llvm dev - Mar 2015 - [LLVMdev] How to Allocate a Variable to a Specific register

Hi,

Im trying to allocate registers for given code..,and my requirement is to
allocate a specific register to a given variable( ex:  int a ; // I want to
allocate register R1 to a).

I think one way to do this is by writing an llvm pass as described here
<http://llvm.org/docs/WritingAnLLVMPass.html#the-machinefunctionpass-class>.
But im not sure it will work..,Another way i thought of is to change
Allocation order in "AltOrder" in "xxxRegisterInfo.td". This
worked for 1
variable..,but if i have two or more variables and more registers.,i cant
get the exact register i want for the exact variable.

Please suggest me a way to do this.
Also..,Is there a way to check contents of each "bit" in a register?

Thanks,
Avinash
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Hi Avinash,

Could you give more details on what you are trying to achieve?

Cheers,
-Quentin
> On Mar 12, 2015, at 11:52 PM, Avinash Bole <boleavinash at gmail.com>
wrote:
> 
> Hi,
> 
> Im trying to allocate registers for given code..,and my requirement is to
allocate a specific register to a given variable( ex:  int a ; // I want to
allocate register R1 to a).
> 
> I think one way to do this is by writing an llvm pass as described here
<http://llvm.org/docs/WritingAnLLVMPass.html#the-machinefunctionpass-class>.
But im not sure it will work..,Another way i thought of is to change Allocation
order in "AltOrder" in "xxxRegisterInfo.td". This worked for
1 variable..,but if i have two or more variables and more registers.,i cant get
the exact register i want for the exact variable.
> 
> Please suggest me a way to do this.
> Also..,Is there a way to check contents of each "bit" in a
register?
> 
> Thanks,
> Avinash
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> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
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