[GNATS 26937] Static assert with vector size fails or internal assertion at templates.c in check_new_class_instantiation

[jhsedg]

Customer bug ID

qvm/test/vec_traits_gnuc_test.test/vec_traits_gnuc_test.cpp, preprocessed test in 26937.C, reduced test is in 26937a.C

Description

​The reduced test case is:
​//options_all:--c++20 --gnu_version=120100 -w -tused
​template struct is_vec;
​template <>
​struct is_vec<float attribute((vector_size(sizeof(float) * 2)))> {
​ enum { value = true };
​};
​typedef float v2sf attribute((vector_size(8)));
​static_assert(is_vec::value, "Boost QVM static assertion failure");
​
​cpfe -DTEST_NUMBER=1 --c++20 --gnu_version=120100 -w -tused Test_name.c
​check_new_class_instantiation:
​ existing list: <typeref vector of float (size = 8UL )>
​ new list:
​"Test_name.c", line 8: internal error: assertion failed at: "templates.c", line
​ in check_new_class_instantiation
​
​ static_assert(is_vec::value, "Boost QVM static assertion failure");
​ ^
​
​1 catastrophic error detected in the compilation of "Test_name.c".
​Compilation aborted.
​Aborted
​eccp: front end returned an exit status of 134
​Dwarf Error: wrong version in compilation unit header (is 5, should be 2, 3, or 4) [in module /mds/gnu/build/gcc-12.2.0/lib64/l
​ibstdc++.so.6]
​Dwarf Error: wrong version in compilation unit header (is 5, should be 2, 3, or 4) [in module /mds/gnu/build/gcc-12.2.0/lib64/l
​ibgcc_s.so.1]
​warning: File "/mds/gnu/build/gcc-12.2.0/lib64/libstdc++.so.6.0.30-gdb.py" auto-loading has been declined by your `auto-load sa
​fe-path' set to "$debugdir:$datadir/auto-load:/usr/bin/mono-gdb.py".
​-----> Context in check_new_class_instantiation ( ):
​ db_template_arg_list(old_list);
​ fprintf(f_debug, "\n new list: ");
​ db_template_arg_list(template_arg_list);
​ fprintf(f_debug, "\n");
​#endif /* DEBUG */
​ unexpected_condition();
​-----> Abbreviated stack trace:
​assertion_failed
​check_new_class_instantiation
​create_partial_instantiation_of_class
​find_template_class
​coalesce_template_class_reference
​coalesce_template_id
​f_is_generalized_identifier_start
​scan_expr_full
​scan_bool_constant_expression
​static_assert_declaration
​check_special_declaration_form
​-----> assertion_failed crash signatures: 2fcfb0ad34fa47e3c773457aaebd08fb from f4ccd58411099bff0ad80d70ed7bc4ee
​
​
​With DEBUG turned off the static_assert fails.