Re: [PING] [C++ Patch] PR 82307
On 10/23/2017 09:15 AM, Paolo Carlini wrote: Hi, following up to a short off-line exchange with Nathan, I'm sending a reworked patch which - among other things - avoids regressing on the second testcase (cpp0x/enum36.C). Tested x86_64-linux. ok, thanks! nathan -- Nathan Sidwell
Re: [PING] [C++ Patch] PR 82307
Hi,
following up to a short off-line exchange with Nathan, I'm sending a
reworked patch which - among other things - avoids regressing on the
second testcase (cpp0x/enum36.C). Tested x86_64-linux.
Thanks,
Paolo.
/cp
2017-10-23 Mukesh Kapoor
Paolo Carlini
PR c++/82307
* cvt.c (type_promotes_to): Implement C++17, 7.6/4, about unscoped
enumeration type whose underlying type is fixed.
/testsuite
2017-10-23 Mukesh Kapoor
Paolo Carlini
PR c++/82307
* g++.dg/cpp0x/enum35.C: New.
* g++.dg/cpp0x/enum36.C: Likewise.
Index: cp/cvt.c
===
--- cp/cvt.c(revision 254005)
+++ cp/cvt.c(working copy)
@@ -1834,12 +1834,27 @@ type_promotes_to (tree type)
|| type == char32_type_node
|| type == wchar_type_node)
{
+ tree prom = type;
+
+ if (TREE_CODE (type) == ENUMERAL_TYPE)
+ {
+ prom = ENUM_UNDERLYING_TYPE (prom);
+ if (!ENUM_IS_SCOPED (type)
+ && ENUM_FIXED_UNDERLYING_TYPE_P (type))
+ {
+ /* ISO C++17, 7.6/4. A prvalue of an unscoped enumeration type
+whose underlying type is fixed (10.2) can be converted to a
+prvalue of its underlying type. Moreover, if integral promotion
+can be applied to its underlying type, a prvalue of an unscoped
+enumeration type whose underlying type is fixed can also be
+converted to a prvalue of the promoted underlying type. */
+ return type_promotes_to (prom);
+ }
+ }
+
int precision = MAX (TYPE_PRECISION (type),
TYPE_PRECISION (integer_type_node));
tree totype = c_common_type_for_size (precision, 0);
- tree prom = type;
- if (TREE_CODE (prom) == ENUMERAL_TYPE)
- prom = ENUM_UNDERLYING_TYPE (prom);
if (TYPE_UNSIGNED (prom)
&& ! int_fits_type_p (TYPE_MAX_VALUE (prom), totype))
prom = c_common_type_for_size (precision, 1);
Index: testsuite/g++.dg/cpp0x/enum35.C
===
--- testsuite/g++.dg/cpp0x/enum35.C (nonexistent)
+++ testsuite/g++.dg/cpp0x/enum35.C (working copy)
@@ -0,0 +1,14 @@
+// PR c++/82307
+// { dg-do run { target c++11 } }
+
+#include
+
+enum : unsigned long long { VAL };
+
+bool foo (unsigned long long) { return true; }
+bool foo (int) { return false; }
+
+int main()
+{
+ assert (foo(VAL));
+}
Index: testsuite/g++.dg/cpp0x/enum36.C
===
--- testsuite/g++.dg/cpp0x/enum36.C (nonexistent)
+++ testsuite/g++.dg/cpp0x/enum36.C (working copy)
@@ -0,0 +1,14 @@
+// PR c++/82307
+// { dg-do run { target c++11 } }
+
+#include
+
+enum : short { VAL };
+
+bool foo (int) { return true; }
+bool foo (unsigned long long) { return false; }
+
+int main()
+{
+ assert (foo (VAL));
+}
Re: [PING] [C++ Patch] PR 82307
The bug happens only for enum types with a fixed underlying type. The existing code tries to create another type based on it's precision by calling c_common_type_for_size(). For the precision value of an unsigned long long type, the call to c_common_type_for_size() returns an unsigned long type and this causes compilation errors later on. The fix is to simply use the fixed underlying type of the enum instead of creating a new one. Mukesh On 10/18/2017 1:10 PM, Nathan Sidwell wrote: On 10/18/2017 12:17 PM, Mukesh Kapoor