[LLVMdev] Problems with 64-bit register operands of inline asm on ARM

[Tim Northover]

Hi Weiming,

> Tim, could you help to review it?

Of course.

I think this breaks thumb register pairs. When I compile your added
tests with a thumbv7 triple the output is clearly nonsense ("ldrd r0,
, [r0]"). It's still valid syntax though, isn't it?

In fact, it looks like your test doesn't make use of the 'R and 'Q'
modifiers you're actually changing at all.

Also, am I misinterpreting or is there no test for the tied operand
changes? If so, there should be. In fact, it might be better as a
separate commit altogether.

Some minor nits too:

> // If it's a use that is tied with a previouse def, it has no

Should be "previous".

> unsigned RegNum

Could we rename this to NumRegs? RegNum suggests it's an index rather
than a count to me and I nearly had a fit when I saw "RegNum != 2"
because of that (it's fine, of course).

Cheers.

Tim.