On 06/22/2018 04:00 PM, Jeff Law wrote:
On 06/18/2018 01:15 PM, Martin Sebor wrote:
While looking into opportunities to detect strnlen/strlen coding
mistakes (pr86199) I noticed a bug in the strnlen implementation
I committed earlier today that lets a strnlen() result be saved
and used in subsequent calls to strlen() with the same argument.
The attached patch changes the handle_builtin_strlen() function
to discard the strnlen() result unless its bound is greater than
the length of the string.
Martin
gcc-86204.diff
PR tree-optimization/86204 - wrong strlen result after prior strnlen
gcc/ChangeLog:
PR tree-optimization/86204
* tree-ssa-strlen.c (handle_builtin_strlen): Avoid storing
a strnlen result if it's less than the length of the string.
gcc/testsuite/ChangeLog:
PR tree-optimization/86204
* gcc.dg/strlenopt-46.c: New test.
OK. Though I must admit I don't like having variables "bounded" and
"bound" in the same function. So consider renaming one to avoid future
confusion.
Done in r262114.
Martin
