From c4e39cea51faa01ec7dcd447c2e89ef988e6a7fb Mon Sep 17 00:00:00 2001
From: Ashay Rane <253344819+raneashay@users.noreply.github.com>
Date: Mon, 2 Mar 2026 16:49:28 +0000
Subject: [PATCH] 8373635: C2: Wrong constant in GraphKit::basic_plus_adr()

Reviewed-by: qamai, mhaessig
---
 src/hotspot/share/opto/graphKit.cpp | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/src/hotspot/share/opto/graphKit.cpp b/src/hotspot/share/opto/graphKit.cpp
index 084b137f313..c969abb85bb 100644
--- a/src/hotspot/share/opto/graphKit.cpp
+++ b/src/hotspot/share/opto/graphKit.cpp
@@ -1177,7 +1177,21 @@ bool GraphKit::compute_stack_effects(int& inputs, int& depth) {
 //------------------------------basic_plus_adr---------------------------------
 Node* GraphKit::basic_plus_adr(Node* base, Node* ptr, Node* offset) {
   // short-circuit a common case
-  if (offset == intcon(0))  return ptr;
+  if (offset == MakeConX(0)) {
+    return ptr;
+  }
+#ifdef ASSERT
+  // Both 32-bit and 64-bit zeros should have been handled by the previous `if`
+  // statement, so if we see either 32-bit or 64-bit zeros here, then we have a
+  // problem.
+  if (offset->is_Con()) {
+    const Type* t = offset->bottom_type();
+    bool is_zero_int = t->isa_int() && t->is_int()->get_con() == 0;
+    bool is_zero_long = t->isa_long() && t->is_long()->get_con() == 0;
+    assert(!is_zero_int && !is_zero_long,
+           "Unexpected zero offset - should have matched MakeConX(0)");
+  }
+#endif
   return _gvn.transform( new AddPNode(base, ptr, offset) );
 }