Make canonical_va_list_type more strict

2016-08-22  Tom de Vries  <tom@codesourcery.com>

	PR C/71602
	* builtins.c (std_canonical_va_list_type): Strictly return non-null for
	va_list type only.
	* config/i386/i386.c (ix86_canonical_va_list_type): Same.
	* gimplify.c (gimplify_va_arg_expr): Handle &va_list.

	* c-common.c (build_va_arg): Handle more strict
	targetm.canonical_va_list_type.

	* c-c++-common/va-arg-va-list-type.c: New test.

---
 gcc/builtins.c                                   | 4 ----
 gcc/c-family/c-common.c                          | 8 ++------
 gcc/config/i386/i386.c                           | 8 --------
 gcc/gimplify.c                                   | 5 +++++
 gcc/testsuite/c-c++-common/va-arg-va-list-type.c | 9 +++++++++
 5 files changed, 16 insertions(+), 18 deletions(-)

diff --git a/gcc/builtins.c b/gcc/builtins.c
index abc934b..101b1e3 100644
--- a/gcc/builtins.c
+++ b/gcc/builtins.c
@@ -4089,10 +4089,6 @@ std_canonical_va_list_type (tree type)
 {
   tree wtype, htype;
 
-  if (INDIRECT_REF_P (type))
-    type = TREE_TYPE (type);
-  else if (POINTER_TYPE_P (type) && POINTER_TYPE_P (TREE_TYPE (type)))
-    type = TREE_TYPE (type);
   wtype = va_list_type_node;
   htype = type;
   /* Treat structure va_list types.  */
diff --git a/gcc/c-family/c-common.c b/gcc/c-family/c-common.c
index 3b61e64..6cf2ffc 100644
--- a/gcc/c-family/c-common.c
+++ b/gcc/c-family/c-common.c
@@ -5813,15 +5813,11 @@ build_va_arg (location_t loc, tree expr, tree type)
     {
       /* Case 1: Not an array type.  */
 
-      /* Take the address, to get '&ap'.  */
+      /* Take the address, to get '&ap'.  Note that &ap is not a va_list
+	 type.  */
       mark_addressable (expr);
       expr = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (expr)), expr);
 
-      /* Verify that &ap is still recognized as having va_list type.  */
-      tree canon_expr_type
-	= targetm.canonical_va_list_type (TREE_TYPE (expr));
-      gcc_assert (canon_expr_type != NULL_TREE);
-
       return build_va_arg_1 (loc, type, expr);
     }
 
diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index 2639c8c..343efa0 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -48565,14 +48565,6 @@ ix86_canonical_va_list_type (tree type)
 {
   tree wtype, htype;
 
-  /* Resolve references and pointers to va_list type.  */
-  if (TREE_CODE (type) == MEM_REF)
-    type = TREE_TYPE (type);
-  else if (POINTER_TYPE_P (type) && POINTER_TYPE_P (TREE_TYPE(type)))
-    type = TREE_TYPE (type);
-  else if (POINTER_TYPE_P (type) && TREE_CODE (TREE_TYPE (type)) == ARRAY_TYPE)
-    type = TREE_TYPE (type);
-
   if (TARGET_64BIT && va_list_type_node != NULL_TREE)
     {
       wtype = va_list_type_node;
diff --git a/gcc/gimplify.c b/gcc/gimplify.c
index 288b472..6ce516a 100644
--- a/gcc/gimplify.c
+++ b/gcc/gimplify.c
@@ -11959,6 +11959,11 @@ gimplify_va_arg_expr (tree *expr_p, gimple_seq *pre_p,
   if (have_va_type == error_mark_node)
     return GS_ERROR;
   have_va_type = targetm.canonical_va_list_type (have_va_type);
+  if (have_va_type == NULL_TREE
+      && TREE_CODE (valist) == ADDR_EXPR)
+    /* Handle 'Case 1: Not an array type' from c-common.c/build_va_arg.  */
+    have_va_type
+      = targetm.canonical_va_list_type (TREE_TYPE (TREE_TYPE (valist)));
   gcc_assert (have_va_type != NULL_TREE);
 
   /* Generate a diagnostic for requesting data of a type that cannot
diff --git a/gcc/testsuite/c-c++-common/va-arg-va-list-type.c b/gcc/testsuite/c-c++-common/va-arg-va-list-type.c
new file mode 100644
index 0000000..cdd97cf
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/va-arg-va-list-type.c
@@ -0,0 +1,9 @@
+/* { dg-do compile } */
+
+__builtin_va_list *pap;
+
+void
+fn1 (void)
+{
+  __builtin_va_arg (pap, double); /* { dg-error "first argument to 'va_arg' not of type 'va_list'" } */
+}