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* [Bug tree-optimization/49730] New: loop not vectorized if inside another loop
@ 2011-07-13 10:43 vincenzo.innocente at cern dot ch
2011-07-13 11:24 ` [Bug tree-optimization/49730] " rguenth at gcc dot gnu.org
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: vincenzo.innocente at cern dot ch @ 2011-07-13 10:43 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49730
Summary: loop not vectorized if inside another loop
Product: gcc
Version: 4.7.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: vincenzo.innocente@cern.ch
I've this simple double loop (used in benchmark)
the inner loop (sloop) is not vectorized when invoked inside the longer loop
(dloop)
c++ -Ofast -c vectdloop.cc -ftree-vectorizer-verbose=7
vectdloop.cc:9: note: Profitability threshold = 6
vectdloop.cc:9: note: Profitability threshold is 6 loop iterations.
vectdloop.cc:9: note: LOOP VECTORIZED.
vectdloop.cc:7: note: vectorized 1 loops in function.
vectdloop.cc:20: note: not vectorized: unexpected loop form.
vectdloop.cc:16: note: vectorized 0 loops in function.
#include<cmath>
inline float fn(float x) {
return 2.f*x+std::sqrt(x);
}
void sloop(float * __restrict__ s, float const * __restrict__ xx) {
const int ls=16;
for (int j=0; j < ls; ++j) {
s[j] = fn(xx[j]);
}
}
int dloop(float yyy) {
int niter = 100000;
float x = 0.5f; yyy=0;
const int ls=16;
for (int i=0; i < niter; ++i) {
float s[ls]; float xx[ls];
for (int j=0; j < ls; ++j) xx[j] =x+(5*(j&1));
sloop(s,xx);
// for (int j=0; j < ls; ++j) s[j] = fn(xx[j]);
x += 1e-6f;
for (int j=0; j < ls; ++j) yyy+=s[j];
}
if (yyy == 2.32132323232f) niter--;
return niter;
}
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug tree-optimization/49730] loop not vectorized if inside another loop
2011-07-13 10:43 [Bug tree-optimization/49730] New: loop not vectorized if inside another loop vincenzo.innocente at cern dot ch
@ 2011-07-13 11:24 ` rguenth at gcc dot gnu.org
2011-07-14 6:35 ` irar at il dot ibm.com
2021-12-04 23:58 ` pinskia at gcc dot gnu.org
2 siblings, 0 replies; 4+ messages in thread
From: rguenth at gcc dot gnu.org @ 2011-07-13 11:24 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49730
Richard Guenther <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Keywords| |missed-optimization
Last reconfirmed| |2011.07.13 11:23:16
CC| |irar at gcc dot gnu.org
Ever Confirmed|0 |1
Severity|normal |enhancement
--- Comment #1 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-07-13 11:23:16 UTC ---
All inner loops are simply completely unrolled which eliminates the s array.
Then we end up with a loop with two reductions which cannot be vectorized
right now.
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug tree-optimization/49730] loop not vectorized if inside another loop
2011-07-13 10:43 [Bug tree-optimization/49730] New: loop not vectorized if inside another loop vincenzo.innocente at cern dot ch
2011-07-13 11:24 ` [Bug tree-optimization/49730] " rguenth at gcc dot gnu.org
@ 2011-07-14 6:35 ` irar at il dot ibm.com
2021-12-04 23:58 ` pinskia at gcc dot gnu.org
2 siblings, 0 replies; 4+ messages in thread
From: irar at il dot ibm.com @ 2011-07-14 6:35 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49730
Ira Rosen <irar at il dot ibm.com> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |irar at il dot ibm.com
--- Comment #2 from Ira Rosen <irar at il dot ibm.com> 2011-07-14 06:35:39 UTC ---
There is no limitation on the number of reductions in vectorization.
The problem here is a non-empty latch block. There are several existing PRs for
similar problems: pr 33447, pr 28643.
Ira
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug tree-optimization/49730] loop not vectorized if inside another loop
2011-07-13 10:43 [Bug tree-optimization/49730] New: loop not vectorized if inside another loop vincenzo.innocente at cern dot ch
2011-07-13 11:24 ` [Bug tree-optimization/49730] " rguenth at gcc dot gnu.org
2011-07-14 6:35 ` irar at il dot ibm.com
@ 2021-12-04 23:58 ` pinskia at gcc dot gnu.org
2 siblings, 0 replies; 4+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-12-04 23:58 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=49730
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|--- |8.0
Resolution|--- |FIXED
Known to work| |8.1.0, 9.1.0
Status|NEW |RESOLVED
--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Fixed in GCC 8.
^ permalink raw reply [flat|nested] 4+ messages in thread
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2011-07-13 10:43 [Bug tree-optimization/49730] New: loop not vectorized if inside another loop vincenzo.innocente at cern dot ch
2011-07-13 11:24 ` [Bug tree-optimization/49730] " rguenth at gcc dot gnu.org
2011-07-14 6:35 ` irar at il dot ibm.com
2021-12-04 23:58 ` pinskia at gcc dot gnu.org
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