Alignment problem on MacOS

The simple test code below is compiled on MacOS (clang version 17.0.0) with Eigen 5.0.0, via

g++ -Wall foo.cc -Ieigen-5.0.0 -std=c++20 -fsanitize=undefined

and runs successfully, but generates the error

assume_aligned.h:35:55: runtime error: assumption of 128 byte alignment for pointer of type 'const double *' failed

0x00016f5cb020: note: address is 32 aligned, misalignment offset is 32 bytes
 00 00 10 40  00 00 00 00 00 00 f0 3f  00 00 00 00 00 00 00 40  00 00 00 00 00 00 00 00  70 b2 5c 6f
              ^ 
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior 
4
6

When compiled without -fsanitize=undefined it runs and produces the expected output. When compiled as

g++ -Wall foo.cc -Ieigen-5.0.0 -std=c++20 -D_LIBCPP_HARDENING_MODE=_LIBCPP_HARDENING_MODE_EXTENSIVE 

(which activates Apple's extra libcpp runtime checks), it fails with a trap. The stack backtrace is attached.

stack_backtrace.txt

The code foo.cc:

#include "Eigen/Dense"
#include <iostream>

int main() {
  Eigen::Vector2d a, b, c;
  a << 1, 2;
  b << 3, 4;
  c = a + b;
  std::cout << c << "\n";
}