We are currently failing to fold equality comparisons involving
PTRMEM_CSTs since (I think) r229018 thus making this a GCC 6 regression.
This regression shows up in the boost testsuite.
Fixed in a straightforward way. OK to commit after bootstrap + regtest?
gcc/cp/ChangeLog:
* constexpr.c (cxx_eval_binary_expression): Expand
the PTRMEM_CST operands of an equality comparison.
gcc/testsuite/ChangeLog:
* g++.dg/cpp0x/constexpr-ptrmem5.C: New test.
---
gcc/cp/constexpr.c | 9 +++++++++
gcc/testsuite/g++.dg/cpp0x/constexpr-ptrmem5.C | 14 ++++++++++++++
2 files changed, 23 insertions(+)
create mode 100644 gcc/testsuite/g++.dg/cpp0x/constexpr-ptrmem5.C
diff --git a/gcc/cp/constexpr.c b/gcc/cp/constexpr.c
index 208f43b..1ad87aa 100644
--- a/gcc/cp/constexpr.c
+++ b/gcc/cp/constexpr.c
@@ -1630,6 +1630,15 @@ cxx_eval_binary_expression (const constexpr_ctx *ctx,
tree t,
location_t loc = EXPR_LOCATION (t);
enum tree_code code = TREE_CODE (t);
tree type = TREE_TYPE (t);
+
+ if (code == EQ_EXPR || code == NE_EXPR)
+ {
+ if (TREE_CODE (lhs) == PTRMEM_CST && CONSTANT_CLASS_P (rhs))
+ lhs = cplus_expand_constant (lhs);
+ if (TREE_CODE (rhs) == PTRMEM_CST && CONSTANT_CLASS_P (lhs))
+ rhs = cplus_expand_constant (rhs);
+ }
+
r = fold_binary_loc (loc, code, type, lhs, rhs);
if (r == NULL_TREE)
{
diff --git a/gcc/testsuite/g++.dg/cpp0x/constexpr-ptrmem5.C
b/gcc/testsuite/g++.dg/cpp0x/constexpr-ptrmem5.C
new file mode 100644
index 0000000..e28c917
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/constexpr-ptrmem5.C
@@ -0,0 +1,14 @@
+// { dg-do compile { target c++11 } }
+
+#define SA(x) static_assert ((x), #x)
+
+struct X { int a, b; };
+
+void
+foo ()
+{
+ SA (&X::a);
+ SA (&X::a == &X::a);
+ SA (&X::a != &X::b);
+ SA ((!&X::b) == 0);
+}
--
2.7.0.rc0.50.g1470d8f.dirty
