diff --git a/CMakeLists.txt b/CMakeLists.txt
index d527232..5ad6eaa 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -99,6 +99,11 @@ set (OSL_PTX_INSTALL_DIR "${CMAKE_INSTALL_FULL_DATADIR}/${PROJECT_NAME}/ptx"
      CACHE STRING "Directory where OptiX PTX files will be installed")
 set (CMAKE_DEBUG_POSTFIX "" CACHE STRING "Library naming postfix for Debug builds (e.g., '_debug')")
 
+set (USE_OIIO_STATIC ON CACHE BOOL "If OIIO is built static")
+if (USE_OIIO_STATIC)
+    add_definitions ("-DOIIO_STATIC_BUILD=1")
+    add_definitions ("-DOIIO_STATIC_DEFINE=1")
+endif ()
 
 set (OSL_NO_DEFAULT_TEXTURESYSTEM OFF CACHE BOOL "Do not use create a raw OIIO::TextureSystem")
 if (OSL_NO_DEFAULT_TEXTURESYSTEM)
diff --git a/src/cmake/externalpackages.cmake b/src/cmake/externalpackages.cmake
index a7e098b..dad11d0 100644
--- a/src/cmake/externalpackages.cmake
+++ b/src/cmake/externalpackages.cmake
@@ -77,6 +77,7 @@ link_directories ("${Boost_LIBRARY_DIRS}")
 
 
 checked_find_package (ZLIB REQUIRED)  # Needed by several packages
+checked_find_package (PNG REQUIRED)  # Needed since OIIO needs it
 
 # IlmBase & OpenEXR
 checked_find_package (OpenEXR REQUIRED
diff --git a/src/liboslcomp/oslcomp.cpp b/src/liboslcomp/oslcomp.cpp
index 8c2e77b..211b8a7 100644
--- a/src/liboslcomp/oslcomp.cpp
+++ b/src/liboslcomp/oslcomp.cpp
@@ -21,6 +21,13 @@
 #if !defined(__STDC_CONSTANT_MACROS)
 #    define __STDC_CONSTANT_MACROS 1
 #endif
+
+// clang uses CALLBACK in its templates which causes issues if it is already defined
+#ifdef _WIN32 && defined(CALLBACK)
+#    undef CALLBACK
+#endif
+
+//
 #include <clang/Basic/TargetInfo.h>
 #include <clang/Frontend/CompilerInstance.h>
 #include <clang/Frontend/TextDiagnosticPrinter.h>
diff --git a/src/liboslexec/llvm_instance.cpp b/src/liboslexec/llvm_instance.cpp
index 8f52546..8c2d0c7 100644
--- a/src/liboslexec/llvm_instance.cpp
+++ b/src/liboslexec/llvm_instance.cpp
@@ -1363,6 +1363,10 @@ BackendLLVM::run()
 #ifdef OSL_LLVM_NO_BITCODE
         OSL_ASSERT(!use_rs_bitcode());
         ll.module(ll.new_module("llvm_ops"));
+        if (use_optix()) {
+            ll.module()->setDataLayout("e-i64:64-i128:128-v16:16-v32:32-n16:32:64");
+            ll.module()->setTargetTriple("nvptx64-nvidia-cuda");
+        }
 #else
         if (!use_optix()) {
             if (use_rs_bitcode()) {
diff --git a/src/liboslexec/shadingsys.cpp b/src/liboslexec/shadingsys.cpp
index 46e4529..8e86486 100644
--- a/src/liboslexec/shadingsys.cpp
+++ b/src/liboslexec/shadingsys.cpp
@@ -2121,6 +2121,11 @@ ShadingSystemImpl::getattribute(ShaderGroup* group, string_view name,
         return true;
     }
 
+    if (name == "groupdata_size" && type == TypeDesc::TypeInt) {
+        *(int*)val = (int)group->m_llvm_groupdata_size;
+        return true;
+    }
+
     return false;
 }
 
diff --git a/src/liboslexec/CMakeLists.txt b/src/liboslexec/CMakeLists.txt
index 6bb0d175..19f13513 100644
--- a/src/liboslexec/CMakeLists.txt
+++ b/src/liboslexec/CMakeLists.txt
@@ -148,7 +148,9 @@ file (GLOB exec_headers "*.h")
 file (GLOB compiler_headers "../liboslcomp/*.h")
 
 FLEX_BISON ( osolex.l osogram.y oso lib_src exec_headers )
-FLEX_BISON ( ../liboslcomp/osllex.l ../liboslcomp/oslgram.y osl lib_src compiler_headers )
+if (BUILD_SHARED_LIBS)
+    FLEX_BISON ( ../liboslcomp/osllex.l ../liboslcomp/oslgram.y osl lib_src compiler_headers )
+endif()
 
 set ( CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -D__STDC_LIMIT_MACROS -D__STDC_CONSTANT_MACROS" )
 
diff --git a/src/include/OSL/mask.h b/src/include/OSL/mask.h
index 24197af..b9275f6 100644
--- a/src/include/OSL/mask.h
+++ b/src/include/OSL/mask.h
@@ -4,7 +4,6 @@
 
 #pragma once
 
-#include <immintrin.h>
 #include <type_traits>
 
 #include <OSL/oslconfig.h>
@@ -23,6 +22,8 @@ using std::countr_zero;
 
 #elif OSL_INTEL_CLASSIC_COMPILER_VERSION
 
+#include <immintrin.h>
+
 OSL_FORCEINLINE int popcount(uint32_t x) noexcept { return _mm_popcnt_u32(x);}
 OSL_FORCEINLINE int popcount(uint64_t x) noexcept { return _mm_popcnt_u64(x); }
 OSL_FORCEINLINE int countr_zero(uint32_t x) noexcept { return _bit_scan_forward(x); }