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* [Bug tree-optimization/97008] New: [openacc] Remove invariant that IFN_UNIQUE is last stmt in bb
@ 2020-09-10 11:08 vries at gcc dot gnu.org
2020-09-10 12:22 ` [Bug tree-optimization/97008] " rguenth at gcc dot gnu.org
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: vries at gcc dot gnu.org @ 2020-09-10 11:08 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97008
Bug ID: 97008
Summary: [openacc] Remove invariant that IFN_UNIQUE is last
stmt in bb
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Severity: enhancement
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: vries at gcc dot gnu.org
Target Milestone: ---
[ spin-off of PR97000 comment 9. ]
There's an invariant that says IFN_UNIQUE needs to be the last stmt in a bb.
The rationale given is that it speeds up lookup.
This is somewhat of a hack, and potentially inhibits various
optimizations/cleanups.
So, can we drop this invariant?
This patch (PR97000 comment 2) is probably needed, possibly more.
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug tree-optimization/97008] [openacc] Remove invariant that IFN_UNIQUE is last stmt in bb
2020-09-10 11:08 [Bug tree-optimization/97008] New: [openacc] Remove invariant that IFN_UNIQUE is last stmt in bb vries at gcc dot gnu.org
@ 2020-09-10 12:22 ` rguenth at gcc dot gnu.org
2020-09-10 12:34 ` vries at gcc dot gnu.org
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: rguenth at gcc dot gnu.org @ 2020-09-10 12:22 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97008
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
Where's this property used? grepping finds searches in omp-offload but those
all(?) search the whole instruction stream.
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug tree-optimization/97008] [openacc] Remove invariant that IFN_UNIQUE is last stmt in bb
2020-09-10 11:08 [Bug tree-optimization/97008] New: [openacc] Remove invariant that IFN_UNIQUE is last stmt in bb vries at gcc dot gnu.org
2020-09-10 12:22 ` [Bug tree-optimization/97008] " rguenth at gcc dot gnu.org
@ 2020-09-10 12:34 ` vries at gcc dot gnu.org
2020-09-10 12:47 ` rguenth at gcc dot gnu.org
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: vries at gcc dot gnu.org @ 2020-09-10 12:34 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97008
--- Comment #2 from Tom de Vries <vries at gcc dot gnu.org> ---
(In reply to Richard Biener from comment #1)
> Where's this property used? grepping finds searches in omp-offload but those
> all(?) search the whole instruction stream.
In ignore_bb_p in gcc/tracer.c, see PR97000 comment 2.
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug tree-optimization/97008] [openacc] Remove invariant that IFN_UNIQUE is last stmt in bb
2020-09-10 11:08 [Bug tree-optimization/97008] New: [openacc] Remove invariant that IFN_UNIQUE is last stmt in bb vries at gcc dot gnu.org
2020-09-10 12:22 ` [Bug tree-optimization/97008] " rguenth at gcc dot gnu.org
2020-09-10 12:34 ` vries at gcc dot gnu.org
@ 2020-09-10 12:47 ` rguenth at gcc dot gnu.org
2020-10-05 8:52 ` vries at gcc dot gnu.org
2020-10-06 8:02 ` vries at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: rguenth at gcc dot gnu.org @ 2020-09-10 12:47 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97008
--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
I see. Wonder if it that shouldn't be in can_duplicate_block_p though (where
the GIMPLE variant doesn't do anything, so a full stmt walk would be
expensive).
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug tree-optimization/97008] [openacc] Remove invariant that IFN_UNIQUE is last stmt in bb
2020-09-10 11:08 [Bug tree-optimization/97008] New: [openacc] Remove invariant that IFN_UNIQUE is last stmt in bb vries at gcc dot gnu.org
` (2 preceding siblings ...)
2020-09-10 12:47 ` rguenth at gcc dot gnu.org
@ 2020-10-05 8:52 ` vries at gcc dot gnu.org
2020-10-06 8:02 ` vries at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: vries at gcc dot gnu.org @ 2020-10-05 8:52 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97008
--- Comment #4 from Tom de Vries <vries at gcc dot gnu.org> ---
I did a libgomp test run with commit f96b6328fa7 "[tree-optimization] Don't
clear ctrl-altering flag for IFN_UNIQUE" reverted, and with this patch:
...
diff --git a/gcc/tracer.c b/gcc/tracer.c
index 0f69b335b8c..3a4403d92b1 100644
--- a/gcc/tracer.c
+++ b/gcc/tracer.c
@@ -93,11 +93,15 @@ can_duplicate_insn_p (gimple *g)
The IFN_GOMP_SIMT_VOTE_ANY is currently part of such a group,
so the same holds there, but it could be argued that the
IFN_GOMP_SIMT_VOTE_ANY could be generated after that group,
- in which case it could be duplicated. */
+ in which case it could be duplicated.
+ An IFN_UNIQUE call must be duplicated as part of its group,
+ or not at all. */
if (is_gimple_call (g)
&& (gimple_call_internal_p (g, IFN_GOMP_SIMT_ENTER_ALLOC)
|| gimple_call_internal_p (g, IFN_GOMP_SIMT_EXIT)
- || gimple_call_internal_p (g, IFN_GOMP_SIMT_VOTE_ANY)))
+ || gimple_call_internal_p (g, IFN_GOMP_SIMT_VOTE_ANY)
+ || (gimple_call_internal_p (g)
+ && gimple_call_internal_unique_p (g))))
return false;
return true;
@@ -117,8 +121,6 @@ can_duplicate_bb_no_insn_iter_p (const_basic_block bb)
if (gimple_code (g) == GIMPLE_TRANSACTION)
return false;
- /* An IFN_UNIQUE call must be duplicated as part of its group,
- or not at all. */
if (is_gimple_call (g)
&& gimple_call_internal_p (g)
&& gimple_call_internal_unique_p (g))
...
No issues found.
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug tree-optimization/97008] [openacc] Remove invariant that IFN_UNIQUE is last stmt in bb
2020-09-10 11:08 [Bug tree-optimization/97008] New: [openacc] Remove invariant that IFN_UNIQUE is last stmt in bb vries at gcc dot gnu.org
` (3 preceding siblings ...)
2020-10-05 8:52 ` vries at gcc dot gnu.org
@ 2020-10-06 8:02 ` vries at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: vries at gcc dot gnu.org @ 2020-10-06 8:02 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97008
--- Comment #5 from Tom de Vries <vries at gcc dot gnu.org> ---
The openacc machinery is the only user of IFN_UNIQUE.
Thomas, as openacc maintainer, is this change ok for you, or are reasons why
you want to keep the IFN_UNIQUE as last stmt of the BB?
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2020-10-06 8:02 UTC | newest]
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2020-09-10 11:08 [Bug tree-optimization/97008] New: [openacc] Remove invariant that IFN_UNIQUE is last stmt in bb vries at gcc dot gnu.org
2020-09-10 12:22 ` [Bug tree-optimization/97008] " rguenth at gcc dot gnu.org
2020-09-10 12:34 ` vries at gcc dot gnu.org
2020-09-10 12:47 ` rguenth at gcc dot gnu.org
2020-10-05 8:52 ` vries at gcc dot gnu.org
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