[Bug c++/80287] C++ crash with __attribute((may_alias))

[paolo.carlini at oracle dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80287

Paolo Carlini  changed:

   What|Removed |Added

 Status|UNCONFIRMED |RESOLVED
 Resolution|--- |FIXED

--- Comment #13 from Paolo Carlini  ---
This can be closed, right?

[Bug c++/80287] C++ crash with __attribute((may_alias))

[aldyh at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80287

--- Comment #12 from Aldy Hernandez  ---
Author: aldyh
Date: Wed Sep 13 17:19:29 2017
New Revision: 252528

URL: https://gcc.gnu.org/viewcvs?rev=252528=gcc=rev
Log:
2017-08-22  Yvan Roux  

PR c++/80287
* g++.dg/pr80287.C: New test.

Added:
branches/range-gen2/gcc/testsuite/g++.dg/pr80287.C
Modified:
branches/range-gen2/gcc/testsuite/ChangeLog

[Bug c++/80287] C++ crash with __attribute((may_alias))

[yroux at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80287

--- Comment #11 from Yvan Roux  ---
Author: yroux
Date: Thu Aug 24 13:20:22 2017
New Revision: 251331

URL: https://gcc.gnu.org/viewcvs?rev=251331=gcc=rev
Log:
PR c++/80287 C++ crash with __attribute((may_alias))

gcc/
2017-08-24  Yvan Roux  

Backport from mainline
2017-04-17  Bernd Edlinger  

PR c++/80287
* class.c (fixup_may_alias): Fix all type variants.

gcc/testsuite
2017-08-24  Yvan Roux  

Backport from mainline
2017-08-22  Yvan Roux  

PR c++/80287
* g++.dg/pr8028.C: New test.

Added:
branches/gcc-6-branch/gcc/testsuite/g++.dg/pr80287.C
Modified:
branches/gcc-6-branch/gcc/ChangeLog
branches/gcc-6-branch/gcc/cp/class.c
branches/gcc-6-branch/gcc/testsuite/ChangeLog

[Bug c++/80287] C++ crash with __attribute((may_alias))

[yroux at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80287

--- Comment #10 from Yvan Roux  ---
Author: yroux
Date: Tue Aug 22 10:51:52 2017
New Revision: 251273

URL: https://gcc.gnu.org/viewcvs?rev=251273=gcc=rev
Log:
2017-08-22  Yvan Roux  

Backport from mainline
2017-08-22  Yvan Roux  

PR c++/80287
* g++.dg/pr80287.C: New test.

Added:
branches/gcc-7-branch/gcc/testsuite/g++.dg/pr80287.C
Modified:
branches/gcc-7-branch/gcc/testsuite/ChangeLog

[Bug c++/80287] C++ crash with __attribute((may_alias))

[yroux at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80287

--- Comment #9 from Yvan Roux  ---
Author: yroux
Date: Tue Aug 22 09:32:38 2017
New Revision: 251268

URL: https://gcc.gnu.org/viewcvs?rev=251268=gcc=rev
Log:
2017-08-22  Yvan Roux  

PR c++/80287
* g++.dg/pr80287.C: New test.


Added:
trunk/gcc/testsuite/g++.dg/pr80287.C
Modified:
trunk/gcc/testsuite/ChangeLog

[Bug c++/80287] C++ crash with __attribute((may_alias))

[yroux at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80287

--- Comment #8 from Yvan Roux  ---
OK, I'll submit a patch to add this second testcase on trunk and then only
include it in the backport on GCC 6.

Thanks

[Bug c++/80287] C++ crash with __attribute((may_alias))

[bernd.edlinger at hotmail dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80287

--- Comment #7 from Bernd Edlinger  ---
Hmm, yes, maybe having a second test case without C++17 would be fine.

[Bug c++/80287] C++ crash with __attribute((may_alias))

[yroux at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80287

--- Comment #6 from Yvan Roux  ---
Hi,

I got a small issue when testing the backport into the branch:

g++.dg/lto/pr80287_0.C is not a suitable testcase for GCC 6 branch, since it
uses c++17 class std:any which is not available in GCC 6.  In the first place
this bug was found when building
libstdc++-v3/testsuite/20_util/any/assign/2.cc, but it is not related to
std:any, I found it on my side in ceph package build, and the issue is
exhibited when compiling this reduced testcase with -g:

struct A {
  operator long() {}
} __attribute__((__may_alias__));
struct {
  A ino;
} a;
char b = a.ino;

So, I wonder what is the best way to handle that, adding this new testcase on
trunk as g++.dg/pr80287.C and only backport this one into GCC 6, or avoid
std:any usage into g++.dg/lto/pr80287_0.C ?

[Bug c++/80287] C++ crash with __attribute((may_alias))

[bernd.edlinger at hotmail dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80287

--- Comment #5 from Bernd Edlinger  ---
(In reply to Yvan Roux from comment #4)
> Hi Bernd,
> 
> gcc-6-branch is impacted by this issue (observed on AArch64 target at
> r250109, with regression introduced at r234768).  I can prepare the backport
> if you whish.

Yes, thanks, go ahead.

[Bug c++/80287] C++ crash with __attribute((may_alias))

[yroux at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80287

Yvan Roux  changed:

   What|Removed |Added

 CC||yroux at gcc dot gnu.org

--- Comment #4 from Yvan Roux  ---
Hi Bernd,

gcc-6-branch is impacted by this issue (observed on AArch64 target at r250109,
with regression introduced at r234768).  I can prepare the backport if you
whish.

[Bug c++/80287] C++ crash with __attribute((may_alias))

[bernd.edlinger at hotmail dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80287

--- Comment #3 from Bernd Edlinger  ---
fixed on trunk.
It's theoretically possible that gcc-6-branch is also affected,
but I have not tried.

[Bug c++/80287] C++ crash with __attribute((may_alias))

[edlinger at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80287

--- Comment #2 from Bernd Edlinger  ---
Author: edlinger
Date: Mon Apr 17 20:41:40 2017
New Revision: 246955

URL: https://gcc.gnu.org/viewcvs?rev=246955=gcc=rev
Log:
017-04-17  Bernd Edlinger  

PR c++/80287
* class.c (fixup_may_alias): Fix all type variants.

gcc/testsuite
2017-04-17  Bernd Edlinger   

PR c++/80287
* g++.dg/lto/pr80287_0.C: New test.

Added:
trunk/gcc/testsuite/g++.dg/lto/pr80287_0.C
Modified:
trunk/gcc/cp/ChangeLog
trunk/gcc/cp/class.c
trunk/gcc/testsuite/ChangeLog

[Bug c++/80287] C++ crash with __attribute((may_alias))

[bernd.edlinger at hotmail dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80287

--- Comment #1 from Bernd Edlinger  ---
good news is, I already have a patch:

Index: gcc/cp/class.c
===
--- gcc/cp/class.c  (revision 246605)
+++ gcc/cp/class.c  (working copy)
@@ -2060,12 +2060,14 @@
 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