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| author | Bernd Edlinger <bernd.edlinger@hotmail.de> | 2018-08-22 23:43:44 +0000 |
|---|---|---|
| committer | Jeff Law <law@gcc.gnu.org> | 2018-08-22 17:43:44 -0600 |
| commit | 36d2d101fa9d21189195cce1e90b955096a79779 (patch) | |
| tree | 5e2dacb95dffb68975016fb56187863415ed909c | |
| parent | f73a5316b6f76fa62979c29f4ec3620bf821dca0 (diff) | |
| download | gcc-36d2d101fa9d21189195cce1e90b955096a79779.zip gcc-36d2d101fa9d21189195cce1e90b955096a79779.tar.gz gcc-36d2d101fa9d21189195cce1e90b955096a79779.tar.bz2 | |
tree-ssa-dse.c (compute_trims): Avoid folding away undefined behaviour.
* tree-ssa-dse.c (compute_trims): Avoid folding away undefined
behaviour.
From-SVN: r263793
| -rw-r--r-- | gcc/ChangeLog | 5 | ||||
| -rw-r--r-- | gcc/tree-ssa-dse.c | 7 |
2 files changed, 12 insertions, 0 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 606fb5f..f362c369 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,8 @@ +2018-08-22 Bernd Edlinger <bernd.edlinger@hotmail.de> + + * tree-ssa-dse.c (compute_trims): Avoid folding away undefined + behaviour. + 2018-08-22 Martin Sebor <msebor@redhat.com> PR middle-end/87052 diff --git a/gcc/tree-ssa-dse.c b/gcc/tree-ssa-dse.c index 4cb8c0f8..016aa6c 100644 --- a/gcc/tree-ssa-dse.c +++ b/gcc/tree-ssa-dse.c @@ -248,6 +248,13 @@ compute_trims (ao_ref *ref, sbitmap live, int *trim_head, int *trim_tail, residual handling in mem* and str* functions is usually reasonably efficient. */ *trim_tail = last_orig - last_live; + + /* But don't trim away out of bounds accesses, as this defeats + proper warnings. */ + if (*trim_tail + && compare_tree_int (TYPE_SIZE_UNIT (TREE_TYPE (ref->base)), + last_orig) <= 0) + *trim_tail = 0; } else *trim_tail = 0; |