https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110860
--- Comment #8 from Paul Dreik <gcc at pauldreik dot se> ---
I do unfortunately not think the fix is entirely correct.
When 0 is passed, log10 returns -inf, which can not be converted to an integer.
I had a bit of problem to reproduce this with gcc, but it worked with clang.
The following program:
#include <cstdio>
#include <format>
#include <string_view>
int main(int argc, char* argv[]) {
[[maybe_unused]] auto x = std::format("{:.292f}", 0.f);
}
causes the following output when compiled with clang-16 using
-fsanitize=undefined -fno-sanitize-recover=all -g -O0:
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/14.0.0/../../../../include/c++/14.0.0/format:1496:15:
runtime error: -inf is outside the range of representable values of type
'unsigned long'
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/14.0.0/../../../../include/c++/14.0.0/format:1496:15
in
Link to reproducer (expected to go stale quick, had to use clang trunk to get a
sufficiently new libstdc++): https://godbolt.org/z/8aGf7YGWs
