6671250: In Parse::do_if() old Cmp node 'c' should be replaced with new one after BoolNode transformation
Summary: In Parse::do_if() 'c' (CmpNode) node may be changed during BoolNode transformation so 'c' may became dead but the node is referenced later in the code.
Reviewed-by: never
--- a/hotspot/src/share/vm/opto/parse2.cpp Fri Feb 29 19:57:41 2008 -0800
+++ b/hotspot/src/share/vm/opto/parse2.cpp Wed Mar 05 11:33:31 2008 -0800
@@ -1022,10 +1022,27 @@
Node* tst = _gvn.transform(tst0);
BoolTest::mask taken_btest = BoolTest::illegal;
BoolTest::mask untaken_btest = BoolTest::illegal;
- if (btest == BoolTest::ne) {
- // For now, these are the only cases of btest that matter. (More later.)
- taken_btest = taken_if_true ? btest : BoolTest::eq;
- untaken_btest = taken_if_true ? BoolTest::eq : btest;
+
+ if (tst->is_Bool()) {
+ // Refresh c from the transformed bool node, since it may be
+ // simpler than the original c. Also re-canonicalize btest.
+ // This wins when (Bool ne (Conv2B p) 0) => (Bool ne (CmpP p NULL)).
+ // That can arise from statements like: if (x instanceof C) ...
+ if (tst != tst0) {
+ // Canonicalize one more time since transform can change it.
+ btest = tst->as_Bool()->_test._test;
+ if (!BoolTest(btest).is_canonical()) {
+ // Reverse edges one more time...
+ tst = _gvn.transform( tst->as_Bool()->negate(&_gvn) );
+ btest = tst->as_Bool()->_test._test;
+ assert(BoolTest(btest).is_canonical(), "sanity");
+ taken_if_true = !taken_if_true;
+ }
+ c = tst->in(1);
+ }
+ BoolTest::mask neg_btest = BoolTest(btest).negate();
+ taken_btest = taken_if_true ? btest : neg_btest;
+ untaken_btest = taken_if_true ? neg_btest : btest;
}
// Generate real control flow