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6671250: In Parse::do_if() old Cmp node 'c' should be replaced with new one after BoolNode transformation

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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
This commit is contained in:
Vladimir Kozlov 2008-03-05 11:33:31 -08:00
parent dc6ad19d70
commit 17458c9660
1 changed files with 21 additions and 4 deletions
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25
hotspot/src/share/vm/opto/parse2.cpp
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@ -1022,10 +1022,27 @@ void Parse::do_if(BoolTest::mask btest, Node* c) {
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