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* [Bug tree-optimization/105490] New: unvectorized loop due to bool condition loaded from memory and different size data @ 2022-05-05 8:39 rguenth at gcc dot gnu.org 2022-05-05 8:39 ` [Bug tree-optimization/105490] " rguenth at gcc dot gnu.org ` (4 more replies) 0 siblings, 5 replies; 6+ messages in thread From: rguenth at gcc dot gnu.org @ 2022-05-05 8:39 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105490 Bug ID: 105490 Summary: unvectorized loop due to bool condition loaded from memory and different size data Product: gcc Version: 13.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: tree-optimization Assignee: unassigned at gcc dot gnu.org Reporter: rguenth at gcc dot gnu.org Target Milestone: --- Cloned from PR104595 #define N 256 typedef short T; extern T a[N]; extern T b[N]; extern T c[N]; extern _Bool pb[N]; void predicate_by_bool() { for (int i = 0; i < N; i++) c[i] = pb[i] ? a[i] : b[i]; } where we expect vect_recog_mask_conversion_pattern to trigger here. That case can be fixed with @@ -4658,9 +4660,9 @@ vect_recog_mask_conversion_pattern (vec_info *vinfo, if (TREE_CODE (rhs1) == SSA_NAME) { - rhs1_type = integer_type_for_mask (rhs1, vinfo); - if (!rhs1_type) + if (integer_type_for_mask (rhs1, vinfo)) return NULL; + rhs1_type = TREE_TYPE (rhs1); } else if (COMPARISON_CLASS_P (rhs1)) { but we then run into the original issue again: t.c:10:6: missed: not vectorized: relevant stmt not supported: patt_28 = (<signed-boolean:16>) _1; The cruical difference between working and not working is the _1 != 0 ?: vs. _1 ?: - I think we do have a duplicate bugreport here, possibly involving combinations of different from memory bools. Trying to make bool pattern recog inserting the relevant compensation code is really iffy, the mask conversion pattern confuses things here - what we are missing seems really be transforming the leafs. Note that we do not try to patter-recog a pattern thus we cannot at the moment have both, vect_recog_bool_pattern and vect_recog_mask_conversion_pattern at the same time on the ?: stmt. Note IIRC vect_recog_bool_pattern has to come last but it's now after vect_recog_mask_conversion_pattern. Unfortunately swapping things does not make vect_recog_bool_pattern recognize and fixup patt_24 = (<signed-boolean:16>) _1; ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug tree-optimization/105490] unvectorized loop due to bool condition loaded from memory and different size data 2022-05-05 8:39 [Bug tree-optimization/105490] New: unvectorized loop due to bool condition loaded from memory and different size data rguenth at gcc dot gnu.org @ 2022-05-05 8:39 ` rguenth at gcc dot gnu.org 2022-10-31 15:46 ` pinskia at gcc dot gnu.org ` (3 subsequent siblings) 4 siblings, 0 replies; 6+ messages in thread From: rguenth at gcc dot gnu.org @ 2022-05-05 8:39 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105490 Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Ever confirmed|0 |1 Last reconfirmed| |2022-05-05 Blocks| |53947 Keywords| |missed-optimization Status|UNCONFIRMED |NEW Referenced Bugs: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53947 [Bug 53947] [meta-bug] vectorizer missed-optimizations ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug tree-optimization/105490] unvectorized loop due to bool condition loaded from memory and different size data 2022-05-05 8:39 [Bug tree-optimization/105490] New: unvectorized loop due to bool condition loaded from memory and different size data 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 ` (2 subsequent siblings) 4 siblings, 0 replies; 6+ messages in thread From: pinskia at gcc dot gnu.org @ 2022-10-31 15:46 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105490 Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Severity|normal |enhancement ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug tree-optimization/105490] unvectorized loop due to bool condition loaded from memory and different size data 2022-05-05 8:39 [Bug tree-optimization/105490] New: unvectorized loop due to bool condition loaded from memory and different size data 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 2023-08-31 6:34 ` rguenther at suse dot de 4 siblings, 0 replies; 6+ messages in thread From: pinskia at gcc dot gnu.org @ 2023-08-30 6:07 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105490 Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- See Also| |https://gcc.gnu.org/bugzill | |a/show_bug.cgi?id=111149 --- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> --- So what is interesting is we do handle: ``` #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]; void predicate_by_bool_ne() { for (int i = 0; i < N; i++) c[i] = pb[i] != pb1[i] ? a[i] : b[i]; } ``` But not: ``` #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]; void predicate_by_bool_and() { for (int i = 0; i < N; i++) c[i] = (pb[i] & pb1[i]) ? a[i] : b[i]; } ``` And If I change the canonical form of `bool != bool` into `bool ^ bool` things break down in a similar way. I tried to look into a reasonible way of handling this in the vectorizer but I could not figure out how to treat `^` in the same way as `!=`. ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug tree-optimization/105490] unvectorized loop due to bool condition loaded from memory and different size data 2022-05-05 8:39 [Bug tree-optimization/105490] New: unvectorized loop due to bool condition loaded from memory and different size data rguenth at gcc dot gnu.org ` (2 preceding siblings ...) 2023-08-30 6:07 ` pinskia at gcc dot gnu.org @ 2023-08-30 15:32 ` pinskia at gcc dot gnu.org 2023-08-31 6:34 ` rguenther at suse dot de 4 siblings, 0 replies; 6+ messages in thread From: pinskia at gcc dot gnu.org @ 2023-08-30 15:32 UTC (permalink / raw) To: gcc-bugs 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 ... ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug tree-optimization/105490] unvectorized loop due to bool condition loaded from memory and different size data 2022-05-05 8:39 [Bug tree-optimization/105490] New: unvectorized loop due to bool condition loaded from memory and different size data rguenth at gcc dot gnu.org ` (3 preceding siblings ...) 2023-08-30 15:32 ` pinskia at gcc dot gnu.org @ 2023-08-31 6:34 ` rguenther at suse dot de 4 siblings, 0 replies; 6+ messages in thread From: rguenther at suse dot de @ 2023-08-31 6:34 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105490 --- Comment #3 from rguenther at suse dot de <rguenther at suse dot de> --- On Wed, 30 Aug 2023, pinskia at gcc dot gnu.org wrote: > 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 ... This is usually due to limits/bugs in the vectorizer bool pattern recognition code which is supposed to replace "mask" uses of bool with x ? -1 : 0 (or make sure comparisons produce them) and data uses with x ? 1 : 0 (or make sure "data" stmts produce them). There are defenses in vectorizable_* to detect cases where that did go wrong (which it does sometimes), leading to missed vectorizations (or wrong code in the worst case). It's a mess. ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2023-08-31 6:34 UTC | newest] Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2022-05-05 8:39 [Bug tree-optimization/105490] New: unvectorized loop due to bool condition loaded from memory and different size data 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 2023-08-31 6:34 ` rguenther at suse dot de
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