C PATCH for c/68668 (grokdeclarator and wrong type of PARM_DECL)

[Marek Polacek]

This ought to fix the fallout from PR c/68162 fix.  Here the problem is that
grokdeclarator created a wrong type for PARM_DECL "p".  It created this decl
with type "const int[<unknown>] *" while it should be "const int *".

I think the problem is that we weren't using TREE_TYPE on orig_qual_type and
thus c_build_qualified_type and subsequent c_build_pointer_type might create
a bogus type.  So when we're transfering const-ness of an array into that of
type pointed to, use TREE_TYPE not only of "type", but even of the orig qual
type.

Bootstrapped/regtested on x86_64-linux, ok for trunk?

2015-12-03  Marek Polacek  <polacek@redhat.com>

	PR c/68668
	* c-decl.c (grokdeclarator): When creating a PARM_DECL of ARRAY_TYPE,
	use TREE_TYPE of orig_qual_type.

	* gcc.dg/pr68668.c: New test.

diff --git gcc/c/c-decl.c gcc/c/c-decl.c
index 9ad8219..0edff2a 100644
--- gcc/c/c-decl.c
+++ gcc/c/c-decl.c
@@ -6417,6 +6417,8 @@ grokdeclarator (const struct c_declarator *declarator,
 	  {
 	    /* Transfer const-ness of array into that of type pointed to.  */
 	    type = TREE_TYPE (type);
+	    if (orig_qual_type != NULL_TREE)
+	      orig_qual_type = TREE_TYPE (orig_qual_type);
 	    if (type_quals)
 	      type = c_build_qualified_type (type, type_quals, orig_qual_type,
 					     orig_qual_indirect);
diff --git gcc/testsuite/gcc.dg/pr68668.c gcc/testsuite/gcc.dg/pr68668.c
index e69de29..d144fb6 100644
--- gcc/testsuite/gcc.dg/pr68668.c
+++ gcc/testsuite/gcc.dg/pr68668.c
@@ -0,0 +1,10 @@
+/* PR c/68668 */
+/* { dg-do compile } */
+
+typedef const int T[];
+
+int
+fn1 (T p)
+{
+  return p[0];
+}

	Marek