The testcase hit an ICE trying to expand a TARGET_EXPR temporary cached from
the other lambda-expression. This patch fixes this in two ways:
1) Avoid reusing a TARGET_EXPR from another function.
2) Avoid ending up with a TARGET_EXPR at all; the use of 'p' had become
<TARGET_EXPR<NON_LVALUE_EXPR<TARGET_EXPR ...>>>, which doesn't make any
sense.
Tested x86_64-pc-linux-gnu, applying to trunk.
gcc/cp/ChangeLog
2020-04-04 Jason Merrill <ja...@redhat.com>
PR c++/94453
* constexpr.c (maybe_constant_value): Use break_out_target_exprs.
* expr.c (mark_use) [VIEW_CONVERT_EXPR]: Don't wrap a TARGET_EXPR in
NON_LVALUE_EXPR.
---
gcc/cp/constexpr.c | 2 +-
gcc/cp/expr.c | 22 +++++++++++----
.../g++.dg/cpp0x/lambda/lambda-constexpr1.C | 28 +++++++++++++++++++
3 files changed, 46 insertions(+), 6 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/cpp0x/lambda/lambda-constexpr1.C
diff --git a/gcc/cp/constexpr.c b/gcc/cp/constexpr.c
index 91f0c3ba269..8c693ea89ef 100644
--- a/gcc/cp/constexpr.c
+++ b/gcc/cp/constexpr.c
@@ -6793,7 +6793,7 @@ maybe_constant_value (tree t, tree decl, bool
manifestly_const_eval,
r = *cached;
if (r != t)
{
- r = unshare_expr_without_location (r);
+ r = break_out_target_exprs (r, /*clear_loc*/true);
protected_set_expr_location (r, EXPR_LOCATION (t));
}
return r;
diff --git a/gcc/cp/expr.c b/gcc/cp/expr.c
index 04e4418c671..9b535708c57 100644
--- a/gcc/cp/expr.c
+++ b/gcc/cp/expr.c
@@ -195,11 +195,23 @@ mark_use (tree expr, bool rvalue_p, bool read_p,
tree nop = RECUR (op);
if (nop == error_mark_node)
return error_mark_node;
- TREE_OPERAND (expr, 0) = nop;
- /* If we're replacing a DECL with a constant, we also need to change
- the TREE_CODE of the location wrapper. */
- if (op != nop && rvalue_p)
- TREE_SET_CODE (expr, NON_LVALUE_EXPR);
+ else if (op == nop)
+ /* No change. */;
+ else if (DECL_P (nop) || CONSTANT_CLASS_P (nop))
+ {
+ /* Reuse the location wrapper. */
+ TREE_OPERAND (expr, 0) = nop;
+ /* If we're replacing a DECL with a constant, we also need to
+ change the TREE_CODE of the location wrapper. */
+ if (rvalue_p)
+ TREE_SET_CODE (expr, NON_LVALUE_EXPR);
+ }
+ else
+ {
+ /* Drop the location wrapper. */
+ expr = nop;
+ protected_set_expr_location (expr, loc);
+ }
return expr;
}
gcc_fallthrough();
diff --git a/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-constexpr1.C
b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-constexpr1.C
new file mode 100644
index 00000000000..7cb1e239ebb
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-constexpr1.C
@@ -0,0 +1,28 @@
+// PR c++/94453
+// { dg-do compile { target c++11 } }
+
+void *ay();
+template <typename f> f ay() { return *static_cast<f *>(ay()); }
+template <typename h>
+void bf() {
+ ay<h>()();
+}
+struct az {
+ template <typename h>
+ az(h);
+ using bk = void (*)();
+ bk bl;
+};
+template <typename h>
+az::az(h) { bl = bf<h>; }
+struct A {};
+void da(az);
+void di(A, int);
+void dk(A, az, az);
+void b() {
+ int data = 0;
+ auto n = [] {};
+ constexpr auto p = A{};
+ auto q = [=] { di(p, data); };
+ da([=] { dk(p, n, q); });
+}
base-commit: bab8d9625f4cdeaf9bb45e28ab62abe47c3827f9
--
2.18.1
