[google/gcc-4_7] Allow static const floats unless -pedantic is passed (issue6212051)

[Ollie Wild]

To be applied to google/gcc-4_7.

Allow static const floats unless -pedantic is passed.

This patch allows us to migrate to C++11 more incrementally, since we can leave
the static const float initializations in place, flip the switch, and then
change it to use constexpr.

This is a forward port of r180638 from google/gcc-4_6 (despite the fact that
that revision says to NOT forward-port this).  Minor additional fixups have
been applied.

2012-05-15   Ollie Wild  <a...@google.com>

        * gcc/cp/decl.c (check_static_variable_definition): Only generate a
        constexpr warning when -pedantic is enabled.
        * gcc/testsuite/g++.dg/cpp0x/constexpr-static8.C: Replace -fpermissive
        with -pedantic.
        * gcc/testsuite/g++.dg/cpp0x/constexpr-static8_nonpedantic.C: New test.
        * gcc/testsuite/g++.old-deja/g++.ext/memconst.C: Compile with -pedantic
        -pedantic-errors to work around test failures with -std=gnu++11.

diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index bb26d15..d2fe731 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -7861,9 +7861,18 @@ check_static_variable_definition (tree decl, tree type)
        error ("in-class initialization of static data member %q#D of "
               "incomplete type", decl);
       else if (literal_type_p (type))
-       permerror (input_location,
-                  "%<constexpr%> needed for in-class initialization of "
-                  "static data member %q#D of non-integral type", decl);
+       {
+          /* FIXME google: This local modification allows us to
+             transition from C++98 to C++11 without moving static
+             const floats out of the class during the transition.  It
+             should not be forward-ported to a 4.8 branch, since by
+             then we should be able to just fix the code to use
+             constexpr.  */
+          pedwarn (input_location, OPT_pedantic,
+                   "%<constexpr%> needed for in-class initialization of "
+                   "static data member %q#D of non-integral type", decl);
+          return 0;
+       }
       else
        error ("in-class initialization of static data member %q#D of "
               "non-literal type", decl);
diff --git a/gcc/testsuite/g++.dg/cpp0x/constexpr-static8.C 
b/gcc/testsuite/g++.dg/cpp0x/constexpr-static8.C
index 7c84cf8..658a458 100644
--- a/gcc/testsuite/g++.dg/cpp0x/constexpr-static8.C
+++ b/gcc/testsuite/g++.dg/cpp0x/constexpr-static8.C
@@ -1,5 +1,5 @@
 // PR c++/50258
-// { dg-options "-std=c++0x -fpermissive" }
+// { dg-options "-std=c++0x -pedantic" }
 
 struct Foo {
   static const double d = 3.14; // { dg-warning "constexpr" }
diff --git a/gcc/testsuite/g++.dg/cpp0x/constexpr-static8_nonpedantic.C 
b/gcc/testsuite/g++.dg/cpp0x/constexpr-static8_nonpedantic.C
new file mode 100644
index 0000000..28d34a1
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/constexpr-static8_nonpedantic.C
@@ -0,0 +1,7 @@
+// PR c++/50258
+// { dg-options "-std=c++0x" }
+
+struct Foo {
+  static const double d = 3.14; // no warning
+};
+const double Foo::d;
diff --git a/gcc/testsuite/g++.old-deja/g++.ext/memconst.C 
b/gcc/testsuite/g++.old-deja/g++.ext/memconst.C
index d934763..7e86156 100644
--- a/gcc/testsuite/g++.old-deja/g++.ext/memconst.C
+++ b/gcc/testsuite/g++.old-deja/g++.ext/memconst.C
@@ -1,5 +1,5 @@
 // { dg-do assemble  }
-// { dg-options "" }
+// { dg-options "-pedantic -pedantic-errors" }
 // From: ove.ewer...@syscon.uu.se (Ove Ewerlid)
 // Subject: ss-940630:cc1plus: internal error
 // Date: Sat, 2 Jul 1994 05:07:20 +0200

--
This patch is available for review at http://codereview.appspot.com/6212051