[PATCH] c++: duplicated side effects of xobj arg [PR113640]
Bootstrapped and regtested on x86_64-pc-linu-xgnu, does this look OK for trunk? -- >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 000..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(); +} -- 2.43.0.473.gc5b454771e
Re: [PATCH] c++: duplicated side effects of xobj arg [PR113640]
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 000..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(); +}