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| author | Richard Sandiford <richard.sandiford@arm.com> | 2025-04-10 11:03:04 +0100 |
|---|---|---|
| committer | Richard Sandiford <richard.sandiford@arm.com> | 2025-04-10 11:03:04 +0100 |
| commit | 4c8c373495d7d863dfb7102726ac3b4b41685df4 (patch) | |
| tree | ce9e1c6b620d05be673a05b703b732882163f5fa /gcc | |
| parent | 72dff34bcdd6f05b64bbf07739ab815e673b5946 (diff) | |
| download | gcc-4c8c373495d7d863dfb7102726ac3b4b41685df4.zip gcc-4c8c373495d7d863dfb7102726ac3b4b41685df4.tar.gz gcc-4c8c373495d7d863dfb7102726ac3b4b41685df4.tar.bz2 | |
Avoid using POINTER_DIFF_EXPR for overlap checks [PR119399]
In r10-4803-g8489e1f45b50600c I'd used POINTER_DIFF_EXPR to subtract
the two pointers involved in an overlap test. I'm not sure whether
I'd specifically chosen that over MINUS_EXPR or not; if so, the only
reason I can think of is that it is probably faster on targets with
PSImode pointers. Regardless, as the PR points out, subtracting
unrelated pointers using POINTER_DIFF_EXPR is undefined behaviour.
gcc/
PR tree-optimization/119399
* tree-data-ref.cc (create_waw_or_war_checks): Use a MINUS_EXPR
on two converted pointers, rather than converting a POINTER_DIFF_EXPR
on the pointers.
gcc/testsuite/
PR tree-optimization/119399
* gcc.dg/vect/pr119399.c: New test.
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/testsuite/gcc.dg/vect/pr119399.c | 10 | ||||
| -rw-r--r-- | gcc/tree-data-ref.cc | 7 |
2 files changed, 14 insertions, 3 deletions
diff --git a/gcc/testsuite/gcc.dg/vect/pr119399.c b/gcc/testsuite/gcc.dg/vect/pr119399.c new file mode 100644 index 0000000..8d868f4 --- /dev/null +++ b/gcc/testsuite/gcc.dg/vect/pr119399.c @@ -0,0 +1,10 @@ +/* { dg-do compile } */ +/* { dg-additional-options "-fdump-tree-vect-raw" } */ + +void foo(int *p, int *q, int n) +{ + for (int i = 0; i < n; i++) + p[i] = q[i] + 1; +} + +/* { dg-final { scan-tree-dump-not {<pointer_diff_expr,} "vect" } } */ diff --git a/gcc/tree-data-ref.cc b/gcc/tree-data-ref.cc index 18d9f0f..8a46e6d 100644 --- a/gcc/tree-data-ref.cc +++ b/gcc/tree-data-ref.cc @@ -2498,9 +2498,10 @@ create_waw_or_war_checks (tree *cond_expr, limit = fold_build2 (PLUS_EXPR, sizetype, limit, size_int (last_chunk_a + last_chunk_b)); - tree subject = fold_build2 (POINTER_DIFF_EXPR, ssizetype, addr_b, addr_a); - subject = fold_build2 (PLUS_EXPR, sizetype, - fold_convert (sizetype, subject), bias); + tree subject = fold_build2 (MINUS_EXPR, sizetype, + fold_convert (sizetype, addr_b), + fold_convert (sizetype, addr_a)); + subject = fold_build2 (PLUS_EXPR, sizetype, subject, bias); *cond_expr = fold_build2 (GT_EXPR, boolean_type_node, subject, limit); if (dump_enabled_p ()) |