8247502: PhaseStringOpts crashes while optimising effectively dead code

Reviewed-by: kvn, thartmann
openjdk · Jul 13, 2020 · a14490dd161b9ac9b4f900489fd84e756ff6e740 · a14490d
1 parent deddbe5
commit a14490dd161b9ac9b4f900489fd84e756ff6e740
Unified Split

Showing with 9 additions and 0 deletions.

+9 −0 src/hotspot/share/opto/stringopts.cpp
diff --git a/src/hotspot/share/opto/stringopts.cpp b/src/hotspot/share/opto/stringopts.cpp
@@ -540,6 +540,15 @@ StringConcat* PhaseStringOpts::build_candidate(CallStaticJavaNode* call) {
                 cnode->method()->signature()->as_symbol() == int_sig)) {
       sc->add_control(cnode);
       Node* arg = cnode->in(TypeFunc::Parms + 1);
+      if (arg == NULL || arg->is_top()) {
+#ifndef PRODUCT
+        if (PrintOptimizeStringConcat) {
+          tty->print("giving up because the call is effectively dead");
+          cnode->jvms()->dump_spec(tty); tty->cr();
+        }
+#endif
+        break;
+      }
       if (cnode->method()->signature()->as_symbol() == int_sig) {
         sc->push_int(arg);
       } else if (cnode->method()->signature()->as_symbol() == char_sig) {