extract tests out of src

test/_spill1.ssa

@@ -0,0 +1,22 @@
+# test with NReg == 3
+# there must be a spill
+# happening on %c
+#
+# if you replace the sub
+# by an add or comment
+# the two marked lines
+# there should be no
+# spill
+#
+
+function $test() {
+@start
+	%f =w copy 0      # here
+	%b =w copy 1
+	%c =w copy 2
+	%a =w sub %b, %c
+	%d =w copy %b
+	%e =w copy %f     # and there
+	%g =w copy %a
+	ret
+}