};
bool DeadPhiHandling::UpdateType(HPhi* phi) {
+ if (phi->IsDead()) {
+ // Phi was rendered dead while waiting in the worklist because it was replaced
+ // with an equivalent.
+ return false;
+ }
+
Primitive::Type existing = phi->GetType();
- DCHECK(phi->IsLive());
bool conflict = false;
Primitive::Type new_type = existing;
phi->SetType(Primitive::kPrimVoid);
phi->SetDead();
return true;
- } else {
- DCHECK(phi->IsLive());
- phi->SetType(new_type);
- return existing != new_type;
+ } else if (existing == new_type) {
+ return false;
}
+
+ DCHECK(phi->IsLive());
+ phi->SetType(new_type);
+
+ // There might exist a `new_type` equivalent of `phi` already. In that case,
+ // we replace the equivalent with the, now live, `phi`.
+ HPhi* equivalent = phi->GetNextEquivalentPhiWithSameType();
+ if (equivalent != nullptr) {
+ // There cannot be more than two equivalents with the same type.
+ DCHECK(equivalent->GetNextEquivalentPhiWithSameType() == nullptr);
+ // If doing fix-point iteration, the equivalent might be in `worklist_`.
+ // Setting it dead will make UpdateType skip it.
+ equivalent->SetDead();
+ equivalent->ReplaceWith(phi);
+ }
+
+ return true;
}
void DeadPhiHandling::VisitBasicBlock(HBasicBlock* block) {
--- /dev/null
+# Copyright (C) 2015 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+.class public LTestCase;
+.super Ljava/lang/Object;
+
+# Situation:
+# - PhiA: PrimVoid + PrimNot equivalents
+# - PhiB: PrimVoid (PrimVoid PhiA as input)
+# DeadPhiHandling:
+# - iterate over blocks in reverse post order
+# - update PrimVoid PhiA to PrimNot
+# - update inputs of PrimNot PhiA
+# - set type of PhiB
+# - left with two PrimNot equivalents of PhiA
+
+.method public static testCase_ReversePostOrder(IILjava/lang/Object;)V
+ .registers 5
+
+ # v0 - Phi A
+ # v1 - Phi B
+ # p0 - int arg1
+ # p1 - int arg2
+ # p2 - ref arg3
+
+ if-nez p0, :else1
+ :then1
+ if-nez p1, :else2
+ :then2
+ const/4 v1, 0x0
+ goto :merge2
+
+ :else2
+ move-object v1, p2
+ goto :merge2
+
+ :merge2
+ # PhiA [null, arg3]
+ move-object v0, v1 # create PrimNot PhiA equivalent
+ invoke-static {}, Ljava/lang/System;->nanoTime()J # env use of both PhiA equivalents
+ goto :merge1
+
+ :else1
+ move-object v0, p2
+ goto :merge1
+
+ :merge1
+ # PhiB [PhiA, arg3]
+ invoke-static {}, Ljava/lang/System;->nanoTime()J # env use of PhiB
+
+ return-void
+.end method
+
+# Situation:
+# - PhiA: PrimVoid + PrimNot (PrimInt inputs)
+# - PhiB: PrimVoid + PrimNot (PrimInt inputs)
+# - PhiC: PrimVoid only
+# DeadPhiHandling:
+# - iterate over blocks in reverse post order
+# - add both PhiAs to worklist, set PrimVoid PhiA to PrimInt
+# - update inputs of PrimNot PhiB ; add PrimNot PhiA to worklist
+# - update PhiC to PrimNot
+# - start processing worklist
+# - PrimNot PhiA: update inputs, no equivalent created
+# - PrimInt PhiA: update inputs, set to PrimNot, use instead of PrimNot PhiA
+# - add PhiBs to worklist as users of PhiA
+# - PrimInt PhiB: set type to PrimNot, equivalent live and in worklist
+
+.method public static testCase_FixPointIteration(IILjava/lang/Object;Ljava/lang/Object;)V
+ .registers 6
+
+ # v0 - Phi A, C
+ # v1 - Phi B
+ # p0 - int arg1
+ # p1 - int arg2
+ # p2 - ref arg3
+ # p3 - ref arg4
+
+ const/4 v0, 0x0
+
+ :loop_header
+ # PhiA [null, PhiC] for v0
+
+ if-eqz p0, :else1
+ :then1
+ const/4 v1, 0x0
+ goto :merge1
+ :else1
+ move-object v1, v0 # create PrimNot equivalent of PhiA
+ invoke-static {}, Ljava/lang/System;->nanoTime()J # env use of both PhiA equivalents
+ goto :merge1
+ :merge1
+ # PhiB [null, PhiA] for v1
+
+ move-object v0, v1 # creates PrimNot equivalent of PhiB
+ invoke-static {}, Ljava/lang/System;->nanoTime()J # env use of both PhiB equivalents
+
+ if-eqz p1, :else2
+ :then2
+ move-object v0, p2
+ goto :merge2
+ :else2
+ move-object v0, p3
+ goto :merge2
+ :merge2
+ # PhiC [arg3, arg4] for v0, second input of PhiA
+
+ if-eqz p1, :loop_header
+ return-void
+.end method
--- /dev/null
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+public class Main {
+ // Workaround for b/18051191.
+ class InnerClass {}
+
+ public static void main(String[] args) {}
+}
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