[Bug tree-optimization/42108] [4.4/4.5 Regression] Vectorizer cannot deal with PAREN_EXPR gracefully, 50% performance regression

[sfilippone at uniroma2 dot it]

------- Comment #10 from sfilippone at uniroma2 dot it  2009-11-20 14:03 -------
(In reply to comment #9)
> I am rather confused by some comments:
> 
> (1) Although I am not fluent with x86 assembly, I am pretty sure that no code
> in eval is vectorized (assembly taken from this pr or from the original post
> http://gcc.gnu.org/ml/fortran/2009-11/msg00163.html).
> 
> (2) If I am not mistaken, the k loop always handle 3 elements for i, i+n, and
> i+2*n.
> 
Yup, in the test case, in the original application the factor might be
different from 3. And yes, it may be better to declare the array as 2D


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42108