[LLVMdev] adding support for -ffixed-<reg>

陳韋任 (Wei-Ren Chen) chenwj at iis.sinica.edu.tw
Wed Oct 3 00:13:54 PDT 2012

Hi Chris,

> From the design perspective, I think it would make sense to represent this in
> LLVM IR with named metadata (http://llvm.org/docs/LangRef.html#
> namedmetadatastructure) like "!llvm.fixedregs".  This could then be picked up
> by the code generator, installed as preallocated registers (Jakob would be the
> one to ask how best to do this).

  -ffixed-<reg> and global register seems do the same thing, they both
reserve register from being used by the compiler. IIRC, you don't want
to add global register support before. If so, why would you think
-ffixed-<reg> is O.K.?


Wei-Ren Chen (陳韋任)
Computer Systems Lab, Institute of Information Science,
Academia Sinica, Taiwan (R.O.C.)
Tel:886-2-2788-3799 #1667
Homepage: http://people.cs.nctu.edu.tw/~chenwj

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