[libc-commits] [libc] [libc][math][c++23] Add fabsbf16 math function (PR #148398)

LLVM Continuous Integration via libc-commits libc-commits at lists.llvm.org
Tue Jul 29 09:25:06 PDT 2025 

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `libc-riscv64-debian-dbg` running on `libc-riscv64-debian` while building `libc` at step 4 "annotate".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/188/builds/17736

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 4 (annotate) failure: 'python ../llvm-zorg/zorg/buildbot/builders/annotated/libc-linux.py ...' (failure)
...
  Math tests using MPC will be skipped.


-- check-runtimes does nothing.
-- Configuring done
-- Generating done
-- Build files have been written to: /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-dbg/build
@@@BUILD_STEP build libc@@@
Running: ninja libc
[1/2] Building CXX object libc/src/math/generic/CMakeFiles/libc.src.math.generic.fabsbf16.dir/fabsbf16.cpp.o
FAILED: libc/src/math/generic/CMakeFiles/libc.src.math.generic.fabsbf16.dir/fabsbf16.cpp.o 
/usr/bin/clang++ -DLIBC_NAMESPACE=__llvm_libc_20_0_0_git -D_DEBUG -I/home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-dbg/llvm-project/libc -isystem /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-dbg/build/libc/include -fvisibility-inlines-hidden -Werror=date-time -Werror=unguarded-availability-new -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -Wimplicit-fallthrough -Wcovered-switch-default -Wno-noexcept-type -Wnon-virtual-dtor -Wdelete-non-virtual-dtor -Wsuggest-override -Wno-comment -Wstring-conversion -fdiagnostics-color -g -DLIBC_QSORT_IMPL=LIBC_QSORT_QUICK_SORT -DLIBC_ADD_NULL_CHECKS -DLIBC_ERRNO_MODE=LIBC_ERRNO_MODE_DEFAULT -fpie -fno-builtin -fno-exceptions -fno-lax-vector-conversions -fno-unwind-tables -fno-asynchronous-unwind-tables -fno-rtti -ftrivial-auto-var-init=pattern -fno-omit-frame-pointer -Wall -Wextra -Werror -Wconversion -Wno-sign-conversion -Wdeprecated -Wno-c99-extensions -Wno-gnu-imaginary-constant -Wno-pedantic -Wimplicit-fallthrough -Wwrite-strings -Wextra-semi -Wnewline-eof -Wnonportable-system-include-path -Wstrict-prototypes -Wthread-safety -Wglobal-constructors -DLIBC_COPT_PUBLIC_PACKAGING -std=gnu++17 -MD -MT libc/src/math/generic/CMakeFiles/libc.src.math.generic.fabsbf16.dir/fabsbf16.cpp.o -MF libc/src/math/generic/CMakeFiles/libc.src.math.generic.fabsbf16.dir/fabsbf16.cpp.o.d -o libc/src/math/generic/CMakeFiles/libc.src.math.generic.fabsbf16.dir/fabsbf16.cpp.o -c /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-dbg/llvm-project/libc/src/math/generic/fabsbf16.cpp
In file included from /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-dbg/llvm-project/libc/src/math/generic/fabsbf16.cpp:12:
/home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-dbg/llvm-project/libc/src/__support/FPUtil/bfloat16.h:31:56: error: inline function '__llvm_libc_20_0_0_git::fputil::BFloat16::BFloat16<float>' is not defined [-Werror,-Wundefined-inline]
  template <typename T> LIBC_INLINE constexpr explicit BFloat16(T value) {
                                                       ^
/home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-dbg/llvm-project/libc/src/__support/FPUtil/cast.h:71:10: note: used here
  return static_cast<OutType>(x);
         ^
1 error generated.
ninja: build stopped: subcommand failed.
['ninja', 'libc'] exited with return code 1.
The build step threw an exception...
Traceback (most recent call last):
  File "/home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-dbg/build/../llvm-zorg/zorg/buildbot/builders/annotated/libc-linux.py", line 181, in step
    yield
  File "/home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-dbg/build/../llvm-zorg/zorg/buildbot/builders/annotated/libc-linux.py", line 143, in main
    run_command(['ninja', 'libc'])
  File "/home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-dbg/build/../llvm-zorg/zorg/buildbot/builders/annotated/libc-linux.py", line 196, in run_command
    util.report_run_cmd(cmd, cwd=directory)
  File "/home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-dbg/llvm-zorg/zorg/buildbot/builders/annotated/util.py", line 49, in report_run_cmd
    subprocess.check_call(cmd, shell=shell, *args, **kwargs)
  File "/usr/lib/python3.10/subprocess.py", line 369, in check_call
    raise CalledProcessError(retcode, cmd)
subprocess.CalledProcessError: Command '['ninja', 'libc']' returned non-zero exit status 1.
@@@STEP_FAILURE@@@
@@@BUILD_STEP libc-unit-tests@@@
