用于进行gcc测试

				/* Test for constant expressions: broken optimization with const variables.  */				/* Origin: Joseph Myers  */				/* { dg-do compile } */				/* { dg-options "-std=iso9899:1999 -O2" } */				/* Note: not using -pedantic since the -std option alone should be enough				   to give the correct behavior to conforming programs.  */								static const int ZERO = 0;				static const double DZERO = 0;								int *a;				int b;				long *c;								/* Assertion that n is a constant zero: so the conditional expression				   has type 'int *' instead of 'void *'.				*/				#define ASSERT_NPC(n)	(b = *(1 ? a : (n)))				/* Assertion that n is not a constant zero: so the conditional				   expressions has type 'void *' instead of 'int *'.				*/				#define ASSERT_NOT_NPC(n)	(c = (1 ? a : (void *)(__SIZE_TYPE__)(n)))								void				foo (void)				{				  ASSERT_NPC (0);				  ASSERT_NOT_NPC (ZERO);				  ASSERT_NPC (0 + 0);				  ASSERT_NOT_NPC (ZERO + 0); /* { dg-bogus "incompatible" "bogus null pointer constant" { xfail *-*-* } } */				  ASSERT_NOT_NPC (ZERO + ZERO); /* { dg-bogus "incompatible" "bogus null pointer constant" { xfail *-*-* } } */				  ASSERT_NPC (+0);				  ASSERT_NOT_NPC (+ZERO); /* { dg-bogus "incompatible" "bogus null pointer constant" { xfail *-*-* } } */				  ASSERT_NPC (-0);				  ASSERT_NOT_NPC (-ZERO); /* { dg-bogus "incompatible" "bogus null pointer constant" { xfail *-*-* } } */				  ASSERT_NPC ((char) 0);				  ASSERT_NOT_NPC ((char) ZERO);				  ASSERT_NPC ((int) 0);				  ASSERT_NOT_NPC ((int) ZERO);				  ASSERT_NPC ((int) 0.0);				  ASSERT_NOT_NPC ((int) DZERO);				  ASSERT_NOT_NPC ((int) +0.0); /* { dg-bogus "incompatible" "bogus null pointer constant" { xfail *-*-* } } */				  ASSERT_NOT_NPC ((int) (0.0+0.0)); /* { dg-bogus "incompatible" "bogus null pointer constant" { xfail *-*-* } } */				  ASSERT_NOT_NPC ((int) (double)0.0); /* { dg-bogus "incompatible" "bogus null pointer constant" { xfail *-*-* } } */				}