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* [Bug tree-optimization/35226] Induction with multiplication are not vectorized
[not found] <bug-35226-4@http.gcc.gnu.org/bugzilla/>
@ 2015-04-30 11:28 ` alalaw01 at gcc dot gnu.org
2024-03-18 7:14 ` pinskia at gcc dot gnu.org
2024-03-18 7:29 ` pinskia at gcc dot gnu.org
2 siblings, 0 replies; 3+ messages in thread
From: alalaw01 at gcc dot gnu.org @ 2015-04-30 11:28 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=35226
alalaw01 at gcc dot gnu.org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2015-04-30
CC| |alalaw01 at gcc dot gnu.org
Version|4.3.0 |6.0
Summary|Reduction and induction |Induction with
|with multiplication are not |multiplication are not
|vectorized |vectorized
Ever confirmed|0 |1
--- Comment #1 from alalaw01 at gcc dot gnu.org ---
Multiplication reductions are supported, certainly in gcc 4.9, I think longer.
However, the following induction does not vectorize on gcc 6 development branch
(x86_64, -O3, with or without -mavx or -msse2):
int a[24];
int
main (int argc, char **argv)
{
int p = 1;
for (int i = 0; i < 24; i++, p*=2)
a[i] *= p;
}
-fdump-tree-vect-details suggests the multiplication is recognized as a
reduction but not as an induction:
test_induc.c:7:3: note: Analyze phi: p_13 = PHI <p_9(4), 1(2)>
test_induc.c:7:3: note: reduction used in loop.
test_induc.c:7:3: note: Unknown def-use cycle pattern.
test_induc.c:7:3: note: === vect_pattern_recog ===
test_induc.c:7:3: note: vect_is_simple_use: operand _5
test_induc.c:7:3: note: def_stmt: _5 = a[i_14];
test_induc.c:7:3: note: type of def: 3.
test_induc.c:7:3: note: vect_is_simple_use: operand p_13
test_induc.c:7:3: note: def_stmt: p_13 = PHI <p_9(4), 1(2)>
test_induc.c:7:3: note: Unsupported pattern.
...
test_induc.c:7:3: note: def_stmt: p_13 = PHI <p_9(4), 1(2)>
test_induc.c:7:3: note: Unsupported pattern.
test_induc.c:7:3: note: not vectorized: unsupported use in stmt.
test_induc.c:7:3: note: unexpected pattern.
test_induc.c:4:1: note: vectorized 0 loops in function.
...
<bb 3>:
# p_13 = PHI <p_9(4), 1(2)>
...
p_9 = p_13 * 2;
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug tree-optimization/35226] Induction with multiplication are not vectorized
[not found] <bug-35226-4@http.gcc.gnu.org/bugzilla/>
2015-04-30 11:28 ` [Bug tree-optimization/35226] Induction with multiplication are not vectorized alalaw01 at gcc dot gnu.org
@ 2024-03-18 7:14 ` pinskia at gcc dot gnu.org
2024-03-18 7:29 ` pinskia at gcc dot gnu.org
2 siblings, 0 replies; 3+ messages in thread
From: pinskia at gcc dot gnu.org @ 2024-03-18 7:14 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=35226
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|--- |13.0
Known to fail| |12.3.0
Known to work| |13.1.0
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug tree-optimization/35226] Induction with multiplication are not vectorized
[not found] <bug-35226-4@http.gcc.gnu.org/bugzilla/>
2015-04-30 11:28 ` [Bug tree-optimization/35226] Induction with multiplication are not vectorized alalaw01 at gcc dot gnu.org
2024-03-18 7:14 ` pinskia at gcc dot gnu.org
@ 2024-03-18 7:29 ` pinskia at gcc dot gnu.org
2 siblings, 0 replies; 3+ messages in thread
From: pinskia at gcc dot gnu.org @ 2024-03-18 7:29 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=35226
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Resolution|--- |FIXED
Status|NEW |RESOLVED
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Alan Lawrence from comment #1)
> Multiplication reductions are supported, certainly in gcc 4.9, I think
> longer. However, the following induction does not vectorize on gcc 6
> development branch (x86_64, -O3, with or without -mavx or -msse2):
That in turn was fixed in GCC 13 (or rather it was PR 103144 ).
For reduction:
```
int a[1024];
int
f (void)
{
int p = 1;
for (int i = 0; i < 1024; i++, p*=2)
p *= a[i];
return p;
}
```
That was fixed in GCC 8 (I can't find the patch currectly).
So closing as fixed.
^ permalink raw reply [flat|nested] 3+ messages in thread
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2015-04-30 11:28 ` [Bug tree-optimization/35226] Induction with multiplication are not vectorized alalaw01 at gcc dot gnu.org
2024-03-18 7:14 ` pinskia at gcc dot gnu.org
2024-03-18 7:29 ` pinskia at gcc dot gnu.org
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