We changed months back to use the pre-generic form for constexpr evaluation,
but explain_invalid_constexpr_fn was still using DECL_SAVED_TREE. This
mostly works, but misses some issues due to folding. So with this patch we
save the pre-generic form of constexpr functions even when we know they
can't produce a constant result.
Tested x86_64-pc-linux-gnu, applying to trunk.
* constexpr.c (register_constexpr_fundef): Do store the body of a
template instantiation that is not potentially constant.
(explain_invalid_constexpr_fn): Look it up.
(cxx_eval_call_expression): Check fundef->result.
---
gcc/cp/constexpr.c | 27 +++++++++++++------
gcc/testsuite/g++.dg/cpp0x/constexpr-nsdmi1.C | 12 +++++++++
2 files changed, 31 insertions(+), 8 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/cpp0x/constexpr-nsdmi1.C
diff --git a/gcc/cp/constexpr.c b/gcc/cp/constexpr.c
index f3f03e7d621..87d78d26728 100644
--- a/gcc/cp/constexpr.c
+++ b/gcc/cp/constexpr.c
@@ -885,16 +885,16 @@ register_constexpr_fundef (tree fun, tree body)
return NULL;
}
- if (!potential_rvalue_constant_expression (massaged))
- {
- if (!DECL_GENERATED_P (fun))
- require_potential_rvalue_constant_expression (massaged);
- return NULL;
- }
+ bool potential = potential_rvalue_constant_expression (massaged);
+ if (!potential && !DECL_GENERATED_P (fun))
+ require_potential_rvalue_constant_expression (massaged);
if (DECL_CONSTRUCTOR_P (fun)
&& cx_check_missing_mem_inits (DECL_CONTEXT (fun),
massaged, !DECL_GENERATED_P (fun)))
+ potential = false;
+
+ if (!potential && !DECL_GENERATED_P (fun))
return NULL;
/* Create the constexpr function table if necessary. */
@@ -917,6 +917,12 @@ register_constexpr_fundef (tree fun, tree body)
if (clear_ctx)
DECL_CONTEXT (DECL_RESULT (fun)) = NULL_TREE;
+ if (!potential)
+ /* For a template instantiation, we want to remember the pre-generic body
+ for explain_invalid_constexpr_fn, but do tell cxx_eval_call_expression
+ that it doesn't need to bother trying to expand the function. */
+ entry.result = error_mark_node;
+
gcc_assert (*slot == NULL);
*slot = ggc_alloc<constexpr_fundef> ();
**slot = entry;
@@ -962,11 +968,15 @@ explain_invalid_constexpr_fn (tree fun)
{
/* Then if it's OK, the body. */
if (!DECL_DECLARED_CONSTEXPR_P (fun)
- && !LAMBDA_TYPE_P (CP_DECL_CONTEXT (fun)))
+ && DECL_DEFAULTED_FN (fun))
explain_implicit_non_constexpr (fun);
else
{
- body = massage_constexpr_body (fun, DECL_SAVED_TREE (fun));
+ if (constexpr_fundef *fd = retrieve_constexpr_fundef (fun))
+ body = fd->body;
+ else
+ body = DECL_SAVED_TREE (fun);
+ body = massage_constexpr_body (fun, body);
require_potential_rvalue_constant_expression (body);
if (DECL_CONSTRUCTOR_P (fun))
cx_check_missing_mem_inits (DECL_CONTEXT (fun), body, true);
@@ -1919,6 +1929,7 @@ cxx_eval_call_expression (const constexpr_ctx *ctx, tree
t,
{
new_call.fundef = retrieve_constexpr_fundef (fun);
if (new_call.fundef == NULL || new_call.fundef->body == NULL
+ || new_call.fundef->result == error_mark_node
|| fun == current_function_decl)
{
if (!ctx->quiet)
diff --git a/gcc/testsuite/g++.dg/cpp0x/constexpr-nsdmi1.C
b/gcc/testsuite/g++.dg/cpp0x/constexpr-nsdmi1.C
new file mode 100644
index 00000000000..b94cf3099f4
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/constexpr-nsdmi1.C
@@ -0,0 +1,12 @@
+// PR c++/79592
+// { dg-do compile { target c++11 } }
+
+struct pthread_mutex {
+ void *m_ptr;
+};
+
+struct M {
+ pthread_mutex m = { ((void *) 1LL) }; // { dg-error "reinterpret_cast" }
+};
+
+constexpr M m; // { dg-error "M::M" }
base-commit: 7484780e06a758b7a02f270ae8af30fd2c11fdef
--
2.18.1
