[LLVMdev] Problem selecting the correct registers for a calling convention

Tim Northover t.p.northover at gmail.com
Tue Nov 27 07:50:38 PST 2012

Hi Job,

> This issue is basically that I cannot find a way to distinguish two i16
> arguments from one i32. Is there a way to do this in LLVM? Preferably using
> tablegen, of course:-)

I think the property you want is "isSplit" (or, from the TableGen side

This gets applied to the first of those i16s that are produced.
Unfortunately I can't think of much you can do from TableGen to swap
the registers around (CCIfSplit is useful if the i32 would have to
start at an even-numbered register, for example). But in the C++
ISelLowering code you can use that flag to deal with the two registers
together in a sane way.


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