AArch64 C2 shows an internal error of "bad AD file" with vm option "-XX:-UsePopCountInstruction" specified. This can be reproduced with below program.

public class Foo {

    private static int bar(int x) {
        return Integer.bitCount(x);
    }

    public static void main(String[] args) {
        int sum = 0;
        for (int i = 0; i < 30000; i++) {
          sum += bar(i);
        }
        System.out.println(sum);
    }
}


# A fatal error has been detected by the Java Runtime Environment:
#
# Internal Error (/home/penli01/jdk_src/src/hotspot/share/opto/matcher.cpp:1563), pid=67629, tid=67650
# assert(false) failed: bad AD file
#
# JRE version: OpenJDK Runtime Environment (15.0) (fastdebug build 15-internal+0-adhoc.penli01.jdksrc)
# Java VM: OpenJDK 64-Bit Server VM (fastdebug 15-internal+0-adhoc.penli01.jdksrc, mixed mode, tiered, compressed oops, g1 gc, linux-aarch64)
# Problematic frame:
# V [libjvm.so+0x10484c8]219504
  Matcher::Label_Root(Node const*, State*, Node*, Node const*)+0x6b0