On 3/14/07, Dorit Nuzman <[EMAIL PROTECTED]> wrote:
Hi,
We have a '{2,2}' expression (vector initializer) propagated by dom into a
BIT_FIELD_REF:
before (bug.c.105t.vrp2):
vector long int vect_cst_.47;
vect_cst_.47_66 = {2, 2};
D.2103_79 = BIT_FIELD_REF <vect_cst_.47_66, 64, 0>;
after (bug.c.106t.dom3):
"
Optimizing block #7
Optimizing statement <L0>:;
Optimizing statement D.2102_78 = BIT_FIELD_REF <vect_vec_iv_.48_67,
64, 0>;
Optimizing statement D.2103_79 = BIT_FIELD_REF <vect_cst_.47_66, 64,
0>;
Replaced 'vect_cst_.47_66' with constant '{2, 2}'
"
D.2103_79 = BIT_FIELD_REF <{2, 2}, 64, 0>;
...which causes he following ICE:
"
bug.c:8: error: invalid reference prefix
{2, 2}
bug.c:8: internal compiler error: verify_stmts failed
"
Several testcases are available in the bugzilla report (PR30784).
So, the question is - what needs to be fixed - is it copy propagation that
allows propagating the initializer into a BIT_FIELD_REF? or vect_lower pass
that creates these BIT_FIELD_REFs after vectorization?
I think the BIT_FIELD_REF should be properly folded to a constant or
the propagation
not done. fold_stmt_inplace is the candidate to look at,
propagate_rhs_into_lhs in
tree-ssa-dom.c to reject propagation into BIT_FIELD_REF. fold_ternary should be
able to fold the BIT_FIELD_REF in question, it would be interesting to
know why it
doesn't.
Richard.
