[LLVMdev] Auto-vectorization in GCC 4.0

[Zhiru Zhang]

Hi,
I am trying to turn on the new GCC auto-vectorization feature within
llvmgcc4. Below is the command I used, but nothing was vectorized. Does it
mean that llvmgcc4 has disabled this optimization and all I can do is to
embed SSE intrinsics in the source code by hand?

Thanks!

./llvm-gcc4-x86/bin/llvm-gcc -c -O2 -ftree-vectorize -msse
-ftree-vectorizer-verbose=5 -emit-llvm vec.c -o vec.bc

////////////////////vec.c/////////////////////////
int a[256], b[256], c[256];
foo () {
  int i;
  for (i=0; i<256; i++){
    a[i] = b[i] + c[i];
  }
}
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