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author | Richard Biener <rguenther@suse.de> | 2024-01-17 14:05:42 +0100 |
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committer | Richard Biener <rguenther@suse.de> | 2024-01-18 08:31:41 +0100 |
commit | b981d5c60b8ef78e2adecd6b5d7e36f9e5e61c54 (patch) | |
tree | 0370227d5c2ce54cf95261ab2592d6fd8a54290a /gcc | |
parent | 0f38666680d6ad0e40c4a8b6d94b2c93931cdf42 (diff) | |
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tree-optimization/113431 - wrong dependence with invariant load
The vectorizer dependence analysis is confused with invariant loads
when figuring whether the circumstances are so that we preserve
scalar stmt execution order. The following rectifies this.
PR tree-optimization/113431
* tree-vect-data-refs.cc (vect_preserves_scalar_order_p):
When there is an invariant load we might not preserve
scalar order.
* gcc.dg/vect/pr113431.c: New testcase.
Diffstat (limited to 'gcc')
-rw-r--r-- | gcc/testsuite/gcc.dg/vect/pr113431.c | 18 | ||||
-rw-r--r-- | gcc/tree-vect-data-refs.cc | 6 |
2 files changed, 24 insertions, 0 deletions
diff --git a/gcc/testsuite/gcc.dg/vect/pr113431.c b/gcc/testsuite/gcc.dg/vect/pr113431.c new file mode 100644 index 0000000..04448d9 --- /dev/null +++ b/gcc/testsuite/gcc.dg/vect/pr113431.c @@ -0,0 +1,18 @@ +/* { dg-additional-options "-O3 -fdump-tree-slp1-details" } */ + +#include "tree-vect.h" + +int a[2][9]; +int b; +int main() +{ + check_vect (); + for (b = 0; b < 2; b++) + for (long e = 8; e > 0; e--) + a[b][e] = a[0][1] == 0; + if (a[1][1] != 0) + __builtin_abort (); + return 0; +} + +/* { dg-final { scan-tree-dump-times "optimized: basic block part vectorized" 2 "slp1" { target vect_int } } } */ diff --git a/gcc/tree-vect-data-refs.cc b/gcc/tree-vect-data-refs.cc index 0495842..f592aeb 100644 --- a/gcc/tree-vect-data-refs.cc +++ b/gcc/tree-vect-data-refs.cc @@ -282,6 +282,12 @@ vect_preserves_scalar_order_p (dr_vec_info *dr_info_a, dr_vec_info *dr_info_b) && !STMT_VINFO_GROUPED_ACCESS (stmtinfo_b)) return true; + /* If there is a loop invariant read involved we might vectorize it in + the prologue, breaking scalar oder with respect to the in-loop store. */ + if ((DR_IS_READ (dr_info_a->dr) && integer_zerop (DR_STEP (dr_info_a->dr))) + || (DR_IS_READ (dr_info_b->dr) && integer_zerop (DR_STEP (dr_info_b->dr)))) + return false; + /* STMT_A and STMT_B belong to overlapping groups. All loads are emitted at the position of the first scalar load. Stores in a group are emitted at the position of the last scalar store. |