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authorJason Merrill <jason@redhat.com>2020-01-10 13:47:02 -0500
committerJason Merrill <jason@gcc.gnu.org>2020-01-10 13:47:02 -0500
commite0804c9b5efdf17bbfb692a787df36b86f71af8d (patch)
tree85f98decaabbf13fa0629a17b3dd0716131067bb
parent640b23d7ff5f3fad005dcbfb04a36e27000fc150 (diff)
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PR c++/93143 - incorrect tree sharing with constexpr.
We don't unshare CONSTRUCTORs as often during constexpr evaluation, so we need to unshare them here. * constexpr.c (cxx_eval_outermost_constant_expr): Don't assume CONSTRUCTORs are already unshared. From-SVN: r280127
-rw-r--r--gcc/cp/ChangeLog4
-rw-r--r--gcc/cp/constexpr.c6
-rw-r--r--gcc/testsuite/g++.dg/cpp0x/constexpr-array22.C27
3 files changed, 34 insertions, 3 deletions
diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 96bbcc9..1a36cd3 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,5 +1,9 @@
2020-01-10 Jason Merrill <jason@redhat.com>
+ PR c++/93143 - incorrect tree sharing with constexpr.
+ * constexpr.c (cxx_eval_outermost_constant_expr): Don't assume
+ CONSTRUCTORs are already unshared.
+
PR c++/93173 - incorrect tree sharing.
PR c++/93033
* cp-gimplify.c (cp_gimplify_init_expr, cp_gimplify_expr): Use
diff --git a/gcc/cp/constexpr.c b/gcc/cp/constexpr.c
index 9306a7dc..3ca3b9e 100644
--- a/gcc/cp/constexpr.c
+++ b/gcc/cp/constexpr.c
@@ -6347,10 +6347,10 @@ cxx_eval_outermost_constant_expr (tree t, bool allow_non_constant,
if (!non_constant_p && overflow_p)
non_constant_p = true;
- /* Unshare the result unless it's a CONSTRUCTOR in which case it's already
- unshared. */
+ /* Unshare the result. */
bool should_unshare = true;
- if (r == t || TREE_CODE (r) == CONSTRUCTOR)
+ if (r == t || (TREE_CODE (t) == TARGET_EXPR
+ && TARGET_EXPR_INITIAL (t) == r))
should_unshare = false;
if (non_constant_p && !allow_non_constant)
diff --git a/gcc/testsuite/g++.dg/cpp0x/constexpr-array22.C b/gcc/testsuite/g++.dg/cpp0x/constexpr-array22.C
new file mode 100644
index 0000000..80e24e2
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/constexpr-array22.C
@@ -0,0 +1,27 @@
+// PR c++/93143
+// { dg-do run { target c++11 } }
+
+struct A { char a[2]; };
+
+static constexpr A foo () { return A{1}; }
+
+void bar ()
+{
+ A a = foo ();
+ if (a.a[0] != 1)
+ __builtin_abort();
+}
+
+void foobar ()
+{
+ A x[] = { foo (), foo () };
+ A a = foo ();
+ if (a.a[0] != 1)
+ __builtin_abort();
+}
+
+int main()
+{
+ bar();
+ foobar();
+}