* c-typeck.c (null_pointer_constant_p): New function.

	(build_conditional_expr, build_c_cast, convert_for_assignment,
	build_binary_op): Use it.

testsuite:
	* gcc.dg/c90-const-expr-5.c, gcc.dg/c99-const-expr-5.c: New tests.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@108022 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 39 insertions, 0 deletions

diff --git a/gcc/testsuite/gcc.dg/c99-const-expr-5.c b/gcc/testsuite/gcc.dg/c99-const-expr-5.c
new file mode 100644
index 00000000000..e7fdf2c644b
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/c99-const-expr-5.c
@@ -0,0 +1,39 @@
+/* Test null pointer constants: typedefs for void should be OK but not
+   qualified void.  */
+/* Origin: Joseph Myers <joseph@codesourcery.com> */
+/* { dg-do compile } */
+/* { dg-options "-std=iso9899:1999 -pedantic-errors" } */
+
+typedef void V;
+int *p;
+long *q;
+int j;
+void (*fp)(void);
+
+void
+f (void)
+{
+  /* (V *)0 is a null pointer constant, so the assignment should be
+     diagnosed.  */
+  q = (j ? p : (V *)0); /* { dg-error "error: assignment from incompatible pointer type" } */
+  q = (j ? p : (void *)0); /* { dg-error "error: assignment from incompatible pointer type" } */
+  /* And this conversion should be valid.  */
+  (void (*)(void))(V *)0;
+  (void (*)(void))(void *)0;
+  /* Pointers to qualified void are not valid null pointer
+     constants.  */
+  fp = (const void *)0; /* { dg-error "error: ISO C forbids assignment between function pointer and 'void \\*'" } */
+  fp = (void *)0;
+  fp = (V *)0;
+  fp = 0;
+  fp == 0;
+  0 == fp;
+  fp == (void *)0;
+  (void *)0 == fp;
+  fp == (V *)0;
+  (V *)0 == fp;
+  fp == (V *)1; /* { dg-error "error: ISO C forbids comparison of 'void \\*' with function pointer" } */
+  (V *)1 == fp; /* { dg-error "error: ISO C forbids comparison of 'void \\*' with function pointer" } */
+  fp == (const void *)0; /* { dg-error "error: ISO C forbids comparison of 'void \\*' with function pointer" } */
+  (const void *)0 == fp; /* { dg-error "error: ISO C forbids comparison of 'void \\*' with function pointer" } */
+}