Patch to fix c/182

["Joseph S. Myers" <jsm28 at cam dot ac dot uk>]

This patch fixes PR c/182 (that in certain cases, conditional
expressions get the wrong type).

Bootstrapped with no regressions on i686-pc-linux-gnu.  OK to commit?

gcc/ChangeLog:
2000-11-20  Joseph S. Myers  <jsm28@cam.ac.uk>

	* c-typeck.c (build_conditional_expr): When merging type
	qualifiers for conditional expressions between a pointer and a
	pointer to a void type, merge the qualifiers on the target types
	rather than the pointer type.  Remove obsolete conditioned out
	code.

gcc/testsuite/ChangeLog:
2000-11-20  Joseph S. Myers  <jsm28@cam.ac.uk>

	* gcc.dg/c99-condexpr-1.c: New test.

--- c-typeck.c.orig	Mon Nov 20 00:34:16 2000
+++ c-typeck.c	Mon Nov 20 13:17:36 2000
@@ -3547,13 +3547,15 @@ build_conditional_expr (ifexp, op1, op2)
 	{
 	  if (pedantic && TREE_CODE (TREE_TYPE (type2)) == FUNCTION_TYPE)
 	    pedwarn ("ISO C forbids conditional expr between `void *' and function pointer");
-	  result_type = qualify_type (type1, type2);
+	  result_type = build_pointer_type (qualify_type (TREE_TYPE (type1),
+							  TREE_TYPE (type2)));
 	}
       else if (VOID_TYPE_P (TREE_TYPE (type2)))
 	{
 	  if (pedantic && TREE_CODE (TREE_TYPE (type1)) == FUNCTION_TYPE)
 	    pedwarn ("ISO C forbids conditional expr between `void *' and function pointer");
-	  result_type = qualify_type (type2, type1);
+	  result_type = build_pointer_type (qualify_type (TREE_TYPE (type2),
+							  TREE_TYPE (type1)));
 	}
       else
 	{
@@ -3568,10 +3570,6 @@ build_conditional_expr (ifexp, op1, op2)
       else
 	{
 	  op2 = null_pointer_node;
-#if 0  /* The spec seems to say this is permitted.  */
-	  if (pedantic && TREE_CODE (type1) == FUNCTION_TYPE)
-	    pedwarn ("ANSI C forbids conditional expr between 0 and function pointer");
-#endif
 	}
       result_type = type1;
     }
@@ -3582,10 +3580,6 @@ build_conditional_expr (ifexp, op1, op2)
       else
 	{
 	  op1 = null_pointer_node;
-#if 0  /* The spec seems to say this is permitted.  */
-	  if (pedantic && TREE_CODE (type2) == FUNCTION_TYPE)
-	    pedwarn ("ANSI C forbids conditional expr between 0 and function pointer");
-#endif
 	}
       result_type = type2;
     }
--- testsuite/gcc.dg/c99-condexpr-1.c.orig	Fri Sep 11 11:31:59 1998
+++ testsuite/gcc.dg/c99-condexpr-1.c	Mon Nov 20 13:29:50 2000
@@ -0,0 +1,70 @@
+/* Test for types of conditional expressions.  */
+/* Origin: Joseph Myers <jsm28@cam.ac.uk> */
+/* { dg-do compile } */
+/* { dg-options "-std=iso9899:1999 -pedantic-errors" } */
+
+/* Notes:
+
+   (a) The rules are the same in both C standard versions, but C99 also
+   gives us the "restrict" qualifier to play with.
+
+   (b) Within the C standard, the value of a conditional expression can't
+   have qualified type - but nor can this be detected.  Because of GCC's
+   extended lvalues, the value may in GCC have qualified type if the
+   arguments do.  So don't use the following macro with arguments of
+   qualified type.
+
+*/
+
+/* Assertion that the type of a conditional expression between E1 and E2
+   is T.  Checks the expression both ways round.  */
+#define ASSERT_COND_TYPE(E1, E2, T)			\
+	do {						\
+	  typedef T type;				\
+	  typedef type **typepp;			\
+	  typedef __typeof(0 ? (E1) : (E2)) ctype;	\
+	  typedef __typeof(0 ? (E2) : (E1)) ctype2;	\
+	  typedef ctype **ctypepp;			\
+	  typedef ctype2 **ctype2pp;			\
+	  typepp x = 0;					\
+	  ctypepp y = 0;				\
+	  ctype2pp z = 0;				\
+	  x = y;					\
+	  x = z;					\
+	} while (0)
+
+void
+foo (void)
+{
+  const void *c_vp;
+  void *vp;
+  const int *c_ip;
+  volatile int *v_ip;
+  int *ip;
+  const char *c_cp;
+  int *restrict *r_ipp;
+  typedef void (*fpt)(void);
+  fpt fp;
+  signed char sc;
+  struct s { int p; } st;
+  union u { int p; } un;
+  /* Arithmetic type.  */
+  ASSERT_COND_TYPE (sc, sc, int);
+  /* Structure and union.  */
+  ASSERT_COND_TYPE (st, st, struct s);
+  ASSERT_COND_TYPE (un, un, union u);
+  /* Void.  */
+  ASSERT_COND_TYPE ((void)0, (void)1, void);
+  /* Pointers: examples from 6.5.15 paragraph 8.  */
+  ASSERT_COND_TYPE (c_vp, c_ip, const void *);
+  ASSERT_COND_TYPE (v_ip, 0, volatile int *);
+  ASSERT_COND_TYPE (c_ip, v_ip, const volatile int *);
+  ASSERT_COND_TYPE (vp, c_cp, const void *);
+  ASSERT_COND_TYPE (ip, c_ip, const int *);
+  ASSERT_COND_TYPE (vp, ip, void *);
+  /* Null pointer constants.  */
+  ASSERT_COND_TYPE (v_ip, (void *)0, volatile int *);
+  ASSERT_COND_TYPE (r_ipp, (void *)0, int *restrict *);
+  ASSERT_COND_TYPE (fp, 0, fpt);
+  ASSERT_COND_TYPE (fp, (void *)0, fpt);
+}

-- 
Joseph S. Myers
jsm28@cam.ac.uk