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| author | Richard Biener <rguenther@suse.de> | 2025-01-29 15:09:35 +0100 |
|---|---|---|
| committer | Richard Biener <rguenth@gcc.gnu.org> | 2025-01-30 10:03:02 +0100 |
| commit | 6b56e645a7b481693fe6982f8f09ba2e07768bf8 (patch) | |
| tree | 811f58cd52a0e1808aa67cfa9864e56d15162d45 /gcc/expr.cc | |
| parent | d1c7837d2d6e5a2997228681166ed8c814891881 (diff) | |
| download | gcc-6b56e645a7b481693fe6982f8f09ba2e07768bf8.zip gcc-6b56e645a7b481693fe6982f8f09ba2e07768bf8.tar.gz gcc-6b56e645a7b481693fe6982f8f09ba2e07768bf8.tar.bz2 | |
middle-end/118692 - ICE with out-of-bound ref expansion
The following guards the BIT_FIELD_REF expansion fallback for
MEM_REFs of entities expanded to register (or constant) further,
avoiding large out-of-bound offsets by, when the access does not
overlap the base object, expanding the offset as if it were zero.
PR middle-end/118692
* expr.cc (expand_expr_real_1): When expanding a MEM_REF
as BIT_FIELD_REF avoid large offsets for accesses not
overlapping the base object.
* gcc.dg/pr118692.c: New testcase.
Diffstat (limited to 'gcc/expr.cc')
| -rw-r--r-- | gcc/expr.cc | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/gcc/expr.cc b/gcc/expr.cc index 7f3149b..10467f8 100644 --- a/gcc/expr.cc +++ b/gcc/expr.cc @@ -11806,6 +11806,14 @@ expand_expr_real_1 (tree exp, rtx target, machine_mode tmode, set_mem_size (temp, int_size_in_bytes (type)); return temp; } + /* When the access is fully outside of the underlying object + expand the offset as zero. This avoids out-of-bound + BIT_FIELD_REFs and generates smaller code for these cases + with UB. */ + type_size = tree_to_poly_uint64 (TYPE_SIZE_UNIT (type)); + if (!ranges_maybe_overlap_p (offset, type_size, 0, + GET_MODE_SIZE (DECL_MODE (base)))) + offset = 0; exp = build3 (BIT_FIELD_REF, type, base, TYPE_SIZE (type), bitsize_int (offset * BITS_PER_UNIT)); REF_REVERSE_STORAGE_ORDER (exp) = reverse; |