diff --git a/cmake/QtAutogenHelpers.cmake b/cmake/QtAutogenHelpers.cmake
index aecbf549f0d..bd3162c7468 100644
--- a/cmake/QtAutogenHelpers.cmake
+++ b/cmake/QtAutogenHelpers.cmake
@@ -199,8 +199,8 @@ function(qt_make_output_file infile prefix suffix source_dir binary_dir result)
     get_filename_component(outfilename "${infile}" NAME_WE)
 
     set(base_dir "${source_dir}")
-    string(FIND "${infile}" "${binary_dir}/" in_binary)
-    if (in_binary EQUAL 0)
+    _qt_internal_path_is_prefix(binary_dir "${infile}" in_binary)
+    if(in_binary)
         set(base_dir "${binary_dir}")
     endif()
 
diff --git a/cmake/QtExecutableHelpers.cmake b/cmake/QtExecutableHelpers.cmake
index 0ea4729ec3e..692f76783de 100644
--- a/cmake/QtExecutableHelpers.cmake
+++ b/cmake/QtExecutableHelpers.cmake
@@ -199,8 +199,9 @@ function(qt_internal_add_executable name)
     set(exclude_from_all FALSE)
     if(__qt_exclude_tool_directories)
         foreach(absolute_dir ${__qt_exclude_tool_directories})
-            string(FIND "${CMAKE_CURRENT_SOURCE_DIR}" "${absolute_dir}" dir_starting_pos)
-            if(dir_starting_pos EQUAL 0)
+            _qt_internal_path_is_prefix(absolute_dir "${CMAKE_CURRENT_SOURCE_DIR}"
+                in_current_source)
+            if(in_current_source)
                 set(exclude_from_all TRUE)
                 set_target_properties("${name}" PROPERTIES
                     EXCLUDE_FROM_ALL TRUE
diff --git a/cmake/QtHeadersClean.cmake b/cmake/QtHeadersClean.cmake
index adcf868f5ad..9df20aba946 100644
--- a/cmake/QtHeadersClean.cmake
+++ b/cmake/QtHeadersClean.cmake
@@ -239,8 +239,8 @@ function(qt_internal_add_headersclean_target module_target module_headers)
 
         set(possible_base_dirs "${CMAKE_BINARY_DIR}" "${CMAKE_SOURCE_DIR}")
         foreach(dir IN LISTS possible_base_dirs)
-            string(FIND "${input_path}" "${dir}" idx)
-            if(idx EQUAL "0")
+            _qt_internal_path_is_prefix(dir "${input_path}" dir_is_prefix)
+            if(dir_is_prefix)
                 set(input_base_dir "${dir}")
                 break()
             endif()
diff --git a/cmake/QtModuleHelpers.cmake b/cmake/QtModuleHelpers.cmake
index 137536a5c08..004ff3f1a65 100644
--- a/cmake/QtModuleHelpers.cmake
+++ b/cmake/QtModuleHelpers.cmake
@@ -1619,16 +1619,11 @@ function(qt_internal_collect_module_headers out_var target)
 
         get_filename_component(file_path "${file_path}" ABSOLUTE)
 
-        string(FIND "${file_path}" "${source_dir}" source_dir_pos)
-        if(source_dir_pos EQUAL 0)
-            set(is_outside_module_source_dir FALSE)
-        else()
-            set(is_outside_module_source_dir TRUE)
-        endif()
+        _qt_internal_path_is_prefix(source_dir "${file_path}" is_inside_module_source_dir)
 
         get_source_file_property(is_generated "${file_path}" GENERATED)
         # Skip all header files outside the module source directory, except the generated files.
-        if(is_outside_module_source_dir AND NOT is_generated)
+        if(NOT is_inside_module_source_dir AND NOT is_generated)
             continue()
         endif()
 
@@ -1640,10 +1635,10 @@ function(qt_internal_collect_module_headers out_var target)
                 "\nCondition:\n    ${condition_string}")
         endif()
 
-        if(is_outside_module_source_dir)
-            set(base_dir "${binary_dir}")
-        else()
+        if(is_inside_module_source_dir)
             set(base_dir "${source_dir}")
+        else()
+            set(base_dir "${binary_dir}")
         endif()
 
         file(RELATIVE_PATH file_path_rel "${base_dir}" "${file_path}")
diff --git a/cmake/QtPublicSbomFileHelpers.cmake b/cmake/QtPublicSbomFileHelpers.cmake
index 746dbfad486..ffb60eb2b65 100644
--- a/cmake/QtPublicSbomFileHelpers.cmake
+++ b/cmake/QtPublicSbomFileHelpers.cmake
@@ -771,13 +771,9 @@ function(_qt_internal_sbom_map_path_to_reproducible_relative_path out_var)
         if(IS_ABSOLUTE "${path}")
             set(path_in "${path}")
 
-            string(FIND "${path}" "${PROJECT_SOURCE_DIR}/" src_idx)
-            string(FIND "${path}" "${PROJECT_BINARY_DIR}/" dest_idx)
-
-            if(src_idx EQUAL "0")
-                set(is_in_source_dir TRUE)
-            elseif(dest_idx EQUAL "0")
-                set(is_in_build_dir TRUE)
+            _qt_internal_path_is_prefix(PROJECT_SOURCE_DIR "${path}" is_in_source_dir)
+            if(NOT is_in_source_dir)
+                _qt_internal_path_is_prefix(PROJECT_BINARY_DIR "${path}" is_in_build_dir)
             endif()
         else()
             # We consider relative paths to be relative to the current source dir.