C API shim library fails to build on macOS

[loren-osborn]

Description

While testing the C API shim, I was able to reproduce a build failure on macOS using the following configuration.

Reproduction

On macOS, from the Universal repository root:

cmake -S third_party/universal -B build/universal-shim \
  -DUNIVERSAL_BUILD_ALL=ON \
  -DUNIVERSAL_ENABLE_TESTS=ON \
  -DUNIVERSAL_BUILD_C_API_SHIM_LIB=ON \
  --log-level=VERBOSE && \
cmake --build build/universal-shim --verbose

Notes

• This may be macOS-specific (I have not yet tested it anywhere else).
• CI currently disables the C shims, so this does not affect CI builds.
• I have not yet investigated root cause beyond reproducing the failure.

If you have bandwidth to take a look, I’m happy to help test or provide additional logs.

Details

The current compiler output is as follows:

cd /Users/linux_dr/projects/trfloats/build/universal-shim/mixedprecision/roots && /usr/bin/c++ -DGIT_BRANCH=nuclear_cleanup -DGIT_COMMIT_HASH=3c21e439 -I/Users/linux_dr/projects/trfloats/build/universal-shim/generated -I/Users/linux_dr/projects/trfloats/third_party/universal/./include/sw -Wall -Wpedantic -Wno-narrowing -Wno-deprecated -O3 -DNDEBUG   -Wall -Wpedantic -Wno-narrowing -Wno-deprecated  -ffp-contract=off -std=gnu++20   -D REGRESSION_LEVEL_OVERRIDE -D REGRESSION_LEVEL_1=1 -D REGRESSION_LEVEL_2=0 -D REGRESSION_LEVEL_3=0 -D REGRESSION_LEVEL_4=0 -MD -MT mixedprecision/roots/CMakeFiles/mp_rpoly.dir/rpoly.cpp.o -MF CMakeFiles/mp_rpoly.dir/rpoly.cpp.o.d -o CMakeFiles/mp_rpoly.dir/rpoly.cpp.o -c /Users/linux_dr/projects/trfloats/third_party/universal/mixedprecision/roots/rpoly.cpp
In file included from /Users/linux_dr/projects/trfloats/third_party/universal/mixedprecision/roots/rpoly.cpp:15:
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/c++/v1/complex:938:10: error: no matching function for call to 'hypot'
  938 |   return std::hypot(__c.real(), __c.imag());
      |          ^~~~~~~~~~
/Users/linux_dr/projects/trfloats/third_party/universal/mixedprecision/roots/rpoly.cpp:251:9: note: in instantiation of function template specialization 'std::abs<sw::universal::posit<32, 2>>' requested here
  251 |         abs(sequence(1) - sequence(0)) < abs(sequence(0)) / 2.0;
      |         ^
/Users/linux_dr/projects/trfloats/third_party/universal/mixedprecision/roots/rpoly.cpp:584:22: note: in instantiation of function template specialization 'HasConverged<std::complex<sw::universal::posit<32, 2>>>' requested here
  584 |             else if (HasConverged(t_lambda)) {
      |                      ^
/Users/linux_dr/projects/trfloats/third_party/universal/mixedprecision/roots/rpoly.cpp:371:31: note: in instantiation of member function 'JenkinsTraubSolver<sw::universal::posit<32, 2>>::ApplyFixedShiftToKPolynomial' requested here
  371 |                 convergence = ApplyFixedShiftToKPolynomial(root, kFixedShiftIterationMultiplier * (i + 1));
      |                               ^
/Users/linux_dr/projects/trfloats/third_party/universal/mixedprecision/roots/rpoly.cpp:896:19: note: in instantiation of member function 'JenkinsTraubSolver<sw::universal::posit<32, 2>>::ExtractRoots' requested here
  896 |     return solver.ExtractRoots();
      |                   ^
/Users/linux_dr/projects/trfloats/third_party/universal/mixedprecision/roots/rpoly.cpp:981:13: note: in instantiation of function template specialization 'FindPolynomialRootsJenkinsTraub<sw::universal::posit<32, 2>>' requested here
