HwyMathTestGroup/HwyMathTest.TestAllAtan2/NEON_WITHOUT_AES # GetParam() = 536870912 (Subprocess aborted)

[malaterre]

[sorry for the flood of issues]

Thsi is to track test failure:

• https://buildd.debian.org/status/fetch.php?pkg=highway&arch=arm64&ver=1.0.5%7Egit20230630.17ba660-3&stamp=1689064318&raw=0

[malaterre]

143: Test command: /home/malat/highway/bin/tests/math_test "--gtest_filter=HwyMathTestGroup/HwyMathTest.TestAllAtan2/NEON_WITHOUT_AES" "--gtest_also_run_disabled_tests"
143: Working Directory: /home/malat/highway/bin
143: Test timeout computed to be: 1500
143: Running main() from ./googletest/src/gtest_main.cc
143: Note: Google Test filter = HwyMathTestGroup/HwyMathTest.TestAllAtan2/NEON_WITHOUT_AES
143: [==========] Running 1 test from 1 test suite.
143: [----------] Global test environment set-up.
143: [----------] 1 test from HwyMathTestGroup/HwyMathTest
143: [ RUN      ] HwyMathTestGroup/HwyMathTest.TestAllAtan2/NEON_WITHOUT_AES
143: Mismatch for i=14 expected 2.356194 actual 3.141593
143: Abort at /home/malat/highway/hwy/contrib/math/math_test.cc:401: Assert 0
1/1 Test #143: HwyMathTestGroup/HwyMathTest.TestAllAtan2/NEON_WITHOUT_AES  # GetParam() = 536870912 ...Subprocess aborted***Exception:   0.01 sec

[malaterre]

gcc-12:

73: Test command: /home/malat/highway/bin-gcc12/tests/math_test "--gtest_filter=HwyMathTestGroup/HwyMathTest.TestAllAtan2/NEON_WITHOUT_AES" "--gtest_also_run_disabled_tests"
73: Working Directory: /home/malat/highway/bin-gcc12
73: Test timeout computed to be: 1500
73: Running main() from ./googletest/src/gtest_main.cc
73: Note: Google Test filter = HwyMathTestGroup/HwyMathTest.TestAllAtan2/NEON_WITHOUT_AES
73: [==========] Running 1 test from 1 test suite.
73: [----------] Global test environment set-up.
73: [----------] 1 test from HwyMathTestGroup/HwyMathTest
73: [ RUN      ] HwyMathTestGroup/HwyMathTest.TestAllAtan2/NEON_WITHOUT_AES
73: [       OK ] HwyMathTestGroup/HwyMathTest.TestAllAtan2/NEON_WITHOUT_AES (0 ms)
73: [----------] 1 test from HwyMathTestGroup/HwyMathTest (0 ms total)
73:
73: [----------] Global test environment tear-down
73: [==========] 1 test from 1 test suite ran. (0 ms total)
73: [  PASSED  ] 1 test.
1/1 Test #73: HwyMathTestGroup/HwyMathTest.TestAllAtan2/NEON_WITHOUT_AES  # GetParam() = 536870912 ...   Passed    0.01 sec

The following tests passed:
        HwyMathTestGroup/HwyMathTest.TestAllAtan2/NEON_WITHOUT_AES  # GetParam() = 536870912

[malaterre]

@jan-wassenberg could you remind me how I can refactor the math_test source code in this case.

I always find it confusing the lines:

#undef HWY_TARGET_INCLUDE
#define HWY_TARGET_INCLUDE "hwy/contrib/math/math_test.cc"
#include "hwy/foreach_target.h"  // IWYU pragma: keep

In my case I know I need to compile only against NEON_WITHOUT_AES . Thanks !

[jan-wassenberg]

[sorry for the flood of issues]

I appreciate you taking the time to raise the issues!

So it seems gcc-13 only, gcc-12 is fine. I wasn't able to repro with gcc-12 either.

Here is the full version with dynamic dispatch: https://gcc.godbolt.org/z/bvMEhnxzK
You can delete those lines, here is a shorter example: https://gcc.godbolt.org/z/7xv64xoj6

Hope this helps :)

[malaterre]

• https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110643

[malaterre]

You can delete those lines, here is a shorter example: https://gcc.godbolt.org/z/7xv64xoj6

I did click on the link. I failed to understand how that could compile (automated default to EMU128 when not specified?)

GCC dev expect bug reporter to produce a reduce test case. Last time I manually extracted the math function into a smaller test case I could not reproduce the issue. I really need to use creduce for those. I need to manually remove the HWY_TARGET_INCLUDE trick to get creduce to work.

[jan-wassenberg]

Ah, on aarch64 we always have NEON (without AES) so no flag required :)

In case the link is behaving strangely, here is the start of the file. Note that the math-inl header includes highway.h.

#include <hwy/contrib/math/math-inl.h>

namespace HWY_NAMESPACE {  // required: unique per target

// Can skip hn:: prefixes if already inside hwy::HWY_NAMESPACE.
namespace hn = hwy::HWY_NAMESPACE;

using T = float;

HWY_ATTR void MulAddLoop(const T* HWY_RESTRICT mul_array,
                const T* HWY_RESTRICT add_array,
                const size_t size, T* HWY_RESTRICT x_array) {

[pinskia]

IsInf depends on signed integer being wrapping incorrectly.
It would be better if it was written as:

template <typename T, size_t N, HWY_IF_FLOAT(T)>
HWY_API Mask128<T, N> IsInf(const Vec128<T, N> v) {
  const DFromV<decltype(v)> d;
  const RebindToUnsigned<decltype(d)> du;
  const VFromD<decltype(du)> vi = BitCast(du, v);
  // 'Shift left' to clear the sign bit, check for exponent=max and mantissa=0.
  return RebindMask(d, Eq(Add(vi, vi), Set(du, hwy::MaxExponentTimes2<T>())));
}

So not depending on signed integers here and use unsigned types which are defined to be wrapping.
Note other target codes has the same issue too.

[jan-wassenberg]

Thank you @malaterre for sending the patch, and @pinskia for investigating and commenting here :)

I had thought that signed overflow/underflow was fine for vector (but not scalar) code, also because we do test with ubsan. Good to know that this isn't checking vector code.

After this patch lands, I will update the other IsInf as well, and look for MSB/Clear for similar occurrences.