http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60315
--- Comment #7 from Richard Biener <rguenth at gcc dot gnu.org> ---
Note that we seem to fail to update BB predicates for switch stmts.
size:0.000000, time:0.000000, predicate:(true)
size:3.000000, time:2.000000, predicate:(not inlined)
size:2.000000, time:2.000000, predicate:(op1 changed)
size:8.000000, time:3.200000, predicate:(op1 changed) && (op1 != 2)
I cannot interpret the size 2 case (what is "op1 changed"?), but in that
case we actually shrink compared to not inlining. As && op1 != 2 makes
it more restrictive it's odd that that increases the metrics.
As inliner I would inline all the (op1 changed) cases, thus in the above
case op1 == 2.
We seem to inline fully until hitting the case where only recursive edges
are left. Even for only two switch cases we inline 5(!) calls into Test<E1>.
Ah, the switch isn't handled by the predicates because
BB 3 predicate:(op1 != 1)
s.1_4 = (int) s_2(D);
freq:0.80 size: 0 time: 0
switch (s.1_4) <default: <L8>, case 0: <L1>, case 1: <L2>>
it is not unmodified_parm_or_parm_agg_item (). The parameter is unsigned int
so the cast is not value-preserving.
Of course in general we can't rely on "proper" predicates so we need to avoid
exploding reliably.