  981 |             FindPolynomialRootsJenkinsTraub(poly, realRoots, complexRoots);
      |             ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/c++/v1/__math/hypot.h:34:36: note: candidate function not viable: no known conversion from 'value_type' (aka 'sw::universal::posit<32, 2>') to 'float' for 1st argument
   34 | inline _LIBCPP_HIDE_FROM_ABI float hypot(float __x, float __y) _NOEXCEPT { return __builtin_hypotf(__x, __y); }
      |                                    ^     ~~~~~~~~~
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/c++/v1/__math/hypot.h:37:30: note: candidate function not viable: no known conversion from 'value_type' (aka 'sw::universal::posit<32, 2>') to 'double' for 1st argument
   37 | _LIBCPP_HIDE_FROM_ABI double hypot(double __x, double __y) _NOEXCEPT {
      |                              ^     ~~~~~~~~~~
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/c++/v1/__math/hypot.h:41:42: note: candidate function not viable: no known conversion from 'value_type' (aka 'sw::universal::posit<32, 2>') to 'long double' for 1st argument
   41 | inline _LIBCPP_HIDE_FROM_ABI long double hypot(long double __x, long double __y) _NOEXCEPT {
      |                                          ^     ~~~~~~~~~~~~~~~
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/math.h:431:15: note: candidate function not viable: no known conversion from 'value_type' (aka 'sw::universal::posit<32, 2>') to 'double' for 1st argument
  431 | extern double hypot(double, double);
      |               ^     ~~~~~~
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/c++/v1/__math/hypot.h:46:65: note: candidate template ignored: requirement 'is_arithmetic<sw::universal::posit<32, 2>>::value' was not satisfied [with _A1 = value_type, _A2 = value_type]
   46 | inline _LIBCPP_HIDE_FROM_ABI typename __promote<_A1, _A2>::type hypot(_A1 __x, _A2 __y) _NOEXCEPT {
      |                                                                 ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/c++/v1/__math/hypot.h:82:36: note: candidate function not viable: requires 3 arguments, but 2 were provided
   82 | inline _LIBCPP_HIDE_FROM_ABI float hypot(float __x, float __y, float __z) { return __math::__hypot(__x, __y, __z); }
      |                                    ^     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/c++/v1/__math/hypot.h:84:37: note: candidate function not viable: requires 3 arguments, but 2 were provided
   84 | inline _LIBCPP_HIDE_FROM_ABI double hypot(double __x, double __y, double __z) { return __math::__hypot(__x, __y, __z); }
      |                                     ^     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/c++/v1/__math/hypot.h:86:42: note: candidate function not viable: requires 3 arguments, but 2 were provided
   86 | inline _LIBCPP_HIDE_FROM_ABI long double hypot(long double __x, long double __y, long double __z) {
      |                                          ^     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/c++/v1/__math/hypot.h:94:63: note: candidate function not viable: requires 3 arguments, but 2 were provided
   94 | _LIBCPP_HIDE_FROM_ABI typename __promote<_A1, _A2, _A3>::type hypot(_A1 __x, _A2 __y, _A3 __z) _NOEXCEPT {
      |                                                               ^     ~~~~~~~~~~~~~~~~~~~~~~~~~
1 error generated.
make[2]: *** [mixedprecision/roots/CMakeFiles/mp_rpoly.dir/rpoly.cpp.o] Error 1

