https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110860
Bug ID: 110860
Summary: std::format("{:f}",2e304) invokes undefined behaviour
Product: gcc
Version: 13.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: gcc at pauldreik dot se
Target Milestone: ---
The following program, compiled with gcc 13.2:
#include <format>
#include <cstdio>
int main() {
std::puts(std::format("{:f}",2e304).c_str());
}
causes ubsan to warn:
/opt/compiler-explorer/gcc-13.2.0/include/c++/13.2.0/format:1489:52: runtime
error: negation of -2147483648 cannot be represented in type 'int'; cast to an
unsigned type to negate this value to itself
I believe the problem is using __builtin_abs() which uses integer, but is fed a
double.
Link to reproducer:
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