PR 87059 - internal compiler error: in set_value_range, at tree-vrp.c:289, is apparently due to an argument type mismatch in a MIN_EXPR introduced by expand_builtin_strncmp().
The function calls c_strlen() to compute the length of the two string arguments to strncmp() and then replaces the third (bound) argument with a MIN (len, bound). The type mismatch is caused by len being the signed result of c_strlen(), while bound being the size_t argument (explicitly converted to sizetype by the function). My question is: why does c_strlen() return a ssizetype, a signed type, rather the more natural sizetype? I ask in part because changing expand_builtin_strncmp() to convert the bound to ssizetype has downstream effects in the test suite, in part because it seems unexpected for the function to return a signed type given that the result cannot be negative, and in part also because I see most callers explicitly convert the result to size_type_node. Thanks Martin
