when
>> --
>> 2.43.0
