PR c++/27210

	* cp-tree.h (cp_save_expr): New function.
	* init.c (build_new): Correct logic for zero-element array
	warning.  Use cp_save_expr.
	* tree.c (cp_save_expr): New function.
	PR c++/27210
	* g++.dg/warn/new1.C: New test.
	* g++.dg/template/new5.C: Likewise.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@113958 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 13f25f0..251d21a 100644 (file)
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,11 @@
+2006-05-21  Mark Mitchell  <mark@codesourcery.com>
+
+       PR c++/27210
+       * cp-tree.h (cp_save_expr): New function.
+       * init.c (build_new): Correct logic for zero-element array
+       warning.  Use cp_save_expr.
+       * tree.c (cp_save_expr): New function.
+
 2006-05-21  Volker Reichelt  <reichelt@igpm.rwth-aachen.de>
 
        PR c++/27398

diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index ed5c330..044fe26 100644 (file)
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -4336,6 +4336,7 @@ extern int cp_auto_var_in_fn_p                    (tree,tree);
 extern tree fold_if_not_in_template            (tree);
 extern tree rvalue                              (tree);
 extern tree convert_bitfield_to_declared_type   (tree);
+extern tree cp_save_expr                        (tree);
    
 /* in typeck.c */
 extern int string_conv_p                       (tree, tree, int);

diff --git a/gcc/cp/init.c b/gcc/cp/init.c
index e9528f2..533f9fb 100644 (file)
--- a/gcc/cp/init.c
+++ b/gcc/cp/init.c
@@ -2088,9 +2088,22 @@ build_new (tree placement, tree type, tree nelts, tree init,
     {
       if (!build_expr_type_conversion (WANT_INT | WANT_ENUM, nelts, false))
        pedwarn ("size in array new must have integral type");
-      nelts = save_expr (cp_convert (sizetype, nelts));
-      if (nelts == integer_zero_node)
-       warning (0, "zero size array reserves no space");
+      nelts = cp_save_expr (cp_convert (sizetype, nelts));
+      /* It is valid to allocate a zero-element array:
+
+          [expr.new]
+
+          When the value of the expression in a direct-new-declarator
+          is zero, the allocation function is called to allocate an
+          array with no elements.  The pointer returned by the
+          new-expression is non-null.  [Note: If the library allocation
+          function is called, the pointer returned is distinct from the
+          pointer to any other object.]  
+
+        However, that is not generally useful, so we issue a
+        warning.  */
+      if (integer_zerop (nelts))
+       warning (0, "allocating zero-element array");
     }
 
   /* ``A reference cannot be created by the new operator.  A reference

diff --git a/gcc/cp/tree.c b/gcc/cp/tree.c
index 81b37d6..fdf491a 100644 (file)
--- a/gcc/cp/tree.c
+++ b/gcc/cp/tree.c
@@ -2083,6 +2083,20 @@ cp_auto_var_in_fn_p (tree var, tree fn)
          && nonstatic_local_decl_p (var));
 }
 
+/* Like save_expr, but for C++.  */
+
+tree
+cp_save_expr (tree expr)
+{
+  /* There is no reason to create a SAVE_EXPR within a template; if
+     needed, we can create the SAVE_EXPR when instantiating the
+     template.  Furthermore, the middle-end cannot handle C++-specific
+     tree codes.  */
+  if (processing_template_decl)
+    return expr;
+  return save_expr (expr);
+}
+
 /* Initialize tree.c.  */
 
 void

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 6adae33..b3d146d 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2006-05-21  Mark Mitchell  <mark@codesourcery.com>
+
+       PR c++/27210
+       * g++.dg/warn/new1.C: New test.
+       * g++.dg/template/new5.C: Likewise.
+
 2006-05-21  Roger Sayle  <roger@eyesopen.com>
 
        * gcc.target/i386/20060512-1.c: Add -msse2 command line option.

diff --git a/gcc/testsuite/g++.dg/template/new5.C b/gcc/testsuite/g++.dg/template/new5.C
new file mode 100644 (file)
index 0000000..a2c5601
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/new5.C
@@ -0,0 +1,9 @@
+// PR c++/27210
+
+template <class foo> class junk {
+  void bar(int a)
+  {
+    unsigned char *c = new unsigned char[a*sizeof(foo)];
+  }
+};
+

diff --git a/gcc/testsuite/g++.dg/warn/new1.C b/gcc/testsuite/g++.dg/warn/new1.C
new file mode 100644 (file)
index 0000000..6b78368
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/new1.C
@@ -0,0 +1,3 @@
+void f() {
+  new int[0]; // { dg-warning "zero" }
+}