Arch Linux

julietbravo

Member

From: Hamburg

Registered: 2013-06-13

Posts: 5

[solved] gcc's ftree-vectorizer-verbose no output?

I'm trying to get some vectorization rapports using the ftree-vectorizer-verbose=(e.g.)3 option, which doesn't seem to give any optimization output.

Minimal example:

int main ()
{
  int a[256], b[256], c[256];
  for (int i=0; i<256; i++)
    a[i] = b[i] + c[i];
  return 0;
}

using

g++ -O3 -ftree-vectorizer-verbose=3 ........

On my laptop (GCC 4.8.2) this provides the normal output ("note: ===vect_slp_analyze_bb===", etc.), on my Arch linux system (4.9.1) I get no vectorization output.

Any idea where this might go wrong?

Last edited by julietbravo (2014-08-10 10:17:26)

amdrozd

Member

Registered: 2013-05-01

Posts: 1

Re: [solved] gcc's ftree-vectorizer-verbose no output?

Check Bug 58134.
Read documentation also, especially part with

gcc -O2 -ftree-vectorize -fopt-info-vec-missed

julietbravo

Member

From: Hamburg

Registered: 2013-06-13

Posts: 5

Re: [solved] gcc's ftree-vectorizer-verbose no output?

Ah, thanks! I missed that, the -fopt-info-.... indeed works.