Unable to replicate RPi0 tests about xnnpack

[samveen]

Digging more into the neon dot error shows me that I'm hitting the issue as listed in https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101723 (via #1465 ). As of now, the fix has not made it downstream into Debian bullseye unfortuantely, so successful local builds on Debian Bullseye with the neon-dot kernels is a pipe dream.

Other than that, the other issues still stand.

[Maratyszcza]

Try an older revision of XNNPack. We don't regularly test on pre-NEON ARM systems, and probably a recent refactoring broke something.

[samveen]

@Maratyszcza , I tried that too. The version which last updated the raspberry pi benchmarks table (your commit 3c6d6b4 from Oct 16, 2021). The build failed with the error about unsupported neon instructions, which lead me to the GCC bug report.

I'm in the process of upgrading to Debian Bookwork/Sid to see if I can manage to get the build working, before proceeding further. Upgrade done.

Debian Bookworm/testing is armel, not arm hf, and gcc-12/g++12 generated armel (no VFP) code. So I discarded this and went with Raspberry Pi OS Bookworm/testing which is armhf (armv6+VFP).

Gcc 10.4 and 12.2 are available.

• Building 3c6d6b4 fails with both 10.4 and 12.2 as below:

[ 45%] Building C object CMakeFiles/all_microkernels.dir/src/f16-f32-vcvt/gen/vcvt-neonfp16-x8.c.o
/usr/bin/cc -DFXDIV_USE_INLINE_ASSEMBLY=0 -DPTHREADPOOL_NO_DEPRECATED_API=1 -DXNN_ENABLE_ASSEMBLY=1 -DXNN_ENABLE_MEMOPT=1 -DXNN_ENABLE_SPARSE=1 -I/home/samveen/XNNPACK/include -I/home/samveen/XNNPACK/src -I/home/samveen/XNNPACK/build/local/pthreadpool-source/include -I/home/samveen/XNNPACK/build/local/FXdiv-source/include -I/home/samveen/XNNPACK/build/local/FP16-source/include -D__ARM_FP16_FORMAT_IEEE=1 -O3 -DNDEBUG -fPIC -Wno-psabi -pthread  -marm  -march=armv7-a -mfpu=neon-fp16  -O2  -MD -MT CMakeFiles/all_microkernels.dir/src/f16-f32-vcvt/gen/vcvt-neonfp16-x8.c.o -MF CMakeFiles/all_microkernels.dir/src/f16-f32-vcvt/gen/vcvt-neonfp16-x8.c.o.d -o CMakeFiles/all_microkernels.dir/src/f16-f32-vcvt/gen/vcvt-neonfp16-x8.c.o -c /home/samveen/XNNPACK/src/f16-f32-vcvt/gen/vcvt-neonfp16-x8.c
/home/samveen/XNNPACK/src/f16-f32-vcvt/gen/vcvt-neonfp16-x8.c: In function ‘xnn_f16_f32_vcvt_ukernel__neonfp16_x8’:
/home/samveen/XNNPACK/src/f16-f32-vcvt/gen/vcvt-neonfp16-x8.c:31:11: error: unknown type name ‘float16x8_t’
   31 |     const float16x8_t vh = vreinterpretq_f16_u16(vld1q_u16(i)); i += 8;
      |           ^~~~~~~~~~~