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| author | Jakub Jelinek <jakub@redhat.com> | 2023-01-04 10:52:49 +0100 |
|---|---|---|
| committer | Jakub Jelinek <jakub@redhat.com> | 2023-01-04 10:52:49 +0100 |
| commit | 8692b15ae7c05e3224f285069e070c009d9f6efe (patch) | |
| tree | 72c7c7360e12e17add721f5b3d82c54a872151ff /gcc/fold-const.cc | |
| parent | 44baa34157cf81306be23eacece751aa020985d4 (diff) | |
| download | gcc-8692b15ae7c05e3224f285069e070c009d9f6efe.zip gcc-8692b15ae7c05e3224f285069e070c009d9f6efe.tar.gz gcc-8692b15ae7c05e3224f285069e070c009d9f6efe.tar.bz2 | |
ubsan: Avoid narrowing of multiply for -fsanitize=signed-integer-overflow [PR108256]
We shouldn't narrow multiplications originally done in signed types,
because the original multiplication might overflow but the narrowed
one will be done in unsigned arithmetics and will never overflow.
2023-01-04 Jakub Jelinek <jakub@redhat.com>
PR sanitizer/108256
* convert.cc (do_narrow): Punt for MULT_EXPR if original
type doesn't wrap around and -fsanitize=signed-integer-overflow
is on.
* fold-const.cc (fold_unary_loc) <CASE_CONVERT>: Likewise.
* c-c++-common/ubsan/pr108256.c: New test.
Diffstat (limited to 'gcc/fold-const.cc')
| -rw-r--r-- | gcc/fold-const.cc | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/gcc/fold-const.cc b/gcc/fold-const.cc index 9ab76fb..9aaea71 100644 --- a/gcc/fold-const.cc +++ b/gcc/fold-const.cc @@ -9574,7 +9574,9 @@ fold_unary_loc (location_t loc, enum tree_code code, tree type, tree op0) if (INTEGRAL_TYPE_P (type) && TREE_CODE (op0) == MULT_EXPR && INTEGRAL_TYPE_P (TREE_TYPE (op0)) - && TYPE_PRECISION (type) < TYPE_PRECISION (TREE_TYPE (op0))) + && TYPE_PRECISION (type) < TYPE_PRECISION (TREE_TYPE (op0)) + && (TYPE_OVERFLOW_WRAPS (TREE_TYPE (op0)) + || !sanitize_flags_p (SANITIZE_SI_OVERFLOW))) { /* Be careful not to introduce new overflows. */ tree mult_type; |