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C++ PATCH for c++/48780 (non-promotion of scoped enums)
- From: Jason Merrill <jason at redhat dot com>
- To: gcc-patches List <gcc-patches at gcc dot gnu dot org>
- Date: Fri, 20 May 2011 23:46:03 -0400
- Subject: C++ PATCH for c++/48780 (non-promotion of scoped enums)
As the bug submitter correctly points out, C++0x scoped enums are not
subject to integral promotion like unscoped enums are. Unfortunately,
this represents an ABI change (at least for varargs), so it's
conditional on -fabi-version.
Tested x86_64-pc-linux-gnu, applying to trunk.
commit e2aa4734d644e2c0d658d6d9a42cc36ef2b0087c
Author: Jason Merrill <jason@redhat.com>
Date: Fri May 20 18:32:32 2011 -0400
PR c++/48780
* cvt.c (type_promotes_to): Don't promote scoped enums.
diff --git a/gcc/common.opt b/gcc/common.opt
index ebc2ba7..492d25e 100644
--- a/gcc/common.opt
+++ b/gcc/common.opt
@@ -759,6 +759,9 @@ Driver Undocumented
; function parameters used in other parameters and the return type.
; First selectable in G++ 4.6.
;
+; 6: The version of the ABI that doesn't promote scoped enums to int.
+; First selectable in G++ 4.7.
+;
; Additional positive integers will be assigned as new versions of
; the ABI become the default version of the ABI.
fabi-version=
diff --git a/gcc/cp/cvt.c b/gcc/cp/cvt.c
index db4ea46..e89ce29 100644
--- a/gcc/cp/cvt.c
+++ b/gcc/cp/cvt.c
@@ -1616,6 +1616,10 @@ type_promotes_to (tree type)
if (TREE_CODE (type) == BOOLEAN_TYPE)
type = integer_type_node;
+ /* scoped enums don't promote. */
+ else if (SCOPED_ENUM_P (type) && abi_version_at_least (6))
+ ;
+
/* Normally convert enums to int, but convert wide enums to something
wider. */
else if (TREE_CODE (type) == ENUMERAL_TYPE
diff --git a/gcc/testsuite/g++.dg/cpp0x/enum12.C b/gcc/testsuite/g++.dg/cpp0x/enum12.C
new file mode 100644
index 0000000..b2ec919
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/enum12.C
@@ -0,0 +1,18 @@
+// PR c++/48780
+// { dg-options "-std=c++0x -fabi-version=0" }
+
+typedef __builtin_va_list __gnuc_va_list;
+typedef __gnuc_va_list va_list;
+
+enum struct A : short { X };
+
+void foo(int x, ...) {
+ va_list vl;
+ __builtin_va_start(vl, x);
+ enum A t = __builtin_va_arg(vl, enum A);
+ __builtin_va_end(vl);
+}
+
+int main() {
+ foo(0, A::X);
+}