8329797: Shenandoah: Default case invoked for: "MaxL" (bad AD file)

Reviewed-by: shade, thartmann

src/hotspot/share/opto/compile.cpp

@@ -624,6 +624,7 @@ Compile::Compile( ciEnv* ci_env, ciMethod* target, int osr_bci,
                   _stub_entry_point(nullptr),
                   _max_node_limit(MaxNodeLimit),
                   _post_loop_opts_phase(false),
+                  _allow_macro_nodes(true),
                   _inlining_progress(false),
                   _inlining_incrementally(false),
                   _do_cleanup(false),
@@ -915,6 +916,7 @@ Compile::Compile( ciEnv* ci_env,
     _stub_entry_point(nullptr),
     _max_node_limit(MaxNodeLimit),
     _post_loop_opts_phase(false),
+    _allow_macro_nodes(true),
     _inlining_progress(false),
     _inlining_incrementally(false),
     _has_reserved_stack_access(false),

src/hotspot/share/opto/compile.hpp

@@ -318,6 +318,7 @@ class Compile : public Phase {
   uintx                 _max_node_limit;        // Max unique node count during a single compilation.
 
   bool                  _post_loop_opts_phase;  // Loop opts are finished.
+  bool                  _allow_macro_nodes;     // True if we allow creation of macro nodes.
 
   int                   _major_progress;        // Count of something big happening
   bool                  _inlining_progress;     // progress doing incremental inlining?
@@ -787,6 +788,9 @@ private:
   void   set_post_loop_opts_phase() { _post_loop_opts_phase = true;  }
   void reset_post_loop_opts_phase() { _post_loop_opts_phase = false; }
 
+  bool       allow_macro_nodes() { return _allow_macro_nodes;  }
+  void reset_allow_macro_nodes() { _allow_macro_nodes = false;  }
+
   void record_for_post_loop_opts_igvn(Node* n);
   void remove_from_post_loop_opts_igvn(Node* n);
   void process_for_post_loop_opts_igvn(PhaseIterGVN& igvn);

src/hotspot/share/opto/macro.cpp

@@ -2448,6 +2448,8 @@ void PhaseMacroExpand::eliminate_macro_nodes() {
 //------------------------------expand_macro_nodes----------------------
 //  Returns true if a failure occurred.
 bool PhaseMacroExpand::expand_macro_nodes() {
+  // Do not allow new macro nodes once we started to expand
+  C->reset_allow_macro_nodes();
   if (StressMacroExpansion) {
     C->shuffle_macro_nodes();
   }

src/hotspot/share/opto/movenode.cpp

@@ -200,9 +200,8 @@ CMoveNode *CMoveNode::make(Node *c, Node *bol, Node *left, Node *right, const Ty
 
 // Try to identify min/max patterns in CMoves
 Node* CMoveNode::Ideal_minmax(PhaseGVN* phase, CMoveNode* cmove) {
-  // If we're post loop opts then don't attempt to match the min/max pattern, as this node might have been a
-  // MinL or MaxL that was already expanded during macro expansion.
-  if (phase->C->post_loop_opts_phase()) {
+  // Only create MinL/MaxL if we are allowed to create macro nodes.
+  if (!phase->C->allow_macro_nodes()) {
     return nullptr;
   }
 

test/hotspot/jtreg/compiler/c2/irTests/TestIfMinMax.java

@@ -30,12 +30,12 @@ import jdk.test.lib.Utils;
 
 /*
  * @test
+ * @bug 8324655 8329797
  * @key randomness
- * @bug 8324655
  * @summary Test that if expressions are properly folded into min/max nodes
  * @requires os.arch != "riscv64"
  * @library /test/lib /
- * @run main compiler.c2.irTests.TestIfMinMax
+ * @run driver compiler.c2.irTests.TestIfMinMax
  */
 public class TestIfMinMax {
     private static final Random RANDOM = Utils.getRandomInstance();
@@ -140,6 +140,42 @@ public class TestIfMinMax {
         return a <= b ? b : a;
     }
 
+    public class Dummy {
+        long l;
+        public Dummy(long l) { this.l = l; }
+    }
+
+    @Setup
+    Object[] setupDummyArray() {
+        Dummy[] arr = new Dummy[512];
+        for (int i = 0; i < 512; i++) {
+            arr[i] = new Dummy(RANDOM.nextLong());
+        }
+        return new Object[] { arr };
+    }
+
+    @Test
+    @Arguments(setup = "setupDummyArray")
+    @IR(failOn = { IRNode.MAX_L })
+    public long testMaxLAndBarrierInLoop(Dummy[] arr) {
+        long result = 0;
+        for (int i = 0; i < arr.length; ++i) {
+            result += Math.max(arr[i].l, 1);
+        }
+        return result;
+    }
+
+    @Test
+    @Arguments(setup = "setupDummyArray")
+    @IR(failOn = { IRNode.MIN_L })
+    public long testMinLAndBarrierInLoop(Dummy[] arr) {
+        long result = 0;
+        for (int i = 0; i < arr.length; ++i) {
+            result += Math.min(arr[i].l, 1);
+        }
+        return result;
+    }
+
     @Setup
     static Object[] setupIntArrays() {
         int[] a = new int[512];