ADDITIONAL SYSTEM INFORMATION :
- Operating system: Linux
- Compiler/toolchain: GCC 9.5
- Source commit: 18b30dbc0742f3cc70b3f03ce4417e7c4789cc3b (tag: 11.0.31-internal+0, branch: master)
- Build type: fastdebug
- Build environment: Linux, compiled from source with GCC 9.5

A DESCRIPTION OF THE PROBLEM :
A fatal error occurs in the C2 compiler when compiling a specific method generated by a fuzzer. The crash occurs when running with the `-Xcomp` flag on a fastdebug build of OpenJDK 11.

The crash triggers an assertion failure in `matcher.cpp`:
`internal Error (.../opto/matcher.cpp:1591), pid=..., tid=... assert(false) failed: bad AD file`.
This suggests that the instruction matcher encountered a node configuration in the Ideal Graph that could not be mapped to a machine instruction defined in the AD file.

Specifics:
- **JDK Version:** OpenJDK 11.0.31 (fastdebug build 11.0.31-internal+0-adhoc.syc.jdk11u-dev)
- **OS:** Linux x64 (Arch Linux)
- **Flags:** `-Xcomp` triggers the crash. `-Xint` and `-Xmixed` work correctly.
- **Error:** `assert(false) failed: bad AD file`

The log includes a dump of an `If` node and a `Bool` node immediately prior to the crash, indicating the issue likely arises during the matching of a specific control flow pattern involving a Phi node inside a loop/switch construct.


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1. Save the attached source code as `Test.java`.
2. Compile the source code:
   `javac Test.java`
3. Run the class with `-Xcomp`:
   `java -Xcomp Test`

---------- BEGIN SOURCE ----------

public class Test {
    
    public static long instanceCount = 2772208695340607833L;
    public static int iFld = -8;

    public void mainTest(java.lang.String[] strArr1) {
        byte loclaByte = (byte)73;
        int localInt1 = 63811;
        int localInt2 = 606;
        int localInt3 = 606;
        int localInt4 = 4;
        int localInt5 = -4918;
        int localInt6 = -10;
        Object O21 = new Object();
        switch (((((int) (Test.iFld + Test.instanceCount)) >>> 1) % 1) + 39) {
            case 39 :
                {
                    localInt1 = 1;
                    do {
                        for (localInt4 = ((int) (98)); localInt4 > 1; localInt4--) {
                            localInt2 = localInt1 + localInt4;
                            synchronized(O21) {
                                switch ((localInt1 % 10) + 68) {
                                    case 75 :
                                        {
                                            for (localInt3 = 0; localInt3 < (((localInt2) + ((int)(((byte) ((((byte) ((loclaByte) + ((byte)36)))) + (((byte) (((byte)78) + (loclaByte)))))))))); localInt3++) {
                                                if ((668) > 0) {
                                                    localInt2 = 765;
                                                } else {
                                                    localInt2 = 765;
                                            
                                                }
                                            }
                                        }
                                    case 76 :
                                        {
                                            localInt5 = localInt6;
                                        }
                                    case 77 :
                                }
                            }
                        }
                    } while ((++localInt1) < 125 );
                }
        }
    }
    
    public static void main(java.lang.String[] args) {
        Test _instance = new Test();
        for (int i = 0; i < 10; i++) {
            try {
                _instance.mainTest(args);
            } catch (java.lang.Exception ex) {
                System.out.println(ex.getClass().getCanonicalName());
            }
        }
        System.out.println("PASS");
    }

}

---------- END SOURCE ----------

FREQUENCY :
ALWAYS