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From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/105490] unvectorized loop due to bool condition loaded from memory and different size data
Date: Wed, 30 Aug 2023 15:32:19 +0000	[thread overview]
Message-ID: <bug-105490-4-CvCFwKbNol@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-105490-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105490

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Here is an even odder case:
```
#define N 256
typedef short T;
extern T a[N];
extern T b[N];
extern T c[N];
extern _Bool pb[N];
extern _Bool pb1[N];
extern _Bool pb2[N];

void predicate_by_booland()
{
  for (int i = 0; i < N; i++)
    c[i] = ((pb1[i] != pb[i]) != pb2[i]) ? a[i] : b[i];
}
```
This vectorizes currently with `-O3` but not with `-O3 -fno-tree-vrp`.
IR with -fno-tree-vrp:
```
  _1 = pb1[i_15];
  _2 = pb[i_15];
  _3 = _1 != _2;
  _4 = pb2[i_15];
  iftmp.0_10 = a[i_15];
  _5 = _3 != _4;
  iftmp.0_9 = b[i_15];
```
IR without (VRP turned on):
```
  _1 = pb1[i_15];
  _2 = pb[i_15];
  _3 = _1 ^ _2;
  _4 = pb2[i_15];
  iftmp.0_10 = a[i_15];
  _5 = _3 != _4;
  iftmp.0_9 = b[i_15];
```

So it is even more confusing ...

  parent reply	other threads:[~2023-08-30 15:32 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-05  8:39 [Bug tree-optimization/105490] New: " rguenth at gcc dot gnu.org
2022-05-05  8:39 ` [Bug tree-optimization/105490] " rguenth at gcc dot gnu.org
2022-10-31 15:46 ` pinskia at gcc dot gnu.org
2023-08-30  6:07 ` pinskia at gcc dot gnu.org
2023-08-30 15:32 ` pinskia at gcc dot gnu.org [this message]
2023-08-31  6:34 ` rguenther at suse dot de

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