[Ravenwater]

created a new branch v3.92 and build the linux/gcc version:

-- Build files have been written to: /home/stillwater/dev/stillwater/clones/universal/build
(p311) stillwater@sw-21:~/dev/stillwater/clones/universal/build$ make
[  3%] Building C object c_api/pure_c/posit/CMakeFiles/posit_c_api_pure.dir/posit8.c.o
[  6%] Building C object c_api/pure_c/posit/CMakeFiles/posit_c_api_pure.dir/posit8_1.c.o
[ 10%] Linking C static library libposit_c_api_pure.a
[ 10%] Built target posit_c_api_pure
[ 13%] Building C object c_api/pure_c/test/posit/CMakeFiles/c_api_pure_playground.dir/playground.c.o
[ 17%] Linking C executable c_api_pure_playground
[ 17%] Built target c_api_pure_playground
[ 20%] Building C object c_api/pure_c/test/posit/CMakeFiles/c_api_pure_posit8.dir/posit8.c.o
[ 24%] Linking C executable c_api_pure_posit8
[ 24%] Built target c_api_pure_posit8
[ 27%] Building CXX object c_api/shim/posit/CMakeFiles/posit_c_api_shim.dir/posit_c_api.cpp.o
[ 31%] Linking CXX static library libposit_c_api_shim.a
[ 31%] Built target posit_c_api_shim
[ 34%] Building CXX object c_api/shim/test/posit/CMakeFiles/c_api_shim_exact_test.dir/exact_test.cpp.o
[ 37%] Linking CXX executable c_api_shim_exact_test
[ 37%] Built target c_api_shim_exact_test
[ 41%] Building C object c_api/shim/test/posit/CMakeFiles/c_api_shim_experiment.dir/experiment.c.o
[ 44%] Linking CXX executable c_api_shim_experiment
[ 44%] Built target c_api_shim_experiment
[ 48%] Building C object c_api/shim/test/posit/CMakeFiles/c_api_shim_performance.dir/performance.c.o
[ 51%] Linking CXX executable c_api_shim_performance
[ 51%] Built target c_api_shim_performance
[ 55%] Building C object c_api/shim/test/posit/CMakeFiles/c_api_shim_posit128.dir/posit128.c.o
[ 58%] Linking CXX executable c_api_shim_posit128
[ 58%] Built target c_api_shim_posit128
[ 62%] Building C object c_api/shim/test/posit/CMakeFiles/c_api_shim_posit16.dir/posit16.c.o
[ 65%] Linking CXX executable c_api_shim_posit16
[ 65%] Built target c_api_shim_posit16
[ 68%] Building C object c_api/shim/test/posit/CMakeFiles/c_api_shim_posit256.dir/posit256.c.o
[ 72%] Linking CXX executable c_api_shim_posit256
[ 72%] Built target c_api_shim_posit256
[ 75%] Building C object c_api/shim/test/posit/CMakeFiles/c_api_shim_posit32.dir/posit32.c.o
[ 79%] Linking CXX executable c_api_shim_posit32
[ 79%] Built target c_api_shim_posit32
[ 82%] Building C object c_api/shim/test/posit/CMakeFiles/c_api_shim_posit4.dir/posit4.c.o
[ 86%] Linking CXX executable c_api_shim_posit4
[ 86%] Built target c_api_shim_posit4
[ 89%] Building C object c_api/shim/test/posit/CMakeFiles/c_api_shim_posit64.dir/posit64.c.o
[ 93%] Linking CXX executable c_api_shim_posit64
[ 93%] Built target c_api_shim_posit64
[ 96%] Building C object c_api/shim/test/posit/CMakeFiles/c_api_shim_posit8.dir/posit8.c.o
[100%] Linking CXX executable c_api_shim_posit8
[100%] Built target c_api_shim_posit8
(p311) stillwater@sw-21:~/dev/stillwater/clones/universal/build$ ctest
Test project /home/stillwater/dev/stillwater/clones/universal/build
      Start  1: c_api_pure_playground
 1/12 Test  #1: c_api_pure_playground ............   Passed    0.01 sec
      Start  2: c_api_pure_posit8
 2/12 Test  #2: c_api_pure_posit8 ................   Passed    0.02 sec
      Start  3: c_api_shim_exact_test
 3/12 Test  #3: c_api_shim_exact_test ............   Passed    1.38 sec
      Start  4: c_api_shim_experiment
 4/12 Test  #4: c_api_shim_experiment ............   Passed    0.00 sec
      Start  5: c_api_shim_performance
 5/12 Test  #5: c_api_shim_performance ...........   Passed    0.26 sec
      Start  6: c_api_shim_posit128
 6/12 Test  #6: c_api_shim_posit128 ..............   Passed    1.22 sec
      Start  7: c_api_shim_posit16
 7/12 Test  #7: c_api_shim_posit16 ...............   Passed    0.25 sec
      Start  8: c_api_shim_posit256
 8/12 Test  #8: c_api_shim_posit256 ..............   Passed    1.71 sec
      Start  9: c_api_shim_posit32
 9/12 Test  #9: c_api_shim_posit32 ...............   Passed    0.19 sec
      Start 10: c_api_shim_posit4
10/12 Test #10: c_api_shim_posit4 ................   Passed    0.00 sec
      Start 11: c_api_shim_posit64
11/12 Test #11: c_api_shim_posit64 ...............   Passed    1.88 sec
      Start 12: c_api_shim_posit8
12/12 Test #12: c_api_shim_posit8 ................   Passed    0.09 sec

100% tests passed, 0 tests failed out of 12

Total Test time (real) =   7.02 sec

I should have build the clang version.....

[Ravenwater]

I am getting this error:

(p311) stillwater@sw-21:~/dev/stillwater/clones/universal/build$ make
[  3%] Building C object c_api/pure_c/posit/CMakeFiles/posit_c_api_pure.dir/posit8.c.o
[  6%] Building C object c_api/pure_c/posit/CMakeFiles/posit_c_api_pure.dir/posit8_1.c.o
[ 10%] Linking C static library libposit_c_api_pure.a
[ 10%] Built target posit_c_api_pure
[ 13%] Building C object c_api/pure_c/test/posit/CMakeFiles/c_api_pure_playground.dir/playground.c.o
[ 17%] Linking C executable c_api_pure_playground
/usr/bin/ld: ../../posit/libposit_c_api_pure.a(posit8.c.o): in function `posit8_subMagnitude':
posit8.c:(.text+0x8e3): undefined reference to `posit8_round'
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make[2]: *** [c_api/pure_c/test/posit/CMakeFiles/c_api_pure_playground.dir/build.make:102: c_api/pure_c/test/posit/c_api_pure_playground] Error 1
make[1]: *** [CMakeFiles/Makefile2:633: c_api/pure_c/test/posit/CMakeFiles/c_api_pure_playground.dir/all] Error 2
make: *** [Makefile:146: all] Error 2

Always easier when you have something to work with.

