The following tests have started to fail with fastdebug -Xcomp in the last few days:

tools/javac/tree/TreePosTest.java
tools/javac/tree/SourceTreeScannerTest.java
tools/javac/tree/SourceDocTreeScannerTest.java
tools/javac/tree/JavacTreeScannerTest.java

Sample output from tools/javac/tree/TreePosTest.java

----------System.err:(1043/94806)----------
java.lang.IllegalStateException: java.lang.StackOverflowError
at jdk.compiler/com.sun.tools.javac.api.JavacTaskImpl.parse(JavacTaskImpl.java:252)
at TreePosTest.read(TreePosTest.java:288)
at TreePosTest.test(TreePosTest.java:254)
at TreePosTest.test(TreePosTest.java:243)
at TreePosTest.test(TreePosTest.java:243)
at TreePosTest.test(TreePosTest.java:243)
at TreePosTest.test(TreePosTest.java:243)
at TreePosTest.run(TreePosTest.java:190)
at TreePosTest.main(TreePosTest.java:128)
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
at java.base/java.lang.reflect.Method.invoke(Method.java:580)
at com.sun.javatest.regtest.agent.MainActionHelper$AgentVMRunnable.run(MainActionHelper.java:333)
at java.base/java.lang.Thread.run(Thread.java:1575)
Caused by: java.lang.StackOverflowError
at java.base/java.lang.StringLatin1.hashCode(StringLatin1.java:309)
at java.base/java.lang.String.hashCode(String.java:2458)
at java.base/java.util.HashMap.hash(HashMap.java:338)
at java.base/java.util.HashMap.computeIfAbsent(HashMap.java:1200)
at jdk.compiler/com.sun.tools.javac.util.StringNameTable.fromString(StringNameTable.java:65)
at jdk.compiler/com.sun.tools.javac.util.Names.fromString(Names.java:447)
at jdk.compiler/com.sun.tools.javac.parser.JavaTokenizer.checkIdent(JavaTokenizer.java:657)
at jdk.compiler/com.sun.tools.javac.parser.JavaTokenizer.scanIdent(JavaTokenizer.java:723)
at jdk.compiler/com.sun.tools.javac.parser.JavaTokenizer.readToken(JavaTokenizer.java:823)
:

May need to add test/langtools/ProblemList-Xcomp.txt to exclude.