isel: Fold more in gimple_expand_vec_cond_expr [PR115659]

  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.

Bootstrapped and regtested on x86_64-redhat-linux and
powerpc64{,le}-linux-gnu.

Is it ok for trunk?

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(-)

--
2.43.0
  

On Mon, Jul 1, 2024 at 8:16 AM Kewen.Lin <linkw@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,
Richard.

> +               }
>             }
>
>           /* When the compare has EH we do not want to forward it when
> --
> 2.43.0
  

on 2024/7/1 22:28, Richard Biener wrote:
> On Mon, Jul 1, 2024 at 8:16 AM Kewen.Lin <linkw@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