[loren-osborn]

Have you tried a clean build? Linker errors like that often indicate an inconsistent build tree.

[Ravenwater]

@loren-osborn I just realized that you are tripping over the std::complex<> strict adherence by Apple clang.

We solved that by creating a stand-alone complex<> lib that accepts user-defined types. The first hypothesis is that should be resolved in top of tree and v3.92.

[Ravenwater]

I have enabled both a x86/macos build and brought the C API back into the CI fold:

That commit 1817ae0 appears to be working.

[loren-osborn]

Thank you very much!

[loren-osborn]

Unfortunately this is still failing for me... There error log from the TU that's failing is as follows:

/usr/bin/clang++ -DGIT_BRANCH=losborn_test_erational -DGIT_COMMIT_HASH=6b9e0d6c -I/Users/linux_dr/src/sw_universal/build-ninja-all-clang-cov-x86_64/generated -I/Users/linux_dr/src/sw_universal/./include/sw -O0 -g -fprofile-instr-generate -fcoverage-mapping   -Wall -Wpedantic -Wno-narrowing -Wno-deprecated -O3 -DNDEBUG   -Wall -Wpedantic -Wno-narrowing -Wno-deprecated  -ffp-contract=off -std=gnu++20   -D REGRESSION_LEVEL_OVERRIDE -D REGRESSION_LEVEL_1=1 -D REGRESSION_LEVEL_2=0 -D REGRESSION_LEVEL_3=0 -D REGRESSION_LEVEL_4=0 -MD -MT mixedprecision/roots/CMakeFiles/mp_rpoly.dir/rpoly.cpp.o -MF mixedprecision/roots/CMakeFiles/mp_rpoly.dir/rpoly.cpp.o.d -o mixedprecision/roots/CMakeFiles/mp_rpoly.dir/rpoly.cpp.o -c /Users/linux_dr/src/sw_universal/mixedprecision/roots/rpoly.cpp
In file included from /Users/linux_dr/src/sw_universal/mixedprecision/roots/rpoly.cpp:15:
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/c++/v1/complex:941:10: error: no matching function for call to 'hypot'
  941 |   return std::hypot(__c.real(), __c.imag());
      |          ^~~~~~~~~~
/Users/linux_dr/src/sw_universal/mixedprecision/roots/rpoly.cpp:248:9: note: in instantiation of function template specialization 'std::abs<sw::universal::posit<32, 2>>' requested here
  248 |         abs(sequence(1) - sequence(0)) < abs(sequence(0)) / 2.0;
      |         ^
/Users/linux_dr/src/sw_universal/mixedprecision/roots/rpoly.cpp:581:22: note: in instantiation of function template specialization 'HasConverged<std::complex<sw::universal::posit<32, 2>>>' requested here
  581 |             else if (HasConverged(t_lambda)) {
      |                      ^
/Users/linux_dr/src/sw_universal/mixedprecision/roots/rpoly.cpp:368:31: note: in instantiation of member function 'JenkinsTraubSolver<sw::universal::posit<32, 2>>::ApplyFixedShiftToKPolynomial' requested here
  368 |                 convergence = ApplyFixedShiftToKPolynomial(root, kFixedShiftIterationMultiplier * (i + 1));
      |                               ^
/Users/linux_dr/src/sw_universal/mixedprecision/roots/rpoly.cpp:893:19: note: in instantiation of member function 'JenkinsTraubSolver<sw::universal::posit<32, 2>>::ExtractRoots' requested here
  893 |     return solver.ExtractRoots();
      |                   ^
/Users/linux_dr/src/sw_universal/mixedprecision/roots/rpoly.cpp:978:13: note: in instantiation of function template specialization 'FindPolynomialRootsJenkinsTraub<sw::universal::posit<32, 2>>' requested here
  978 |             FindPolynomialRootsJenkinsTraub(poly, realRoots, complexRoots);
      |             ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/c++/v1/__math/hypot.h:34:36: note: candidate function not viable: no known conversion from 'value_type' (aka 'sw::universal::posit<32, 2>') to 'float' for 1st argument
   34 | inline _LIBCPP_HIDE_FROM_ABI float hypot(float __x, float __y) _NOEXCEPT { return __builtin_hypotf(__x, __y); }
      |                                    ^     ~~~~~~~~~
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/c++/v1/__math/hypot.h:37:30: note: candidate function not viable: no known conversion from 'value_type' (aka 'sw::universal::posit<32, 2>') to 'double' for 1st argument
   37 | _LIBCPP_HIDE_FROM_ABI double hypot(double __x, double __y) _NOEXCEPT {
      |                              ^     ~~~~~~~~~~
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/c++/v1/__math/hypot.h:41:42: note: candidate function not viable: no known conversion from 'value_type' (aka 'sw::universal::posit<32, 2>') to 'long double' for 1st argument
   41 | inline _LIBCPP_HIDE_FROM_ABI long double hypot(long double __x, long double __y) _NOEXCEPT {
      |                                          ^     ~~~~~~~~~~~~~~~
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/math.h:449:15: note: candidate function not viable: no known conversion from 'value_type' (aka 'sw::universal::posit<32, 2>') to 'double' for 1st argument
  449 | extern double hypot(double, double);
      |               ^     ~~~~~~
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/c++/v1/__math/hypot.h:46:65: note: candidate template ignored: requirement 'is_arithmetic<sw::universal::posit<32, 2>>::value' was not satisfied [with _A1 = value_type, _A2 = value_type]
   46 | inline _LIBCPP_HIDE_FROM_ABI typename __promote<_A1, _A2>::type hypot(_A1 __x, _A2 __y) _NOEXCEPT {
      |                                                                 ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/c++/v1/__math/hypot.h:82:36: note: candidate function not viable: requires 3 arguments, but 2 were provided
   82 | inline _LIBCPP_HIDE_FROM_ABI float hypot(float __x, float __y, float __z) { return __math::__hypot(__x, __y, __z); }
      |                                    ^     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/c++/v1/__math/hypot.h:84:37: note: candidate function not viable: requires 3 arguments, but 2 were provided
   84 | inline _LIBCPP_HIDE_FROM_ABI double hypot(double __x, double __y, double __z) { return __math::__hypot(__x, __y, __z); }
      |                                     ^     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/c++/v1/__math/hypot.h:86:42: note: candidate function not viable: requires 3 arguments, but 2 were provided
   86 | inline _LIBCPP_HIDE_FROM_ABI long double hypot(long double __x, long double __y, long double __z) {
      |                                          ^     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/c++/v1/__math/hypot.h:94:63: note: candidate function not viable: requires 3 arguments, but 2 were provided
   94 | _LIBCPP_HIDE_FROM_ABI typename __promote<_A1, _A2, _A3>::type hypot(_A1 __x, _A2 __y, _A3 __z) _NOEXCEPT {
      |                                                               ^     ~~~~~~~~~~~~~~~~~~~~~~~~~
1 error generated.

