Prevents potential matching of literal offsets to non-literal operands.
If there's a literal parsing issue seems like it should be straightforward?
There is no reproducer, and even if we have one, it would still be not reliable, because the order in which the internal AsmParser machinery tries to match operands is generally beyond our control.
What's interesting about this change is that defaultSMRDOffset8() and defaultSMRDLiteralOffset() are not updated to add ImmTyNone operands instead of ImmTyOffset and we still pass the tests. That's because we don't really have any GFX6 tests with these operands dropped, so no default values used. (Addressed in D142231.)
Does your patch fix this bug?
s_load_dword s5, s[2:3], glc
Assembler should trigger an error for GFX7, but glc is misinterpreted as offset operand.
I think your patch should fix this bug, so you may add this code as a test.
LGTM, but I suggest moving the test to some other place. *_unsupported.s are used solely to test identification of unsupported opcodes. gfx7_err_pos.s may be a better place for this test.