Hi, As described in the PR, gcc-6-branch is impacted by this issue. This patch backports the original fix from Bernd and the recently added testcase (which does not rely on c++17 features).
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80287 https://gcc.gnu.org/ml/gcc-patches/2017-07/msg00730.html Bootstrapped and regression tested on x86, ARM and AArch64 targets. Ok for gcc-6-branch ? Thanks, Yvan 2017-08-24 Yvan Roux <yvan.r...@linaro.org> PR c++/80287 C++ crash with __attribute((may_alias)) Backport from mainline 2017-04-17 Bernd Edlinger <bernd.edlin...@hotmail.de> PR c++/80287 * class.c (fixup_may_alias): Fix all type variants. gcc/testsuite 2017-08-22 Yvan Roux <yvan.r...@linaro.org> PR c++/80287 * g++.dg/pr8028.C: New test.
diff --git a/gcc/cp/class.c b/gcc/cp/class.c index 35deb1e99cd..86e7e003fe4 100644 --- a/gcc/cp/class.c +++ b/gcc/cp/class.c @@ -1999,12 +1999,14 @@ fixup_type_variants (tree t) static void fixup_may_alias (tree klass) { - tree t; + tree t, v; for (t = TYPE_POINTER_TO (klass); t; t = TYPE_NEXT_PTR_TO (t)) - TYPE_REF_CAN_ALIAS_ALL (t) = true; + for (v = TYPE_MAIN_VARIANT (t); v; v = TYPE_NEXT_VARIANT (v)) + TYPE_REF_CAN_ALIAS_ALL (v) = true; for (t = TYPE_REFERENCE_TO (klass); t; t = TYPE_NEXT_REF_TO (t)) - TYPE_REF_CAN_ALIAS_ALL (t) = true; + for (v = TYPE_MAIN_VARIANT (t); v; v = TYPE_NEXT_VARIANT (v)) + TYPE_REF_CAN_ALIAS_ALL (v) = true; } /* Early variant fixups: we apply attributes at the beginning of the class diff --git a/gcc/testsuite/g++.dg/pr80287.C b/gcc/testsuite/g++.dg/pr80287.C new file mode 100644 index 00000000000..da8d3fab150 --- /dev/null +++ b/gcc/testsuite/g++.dg/pr80287.C @@ -0,0 +1,13 @@ +// PR c++/80287 +// { dg-do compile { target c++11 } } +// { dg-options "-g" } + +struct A { + operator long() {} +} __attribute__((__may_alias__)); + +struct { + A ino; +} a; + +char b = a.ino;