[pushed] c++: fix contracts with NRV
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Commit Message
Tested x86_64-pc-linux-gnu, applying to trunk.
-- 8< --
The NRV implementation was blindly replacing the operand of RETURN_EXPR,
clobbering anything that check_return_expr might have added on to the actual
initialization, such as checking the postcondition.
gcc/cp/ChangeLog:
* semantics.cc (finalize_nrv_r): [RETURN_EXPR]: Only replace the
INIT_EXPR.
gcc/testsuite/ChangeLog:
* g++.dg/contracts/contracts-post7.C: New test.
---
gcc/cp/semantics.cc | 12 ++++++--
.../g++.dg/contracts/contracts-post7.C | 29 +++++++++++++++++++
2 files changed, 39 insertions(+), 2 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/contracts/contracts-post7.C
base-commit: 29c82c6ca929e0f5eccfe038dea71177d814c6b7
prerequisite-patch-id: aed53cdac161144c31cb1433282e1ad1d49d3770
@@ -4940,9 +4940,17 @@ finalize_nrv_r (tree* tp, int* walk_subtrees, void* data)
*walk_subtrees = 0;
/* Change all returns to just refer to the RESULT_DECL; this is a nop,
but differs from using NULL_TREE in that it indicates that we care
- about the value of the RESULT_DECL. */
+ about the value of the RESULT_DECL. But preserve anything appended
+ by check_return_expr. */
else if (TREE_CODE (*tp) == RETURN_EXPR)
- TREE_OPERAND (*tp, 0) = dp->result;
+ {
+ tree *p = &TREE_OPERAND (*tp, 0);
+ while (TREE_CODE (*p) == COMPOUND_EXPR)
+ p = &TREE_OPERAND (*p, 0);
+ gcc_checking_assert (TREE_CODE (*p) == INIT_EXPR
+ && TREE_OPERAND (*p, 0) == dp->result);
+ *p = dp->result;
+ }
/* Change all cleanups for the NRV to only run when an exception is
thrown. */
else if (TREE_CODE (*tp) == CLEANUP_STMT
new file mode 100644
@@ -0,0 +1,29 @@
+// { dg-do run }
+// { dg-options "-std=c++2a -fcontracts" }
+
+#include <experimental/contract>
+
+using std::experimental::contract_violation;
+void handle_contract_violation(const contract_violation &violation)
+{
+ __builtin_exit (0);
+}
+
+struct A {
+ int i;
+ A(): i(42) {}
+ A(const A&);
+};
+
+A f()
+ [[ post r: r.i == 24 ]]
+{
+ A a;
+ return a;
+}
+
+int main()
+{
+ f();
+ return -1;
+}