Fix a bug in the type propagation phase of optimizing.
The compiler was placing phis (and their floating point equivalent),
in a way that it did not expect.
Change-Id: I974be1ee4aae5d27d68c6bba171db0ed25377b70
diff --git a/compiler/optimizing/ssa_builder.cc b/compiler/optimizing/ssa_builder.cc
index fec40f9..b2cc119 100644
--- a/compiler/optimizing/ssa_builder.cc
+++ b/compiler/optimizing/ssa_builder.cc
@@ -183,8 +183,7 @@
static HPhi* GetFloatOrDoubleEquivalentOfPhi(HPhi* phi, Primitive::Type type) {
// We place the floating point phi next to this phi.
HInstruction* next = phi->GetNext();
- if (next == nullptr
- || (next->GetType() != Primitive::kPrimDouble && next->GetType() != Primitive::kPrimFloat)) {
+ if (next == nullptr || (next->AsPhi()->GetRegNumber() != phi->GetRegNumber())) {
ArenaAllocator* allocator = phi->GetBlock()->GetGraph()->GetArena();
HPhi* new_phi = new (allocator) HPhi(allocator, phi->GetRegNumber(), phi->InputCount(), type);
for (size_t i = 0, e = phi->InputCount(); i < e; ++i) {
@@ -195,9 +194,7 @@
phi->GetBlock()->InsertPhiAfter(new_phi, phi);
return new_phi;
} else {
- // If there is already a phi with the expected type, we know it is the floating
- // point equivalent of this phi.
- DCHECK_EQ(next->AsPhi()->GetRegNumber(), phi->GetRegNumber());
+ DCHECK_EQ(next->GetType(), type);
return next->AsPhi();
}
}
diff --git a/compiler/optimizing/ssa_type_propagation.cc b/compiler/optimizing/ssa_type_propagation.cc
index 3828142..cb5ce20 100644
--- a/compiler/optimizing/ssa_type_propagation.cc
+++ b/compiler/optimizing/ssa_type_propagation.cc
@@ -90,10 +90,12 @@
}
} else {
for (HInstructionIterator it(block->GetPhis()); !it.Done(); it.Advance()) {
- HPhi* phi = it.Current()->AsPhi();
- if (UpdateType(phi)) {
- AddDependentInstructionsToWorklist(phi);
- }
+ // Eagerly compute the type of the phi, for quicker convergence. Note
+ // that we don't need to add users to the worklist because we are
+ // doing a reverse post-order visit, therefore either the phi users are
+ // non-loop phi and will be visited later in the visit, or are loop-phis,
+ // and they are already in the work list.
+ UpdateType(it.Current()->AsPhi());
}
}
}
diff --git a/test/429-ssa-builder/expected.txt b/test/429-ssa-builder/expected.txt
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/test/429-ssa-builder/expected.txt
diff --git a/test/429-ssa-builder/info.txt b/test/429-ssa-builder/info.txt
new file mode 100644
index 0000000..509d00f
--- /dev/null
+++ b/test/429-ssa-builder/info.txt
@@ -0,0 +1,3 @@
+Regression test for the type propagation phase of the optimizing
+compiler, that used to crash when dealing with phi floating-point
+equivalents.
diff --git a/test/429-ssa-builder/src/Main.java b/test/429-ssa-builder/src/Main.java
new file mode 100644
index 0000000..32fcef0
--- /dev/null
+++ b/test/429-ssa-builder/src/Main.java
@@ -0,0 +1,49 @@
+/*
+ * Copyright (C) 2014 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 {
+ public static void main(String[] args) {
+ if (new Main().$opt$TestFloatPhi() != 33.0f) {
+ throw new Error("Unexpected result");
+ }
+ }
+
+ public float $opt$TestFloatPhi() {
+ float a = floatField;
+ float b = 42.0f;
+ if (test1) {
+ // The phi for `a` will be found to be of type float.
+ a = otherFloatField;
+ // The phi for `b` will be found to be of type int (constants in DEX).
+ b = 33.0f;
+ }
+ // Use a different condition to avoid having dx being too clever.
+ if (test2) {
+ // Type propagation now realizes that `b` must be of type float. So
+ // it requests a float equivalent for `b`. Because the phi for `a` is
+ // next to the phi for `b` in the phi list, the compiler used to crash,
+ // assuming that a float phi following a phi *must* be for the same DEX
+ // register.
+ a = b;
+ }
+ return a;
+ }
+
+ float floatField = 4.2f;
+ float otherFloatField = 42.2f;
+ boolean test1 = true;
+ boolean test2 = true;
+}