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* [Bug middle-end/114653] New: Not vectoring the loop with openmp reduction.
@ 2024-04-09 9:53 kugan at gcc dot gnu.org
2024-04-09 12:53 ` [Bug middle-end/114653] Not vectorizing " rguenth at gcc dot gnu.org
` (5 more replies)
0 siblings, 6 replies; 7+ messages in thread
From: kugan at gcc dot gnu.org @ 2024-04-09 9:53 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114653
Bug ID: 114653
Summary: Not vectoring the loop with openmp reduction.
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: middle-end
Assignee: unassigned at gcc dot gnu.org
Reporter: kugan at gcc dot gnu.org
Target Milestone: ---
Created attachment 57910
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=57910&action=edit
testcase
Main loop in the attached test case is not vectorized with -fopenmp. It gets
vectorized with -fopenmp-simd.
In the case of -fopenmp reduction variables lax,lay,laz gets assigned to an
array. data reference calculation for this seem to fail. See:
offset from base address: (ssizetype) ((sizetype) _20 * 4)
constant offset from base address: 0
step: 0
base alignment: 16
base misalignment: 0
offset alignment: 4
step alignment: 128
base_object: D.4806[_20]
Creating dr for D.4808[_20]
analyze_innermost: Applying pattern match.pd:219, generic-match-1.cc:3190
test.cpp:37:9: missed: failed: evolution of offset is not affine.
command used:
test.cpp -Ofast -fopenmp -mcpu=neoverse-v2
gcc -v:
Using built-in specs.
COLLECT_GCC=/home/kvivekananda/install/bin/gcc
COLLECT_LTO_WRAPPER=/home/kvivekananda/install/libexec/gcc/aarch64-unknown-linux-gnu/14.0.1/lto-wrapper
Target: aarch64-unknown-linux-gnu
Configured with: ../gcc/configure --enable-multiarch=yes
--enable-languages=c,c++,fortran,lto --disable-bootstrap
--prefix=/home/kvivekananda/install
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 14.0.1 20240314 (experimental) (GCC)
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug middle-end/114653] Not vectorizing the loop with openmp reduction.
2024-04-09 9:53 [Bug middle-end/114653] New: Not vectoring the loop with openmp reduction kugan at gcc dot gnu.org
@ 2024-04-09 12:53 ` rguenth at gcc dot gnu.org
2024-04-10 3:55 ` kugan at gcc dot gnu.org
` (4 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: rguenth at gcc dot gnu.org @ 2024-04-09 12:53 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114653
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Blocks| |53947
Keywords| |openmp
Summary|Not vectoring the loop with |Not vectorizing the loop
|openmp reduction. |with openmp reduction.
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
Note the cited problem isn't the problem. There's several OMP reduction
vectorizing PRs already.
Referenced Bugs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53947
[Bug 53947] [meta-bug] vectorizer missed-optimizations
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug middle-end/114653] Not vectorizing the loop with openmp reduction.
2024-04-09 9:53 [Bug middle-end/114653] New: Not vectoring the loop with openmp reduction kugan at gcc dot gnu.org
2024-04-09 12:53 ` [Bug middle-end/114653] Not vectorizing " rguenth at gcc dot gnu.org
@ 2024-04-10 3:55 ` kugan at gcc dot gnu.org
2024-04-10 3:58 ` kugan at gcc dot gnu.org
` (3 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: kugan at gcc dot gnu.org @ 2024-04-10 3:55 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114653
--- Comment #2 from kugan at gcc dot gnu.org ---
Thanks. I see the following in the log:
test.cpp:33:53: missed: not vectorized: relevant stmt not supported: _54 =
.MASK_LOAD (_53, 32B, _171);
test.cpp:22:19: missed: bad operation or unsupported loop bound.
test.cpp:22:19: note: ***** Analysis failed with vector mode V4SF
test.cpp:22:19: note: === vect_analyze_data_ref_dependences ===
test.cpp:22:19: missed: bad data dependence.
test.cpp:22:19: note: ***** Analysis failed with vector mode VNx16QI
test.cpp:33:53: missed: not vectorized: relevant stmt not supported: _54 =
.MASK_LOAD (_53, 32B, _171);
test.cpp:22:19: missed: bad operation or unsupported loop bound.
test.cpp:22:19: note: ***** Analysis failed with vector mode V8QI
test.cpp:22:19: note: === vect_analyze_data_ref_dependences ===
test.cpp:22:19: missed: bad data dependence.
test.cpp:22:19: note: ***** Analysis failed with vector mode VNx8QI
test.cpp:33:53: missed: not vectorized: relevant stmt not supported: _54 =
.MASK_LOAD (_53, 32B, _171);
test.cpp:22:19: missed: bad operation or unsupported loop bound.
test.cpp:22:19: note: ***** Analysis failed with vector mode V4HI
test.cpp:22:19: note: === vect_analyze_data_ref_dependences ===
test.cpp:22:19: missed: bad data dependence.