wrote: On 10/9/2017 12:20 PM, Mukesh Kapoor wrote: Hi, This patch fixes https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82307. For an unscoped enum with a fixed underlying type, the function type_promotes_to() does not always return the same type as the underlying type. The fix is to use the underlying type of the enum instead of creating a new one by calling c_common_type_for_size(). The diff looks wrong. Just before the changed piece it (attempts to) deal with enum types. Why is that failing? nathan
Re: [PING] [C++ Patch] PR 82307
On 10/18/2017 12:17 PM, Mukesh Kapoor wrote: On 10/9/2017 12:20 PM, Mukesh Kapoor wrote: Hi, This patch fixes https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82307. For an unscoped enum with a fixed underlying type, the function type_promotes_to() does not always return the same type as the underlying type. The fix is to use the underlying type of the enum instead of creating a new one by calling c_common_type_for_size(). The diff looks wrong. Just before the changed piece it (attempts to) deal with enum types. Why is that failing? nathan -- Nathan Sidwell
Re: [PING] [C++ Patch] PR 82307
On 10/9/2017 12:20 PM, Mukesh Kapoor wrote: Hi, This patch fixes https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82307. For an unscoped enum with a fixed underlying type, the function type_promotes_to() does not always return the same type as the underlying type. The fix is to use the underlying type of the enum instead of creating a new one by calling c_common_type_for_size(). Bootstrapped and tested with 'make check' on x86_64-linux. New test case added. Mukesh
[C++ Patch] PR 82307
Hi,
This patch fixes https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82307.
For an unscoped enum with a fixed underlying type, the function
type_promotes_to() does not always return the same type as the
underlying type. The fix is to use the underlying type of the enum
instead of creating a new one by calling c_common_type_for_size().
Bootstrapped and tested with 'make check' on x86_64-linux. New test case
added.
Mukesh
Index: gcc/cp/cvt.c
===
--- gcc/cp/cvt.c(revision 253551)
+++ gcc/cp/cvt.c(working copy)
@@ -1854,11 +1854,16 @@
tree prom = type;
if (TREE_CODE (prom) == ENUMERAL_TYPE)
prom = ENUM_UNDERLYING_TYPE (prom);
- if (TYPE_UNSIGNED (prom)
- && ! int_fits_type_p (TYPE_MAX_VALUE (prom), totype))
- prom = c_common_type_for_size (precision, 1);
- else
- prom = totype;
+ // If an unscoped enum has fixed underlying type,
+ // use that type (bug 82307)
+ if (!ENUM_FIXED_UNDERLYING_TYPE_P (type) || SCOPED_ENUM_P (type))
+ {
+ if (TYPE_UNSIGNED (prom)
+ && ! int_fits_type_p (TYPE_MAX_VALUE (prom), totype))
+ prom = c_common_type_for_size (precision, 1);
+ else
+ prom = totype;
+ }
if (SCOPED_ENUM_P (type))
{
if (abi_version_crosses (6)
Index: gcc/testsuite/g++.dg/cpp0x/pr_82307.C
===
--- gcc/testsuite/g++.dg/cpp0x/pr_82307.C (revision 0)
+++ gcc/testsuite/g++.dg/cpp0x/pr_82307.C (working copy)
@@ -0,0 +1,24 @@
+// PR c++/82307
+// { dg-do compile { target c++11 } }
+
+#include
+#include
+
+enum : unsigned long long { VAL };
+
+const char* foo( unsigned long long )
+{
+ return "unsigned long long";
+}
+
+const char* foo( int )
+{
+ return "int";
+}
+
+int main( void )
+{
+ if (strcmp(foo(VAL), "unsigned long long") != 0)
+abort();
+}
+
