diff --git a/infer/lib/clang_wrappers/attach_plugin_and_run_clang_frontend.sh b/infer/lib/clang_wrappers/attach_plugin_and_run_clang_frontend.sh
index 1fcbc91db..fae4c50b9 100755
--- a/infer/lib/clang_wrappers/attach_plugin_and_run_clang_frontend.sh
+++ b/infer/lib/clang_wrappers/attach_plugin_and_run_clang_frontend.sh
@@ -104,10 +104,6 @@ CLANG_CMD+=(
     "-plugin-arg-${PLUGIN_NAME}"
     "PREPEND_CURRENT_DIR=1")
 
-if [ -n "$SYNTAX_ONLY" ]; then
-    CLANG_CMD+=("-fsyntax-only")
-fi
-
 if [ -n "$LLVM_MODE" ]; then
     CLANG_CMD+=("-o" "-" "-g" "-S" "-emit-llvm")
 fi
@@ -122,6 +118,11 @@ if ! [[ "$SOURCE_FILENAME" = /* ]]; then
     SOURCE_FILENAME="$(pwd)/$SOURCE_FILENAME"
 fi
 
+# add fsyntax-only to the end of arg list to override previous options
+if [ -n "$SYNTAX_ONLY" ]; then
+    CLANG_CMD+=("-fsyntax-only")
+fi
+
 if [ -n "$LLVM_MODE" ]; then
     INFER_FRONTEND_CMD=(
         "${BIN_DIR}/InferLLVM"
diff --git a/infer/lib/clang_wrappers/hijack_and_normalize_clang_command.sh b/infer/lib/clang_wrappers/hijack_and_normalize_clang_command.sh
index c94ebc51e..b5b7dd76f 100755
--- a/infer/lib/clang_wrappers/hijack_and_normalize_clang_command.sh
+++ b/infer/lib/clang_wrappers/hijack_and_normalize_clang_command.sh
@@ -26,8 +26,11 @@ APPLE_CLANG="$FCP_APPLE_CLANG"
 # Main
 if [ "${0%++}" != "$0" ]; then XX="++"; fi
 
+# Skip -cc1as commands
+if [ "$1" = "-cc1as" ]; then
+  STATUS=0
 # Normalize clang command if not -cc1 already. -cc1 is always the first argument if present.
-if [ "$1" = "-cc1" ]; then
+elif [ "$1" = "-cc1" ]; then
     "$CLANG_CC1_CAPTURE" "$@"
     STATUS=$?
 else
@@ -50,6 +53,10 @@ else
         grep -e '^\([[:space:]]\"\|clang: error:\)' | \
         # replace -cc1 commands with our clang wrapper
         sed -e "s#^[[:space:]]\"\([^\"]*\)\" \"-cc1\" \(.*\)\$# \"$CLANG_CC1_CAPTURE\" \"-cc1\" \2#g" | \
+        # do not run if language is assembler or assembler-with-cpp
+        grep -v -- '"-x" "assembler' | \
+        # do not run -cc1as commands
+        grep -v -- '"-cc1as"' | \
         # replace error messages by failures
         sed -e 's#^\(^clang: error:.*$\)#echo "\1"; exit 1#g' | \
         # add trailing ; to each line