I'll see if I have time to work on this. This was as of commit 6b9e0d6

[Ravenwater]

it looks like we are giving std::hypot() posit values and that is no longer supported by the Apple compiler.

triggered by rpoly, which needs the enhanced universal complex<> implementation that does allow user-defined types.

The more intriguing bug is why there is a path in Intel Mac environments that still triggers this. First hypothesis is that rpoly is not configured properly with the right compile guards.

[loren-osborn]

Definitely a mystery. Unfortunately, that sort of CMake black magic is currently beyond me.

[UPDATED:]

When I’m back at my machine later, I’m happy to dump my full build environment and toolchain details for comparison, if there’s a specific command or set of commands you’d like me to run. That may help explain why this code path is being exercised on x86_64 but not on arm64.

No rush on this — but if there’s a preferred way you’d like the environment captured (e.g. compile_commands.json, toolchain versions, or specific CMake variables), I’m happy to do that once I’m back at my desk.

[loren-osborn]

Now that #500 is merged, this issue should be effectively resolved from a build-failure perspective. (I will verify.)

That said, it still seems worth understanding why mixedprecision/roots/rpoly.cpp was not being compiled (or otherwise not exercising this path) in the clang ARM build, even though it was in the x86_64 build. The fix avoids relying on that unsupported std::complex path, but the architecture-dependent discrepancy itself may still be informative.

[loren-osborn]

I verified that 0a05059 builds successfully with "C API Shims" and "All" settings both ON and in Unity and non-Unity configuration on macOS CLang on x86_64.

✔️