8362832: compiler/macronodes/TestTopInMacroElimination.java hits assert(false) failed: unexpected node

benoitmaillard · benoitmaillard · commit a98b9e7cfa43 · 2025-11-04T09:42:18.000Z
Reviewed-by: dlunden, epeter, kvn
diff --git a/src/hotspot/share/opto/macro.cpp b/src/hotspot/share/opto/macro.cpp
@@ -501,6 +501,11 @@ Node *PhaseMacroExpand::value_from_mem(Node *sfpt_mem, Node *sfpt_ctl, BasicType
       }
     } else if (mem->is_ArrayCopy()) {
       done = true;
+    } else if (mem->is_top()) {
+      // The slice is on a dead path. Returning nullptr would lead to elimination
+      // bailout, but we want to prevent that. Just forwarding the top is also legal,
+      // and IGVN can just clean things up, and remove whatever receives top.
+      return mem;
     } else {
       DEBUG_ONLY( mem->dump(); )
       assert(false, "unexpected node");
diff --git a/test/hotspot/jtreg/ProblemList-jvmti-stress-agent.txt b/test/hotspot/jtreg/ProblemList-jvmti-stress-agent.txt
@@ -27,9 +27,6 @@
 #
 #############################################################################
 
-
-compiler/macronodes/TestTopInMacroElimination.java      8362832 generic-all
-
 gc/stringdedup/TestStringDeduplicationAgeThreshold.java 8362562 generic-all
 gc/stringdedup/TestStringDeduplicationInterned.java     8362562 generic-all
 gc/stringdedup/TestStringDeduplicationPrintOptions.java 8362562 generic-all
diff --git a/test/hotspot/jtreg/compiler/macronodes/TestTopInMacroElimination.java b/test/hotspot/jtreg/compiler/macronodes/TestTopInMacroElimination.java
@@ -23,7 +23,7 @@
 
 /*
  * @test
- * @bug 8325030
+ * @bug 8325030 8362832
  * @summary Regression test for an assert triggered during allocation elimination because top is found during
  * constructing new phis.
  * @run main/othervm -XX:-ProfileExceptionHandlers compiler.macronodes.TestTopInMacroElimination

Original file line number	Diff line number	Diff line change
`@@ -27,9 +27,6 @@`
`27`	`27`	`#`
`28`	`28`	`#############################################################################`
`29`	`29`
`30`		`-`
`31`		`-compiler/macronodes/TestTopInMacroElimination.java 8362832 generic-all`
`32`		`-`
`33`	`30`	`gc/stringdedup/TestStringDeduplicationAgeThreshold.java 8362562 generic-all`
`34`	`31`	`gc/stringdedup/TestStringDeduplicationInterned.java 8362562 generic-all`
`35`	`32`	`gc/stringdedup/TestStringDeduplicationPrintOptions.java 8362562 generic-all`