Created attachment 22089 [details] .bc file of the source code $clang -v clang version 9.0.0 (trunk 362492) Target: x86_64-unknown-linux-gnu Thread model: posix InstalledDir: /home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build/bin Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/8 Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5 Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5.5.0 Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6 Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6.5.0 Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7 Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7.4.0 Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/8 Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7.4.0 Candidate multilib: .;@m64 Candidate multilib: 32;@m32 Candidate multilib: x32;@mx32 Selected multilib: .;@m64 $gcc small.c -o small1.out && ./small1.out 0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 $clang small.c -o small2.out && ./small2.out 0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 $clang -O3 -c -emit-llvm -mllvm -disable-llvm-optzns small.c $opt -mem2reg -loop-unswitch -indvars -loop-rotate -loop-unswitch -jump-threading -loop-unroll -jump-threading small.bc -o small-opt.bc $clang small-opt.bc -o small3.out && ./small3.out Segmentation fault (core dumped) without loop-reroll pass, the output is correct. $$opt -mem2reg -loop-unswitch -indvars -loop-rotate -loop-unswitch -jump-threading -loop-unroll -jump-threading small.bc -o small-opt1.bc $clang small-opt1.bc -o small4.out && ./small4.out 0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 --------------------------------------- #include<stdio.h> int a[8][10][2]; void main() { int b, c, d; for (b = 0; b < 8; b++) for (c = 0; c < 10; c++) for (d = 0; d < 2; d++) printf("%d", a[b][c][d]); }
Created attachment 22090 [details] small-opt.bc
Created attachment 22228 [details] small-before-reroll.bc I've attached small-before-reroll.bc, which requires only -loop-reroll to trigger different behavior opt -loop-reroll small-before-reroll.bc -o small-opt.bc clang small-opt.bc -o small3.out && ./small3.out 000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001935631468168495753894372981769107551144159403213319694483121701077349723593702-187904742400206211048847123191027111677721701677721705160006147219694483121701077349016345576961852404336160041688918524002232036621151163515019400000000000000000000000000000000000000000000000 clang small-before-reroll -o small3.out && ./small3.out 0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000