On 1/4/19 3:54 PM, Jakub Jelinek wrote:
> Hi!
>
> The following patch fixes ICU miscompilation, where an initial part of a
> buffer is initializer from non-zero terminated string literal (in ICU
> actually from an array of non-zero chars that the FE newly turns into
> non-zero terminated string literal), but the code recently added to
> tree-ssa-strlen.c doesn't consider the possibility of string literals that
> aren't zero terminated.
>
> STRING_CSTs actually are always zero terminated, but if TREE_STRING_LENGTH
> doesn't include the terminating character, it is just bytes.
>
> Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for
> trunk?
>
> I was considering using strnlen, but if all STRING_CSTs are actually zero
> terminated, it will mean it reads are most one further byte and on many
> targets strlen is more optimized than strnlen.
>
> 2019-01-04 Jakub Jelinek <ja...@redhat.com>
>
> PR tree-optimization/88693
> * tree-ssa-strlen.c (get_min_string_length): Don't set *full_string_p
> for STRING_CSTs that don't contain any NUL characters in the first
> TREE_STRING_LENGTH bytes.
>
> * gcc.c-torture/execute/pr88693.c: New test.
OK
jeff
