[Bug tree-optimization/33711] Missed optimization: reduction by subtraction (vectorizer)

[eres at il dot ibm dot com]

------- Comment #1 from eres at il dot ibm dot com  2007-10-09 13:49 -------
The loop in the above example does not get vectorized because of the
subtraction in reduction; which is currently not supported.

Taken from the vectorizer dump:
test.c:19: note: worklist: examine stmt: udiff_7 = udiff_20 - D.2210_6
test.c:19: note: vect_is_simple_use: operand udiff_20
test.c:19: note: def_stmt: udiff_20 = PHI <udiff_7(4), 1.5e+3(2)>
test.c:19: note: Unsupported pattern.
test.c:19: note: not vectorized: unsupported use in stmt.
test.c:19: note: unexpected pattern.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33711