[nvptx, testsuite] Fix gcc.target/nvptx/alias-*.c on sm_80
When running test-cases gcc.target/nvptx/alias-*.c on target board
nvptx-none-run/-misa=sm_80 we run into fails because the test-cases add
-mptx=6.3, which doesn't support sm_80.
Fix this by only adding -mptx=6.3 if necessary, and simplify the test-cases by
using ptx_alias feature abstractions:
...
/* { dg-do run { target runtime_ptx_alias } } */
/* { dg-add-options ptx_alias } */
...
Tested on nvptx.
gcc/testsuite/ChangeLog:
2022-04-01 Tom de Vries <tdevries@suse.de>
* gcc.target/nvptx/nvptx.exp
(check_effective_target_runtime_ptx_isa_version_6_3): Rename and
generalize to ...
(check_effective_target_runtime_ptx_isa_version_at_least): .. this.
(check_effective_target_default_ptx_isa_version_at_least)
(check_effective_target_runtime_ptx_alias, add_options_for_ptx_alias):
New proc.
* gcc.target/nvptx/alias-1.c: Use "target runtime_ptx_alias" and
"dg-add-options ptx_alias".
* gcc.target/nvptx/alias-2.c: Same.
* gcc.target/nvptx/alias-3.c: Same.
* gcc.target/nvptx/alias-4.c: Same.