diff --git a/eng/native/configurecompiler.cmake b/eng/native/configurecompiler.cmake
index 9a8f16fb457642..5da65d586f8613 100644
--- a/eng/native/configurecompiler.cmake
+++ b/eng/native/configurecompiler.cmake
@@ -500,9 +500,21 @@ if (CLR_CMAKE_HOST_UNIX)
   #-fms-compatibility      Enable full Microsoft Visual C++ compatibility
   #-fms-extensions         Accept some non-standard constructs supported by the Microsoft compiler
 
-  # Make signed arithmetic overflow of addition, subtraction, and multiplication wrap around
-  # using twos-complement representation (this is normally undefined according to the C++ spec).
-  add_compile_options(-fwrapv)
+  if((CMAKE_C_COMPILER_ID STREQUAL "Clang" AND CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 20.0) OR
+      (CMAKE_CXX_COMPILER_ID STREQUAL "Clang" AND CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL 20.0))
+    # Make signed overflow well-defined. Implies the following flags in clang-20 and above.
+    # -fwrapv - Make signed arithmetic overflow of addition, subtraction, and multiplication wrap around
+    # using twos-complement representation (this is normally undefined according to the C++ spec).
+    # -fwrapv-pointer - The same as -fwrapv but for pointers.
+    add_compile_options(-fno-strict-overflow)
+
+    # Suppress C++ strict aliasing rules. This matches our use of MSVC.
+    add_compile_options(-fno-strict-aliasing)
+  else()
+    # Make signed arithmetic overflow of addition, subtraction, and multiplication wrap around
+    # using twos-complement representation (this is normally undefined according to the C++ spec).
+    add_compile_options(-fwrapv)
+  endif()
 
   if(CLR_CMAKE_HOST_APPLE)
     # Clang will by default emit objc_msgSend stubs in Xcode 14, which ld from earlier Xcodes doesn't understand.
diff --git a/src/coreclr/debug/di/rspriv.h b/src/coreclr/debug/di/rspriv.h
index 4f55cea3ee3b85..dca8726db8bebf 100644
--- a/src/coreclr/debug/di/rspriv.h
+++ b/src/coreclr/debug/di/rspriv.h
@@ -6354,8 +6354,8 @@ class CordbThread : public CordbBase, public ICorDebugThread,
     // Lazily initialized.
     EXCEPTION_RECORD *  m_pExceptionRecord;
 
-    static const CorDebugUserState kInvalidUserState = CorDebugUserState(-1);
-    CorDebugUserState     m_userState;  // This is the current state of the
+    static const int kInvalidUserState = -1;
+    int                   m_userState;  // This is the current state of the
                                         // thread, at the time that the
                                         // left side synchronized
 
diff --git a/src/coreclr/debug/di/rsthread.cpp b/src/coreclr/debug/di/rsthread.cpp
index 4cc387235910c9..c23875b8e016b3 100644
--- a/src/coreclr/debug/di/rsthread.cpp
+++ b/src/coreclr/debug/di/rsthread.cpp
@@ -783,7 +783,7 @@ CorDebugUserState CordbThread::GetUserState()
         m_userState = pDAC->GetUserState(m_vmThreadToken);
     }
 
-    return m_userState;
+    return (CorDebugUserState)m_userState;
 }
 
 
@@ -887,7 +887,7 @@ HRESULT CordbThread::CreateStepper(ICorDebugStepper ** ppStepper)
 //Returns true if current user state of a thread is USER_WAIT_SLEEP_JOIN
 bool CordbThread::IsThreadWaitingOrSleeping()
 {
-    CorDebugUserState userState = m_userState;
+    int userState = m_userState;
     if (userState == kInvalidUserState)
     {
         //If m_userState is not ready, we'll read from DAC only part of it which