[Bug target/79905] New: ICE in canonical types differ for identical types __vector(4) int and V4i {aka __vector(4) int}

["marxin at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79905

            Bug ID: 79905
           Summary: ICE in canonical types differ for identical types
                    __vector(4) int and V4i {aka __vector(4) int}
           Product: gcc
           Version: 7.0
            Status: UNCONFIRMED
          Keywords: ice-on-invalid-code
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: marxin at gcc dot gnu.org
  Target Milestone: ---
              Host: ppc64le-linux-gnu

Created attachment 40889
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=40889&action=edit
test-case

Following ICEs on ppc64le-linux-gnu (with cross-compiler):

$ ppc64le-linux-gnu-g++ altivec.cpp 
altivec.cpp: In function ‘void test_vec_step(__vector(8) short int)’:
altivec.cpp:20:12: error: ‘vec_step’ was not declared in this scope
   int res1[vec_step(arg1) == 8 ? 1 : -1];
            ^~~~~~~~
altivec.cpp:20:12: note: suggested alternative: ‘vector’
   int res1[vec_step(arg1) == 8 ? 1 : -1];
            ^~~~~~~~
            vector
altivec.cpp: In function ‘void test1()’:
altivec.cpp:44:13: internal compiler error: canonical types differ for
identical types __vector(4) int and V4i {aka __vector(4) int}
   f(vAltiVec);
             ^
0x75287f comptypes(tree_node*, tree_node*, int)
        .././../gcc/cp/typeck.c:1434
0x5ed46c standard_conversion
        .././../gcc/cp/call.c:1187
0x5f8748 implicit_conversion
        .././../gcc/cp/call.c:1839
0x5facc1 add_function_candidate
        .././../gcc/cp/call.c:2197
0x5fca7f add_candidates
        .././../gcc/cp/call.c:5504
0x5ff341 perform_overload_resolution
        .././../gcc/cp/call.c:4148
0x6018ce build_new_function_call(tree_node*, vec<tree_node*, va_gc,
vl_embed>**, bool, int)
        .././../gcc/cp/call.c:4233
0x7a4bac finish_call_expr(tree_node*, vec<tree_node*, va_gc, vl_embed>**, bool,
bool, int)
        .././../gcc/cp/semantics.c:2441
0x71c67b cp_parser_postfix_expression
        .././../gcc/cp/parser.c:6994
0x71aa94 cp_parser_unary_expression
        .././../gcc/cp/parser.c:8102
0x724fd7 cp_parser_cast_expression
        .././../gcc/cp/parser.c:8780
0x72556d cp_parser_binary_expression
        .././../gcc/cp/parser.c:8881
0x725e30 cp_parser_assignment_expression
        .././../gcc/cp/parser.c:9168
0x7289ea cp_parser_expression
        .././../gcc/cp/parser.c:9337
0x728fa9 cp_parser_expression_statement
        .././../gcc/cp/parser.c:10885
0x73a70c cp_parser_statement
        .././../gcc/cp/parser.c:10701
0x73ba14 cp_parser_statement_seq_opt
        .././../gcc/cp/parser.c:11027
0x73bb1f cp_parser_compound_statement
        .././../gcc/cp/parser.c:10981
0x73652d cp_parser_function_body
        .././../gcc/cp/parser.c:21438
0x73652d cp_parser_ctor_initializer_opt_and_function_body
        .././../gcc/cp/parser.c:21474