On 08/14/2018 01:01 PM, Martin Sebor wrote:
> Attached is a patch to avoid calling array_at_struct_end_p()
> with a MEM_REF argument. The function returns false even if
> the reference does point into such a flexible array member,
> as in:
>
> struct A { char i, a[1]; };
> void f (struct A *p)
> {
> return strlen (p->a + 1);
> }
>
> This fix will likely be made obsolete once the string length
> range optimization is relaxed but since that's a bigger change
> I think GCC might as well emit the correct code for this case
> until then.
>
> Martin
>
> gcc-86914.diff
>
>
> PR tree-optimization/86914 - wrong code with strlen() of poor-man's flexible
> array member plus offset
>
> gcc/ChangeLog:
>
> PR tree-optimization/86914
> * tree-ssa-strlen.c (maybe_set_strlen_range): Avoid MEM_REF.
>
> gcc/testsuite/ChangeLog:
>
> PR tree-optimization/86914
> * gcc.dg/strlenopt-57.c: New test.
OK.
jeff
