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* [PATCH] c++/58109 - alignas() fails to compile with constant expression
@ 2015-12-23  2:32 Martin Sebor
  2015-12-23  7:53 ` Marc Glisse
                   ` (2 more replies)
  0 siblings, 3 replies; 10+ messages in thread
From: Martin Sebor @ 2015-12-23  2:32 UTC (permalink / raw)
  To: Gcc Patch List; +Cc: Jason Merrill

[-- Attachment #1: Type: text/plain, Size: 212 bytes --]

The attached patch adds handling of dependent arguments to
attribute aligned and attribute vector_size, fixing c++/58109
and 69022 - attribute vector_size ignored with dependent bytes.

Tested on x86_64.

Martin

[-- Attachment #2: gcc-58109-69022.patch --]
[-- Type: text/x-patch, Size: 3838 bytes --]

gcc/testsuite/ChangeLog:
2015-12-22  Martin Sebor  <msebor@redhat.com>

	PR c++/58109
	PR c++/69022
	* g++.dg/cpp0x/alignas5.C: New test.
	* g++.dg/ext/vector29.C: Same.

gcc/cp/ChangeLog:
2015-12-22  Martin Sebor  <msebor@redhat.com>

	PR c++/58109
	PR c++/69022
	* decl2.c (is_late_template_attribute): Handle dependent argument
	to attribute align and attribute vector_size.

Index: gcc/cp/decl2.c
===================================================================
--- gcc/cp/decl2.c	(revision 231903)
+++ gcc/cp/decl2.c	(working copy)
@@ -1183,6 +1183,16 @@
   if (args && PACK_EXPANSION_P (args))
     return true;
 
+  if (is_attribute_p ("aligned", name)
+      || is_attribute_p ("vector_size", name))
+    {
+      /* Attribute argument may be a dependent indentifier.  */
+      if (tree t = args ? TREE_VALUE (args) : NULL_TREE)
+	if (value_dependent_expression_p (t)
+	    || type_dependent_expression_p (t))
+	  return true;
+    }
+  
   /* If any of the arguments are dependent expressions, we can't evaluate
      the attribute until instantiation time.  */
   for (arg = args; arg; arg = TREE_CHAIN (arg))
Index: gcc/testsuite/g++.dg/cpp0x/alignas5.C
===================================================================
--- gcc/testsuite/g++.dg/cpp0x/alignas5.C	(revision 0)
+++ gcc/testsuite/g++.dg/cpp0x/alignas5.C	(working copy)
@@ -0,0 +1,45 @@
+// PR c++/58109  - alignas() fails to compile with constant expression
+// { dg-do compile }
+
+template <typename T>
+struct Base {
+  static const int Align = sizeof (T);
+};
+
+// Never instantiated.
+template <typename T>
+struct Derived: Base<T>
+{
+#if __cplusplus >= 201102L
+  // This is the meat of the (simplified) regression test for c++/58109.
+  using B = Base<T>;
+  using B::Align;
+
+  alignas (Align) char a [1];
+  alignas (Align) T b [1];
+#else
+  // Fake the test for C++ 98.
+#  define Align Base<T>::Align
+#endif
+
+  char __attribute__ ((aligned (Align))) c [1];
+  T __attribute__ ((aligned (Align))) d [1];
+};
+
+// Instantiated to verify that the code is accepted even when instantiated.
+template <typename T>
+struct InstDerived: Base<T>
+{
+#if __cplusplus >= 201102L
+  using B = Base<T>;
+  using B::Align;
+
+  alignas (Align) char a [1];
+  alignas (Align) T b [1];
+#endif
+
+  char __attribute__ ((aligned (Align))) c [1];
+  T __attribute__ ((aligned (Align))) d [1];
+};
+
+InstDerived<int> dx;
Index: gcc/testsuite/g++.dg/ext/vector29.C
===================================================================
--- gcc/testsuite/g++.dg/ext/vector29.C	(revision 0)
+++ gcc/testsuite/g++.dg/ext/vector29.C	(working copy)
@@ -0,0 +1,53 @@
+// PR c++/69022 - attribute vector_size ignored with dependent bytes
+// { dg-do compile }
+
+template <int N>
+struct A { static const int X = N; };
+
+#if __cplusplus >= 201202L
+#  define ASSERT(e) static_assert (e, #e)
+#else
+#  define ASSERT(e)   \
+  do { struct S { bool: !!(e); } asrt; (void)&asrt; } while (0)
+#endif
+
+template <class T, int N>
+struct B: A<N>
+{
+#if __cplusplus >= 201202L
+  using A<N>::X;
+#  define VecSize X
+#else
+#  define VecSize A<N>::X
+#endif
+
+    static void foo ()
+    {
+        char a __attribute__ ((vector_size (N)));
+        ASSERT (sizeof a == N);
+
+        T b __attribute__ ((vector_size (N)));
+        ASSERT (sizeof b == N);
+    }
+
+    static void bar ()
+    {
+        char c1 __attribute__ ((vector_size (VecSize)));
+        ASSERT (sizeof c1 == VecSize);
+
+        char c2 __attribute__ ((vector_size (A<N>::X)));
+        ASSERT (sizeof c2 == A<N>::X);
+
+        T d1 __attribute__ ((vector_size (VecSize)));
+        ASSERT (sizeof d1 == VecSize);
+
+        T d2 __attribute__ ((vector_size (A<N>::X)));
+        ASSERT (sizeof d2 == A<N>::X);
+    }
+};
+
+void bar ()
+{
+    B<int, 16>::foo ();
+    B<int, 16>::bar ();
+}

^ permalink raw reply	[flat|nested] 10+ messages in thread
end of thread, other threads:[~2016-01-22 20:41 UTC | newest]

Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2015-12-23  2:32 [PATCH] c++/58109 - alignas() fails to compile with constant expression Martin Sebor
2015-12-23  7:53 ` Marc Glisse
2016-01-05  4:49 ` Martin Sebor
2016-01-12  0:46   ` PING #2 " Martin Sebor
2016-01-12  5:20 ` Jason Merrill
2016-01-12 18:11   ` Martin Sebor
2016-01-15 17:39     ` Martin Sebor
2016-01-18 16:11     ` Jason Merrill
2016-01-20 23:04       ` Martin Sebor
2016-01-22 20:41         ` Jason Merrill

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