------- Comment #2 from dorit at il dot ibm dot com 2007-05-08 21:00 -------
Here is what happens in the three loops that don't get vectorized:
(1) the loop in testvectdp2:
This is the loop we analyze:
# prephitmp.192_37 = PHI <storetmp.191_30(3), D.1443_42(5)>
# i_1 = PHI <1(3), i_44(5)>
<L15>:;
D.1437_32 = prephitmp.192_37;
D.1438_33 = (int8) i_1;
D.1439_34 = D.1438_33 + -1;
D.1440_36 = (*a_35(D))[D.1439_34];
D.1441_40 = (*b_39(D))[D.1439_34];
D.1442_41 = D.1441_40 * D.1440_36;
D.1443_42 = prephitmp.192_37 + D.1442_41;
storetmp.191_38 = D.1443_42;
c__lsm.199_17 = D.1443_42;
i_44 = i_1 + 1;
if (i_1 == D.1429_5)
goto <bb 6> (<L21>);
else
goto <bb 5> (<L20>);
We recognize the reduction, but we think that it is used in the loop:
pr31738.f90:14: note: reduction used in loop.
and indeed, prephitmp.192_37 is used in:
D.1443_42 = prephitmp.192_37 + D.1442_41;
which is ok, because this is the reduction stmt,
but also used here:
D.1437_32 = prephitmp.192_37;
which is indeed something that we normally don't allow.
so the vectorizer is ok, except that in this case D.1437_32 doesn't seem to be
used anywhere in the function, so this stmt looks dead to me, but for some
reason it is not cleaned away before the vectorizer... Still need to
investigate why.
(2) the loop in testvecm:
This looks like the problem reported in PR31756:
failed to compute offset or step for (*a.0_11)[D.1559_52]
create_data_ref: failed to create a dr for (*a.0_11)[D.1559_52]
pr31738.f90:24: note: not vectorized: unhandled data-ref
(3) the loop in testvecm2
Same story (the PR31756 problem):
failed to compute offset or step for (*a.0_10)[D.1509_52]
create_data_ref: failed to create a dr for (*a.0_10)[D.1509_52]
pr31738.f90:32: note: not vectorized: unhandled data-ref
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31738
