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C++ PATCH for c++/70344 (ICE with recursive constexpr)
- From: Jason Merrill <jason at redhat dot com>
- To: gcc-patches List <gcc-patches at gcc dot gnu dot org>
- Date: Wed, 23 Mar 2016 14:22:16 -0400
- Subject: C++ PATCH for c++/70344 (ICE with recursive constexpr)
- Authentication-results: sourceware.org; auth=none
cp_fold tries to fold calls to constexpr functions. When we are inside
a constexpr function at the time and see a call to the same function,
this caused trouble because we hadn't adjusted the parameter types yet.
Fixed by handling this special case of calling a constexpr function
that isn't defined yet.
Tested x86_64-pc-linux-gnu, applying to trunk.
commit 4d4c5c65269b6dcde93fa13a90f2af925c8082c7
Author: Jason Merrill <jason@redhat.com>
Date: Wed Mar 23 13:51:42 2016 -0400
PR c++/70344
* constexpr.c (cxx_eval_call_expression): Catch invalid recursion.
diff --git a/gcc/cp/constexpr.c b/gcc/cp/constexpr.c
index 7b13633..d71e488 100644
--- a/gcc/cp/constexpr.c
+++ b/gcc/cp/constexpr.c
@@ -1239,6 +1239,21 @@ cxx_eval_call_expression (const constexpr_ctx *ctx, tree t,
return t;
}
+ if (fun == current_function_decl)
+ {
+ /* A call to the current function, i.e.
+ constexpr int f (int i) {
+ constexpr int j = f(i-1);
+ return j;
+ }
+ This would be OK without the constexpr on the declaration of j. */
+ if (!ctx->quiet)
+ error_at (loc, "%qD called in a constant expression before its "
+ "definition is complete", fun);
+ *non_constant_p = true;
+ return t;
+ }
+
constexpr_ctx new_ctx = *ctx;
if (DECL_CONSTRUCTOR_P (fun) && !ctx->object
&& TREE_CODE (t) == AGGR_INIT_EXPR)
diff --git a/gcc/testsuite/g++.dg/cpp0x/constexpr-recursion2.C b/gcc/testsuite/g++.dg/cpp0x/constexpr-recursion2.C
new file mode 100644
index 0000000..978b998
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/constexpr-recursion2.C
@@ -0,0 +1,17 @@
+// PR c++/70344
+// { dg-do compile { target c++11 } }
+
+struct Z
+{
+ Z () = default;
+ Z (Z const &) = default;
+ constexpr Z (Z &&) {}
+};
+
+constexpr int
+fn (Z v)
+{
+ return fn (v);
+}
+
+auto t = fn (Z ());