When calling a static member function we still need to evaluate an explicit
object argument. But we don't want to force a load of the entire object
if the argument is volatile, so we take its address. If as a result it no
longer has any side-effects, we don't need to evaluate it after all.
Tested x86_64-pc-linux-gnu, applying to trunk.
gcc/cp/ChangeLog:
PR c++/80456
* call.c (build_new_method_call_1): Check again for side-effects
with a volatile object.
gcc/testsuite/ChangeLog:
PR c++/80456
* g++.dg/cpp0x/constexpr-volatile3.C: New test.
---
gcc/cp/call.c | 3 ++-
gcc/testsuite/g++.dg/cpp0x/constexpr-volatile3.C | 15 +++++++++++++++
2 files changed, 17 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/g++.dg/cpp0x/constexpr-volatile3.C
diff --git a/gcc/cp/call.c b/gcc/cp/call.c
index c9a8c0d305f..678e120a165 100644
--- a/gcc/cp/call.c
+++ b/gcc/cp/call.c
@@ -10793,7 +10793,8 @@ build_new_method_call_1 (tree instance, tree fns,
vec<tree, va_gc> **args,
tree a = instance;
if (TREE_THIS_VOLATILE (a))
a = build_this (a);
- call = build2 (COMPOUND_EXPR, TREE_TYPE (call), a, call);
+ if (TREE_SIDE_EFFECTS (a))
+ call = build2 (COMPOUND_EXPR, TREE_TYPE (call), a, call);
}
else if (call != error_mark_node
&& DECL_DESTRUCTOR_P (cand->fn)
diff --git a/gcc/testsuite/g++.dg/cpp0x/constexpr-volatile3.C
b/gcc/testsuite/g++.dg/cpp0x/constexpr-volatile3.C
new file mode 100644
index 00000000000..5c1e865e0ac
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/constexpr-volatile3.C
@@ -0,0 +1,15 @@
+// PR c++/80456
+// { dg-do compile { target c++11 } }
+
+struct A {
+ static constexpr bool test() noexcept { return true; }
+
+ void f() volatile {
+ constexpr bool b = test();
+ }
+};
+
+void g() {
+ A a;
+ a.f();
+}
base-commit: 2efbbba16a0630fac8cadcd6d9e0ffaabfadb79f
--
2.27.0
