[SIMD - fast-chain] illegal instruction in software emulation for __builtin_epi_softw_vclz_8xi8 (epi_softw_vclz.h)
Compiler: llvm-EPI-0.7-development-toolchain-native-2022-11-15-1202
Machine: allwinnerd1
How to compile:
${LLVM}/bin/clang -mepi -I${LLVM}/include -L${LLVM}/lib -Wl,-rpath,${LLVM}/lib -Wall -fopenmp -g -O3 -fno-vectorize -U__clang__ rep_clz.c -o rep_clz.o
Run:
./rep_clz.o
According to gdb, the illegal instruction in vmerge (__builtin_epi_vmerge_8xi8
) in line 15. \
In the following cases the bug will not reproduce:
- Using
-O0
optimization level instead of-O3
. - If both merge instructions (L13 & L15) will use the same mask (
ge_2to*
). - Running using QEMU.