llvm dev - Nov 2011 - [LLVMdev] ifconversion following br_cc instructions

Hi,

I am trying to implement support for an if-conversion pass in a backend for the
ADRES CGRA architecture. 
>From studying the existing IfConversion pass,  I observed the following:
- The PredicateInstruction method is meant to insert guards into conditional
instructions.
- This method assumes that one will be able to get the predicate from the
conditional branch instruction
   on which the conditional instruction depends. 
- So implicitly, this method assumes that the conditional branch instruction is
a brcond-like instruction
  (which has a predicate operand), not a br_cc-like instruction (which does not
have a predicate operand).
- As far as I can see, no generic method is available to insert a predicate
generating instruction that will
   replace the br_cc instruction. 

Is that correct? 

If so, what would be the best place in the code to implement and invoke
functionality for inserting such an
instruction?

Thanks,

Bjorn De Sutter
Computer Systems Lab
Ghent University