[LLVMdev] Undoing DAG Combiner patterns
martin.filteau at octasic.com
Wed May 15 19:03:14 PDT 2013
It's the first LLVM backend we do for our asynchronous DSP. So, I apologize if this is a trivial question!
The target-independent DAG combiner performs the following transformation:
sub n, c -> add n, -c
For our target, negative constants are more costly to encode. What is the best place to revert to a sub instruction?
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