Hi Everyone, I'm working on a port of some software to ARM v7, v7-a and v8-a, which means SIMD coprocessor/NEON is available. The performance increases when the data types are 32-bit using int32x4_t vectors, but its not quite what I expected. As a measurement, Clang produces code near the theoretical throughput, and its about 2 cycles per byte faster than GCC. But GCC NEON is better than the C/C++ measurements. I'm not seeing the performance gain I expected when the data types are 64-bit using int64x2_t vectors. GCC produces code that's nowhere near Clang or the theoretical limit. In fact, its slower than the C/C++ code. I feel like I'm missing something with respect to using GCC and NEON intrinsics. For example, maybe there's a technique or pattern to help GCC minimizes stalls. For completeness, here are the CFLAGS I am using: ARMv7: -DNDEBUG -O3 -march=armv7-a -mfpu=neon -DNDEBUG -O3 -mcpu=cortex-a7 -mfpu=neon ARMv8: -DNDEBUG -O3 -O3 -march=armv8-a+crc -mcpu=cortex-a53 -DNDEBUG -O3 -O3 -march=armv8-a+crc -mcpu=cortex-a53 -mfpu=neon Is there a GCC guide for NEON intinsics?