[Bug tree-optimization/122624] [16 Regression] AArch64: Miscompile at -O2 with _BitInt

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122624

--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
I see it with:

[apinski@xeond2 upstream-cross-aarch64]$ ./install/bin/aarch64-linux-gnu-gcc -v
Using built-in specs.
COLLECT_GCC=./install/bin/aarch64-linux-gnu-gcc
COLLECT_LTO_WRAPPER=/bajas/pinskia/src/upstream-cross-aarch64/install/bin/../libexec/gcc/aarch64-linux-gnu/16.0.0/lto-wrapper
Target: aarch64-linux-gnu
Configured with: ../configure --target=aarch64-linux-gnu
--prefix=/home/apinski/src/upstream-cross-aarch64/install
--enable-languages=c,c++,fortran
--with-sysroot=/home/apinski/src/upstream-cross-aarch64/install/aarch64-linux-gnu/sysroot
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 16.0.0 20251115 (experimental) [trunk 05a3346353d] (GCC)

aka r16-5297-g05a3346353dce2

```
  ivtmp.105_7 = (unsigned long) &BS_VAR_11;
  _23 = ivtmp.105_7 + 160;

  <bb 3> [local count: 976138696]:
  # checksum_lsm.97_5 = PHI <_4(3), checksum_lsm.97_18(2)>
  # ivtmp.105_12 = PHI <ivtmp.105_3(3), ivtmp.105_7(2)>
  _15 = (void *) ivtmp.105_12;
  _1 = MEM[(unsigned _BitInt(66) *)_15];
  _2 = (long unsigned int) _1;
  _4 = _2 ^ checksum_lsm.97_5;
  ivtmp.105_3 = ivtmp.105_12 + 16;
  if (ivtmp.105_3 != _23)
    goto <bb 3>; [90.00%]
  else
    goto <bb 4>; [10.00%]
```
This the IR for the loop.