src/share/vm/opto/graphKit.cpp
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rev 5127 : 8023597: Optimize G1 barriers code for unsafe load_store
Summary: Avoid loading old values in G1 pre-barriers for inlined unsafe load_store nodes.
@@ -1499,10 +1499,29 @@
ShouldNotReachHere();
}
}
+bool GraphKit::can_move_pre_barrier() const {
+ BarrierSet* bs = Universe::heap()->barrier_set();
+ switch (bs->kind()) {
+ case BarrierSet::G1SATBCT:
+ case BarrierSet::G1SATBCTLogging:
+ return true; // Can move it if no safepoint
+
+ case BarrierSet::CardTableModRef:
+ case BarrierSet::CardTableExtension:
+ case BarrierSet::ModRef:
+ return true; // There is no pre-barrier
+
+ case BarrierSet::Other:
+ default :
+ ShouldNotReachHere();
+ }
+ return false;
+}
+
void GraphKit::post_barrier(Node* ctl,
Node* store,
Node* obj,
Node* adr,
uint adr_idx,
@@ -3549,10 +3568,12 @@
assert(pre_val == NULL, "loaded already?");
assert(val_type != NULL, "need a type");
} else {
// In this case both val_type and alias_idx are unused.
assert(pre_val != NULL, "must be loaded already");
+ // Nothing to be done if pre_val is null.
+ if (pre_val->bottom_type() == TypePtr::NULL_PTR) return;
assert(pre_val->bottom_type()->basic_type() == T_OBJECT, "or we shouldn't be here");
}
assert(bt == T_OBJECT, "or we shouldn't be here");
IdealKit ideal(this, true);