| Message ID | 20240130150904.3447219-1-ppalka@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | c++: duplicated side effects of xobj arg [PR113640] | expand |
On 1/30/24 10:09, Patrick Palka wrote: > Bootstrapped and regtested on x86_64-pc-linu-xgnu, does this > look OK for trunk? OK. > -- >8 -- > > We miscompile the below testcase because keep_unused_object_arg > duplicates the side effects of a (by-value) object argument of a > xobj member function. > > PR c++/113640 > > gcc/cp/ChangeLog: > > * call.cc (keep_unused_object_arg): Punt for an xobj member > function. > > gcc/testsuite/ChangeLog: > > * g++.dg/cpp23/explicit-obj-lambda14.C: New test. > --- > gcc/cp/call.cc | 2 +- > .../g++.dg/cpp23/explicit-obj-lambda14.C | 27 +++++++++++++++++++ > 2 files changed, 28 insertions(+), 1 deletion(-) > create mode 100644 gcc/testsuite/g++.dg/cpp23/explicit-obj-lambda14.C > > diff --git a/gcc/cp/call.cc b/gcc/cp/call.cc > index 9de0d77c423..451a189f7cf 100644 > --- a/gcc/cp/call.cc > +++ b/gcc/cp/call.cc > @@ -5256,7 +5256,7 @@ keep_unused_object_arg (tree result, tree obj, tree fn) > { > if (result == NULL_TREE > || result == error_mark_node > - || TREE_CODE (TREE_TYPE (fn)) == METHOD_TYPE > + || DECL_OBJECT_MEMBER_FUNCTION_P (fn) > || !TREE_SIDE_EFFECTS (obj)) > return result; > > diff --git a/gcc/testsuite/g++.dg/cpp23/explicit-obj-lambda14.C b/gcc/testsuite/g++.dg/cpp23/explicit-obj-lambda14.C > new file mode 100644 > index 00000000000..03dededfe33 > --- /dev/null > +++ b/gcc/testsuite/g++.dg/cpp23/explicit-obj-lambda14.C > @@ -0,0 +1,27 @@ > +// PR c++/113640 > +// { dg-do run { target c++23 } } > + > +static int total; > + > +struct A { > + A f(this auto self, int n) { > + total += n; > + return self; > + } > +}; > + > +int main() { > + A a; > + a.f(1).f(42).f(100); > + if (total != 143) > + __builtin_abort(); > + > + total = 0; > + auto l = [](this auto self, int n) { > + total += n; > + return self; > + }; > + l(1)(42)(100); > + if (total != 143) > + __builtin_abort(); > +}
diff --git a/gcc/cp/call.cc b/gcc/cp/call.cc index 9de0d77c423..451a189f7cf 100644 --- a/gcc/cp/call.cc +++ b/gcc/cp/call.cc @@ -5256,7 +5256,7 @@ keep_unused_object_arg (tree result, tree obj, tree fn) { if (result == NULL_TREE || result == error_mark_node - || TREE_CODE (TREE_TYPE (fn)) == METHOD_TYPE + || DECL_OBJECT_MEMBER_FUNCTION_P (fn) || !TREE_SIDE_EFFECTS (obj)) return result; diff --git a/gcc/testsuite/g++.dg/cpp23/explicit-obj-lambda14.C b/gcc/testsuite/g++.dg/cpp23/explicit-obj-lambda14.C new file mode 100644 index 00000000000..03dededfe33 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp23/explicit-obj-lambda14.C @@ -0,0 +1,27 @@ +// PR c++/113640 +// { dg-do run { target c++23 } } + +static int total; + +struct A { + A f(this auto self, int n) { + total += n; + return self; + } +}; + +int main() { + A a; + a.f(1).f(42).f(100); + if (total != 143) + __builtin_abort(); + + total = 0; + auto l = [](this auto self, int n) { + total += n; + return self; + }; + l(1)(42)(100); + if (total != 143) + __builtin_abort(); +}