[Bug c++/65734] New: Yet another case of lost alignment by stor_layout

[Bug c++/65734] New: Yet another case of lost alignment by stor_layout

[hubicka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65734

            Bug ID: 65734
           Summary: Yet another case of lost alignment by stor_layout
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: hubicka at gcc dot gnu.org

template <typename T>
struct BVector
{
  typedef T T2;
    typedef T value_type [[gnu::aligned(8)]];    // { dg-bogus "attribute"
"attribute" }
    typedef T2 value_type2 [[gnu::aligned(8)]];  // { dg-bogus "attribute"
"attribute" }
  value_type v;
};
BVector<int> m;

template <template <class> class T>
struct BV2
{
    typedef T<float> value_type [[gnu::aligned(16)]]; // { dg-bogus "attribute"
"attribute" }
  value_type v;
};
BV2<BVector> m2;
int
main()
{
  if (__alignof__ (BV2<BVector>::value_type) != 16)
    __builtin_abort ();
}


$ /aux/hubicka/trunk-install/bin/gcc  -O2 a.C -std=gnu++11
$ ./a.out
Aborted
$ /aux/hubicka/llvm2-install/bin/clang  -O2 a.C -std=gnu++11
$ ./a.out
$ 


I think we have problem with re-layouting the type here.

[Bug c++/65734] Yet another case of lost alignment by stor_layout

[hubicka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65734

Jan Hubicka <hubicka at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |hubicka at gcc dot gnu.org,
                   |                            |jakub at redhat dot com,
                   |                            |jason at redhat dot com

--- Comment #1 from Jan Hubicka <hubicka at gcc dot gnu.org> ---
With the following check in stor-laout.c

Index: stor-layout.c
===================================================================
--- stor-layout.c       (revision 221977)
+++ stor-layout.c       (working copy)
@@ -1831,6 +1831,8 @@ finalize_type_size (tree type)
        {
          TYPE_SIZE (variant) = size;
          TYPE_SIZE_UNIT (variant) = size_unit;
+         if (TYPE_USER_ALIGN (variant))
+           gcc_assert (user_align && TYPE_ALIGN (variant) == align);
          TYPE_ALIGN (variant) = align;
          TYPE_PRECISION (variant) = precision;
          TYPE_USER_ALIGN (variant) = user_align;


I get:

0xa87ace finalize_type_size
        ../../gcc/stor-layout.c:1835
0xa87bbe finish_record_layout(record_layout_info_s*, int)
        ../../gcc/stor-layout.c:2079
0x6454bc layout_class_type
        ../../gcc/cp/class.c:6468
0x6454bc finish_struct_1(tree_node*)
        ../../gcc/cp/class.c:6598
0x631f4e instantiate_class_template_1
        ../../gcc/cp/pt.c:9648
0x631f4e instantiate_class_template(tree_node*)
        ../../gcc/cp/pt.c:9688
0x68a20d complete_type(tree_node*)
        ../../gcc/cp/typeck.c:146
0x63216c instantiate_class_template_1
        ../../gcc/cp/pt.c:9469
0x63216c instantiate_class_template(tree_node*)
        ../../gcc/cp/pt.c:9688
0x68a20d complete_type(tree_node*)
        ../../gcc/cp/typeck.c:146
0x5f6876 start_decl_1(tree_node*, bool)
        ../../gcc/cp/decl.c:4900
0x60567f start_decl(cp_declarator const*, cp_decl_specifier_seq*, int,
tree_node*, tree_node*, tree_node**)
        ../../gcc/cp/decl.c:4863
0x67b646 cp_parser_init_declarator
        ../../gcc/cp/parser.c:17170
0x67cc1c cp_parser_simple_declaration
        ../../gcc/cp/parser.c:11607
0x666503 cp_parser_block_declaration
        ../../gcc/cp/parser.c:11481
0x6860b9 cp_parser_declaration
        ../../gcc/cp/parser.c:11378
0x6849aa cp_parser_declaration_seq_opt
        ../../gcc/cp/parser.c:11264
0x684cbf cp_parser_translation_unit
        ../../gcc/cp/parser.c:4100
0x684cbf c_parse_file()
        ../../gcc/cp/parser.c:33192
0x736ac2 c_common_parse_file()
        ../../gcc/c-family/c-opts.c:1057

[Bug c++/65734] Yet another case of lost alignment by stor_layout

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65734

Jason Merrill <jason at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2015-04-10
                 CC|                            |jason at gcc dot gnu.org
           Assignee|unassigned at gcc dot gnu.org      |jason at gcc dot gnu.org
     Ever confirmed|0                           |1

[Bug c++/65734] Yet another case of lost alignment by stor_layout

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65734

--- Comment #2 from Jason Merrill <jason at gcc dot gnu.org> ---
Created attachment 35297
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=35297&action=edit
patch

A fix for after GCC 5 branches.

[Bug c++/65734] Yet another case of lost alignment by stor_layout

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65734

--- Comment #3 from Jason Merrill <jason at gcc dot gnu.org> ---
Author: jason
Date: Tue Apr 28 14:43:48 2015
New Revision: 222529

URL: https://gcc.gnu.org/viewcvs?rev=222529&root=gcc&view=rev
Log:
        PR c++/65734
gcc/
        * stor-layout.c (layout_type): Layout the TYPE_MAIN_VARIANT.
        (finalize_type_size): Respect TYPE_USER_ALIGN.
        (layout_type) [ARRAY_TYPE]: Likewise.
gcc/cp/
        * class.c (fixup_attribute_variants): Respect TYPE_USER_ALIGN.

Added:
    trunk/gcc/testsuite/g++.dg/cpp0x/alignas1.C
    trunk/gcc/testsuite/g++.dg/cpp0x/alignas2.C
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/class.c
    trunk/gcc/stor-layout.c

[Bug c++/65734] Yet another case of lost alignment by stor_layout

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65734

Jason Merrill <jason at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED
   Target Milestone|---                         |6.0

--- Comment #4 from Jason Merrill <jason at gcc dot gnu.org> ---
Fixed.

[Bug c++/65734] Yet another case of lost alignment by stor_layout

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65734

--- Comment #5 from Jason Merrill <jason at gcc dot gnu.org> ---
Author: jason
Date: Mon Aug 17 15:44:35 2015
New Revision: 226941

URL: https://gcc.gnu.org/viewcvs?rev=226941&root=gcc&view=rev
Log:
        PR c++/65734
gcc/
        * stor-layout.c (layout_type): Layout the TYPE_MAIN_VARIANT.
        (finalize_type_size): Respect TYPE_USER_ALIGN.
        (layout_type) [ARRAY_TYPE]: Likewise.
gcc/cp/
        * class.c (fixup_attribute_variants): Respect TYPE_USER_ALIGN.

Added:
    branches/gcc-5-branch/gcc/testsuite/g++.dg/cpp0x/alignas1.C
    branches/gcc-5-branch/gcc/testsuite/g++.dg/cpp0x/alignas2.C
Modified:
    branches/gcc-5-branch/gcc/ChangeLog
    branches/gcc-5-branch/gcc/cp/ChangeLog
    branches/gcc-5-branch/gcc/cp/class.c
    branches/gcc-5-branch/gcc/stor-layout.c