diff --git a/Modules/CMakeASM-ATTInformation.cmake b/Modules/CMakeASM-ATTInformation.cmake
index 353473af9..ccd8b12b4 100644
--- a/Modules/CMakeASM-ATTInformation.cmake
+++ b/Modules/CMakeASM-ATTInformation.cmake
@@ -1,6 +1,8 @@
 # support for AT&T syntax assemblers, e.g. GNU as
 
 SET(ASM_DIALECT "-ATT")
-SET(CMAKE_ASM${ASM_DIALECT}_SOURCE_FILE_EXTENSIONS s;S;asm)
+# *.S files are supposed to be preprocessed, so they should not be passed to
+# assembler but should be processed by gcc
+SET(CMAKE_ASM${ASM_DIALECT}_SOURCE_FILE_EXTENSIONS s;asm)
 INCLUDE(CMakeASMInformation)
 SET(ASM_DIALECT)