https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116924
Bug ID: 116924
Summary: -ffast-math -Wunused-value warnings in <cmath>
Product: gcc
Version: 15.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: jason at gcc dot gnu.org
Target Milestone: ---
With my recent libstdc++ warning changes, compiling
#include <cmath>
with -ffast-math -Wunused-value produces
/home/jason/s/gcc/x86_64-pc-linux-gnu/libstdc++-v3/include/cmath: In function
‘constexpr _Float16 std::nextafter(_Float16, _Float16)’:
/home/jason/s/gcc/x86_64-pc-linux-gnu/libstdc++-v3/include/cmath:2903:29:
warning: statement has no effect [-Wunused-value]
2903 | __builtin_nextafterf(0.0f, 1.0f); // raise underflow
| ~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~
/home/jason/s/gcc/x86_64-pc-linux-gnu/libstdc++-v3/include/cmath:2922:27:
warning: statement has no effect [-Wunused-value]
2922 | __builtin_nextafterf(__FLT_MAX__, __builtin_inff()); //
overflow
| ~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/jason/s/gcc/x86_64-pc-linux-gnu/libstdc++-v3/include/cmath:2924:27:
warning: statement has no effect [-Wunused-value]
2924 | __builtin_nextafterf(__FLT_MIN__, 0.0f); // underflow
| ~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~
/home/jason/s/gcc/x86_64-pc-linux-gnu/libstdc++-v3/include/cmath: In function
‘constexpr __gnu_cxx::__bfloat16_t std::nextafter(__gnu_cxx::__bfloat16_t,
__gnu_cxx::__bfloat16_t)’:
/home/jason/s/gcc/x86_64-pc-linux-gnu/libstdc++-v3/include/cmath:3621:29:
warning: statement has no effect [-Wunused-value]
3621 | __builtin_nextafterf(0.0f, 1.0f); // raise underflow
| ~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~
/home/jason/s/gcc/x86_64-pc-linux-gnu/libstdc++-v3/include/cmath:3640:27:
warning: statement has no effect [-Wunused-value]
3640 | __builtin_nextafterf(__FLT_MAX__, __builtin_inff()); //
overflow
| ~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/jason/s/gcc/x86_64-pc-linux-gnu/libstdc++-v3/include/cmath:3642:27:
warning: statement has no effect [-Wunused-value]
3642 | __builtin_nextafterf(__FLT_MIN__, 0.0f); // underflow
| ~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~
