llvm dev - May 2014 - [LLVMdev] How to construct a new register allocation algorithm

There are three main register allocation strategies in the backend of LLVM. If I
want to design and implement a new algorithm, how can I add it to LLVM and call
it from llc just as the three options like
llc -regalloc=fast file.bc -o fa.sllc -regalloc=new file.bc -o new.s
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On 22 May 2014 02:37, 蜡笔小新 <841224078 at qq.com>
wrote:
> There are three main register allocation strategies in the backend of LLVM.
> If I want to design and implement a new algorithm, how can I add it to LLVM
> and call it from llc just as the three options like
It's probably easiest to copy one of the existing allocators and
replace its code with yours. For example lib/CodeGen/RegAllocBasic.cpp
is the smallest.
> llc -regalloc=fast file.bc -o fa.s
This particular option seems to be handled by the "RegisterRegAlloc"
declarations in each file.

Cheers.

Tim.

Just out curiosity, have you implemented a new register allocation algorithm
and if so, which one? I'm working on code generator right now and I'm
looking for a simple register allocation algorithm to implement and how to
deal with fixed registers to cetain instructions like eax/ebx to mul/div on
x86. I've asked this before
(http://llvm.1065342.n5.nabble.com/How-do-I-deal-with-fixed-registers-td68697.html)
but no one asnwered yet.



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