// our code generator will complain if the inputs of a phi do not have the same
// type. The marking allows the type propagation to know which phis it needs
// to handle. We mark but do not eliminate: the elimination will be done in
- // step 8).
- SsaDeadPhiElimination dead_phis(GetGraph());
- dead_phis.MarkDeadPhis();
+ // step 9).
+ SsaDeadPhiElimination dead_phis_for_type_propagation(GetGraph());
+ dead_phis_for_type_propagation.MarkDeadPhis();
// 4) Propagate types of phis. At this point, phis are typed void in the general
// case, or float/double/reference when we created an equivalent phi. So we
PrimitiveTypePropagation type_propagation(GetGraph());
type_propagation.Run();
- // 5) Now that the graph is correclty typed, we can get rid of redundant phis.
+ // 5) Mark dead phis again. Steph 4) may have introduced new phis.
+ SsaDeadPhiElimination dead_phis(GetGraph());
+ dead_phis.MarkDeadPhis();
+
+ // 6) Now that the graph is correclty typed, we can get rid of redundant phis.
// Note that we cannot do this phase before type propagation, otherwise
// we could get rid of phi equivalents, whose presence is a requirement for the
// type propagation phase. Note that this is to satisfy statement (a) of the
SsaRedundantPhiElimination redundant_phi(GetGraph());
redundant_phi.Run();
- // 6) Make sure environments use the right phi "equivalent": a phi marked dead
+ // 7) Make sure environments use the right phi "equivalent": a phi marked dead
// can have a phi equivalent that is not dead. We must therefore update
// all environment uses of the dead phi to use its equivalent. Note that there
// can be multiple phis for the same Dex register that are live (for example
}
}
- // 7) Deal with phis to guarantee liveness of phis in case of a debuggable
+ // 8) Deal with phis to guarantee liveness of phis in case of a debuggable
// application. This is for satisfying statement (c) of the SsaBuilder
// (see ssa_builder.h).
if (GetGraph()->IsDebuggable()) {
dead_phi_handler.Run();
}
- // 8) Now that the right phis are used for the environments, and we
+ // 9) Now that the right phis are used for the environments, and we
// have potentially revive dead phis in case of a debuggable application,
// we can eliminate phis we do not need. Regardless of the debuggable status,
// this phase is necessary for statement (b) of the SsaBuilder (see ssa_builder.h),
// input types.
dead_phis.EliminateDeadPhis();
- // 9) Clear locals.
+ // 10) Clear locals.
for (HInstructionIterator it(GetGraph()->GetEntryBlock()->GetInstructions());
!it.Done();
it.Advance()) {
--- /dev/null
+Regression test for optimizing when it is building the SSA form.
--- /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 LEquivalentPhi;
+
+.super Ljava/lang/Object;
+
+.method public static equivalentPhi([F)F
+ .registers 5
+ const/4 v0, 0x0
+ # aget is initally expected to be an int, but will
+ # rightly become a float after type propagation.
+ aget v1, p0, v0
+ move v2, v1
+ if-eq v0, v0, :else
+ move v2, v0
+ :else
+ # v2 will be a phi with (int, int) as input
+ move v3, v2
+ if-eq v0, v0, :else2
+ move v3, v0
+ # v3 will be a phi with (int, int) as input.
+ : else2
+ # This instruction will lead to creating a phi equivalent
+ # for v3 with float type, which in turn will lead to creating
+ # a phi equivalent for v2 of type float. We used to forget to
+ # delete the old phi, which ends up having incompatible input
+ # types.
+ return v3
+.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.
+ */
+
+import java.lang.reflect.Method;
+
+public class Main {
+
+ // Workaround for b/18051191.
+ class InnerClass {}
+
+ public static void main(String[] args) throws Exception {
+ Class<?> c = Class.forName("EquivalentPhi");
+ Method m = c.getMethod("equivalentPhi", float[].class);
+ System.out.println(m.invoke(null, new float[] { 0.0f }));
+ }
+}
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