Reduced fuzz test case:

public class Test {
    static {
        init();
    }

    public static void init() {
    }

    public void mainTest() {
        int i = 8;
        while ((i -= 3) > 0);
        System.out.println("i" + i);
    }

    public static void main(String[] args) {
        Test _instance = new Test();
        _instance.mainTest();
        _instance.mainTest();
    }
}


Two steps to reproduce the bug: 
Step1: Compile the test case with a 8u javac: javac Test.java
Step2: Run the test case with latest jdk14: java -XX:-BackgroundCompilation -XX:-TieredCompilation -Xcomp -XX:CompileCommand=compileonly,\*Test.\* Test

Expected output:
CompileCommand: compileonly *Test.*
i-1
i-1

Unexpected output:
CompileCommand: compileonly *Test.*
i-1
i/


Proposed fix which is currently under testing:
diff -r 5b5de2618756 src/hotspot/share/opto/loopTransform.cpp
--- a/src/hotspot/share/opto/loopTransform.cpp  Mon Oct 07 17:13:59 2019 -0700
+++ b/src/hotspot/share/opto/loopTransform.cpp  Wed Oct 09 15:39:42 2019 +0800
@@ -3129,6 +3129,13 @@
     // We also need to replace the original limit to collapse loop exit.
     Node* cmp = cl->loopexit()->cmp_node();
     assert(cl->limit() == cmp->in(2), "sanity");
+    // Duplicate cmp node if it has other users
+    if (cmp->outcnt() > 1) {
+      cmp = cmp->clone();
+      cmp = phase->_igvn.register_new_node_with_optimizer(cmp);
+      BoolNode *bol = cl->loopexit()->in(CountedLoopEndNode::TestValue)->as_Bool();
+      phase->_igvn.replace_input_of(bol, 1, cmp); // put bol on worklist
+    }
     phase->_igvn._worklist.push(cmp->in(2)); // put limit on worklist
     phase->_igvn.replace_input_of(cmp, 2, exact_limit); // put cmp on worklist
   }