[libc-commits] [libc] [libc][math] Fix incorrect logic in fputil::generic::add_or_sub (PR #116129)

[LLVM Continuous Integration via libc-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `libc-aarch64-ubuntu-dbg` running on `libc-aarch64-ubuntu` while building `libc` at step 4 "annotate".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/104/builds/18422

<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)
...
[       OK ] LlvmLibcLdExpTest.NormalOperation (310 us)
Ran 6 tests.  PASS: 6  FAIL: 0
[129/1317] Running unit test libc.test.src.math.fmodf_test.__unit__
[==========] Running 2 tests from 1 test suite.
[ RUN      ] LlvmLibcFmodTest.SpecialNumbers
[       OK ] LlvmLibcFmodTest.SpecialNumbers (131 us)
[ RUN      ] LlvmLibcFmodTest.RegularExtreme
[       OK ] LlvmLibcFmodTest.RegularExtreme (12 us)
Ran 2 tests.  PASS: 2  FAIL: 0
[130/1317] Building CXX object libc/utils/MPFRWrapper/CMakeFiles/libcMPFRWrapper.dir/MPFRUtils.cpp.o
FAILED: libc/utils/MPFRWrapper/CMakeFiles/libcMPFRWrapper.dir/MPFRUtils.cpp.o 
/usr/bin/clang++ -DLIBC_NAMESPACE=__llvm_libc_20_0_0_git -D_DEBUG -I/home/libc-buildbot/libc-aarch64-ubuntu/libc-aarch64-ubuntu/llvm-project/libc -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 -O3 -fpie -Wconversion -Wno-sign-conversion -Wimplicit-fallthrough -Wwrite-strings -Wno-c99-extensions -Wno-gnu-imaginary-constant -Wno-pedantic -Wstrict-prototypes -Wextra-semi -Wnewline-eof -Wnonportable-system-include-path -Wthread-safety -std=gnu++17 -MD -MT libc/utils/MPFRWrapper/CMakeFiles/libcMPFRWrapper.dir/MPFRUtils.cpp.o -MF libc/utils/MPFRWrapper/CMakeFiles/libcMPFRWrapper.dir/MPFRUtils.cpp.o.d -o libc/utils/MPFRWrapper/CMakeFiles/libcMPFRWrapper.dir/MPFRUtils.cpp.o -c /home/libc-buildbot/libc-aarch64-ubuntu/libc-aarch64-ubuntu/llvm-project/libc/utils/MPFRWrapper/MPFRUtils.cpp
/home/libc-buildbot/libc-aarch64-ubuntu/libc-aarch64-ubuntu/llvm-project/libc/utils/MPFRWrapper/MPFRUtils.cpp:405:15: error: duplicate explicit instantiation of 'explain_binary_operation_one_output_error<long double, long double>'
template void explain_binary_operation_one_output_error(
              ^
/home/libc-buildbot/libc-aarch64-ubuntu/libc-aarch64-ubuntu/llvm-project/libc/utils/MPFRWrapper/MPFRUtils.cpp:390:1: note: previous explicit instantiation is here
explain_binary_operation_one_output_error(Operation,
^
/home/libc-buildbot/libc-aarch64-ubuntu/libc-aarch64-ubuntu/llvm-project/libc/utils/MPFRWrapper/MPFRUtils.cpp:633:15: error: duplicate explicit instantiation of 'compare_binary_operation_one_output<long double, long double>'
template bool compare_binary_operation_one_output(Operation,
              ^
/home/libc-buildbot/libc-aarch64-ubuntu/libc-aarch64-ubuntu/llvm-project/libc/utils/MPFRWrapper/MPFRUtils.cpp:609:1: note: previous explicit instantiation is here
compare_binary_operation_one_output(Operation, const BinaryInput<long double> &,
^
2 errors generated.
[131/1317] Running unit test libc.test.src.math.fdiml_test.__unit__
[==========] Running 5 tests from 1 test suite.
[ RUN      ] LlvmLibcFDimTest.NaNArg_fdiml
[       OK ] LlvmLibcFDimTest.NaNArg_fdiml (4 us)
[ RUN      ] LlvmLibcFDimTest.InfArg_fdiml
[       OK ] LlvmLibcFDimTest.InfArg_fdiml (3 us)
[ RUN      ] LlvmLibcFDimTest.NegInfArg_fdiml
[       OK ] LlvmLibcFDimTest.NegInfArg_fdiml (2 us)
[ RUN      ] LlvmLibcFDimTest.BothZero_fdiml
[       OK ] LlvmLibcFDimTest.BothZero_fdiml (1 us)
[ RUN      ] LlvmLibcFDimTest.InLongDoubleRange_fdiml
[       OK ] LlvmLibcFDimTest.InLongDoubleRange_fdiml (48 ms)
Ran 5 tests.  PASS: 5  FAIL: 0
[132/1317] Running unit test libc.test.src.math.modf_test.__unit__
[==========] Running 4 tests from 1 test suite.
[ RUN      ] LlvmLibcModfTest.SpecialNumbers
[       OK ] LlvmLibcModfTest.SpecialNumbers (4 us)
[ RUN      ] LlvmLibcModfTest.RoundedNubmers
[       OK ] LlvmLibcModfTest.RoundedNubmers (3 us)
[ RUN      ] LlvmLibcModfTest.Fractions
[       OK ] LlvmLibcModfTest.Fractions (3 us)
[ RUN      ] LlvmLibcModfTest.Range
[       OK ] LlvmLibcModfTest.Range (61 ms)
Ran 4 tests.  PASS: 4  FAIL: 0

```

</details>

https://github.com/llvm/llvm-project/pull/116129