>Something along these lines may be useful to do in the vectorizer when we >get code like this: > > ((char)x) = ((char)( ((int)((char)x)) << ((int)c) ) ) >and don't feel like doing all the unpacking of chars to ints and then >packing the ints to chars after the shift. An alternative could be to >transform the above pattern to: > char_x1 = 0 > char_x2 = char_x << c > char_x = ((int)c < size_of_char) ? char_x2 : char_x1 >and vectorize that (since we already know how to vectorize selects).
Alternatively, do char_c2 = (c < size_of_char ? c : 0) char_x2 = char_x << char_c2 which is like saturating the shift amount. You could also try char_c2 = min(c, size_of_char) /* And mask off a bit perhaps. */ char_x2 = char_x << char_c2 if you don't have general selects but do have min. Ayal.
