Optimize methods returning constant argument
Change-Id: I26fbe0acac0a2c39a842c9d786c841c7a554ddaa
diff --git a/src/main/java/com/android/tools/r8/optimize/argumentpropagation/ArgumentPropagatorOptimizationInfoPopulator.java b/src/main/java/com/android/tools/r8/optimize/argumentpropagation/ArgumentPropagatorOptimizationInfoPopulator.java
index 4ec1be1..7118043 100644
--- a/src/main/java/com/android/tools/r8/optimize/argumentpropagation/ArgumentPropagatorOptimizationInfoPopulator.java
+++ b/src/main/java/com/android/tools/r8/optimize/argumentpropagation/ArgumentPropagatorOptimizationInfoPopulator.java
@@ -14,6 +14,8 @@
import com.android.tools.r8.ir.analysis.type.DynamicType;
import com.android.tools.r8.ir.analysis.type.Nullability;
import com.android.tools.r8.ir.optimize.info.ConcreteCallSiteOptimizationInfo;
+import com.android.tools.r8.ir.optimize.info.MethodOptimizationInfo;
+import com.android.tools.r8.ir.optimize.info.OptimizationFeedback;
import com.android.tools.r8.optimize.argumentpropagation.codescanner.ConcreteArrayTypeParameterState;
import com.android.tools.r8.optimize.argumentpropagation.codescanner.ConcreteClassTypeParameterState;
import com.android.tools.r8.optimize.argumentpropagation.codescanner.ConcreteMethodState;
@@ -80,9 +82,6 @@
// instructions, build a flow graph where nodes are parameters and there is an edge from a
// parameter p1 to p2 if the value of p2 is at least the value of p1. Then propagate the
// collected argument information throughout the flow graph.
- // TODO(b/190154391): If we learn that parameter p1 is constant, and that the enclosing method
- // returns p1 according to the optimization info, then update the optimization info to describe
- // that the method returns the constant.
timing.begin("Propagate argument information for virtual methods");
ThreadUtils.processItems(
stronglyConnectedProgramComponents,
@@ -221,11 +220,22 @@
return;
}
+ ConcreteMonomorphicMethodState finalMethodState = widenedMethodState.asMonomorphic();
method
.getDefinition()
.setCallSiteOptimizationInfo(
- ConcreteCallSiteOptimizationInfo.fromMethodState(
- appView, method, widenedMethodState.asMonomorphic()));
+ ConcreteCallSiteOptimizationInfo.fromMethodState(appView, method, finalMethodState));
+
+ // Strengthen the return value of the method if the method is known to return one of the
+ // arguments.
+ MethodOptimizationInfo optimizationInfo = method.getOptimizationInfo();
+ if (optimizationInfo.returnsArgument()) {
+ ParameterState returnedArgumentState =
+ finalMethodState.getParameterState(optimizationInfo.getReturnedArgument());
+ OptimizationFeedback.getSimple()
+ .methodReturnsAbstractValue(
+ method.getDefinition(), appView, returnedArgumentState.getAbstractValue(appView));
+ }
}
private MethodState getMethodStateAfterUninstantiatedParameterRemoval(
diff --git a/src/test/java/com/android/tools/r8/optimize/argumentpropagation/ConstantReturnAfterArgumentPropagationTest.java b/src/test/java/com/android/tools/r8/optimize/argumentpropagation/ConstantReturnAfterArgumentPropagationTest.java
index 6c08989..ba07988 100644
--- a/src/test/java/com/android/tools/r8/optimize/argumentpropagation/ConstantReturnAfterArgumentPropagationTest.java
+++ b/src/test/java/com/android/tools/r8/optimize/argumentpropagation/ConstantReturnAfterArgumentPropagationTest.java
@@ -5,7 +5,6 @@
package com.android.tools.r8.optimize.argumentpropagation;
import static com.android.tools.r8.utils.codeinspector.Matchers.isPresent;
-import static junit.framework.TestCase.assertFalse;
import static junit.framework.TestCase.assertTrue;
import static org.hamcrest.MatcherAssert.assertThat;
@@ -51,7 +50,7 @@
mainClassSubject.uniqueMethodWithName("identity");
assertThat(identityMethodSubject, isPresent());
assertTrue(identityMethodSubject.getProgramMethod().getParameters().isEmpty());
- assertFalse(identityMethodSubject.getProgramMethod().getReturnType().isVoidType());
+ assertTrue(identityMethodSubject.getProgramMethod().getReturnType().isVoidType());
})
.run(parameters.getRuntime(), Main.class)
.assertSuccessWithOutputLines("identity(42) = 42");