Running: ninja libc-unit-tests
[1/1205] Running unit test libc.test.src.__support.block_test.__unit__
[==========] Running 23 tests from 1 test suite.
[ RUN      ] LlvmLibcBlockTest.CanCreateSingleAlignedBlock
[       OK ] LlvmLibcBlockTest.CanCreateSingleAlignedBlock (16 us)
[ RUN      ] LlvmLibcBlockTest.CanCreateUnalignedSingleBlock
[       OK ] LlvmLibcBlockTest.CanCreateUnalignedSingleBlock (6 us)
[ RUN      ] LlvmLibcBlockTest.CannotCreateTooSmallBlock
[       OK ] LlvmLibcBlockTest.CannotCreateTooSmallBlock (3 us)
[ RUN      ] LlvmLibcBlockTest.CanSplitBlock
[       OK ] LlvmLibcBlockTest.CanSplitBlock (9 us)
[ RUN      ] LlvmLibcBlockTest.CanSplitBlockUnaligned
Step 6 (build libc) failure: build libc (failure)
@@@BUILD_STEP build libc@@@
Running: ninja libc
[1/2] Building CXX object libc/src/math/generic/CMakeFiles/libc.src.math.generic.fabsbf16.dir/fabsbf16.cpp.o
FAILED: libc/src/math/generic/CMakeFiles/libc.src.math.generic.fabsbf16.dir/fabsbf16.cpp.o 
/usr/bin/clang++ -DLIBC_NAMESPACE=__llvm_libc_20_0_0_git -D_DEBUG -I/home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-dbg/llvm-project/libc -isystem /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-dbg/build/libc/include -fvisibility-inlines-hidden -Werror=date-time -Werror=unguarded-availability-new -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -Wimplicit-fallthrough -Wcovered-switch-default -Wno-noexcept-type -Wnon-virtual-dtor -Wdelete-non-virtual-dtor -Wsuggest-override -Wno-comment -Wstring-conversion -fdiagnostics-color -g -DLIBC_QSORT_IMPL=LIBC_QSORT_QUICK_SORT -DLIBC_ADD_NULL_CHECKS -DLIBC_ERRNO_MODE=LIBC_ERRNO_MODE_DEFAULT -fpie -fno-builtin -fno-exceptions -fno-lax-vector-conversions -fno-unwind-tables -fno-asynchronous-unwind-tables -fno-rtti -ftrivial-auto-var-init=pattern -fno-omit-frame-pointer -Wall -Wextra -Werror -Wconversion -Wno-sign-conversion -Wdeprecated -Wno-c99-extensions -Wno-gnu-imaginary-constant -Wno-pedantic -Wimplicit-fallthrough -Wwrite-strings -Wextra-semi -Wnewline-eof -Wnonportable-system-include-path -Wstrict-prototypes -Wthread-safety -Wglobal-constructors -DLIBC_COPT_PUBLIC_PACKAGING -std=gnu++17 -MD -MT libc/src/math/generic/CMakeFiles/libc.src.math.generic.fabsbf16.dir/fabsbf16.cpp.o -MF libc/src/math/generic/CMakeFiles/libc.src.math.generic.fabsbf16.dir/fabsbf16.cpp.o.d -o libc/src/math/generic/CMakeFiles/libc.src.math.generic.fabsbf16.dir/fabsbf16.cpp.o -c /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-dbg/llvm-project/libc/src/math/generic/fabsbf16.cpp
In file included from /home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-dbg/llvm-project/libc/src/math/generic/fabsbf16.cpp:12:
/home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-dbg/llvm-project/libc/src/__support/FPUtil/bfloat16.h:31:56: error: inline function '__llvm_libc_20_0_0_git::fputil::BFloat16::BFloat16<float>' is not defined [-Werror,-Wundefined-inline]
  template <typename T> LIBC_INLINE constexpr explicit BFloat16(T value) {
                                                       ^
/home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-dbg/llvm-project/libc/src/__support/FPUtil/cast.h:71:10: note: used here
  return static_cast<OutType>(x);
         ^
1 error generated.
ninja: build stopped: subcommand failed.
['ninja', 'libc'] exited with return code 1.
The build step threw an exception...
Traceback (most recent call last):
  File "/home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-dbg/build/../llvm-zorg/zorg/buildbot/builders/annotated/libc-linux.py", line 181, in step
    yield
  File "/home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-dbg/build/../llvm-zorg/zorg/buildbot/builders/annotated/libc-linux.py", line 143, in main
    run_command(['ninja', 'libc'])
  File "/home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-dbg/build/../llvm-zorg/zorg/buildbot/builders/annotated/libc-linux.py", line 196, in run_command
    util.report_run_cmd(cmd, cwd=directory)
  File "/home/libc_worker/libc-riscv64-debian/libc-riscv64-debian-dbg/llvm-zorg/zorg/buildbot/builders/annotated/util.py", line 49, in report_run_cmd
    subprocess.check_call(cmd, shell=shell, *args, **kwargs)
  File "/usr/lib/python3.10/subprocess.py", line 369, in check_call
    raise CalledProcessError(retcode, cmd)
subprocess.CalledProcessError: Command '['ninja', 'libc']' returned non-zero exit status 1.

```

</details>

https://github.com/llvm/llvm-project/pull/148398

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