test.cpp:22:19: note: ***** Analysis failed with vector mode VNx4QI
test.cpp:33:53: missed: not vectorized: relevant stmt not supported: _54 =
.MASK_LOAD (_53, 32B, _171);
test.cpp:22:19: missed: bad operation or unsupported loop bound.
test.cpp:22:19: note: ***** Analysis failed with vector mode V2SI
test.cpp:22:19: note: worklist: examine stmt: _57 = D.4803[_20];
test.cpp:22:19: note: === vect_analyze_data_ref_dependences ===
test.cpp:22:19: missed: bad data dependence.
test.cpp:22:19: note: ***** Analysis failed with vector mode VNx2QI
test.cpp:22:19: missed: couldn't vectorize loop
test.cpp:22:19: missed: bad data dependence.
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug middle-end/114653] Not vectorizing the loop with openmp reduction.
2024-04-09 9:53 [Bug middle-end/114653] New: Not vectoring the loop with openmp reduction kugan at gcc dot gnu.org
2024-04-09 12:53 ` [Bug middle-end/114653] Not vectorizing " rguenth at gcc dot gnu.org
2024-04-10 3:55 ` kugan at gcc dot gnu.org
@ 2024-04-10 3:58 ` kugan at gcc dot gnu.org
2024-04-10 5:05 ` kugan at gcc dot gnu.org
` (2 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: kugan at gcc dot gnu.org @ 2024-04-10 3:58 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114653
--- Comment #3 from kugan at gcc dot gnu.org ---
For SVE mode in vect_analyze_loop_2, we have
(gdb) p min_vf
$15 = {coeffs = {4, 4}}
(gdb) p max_vf
$16 = 16
Thus maybe_lt (max_vf, min_vf)) is false. This results in bad data dependence.
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug middle-end/114653] Not vectorizing the loop with openmp reduction.
2024-04-09 9:53 [Bug middle-end/114653] New: Not vectoring the loop with openmp reduction kugan at gcc dot gnu.org
` (2 preceding siblings ...)
2024-04-10 3:58 ` kugan at gcc dot gnu.org
@ 2024-04-10 5:05 ` kugan at gcc dot gnu.org
2024-04-10 6:48 ` kugan at gcc dot gnu.org
2024-04-10 6:53 ` kugan at gcc dot gnu.org
5 siblings, 0 replies; 7+ messages in thread
From: kugan at gcc dot gnu.org @ 2024-04-10 5:05 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114653
--- Comment #4 from kugan at gcc dot gnu.org ---
This particular loop has loop->safelen set to 16. Does this mean this can never
be loop vectorized for VLA?
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug middle-end/114653] Not vectorizing the loop with openmp reduction.
2024-04-09 9:53 [Bug middle-end/114653] New: Not vectoring the loop with openmp reduction kugan at gcc dot gnu.org
` (3 preceding siblings ...)
2024-04-10 5:05 ` kugan at gcc dot gnu.org
@ 2024-04-10 6:48 ` kugan at gcc dot gnu.org
2024-04-10 6:53 ` kugan at gcc dot gnu.org
5 siblings, 0 replies; 7+ messages in thread
From: kugan at gcc dot gnu.org @ 2024-04-10 6:48 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114653
--- Comment #5 from kugan at gcc dot gnu.org ---
ddd for the :
ref_a:
_57 = D.4803[_20];
ref_b:
D.4803[_20] = _ifc__174;
We get DDR_ARE_DEPENDENT (ddr) == chrec_dont_know. Hence apply_safelen ().
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug middle-end/114653] Not vectorizing the loop with openmp reduction.
2024-04-09 9:53 [Bug middle-end/114653] New: Not vectoring the loop with openmp reduction kugan at gcc dot gnu.org
` (4 preceding siblings ...)
2024-04-10 6:48 ` kugan at gcc dot gnu.org
@ 2024-04-10 6:53 ` kugan at gcc dot gnu.org
5 siblings, 0 replies; 7+ messages in thread
From: kugan at gcc dot gnu.org @ 2024-04-10 6:53 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114653
kugan at gcc dot gnu.org changed:
What |Removed |Added
----------------------------------------------------------------------------
Resolution|--- |DUPLICATE
Status|UNCONFIRMED |RESOLVED
--- Comment #6 from kugan at gcc dot gnu.org ---
Duplicate
*** This bug has been marked as a duplicate of bug 114635 ***
^ permalink raw reply [flat|nested] 7+ messages in thread
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2024-04-09 9:53 [Bug middle-end/114653] New: Not vectoring the loop with openmp reduction kugan at gcc dot gnu.org
2024-04-09 12:53 ` [Bug middle-end/114653] Not vectorizing " rguenth at gcc dot gnu.org
2024-04-10 3:55 ` kugan at gcc dot gnu.org
2024-04-10 3:58 ` kugan at gcc dot gnu.org
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