From 54c8d6d048d2203119113dc4030cedc322ca212c Mon Sep 17 00:00:00 2001
From: Katelyn Gadd <kg@luminance.org>
Date: Tue, 16 Sep 2025 10:57:35 -0700
Subject: [PATCH] Suppress tailcall flag if target is a non-marshaled pinvoke
 (tail calling a marshaled pinvoke should work since the stub is IL)

---
 src/coreclr/interpreter/compiler.cpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/coreclr/interpreter/compiler.cpp b/src/coreclr/interpreter/compiler.cpp
index a6ca51b83b0984..cf9a1e04385121 100644
--- a/src/coreclr/interpreter/compiler.cpp
+++ b/src/coreclr/interpreter/compiler.cpp
@@ -3551,6 +3551,10 @@ void InterpCompiler::EmitCall(CORINFO_RESOLVED_TOKEN* pConstrainedToken, bool re
             }
             else
             {
+                // Tail call target needs to be IL
+                if (tailcall && isPInvoke && !isMarshaledPInvoke)
+                    tailcall = false;
+
                 // Normal call
                 InterpOpcode opcode;
                 if (isDelegateInvoke)
@@ -3560,7 +3564,6 @@ void InterpCompiler::EmitCall(CORINFO_RESOLVED_TOKEN* pConstrainedToken, bool re
                 }
                 else if (tailcall)
                 {
-                    assert(!isPInvoke && !isMarshaledPInvoke);
                     opcode = INTOP_CALL_TAIL;
                 }
                 else