title: How to turn off vectorization in opt (LLVM)
body: <p>I'm struggling with understanding inner works of polly (polyhedral optimizer for LLVM) and I'm stuck at a problem: I know how to turn off vectorization in Clang (-fno-vectorize command option does it), but doing the same in opt eludes me. Documentation shows only how to turn this pass ON, not off. The only way to omit it is, as far as I know, using clang, which can't print stats of passes (or I couldn't find how to).
  Can anyone help me? Thanks!</p>
  
  <p>I'm using the following commands to run the programs:</p>
  
  <pre><code>clang -Xclang -load -Xclang ~/llvm_build/tools/polly/Debug+Asserts/lib/LLVMPolly.so -O3 -fno-vectorize -mllvm -polly -mllvm -polly-vectorizer=polly -S -emit-llvm in.c -o out.ll
  opt -load ~/{Polly shared lib}.so -O3 -polly -polly-vectorizer=polly -stats in.ll -o out.ll
  </code></pre>
  
  <p>First one omits clang vectorization, but does not print stats, second prints stats, but uses the vectorization I don't want.</p>