[LLVMdev] LLVM Code Generation on flattened IR code

[charlessl at free.fr]

Hello,

I made two flattening transformation filters, one use a switch instruction for the dispatcher, and the other an indirectbranch instruction. Both work well but llc is very time consuming in the second case : 10 minutes for a 500 basic block function, while it takes 10 seconds for the switchcase implementation . The instrumentation of llc shows that most of the time is passed in  the Machine Block Frequency Analysis pass


I don't understand why there is so huge difference. Is there a way to speed up llc ?

Charles Salmon