Re: [PATCH] vect: Call vect_convert_output with the right vecitype [PR114108]

[Tejas Belagod <tejas.belagod@arm.com>]

Ping.

Thanks,
Tejas.

On 3/13/24 6:07 PM, Tejas Belagod wrote:
> Ping!
> 
> On 3/7/24 4:14 PM, Tejas Belagod wrote:
>> This patch fixes a bug where vect_recog_abd_pattern called 
>> vect_convert_output
>> with the incorrect vecitype for the corresponding pattern_stmt.
>> vect_convert_output expects vecitype to be the vector form of the 
>> scalar type
>> of the LHS of pattern_stmt, but we were passing in the vector form of 
>> the LHS
>> of the new impending conversion statement.  This caused a skew in ABD's
>> pattern_stmt having the vectype of the following gimple pattern_stmt.
>>
>>     2024-03-06  Tejas Belagod  <tejas.belagod@arm.com>
>>
>> gcc/ChangeLog:
>>
>>     PR middle-end/114108
>>     * tree-vect-patterns.cc (vect_recog_abd_pattern): Call
>>     vect_convert_output with the correct vecitype.
>>
>> gcc/testsuite/ChangeLog:
>>     * gcc.dg/vect/pr114108.c: New test.
>> ---
>>   gcc/testsuite/gcc.dg/vect/pr114108.c | 19 +++++++++++++++++++
>>   gcc/tree-vect-patterns.cc            |  5 ++---
>>   2 files changed, 21 insertions(+), 3 deletions(-)
>>   create mode 100644 gcc/testsuite/gcc.dg/vect/pr114108.c
>>
>> diff --git a/gcc/testsuite/gcc.dg/vect/pr114108.c 
>> b/gcc/testsuite/gcc.dg/vect/pr114108.c
>> new file mode 100644
>> index 00000000000..b3075d41398
>> --- /dev/null
>> +++ b/gcc/testsuite/gcc.dg/vect/pr114108.c
>> @@ -0,0 +1,19 @@
>> +/* { dg-do compile } */
>> +
>> +#include "tree-vect.h"
>> +
>> +typedef signed char schar;
>> +
>> +__attribute__((noipa, noinline, optimize("O3")))
>> +void foo(const schar *a, const schar *b, schar *c, int n)
>> +{
>> +  for (int i = 0; i < n; i++)
>> +    {
>> +      unsigned u = __builtin_abs (a[i] - b[i]);
>> +      c[i] = u <= 7U ? u : 7U;
>> +    }
>> +}
>> +
>> +
>> +/* { dg-final { scan-tree-dump "LOOP VECTORIZED" "vect" { target 
>> aarch64*-*-* } } } */
>> +/* { dg-final { scan-tree-dump "vect_recog_abd_pattern: detected" 
>> "vect" { target aarch64*-*-* } } } */
>> diff --git a/gcc/tree-vect-patterns.cc b/gcc/tree-vect-patterns.cc
>> index d562f57920f..4f491c6b833 100644
>> --- a/gcc/tree-vect-patterns.cc
>> +++ b/gcc/tree-vect-patterns.cc
>> @@ -1576,9 +1576,8 @@ vect_recog_abd_pattern (vec_info *vinfo,
>>         && !TYPE_UNSIGNED (abd_out_type))
>>       {
>>         tree unsign = unsigned_type_for (abd_out_type);
>> -      tree unsign_vectype = get_vectype_for_scalar_type (vinfo, unsign);
>> -      stmt = vect_convert_output (vinfo, stmt_vinfo, unsign, stmt,
>> -                  unsign_vectype);
>> +      stmt = vect_convert_output (vinfo, stmt_vinfo, unsign, stmt, 
>> vectype_out);
>> +      vectype_out = get_vectype_for_scalar_type (vinfo, unsign);
>>       }
>>     return vect_convert_output (vinfo, stmt_vinfo, out_type, stmt, 
>> vectype_out);
>