gcc/testsuite/gcc.dg/cpp/cmdlne-dU-9.c - gcc - Git at Google

 /* { dg-do preprocess } */
 /* { dg-options "-nostdinc -P -dU" } */
 /* { dg-final { scan-file cmdlne-dU-9.i "^\n*C\n+#define B C\n+#define A B\n*$" } } */
 #define A B
 #define B C
 A
	/* { dg-do preprocess } */
	/* { dg-options "-nostdinc -P -dU" } */
	/* { dg-final { scan-file cmdlne-dU-9.i "^\nC\n+#define B C\n+#define A B\n$" } } */
	#define A B
	#define B C
	A