[Bug middle-end/94098] New: [10 Regression] ICE: canonical types differ for identical types 'int(void*, void*)' and 'int(void*, void*)'

[asolokha at gmx dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94098

            Bug ID: 94098
           Summary: [10 Regression] ICE: canonical types differ for
                    identical types 'int(void*, void*)' and 'int(void*,
                    void*)'
           Product: gcc
           Version: 10.0
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code
          Severity: normal
          Priority: P3
         Component: middle-end
          Assignee: unassigned at gcc dot gnu.org
          Reporter: asolokha at gmx dot com
  Target Milestone: ---

PR92721 strikes back.

g++-10.0.1-alpha20200308 snapshot (g:9de42a8e995451cb13dceb3970ae23ff88240bff)
ICEs when compiling the following testcase reduced from
gcc/testsuite/gcc.dg/attr-access-read-write-2.c:

int rdwr1_rdwr1 (void*, void*);
int __attribute__ ((access (read_write, 1))) rdwr1_rdwr1 (void*, void*);
int __attribute__ ((access (read_write, 2))) rdwr1_rdwr1 (void*, void*);

% g++-10.0.1 -w -c drii2dyo.cc
drii2dyo.cc:3:71: internal compiler error: canonical types differ for identical
types 'int(void*, void*)' and 'int(void*, void*)'
    3 | int __attribute__ ((access (read_write, 2))) rdwr1_rdwr1 (void*,
void*);
      |                                                                       ^
0xa63b0b comptypes(tree_node*, tree_node*, int)
       
/var/tmp/portage/sys-devel/gcc-10.0.1_alpha20200308/work/gcc-10-20200308/gcc/cp/typeck.c:1519
0x8f21d8 duplicate_decls(tree_node*, tree_node*, bool)
       
/var/tmp/portage/sys-devel/gcc-10.0.1_alpha20200308/work/gcc-10-20200308/gcc/cp/decl.c:2308
0x972360 do_pushdecl
       
/var/tmp/portage/sys-devel/gcc-10.0.1_alpha20200308/work/gcc-10-20200308/gcc/cp/name-lookup.c:3044
0x9751b2 pushdecl(tree_node*, bool)
       
/var/tmp/portage/sys-devel/gcc-10.0.1_alpha20200308/work/gcc-10-20200308/gcc/cp/name-lookup.c:3173
0x9751b2 maybe_push_decl(tree_node*)
       
/var/tmp/portage/sys-devel/gcc-10.0.1_alpha20200308/work/gcc-10-20200308/gcc/cp/name-lookup.c:3204
0x907331 start_decl(cp_declarator const*, cp_decl_specifier_seq*, int,
tree_node*, tree_node*, tree_node**)
       
/var/tmp/portage/sys-devel/gcc-10.0.1_alpha20200308/work/gcc-10-20200308/gcc/cp/decl.c:5377
0x9b5f81 cp_parser_init_declarator
       
/var/tmp/portage/sys-devel/gcc-10.0.1_alpha20200308/work/gcc-10-20200308/gcc/cp/parser.c:20703
0x996d46 cp_parser_simple_declaration
       
/var/tmp/portage/sys-devel/gcc-10.0.1_alpha20200308/work/gcc-10-20200308/gcc/cp/parser.c:13689
0x9c1002 cp_parser_declaration
       
/var/tmp/portage/sys-devel/gcc-10.0.1_alpha20200308/work/gcc-10-20200308/gcc/cp/parser.c:13388
0x9c179f cp_parser_translation_unit
       
/var/tmp/portage/sys-devel/gcc-10.0.1_alpha20200308/work/gcc-10-20200308/gcc/cp/parser.c:4731
0x9c179f c_parse_file()
       
/var/tmp/portage/sys-devel/gcc-10.0.1_alpha20200308/work/gcc-10-20200308/gcc/cp/parser.c:43760
0xad99db c_common_parse_file()
       
/var/tmp/portage/sys-devel/gcc-10.0.1_alpha20200308/work/gcc-10-20200308/gcc/c-family/c-opts.c:1186