https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100137
--- Comment #4 from Moritz Beutel <spamandnoise at gmail dot com> ---
Interesting. I had figured that the test case could probably be reduced
further, but I didn't try because the bug appeared so brittle. Slightly
changing seemingly unrelated details made it vanish:
-----
// line 10:
if ( _size != 0 && _data == nullptr ) throw 42; // bug
//if ( _size != 0 && _data == nullptr ) throw 42; // no bug
// line 23:
size_t string_length( char const * ptr, size_t max = (size_t) -1 ) // bug
size_t string_length( char const * ptr, size_t max = (size_t) -2 ) // no bug
// line 26:
while ( len < max && ptr[len] ) // bug
while ( ptr[len] ) // no bug
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Link for experimentation: https://gcc.godbolt.org/z/af8P7v64T
