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| author | Richard Biener <rguenther@suse.de> | 2021-01-11 12:04:32 +0100 |
|---|---|---|
| committer | Richard Biener <rguenther@suse.de> | 2021-01-11 13:38:18 +0100 |
| commit | 84684e0f78c20c51492722a5b95cda778ad77073 (patch) | |
| tree | 34dd14796ef4d822348833a2b360f2f42c19f54d | |
| parent | 6ebf79fcd4cfb43353e6a000f700b07295e78026 (diff) | |
| download | gcc-84684e0f78c20c51492722a5b95cda778ad77073.zip gcc-84684e0f78c20c51492722a5b95cda778ad77073.tar.gz gcc-84684e0f78c20c51492722a5b95cda778ad77073.tar.bz2 | |
tree-optimization/91403 - avoid excessive code-generation
The vectorizer, for large permuted grouped loads, generates
inefficient intermediate code (cleaned up only later) that runs
into complexity issues in SCEV analysis and elsewhere. For the
non-single-element interleaving case we already put a hard limit
in place, this applies the same limit to the missing case.
2021-01-11 Richard Biener <rguenther@suse.de>
PR tree-optimization/91403
* tree-vect-data-refs.c (vect_analyze_group_access_1): Cap
single-element interleaving group size at 4096 elements.
* gcc.dg/vect/pr91403.c: New testcase.
| -rw-r--r-- | gcc/testsuite/gcc.dg/vect/pr91403.c | 11 | ||||
| -rw-r--r-- | gcc/tree-vect-data-refs.c | 6 |
2 files changed, 16 insertions, 1 deletions
diff --git a/gcc/testsuite/gcc.dg/vect/pr91403.c b/gcc/testsuite/gcc.dg/vect/pr91403.c new file mode 100644 index 0000000..5b9b760 --- /dev/null +++ b/gcc/testsuite/gcc.dg/vect/pr91403.c @@ -0,0 +1,11 @@ +/* { dg-do compile } */ +/* { dg-additional-options "-O3" } */ + +extern int a[][1000000]; +int b; +void c() +{ + for (int d = 2; d <= 9; d++) + for (int e = 32; e <= 41; e++) + b += a[d][5]; +} diff --git a/gcc/tree-vect-data-refs.c b/gcc/tree-vect-data-refs.c index c71ff73..97c8577 100644 --- a/gcc/tree-vect-data-refs.c +++ b/gcc/tree-vect-data-refs.c @@ -2538,7 +2538,11 @@ vect_analyze_group_access_1 (vec_info *vinfo, dr_vec_info *dr_info) size. */ if (DR_IS_READ (dr) && (dr_step % type_size) == 0 - && groupsize > 0) + && groupsize > 0 + /* This could be UINT_MAX but as we are generating code in a very + inefficient way we have to cap earlier. + See PR91403 for example. */ + && groupsize <= 4096) { DR_GROUP_FIRST_ELEMENT (stmt_info) = stmt_info; DR_GROUP_SIZE (stmt_info) = groupsize; |