Ping...
thanks,
Cong
On Wed, Oct 2, 2013 at 11:18 AM, Cong Hou <co...@google.com> wrote:
> Ping.. Any comment on this patch?
>
>
> thanks,
> Cong
>
>
> On Sat, Sep 28, 2013 at 9:34 AM, Xinliang David Li <davi...@google.com> wrote:
>> You can also add a test case of this form:
>>
>> int foo( int t, int n, int *dst)
>> {
>> int j = 0;
>> int s = 1;
>> t++;
>> for (j = 0; j < n; j++)
>> {
>> dst[j] = t;
>> s *= t;
>> }
>>
>> return s;
>> }
>>
>> where without the fix the loop vectorization is missed.
>>
>> David
>>
>> On Fri, Sep 27, 2013 at 6:28 PM, Cong Hou <co...@google.com> wrote:
>>> The current GCC vectorizer requires the following pattern as a simple
>>> reduction computation:
>>>
>>> loop_header:
>>> a1 = phi < a0, a2 >
>>> a3 = ...
>>> a2 = operation (a3, a1)
>>>
>>> But a3 can also be defined outside of the loop. For example, the
>>> following loop can benefit from vectorization but the GCC vectorizer
>>> fails to vectorize it:
>>>
>>>
>>> int foo(int v)
>>> {
>>> int s = 1;
>>> ++v;
>>> for (int i = 0; i < 100000; ++i)
>>> s *= v;
>>> return s;
>>> }
>>>
>>>
>>> This patch relaxes the original requirement by also considering the
>>> following pattern:
>>>
>>>
>>> a3 = ...
>>> loop_header:
>>> a1 = phi < a0, a2 >
>>> a2 = operation (a3, a1)
>>>
>>>
>>> A test case is also added. The patch is tested on x86-64.
>>>
>>>
>>> thanks,
>>> Cong
>>>
>>> ================================
>>>
>>> diff --git a/gcc/ChangeLog b/gcc/ChangeLog
>>> index 39c786e..45c1667 100644
>>> --- a/gcc/ChangeLog
>>> +++ b/gcc/ChangeLog
>>> @@ -1,3 +1,9 @@
>>> +2013-09-27 Cong Hou <co...@google.com>
>>> +
>>> + * tree-vect-loop.c: Relax the requirement of the reduction
>>> + pattern so that one operand of the reduction operation can
>>> + come from outside of the loop.
>>> +
>>> 2013-09-25 Tom Tromey <tro...@redhat.com>
>>>
>>> * Makefile.in (PARTITION_H, LTO_SYMTAB_H, COMMON_TARGET_DEF_H)
>>> diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
>>> index 09644d2..90496a2 100644
>>> --- a/gcc/testsuite/ChangeLog
>>> +++ b/gcc/testsuite/ChangeLog
>>> @@ -1,3 +1,7 @@
>>> +2013-09-27 Cong Hou <co...@google.com>
>>> +
>>> + * gcc.dg/vect/vect-reduc-pattern-3.c: New test.
>>> +
>>> 2013-09-25 Marek Polacek <pola...@redhat.com>
>>>
>>> PR sanitizer/58413
>>> diff --git a/gcc/tree-vect-loop.c b/gcc/tree-vect-loop.c
>>> index 2871ba1..3c51c3b 100644
>>> --- a/gcc/tree-vect-loop.c
>>> +++ b/gcc/tree-vect-loop.c
>>> @@ -2091,6 +2091,13 @@ vect_is_slp_reduction (loop_vec_info loop_info,
>>> gimple phi, gimple first_stmt)
>>> a3 = ...
>>> a2 = operation (a3, a1)
>>>
>>> + or
>>> +
>>> + a3 = ...
>>> + loop_header:
>>> + a1 = phi < a0, a2 >
>>> + a2 = operation (a3, a1)
>>> +
>>> such that:
>>> 1. operation is commutative and associative and it is safe to
>>> change the order of the computation (if CHECK_REDUCTION is true)
>>> @@ -2451,6 +2458,7 @@ vect_is_simple_reduction_1 (loop_vec_info
>>> loop_info, gimple phi,
>>> if (def2 && def2 == phi
>>> && (code == COND_EXPR
>>> || !def1 || gimple_nop_p (def1)
>>> + || !flow_bb_inside_loop_p (loop, gimple_bb (def1))
>>> || (def1 && flow_bb_inside_loop_p (loop, gimple_bb (def1))
>>> && (is_gimple_assign (def1)
>>> || is_gimple_call (def1)
>>> @@ -2469,6 +2477,7 @@ vect_is_simple_reduction_1 (loop_vec_info
>>> loop_info, gimple phi,
>>> if (def1 && def1 == phi
>>> && (code == COND_EXPR
>>> || !def2 || gimple_nop_p (def2)
>>> + || !flow_bb_inside_loop_p (loop, gimple_bb (def2))
>>> || (def2 && flow_bb_inside_loop_p (loop, gimple_bb (def2))
>>> && (is_gimple_assign (def2)
>>> || is_gimple_call (def2)
>>> diff --git gcc/testsuite/gcc.dg/vect/vect-reduc-pattern-3.c
>>> gcc/testsuite/gcc.dg/vect/vect-reduc-pattern-3.c
>>> new file mode 100644
>>> index 0000000..06a9416
>>> --- /dev/null
>>> +++ gcc/testsuite/gcc.dg/vect/vect-reduc-pattern-3.c
>>> @@ -0,0 +1,41 @@
>>> +/* { dg-require-effective-target vect_int } */
>>> +
>>> +#include <stdarg.h>
>>> +#include "tree-vect.h"
>>> +
>>> +#define N 10
>>> +#define RES 1024
>>> +
>>> +/* A reduction pattern in which there is no data ref in
>>> + the loop and one operand is defined outside of the loop. */
>>> +
>>> +__attribute__ ((noinline)) int
>>> +foo (int v)
>>> +{
>>> + int i;
>>> + int result = 1;
>>> +
>>> + ++v;
>>> + for (i = 0; i < N; i++)
>>> + result *= v;
>>> +
>>> + return result;
>>> +}
>>> +
>>> +int
>>> +main (void)
>>> +{
>>> + int res;
>>> +
>>> + check_vect ();
>>> +
>>> + res = foo (1);
>>> + if (res != RES)
>>> + abort ();
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" } } */
>>> +/* { dg-final { cleanup-tree-dump "vect" } } */
>>> +
