diff --git a/demos/asm/wscript b/demos/asm/wscript
index 6d9e5ea5..b17b57db 100644
--- a/demos/asm/wscript
+++ b/demos/asm/wscript
@@ -18,6 +18,7 @@ def build(bld):
 		source   = 'main.c test.S',
 		target   = 'asmtest',
 		defines  = 'foo=12',
+		asflags  = '-Os',
 		includes = '.')
 
 	def disp(ctx):
diff --git a/waflib/Tools/c_aliases.py b/waflib/Tools/c_aliases.py
index c9d53692..985e048b 100644
--- a/waflib/Tools/c_aliases.py
+++ b/waflib/Tools/c_aliases.py
@@ -47,10 +47,12 @@ def sniff_features(**kw):
 		if x in exts:
 			feats.append('cxx')
 			break
-
 	if 'c' in exts or 'vala' in exts or 'gs' in exts:
 		feats.append('c')
 
+	if 's' in exts or 'S' in exts:
+		feats.append('asm')
+
 	for x in 'f f90 F F90 for FOR'.split():
 		if x in exts:
 			feats.append('fc')
@@ -66,7 +68,7 @@ def sniff_features(**kw):
 	if typ in ('program', 'shlib', 'stlib'):
 		will_link = False
 		for x in feats:
-			if x in ('cxx', 'd', 'fc', 'c'):
+			if x in ('cxx', 'd', 'fc', 'c', 'asm'):
 				feats.append(x + typ)
 				will_link = True
 		if not will_link and not kw.get('features', []):