diff --git a/src/geopackage/CMakeLists.txt b/src/geopackage/CMakeLists.txt
index c06ddba4d4..2aead82963 100644
--- a/src/geopackage/CMakeLists.txt
+++ b/src/geopackage/CMakeLists.txt
@@ -1,4 +1,16 @@
 cmake_minimum_required(VERSION 3.10)
+
+
+string(COMPARE EQUAL "${CMAKE_CXX_COMPILER_ID}" "IntelLLVM" _cmp)
+if (NOT _cmp)
+    message(WARNING "[NGen::geopackage] geometry.cpp cannot be optimized with "
+                    "${CMAKE_CXX_COMPILER_ID} due to a suspected compiler/boost issue. "
+                    "Use IntelLLVM if optimization for this source file is required.")
+    # !! Required due to optimizer issue with either clang or
+    # !! boost::geometry::srs::transformation
+    set_source_files_properties(geometry.cpp PROPERTIES COMPILE_FLAGS -O0)
+endif()
+
 add_library(geopackage STATIC geometry.cpp
                               properties.cpp
                               feature.cpp
diff --git a/src/geopackage/geometry.cpp b/src/geopackage/geometry.cpp
index 7949242355..af89b51b07 100644
--- a/src/geopackage/geometry.cpp
+++ b/src/geopackage/geometry.cpp
@@ -27,7 +27,7 @@ geojson::geometry geopackage::build_geometry(
     utils::copy_from(geometry_blob, index, srs_id, endian);
     
     const auto epsg = wkb::get_prj(srs_id);
-    const auto prj = bg::srs::transformation<>(epsg, wkb::get_prj(4326));
+    const bg::srs::transformation<> prj{epsg, wkb::get_prj(4326)};
     wkb::wgs84 pvisitor{srs_id, prj};
     
     if (indicator > 0 & indicator < 5) {
diff --git a/src/geopackage/sqlite/iterator.cpp b/src/geopackage/sqlite/iterator.cpp
index cb4d1dc309..704bb7a476 100644
--- a/src/geopackage/sqlite/iterator.cpp
+++ b/src/geopackage/sqlite/iterator.cpp
@@ -94,7 +94,7 @@ int sqlite_iter::num_columns() const noexcept
 
 int sqlite_iter::column_index(const std::string& name) const noexcept
 {
-    const ptrdiff_t pos =
+    const size_t pos =
       std::distance(this->column_names.begin(), std::find(this->column_names.begin(), this->column_names.end(), name));
 
     return pos >= this->column_names.size() ? -1 : pos;