[LLVMdev] llvm 'select' instruction

[lyr338]

I am not sure what situation is. Your c code in llvm travel as:
     |    clang       |    IR build    |    combine ...   |               isel                     |     ...               |
 c code    ->     IR      ->       DAG       ->       DAG            ->        DAG(machine relative) ----> machine code
                        I                    II                                                                  III
situation I: you need to aviod 'select' in IR?
     -> Maybe you need to chang the 'clang';
situation II: you need to aviod 'select' DAG node?
     -> you can focuse on IR build;
situation III: you need to aviod 'select' machine instruction (your ISA relative)?
     -> you can add pattern for 'select' node, to map for your own instruction.








At 2013-04-15 00:05:07,"Dong Chen" <jameschennerd at gmail.com> wrote:
>hi Sam: 
>thank you for your reply.
>but i have another question about this 'select' instruction. 
>i think that in LLVM IR, i can use a branch and two seperate assignments to
>replace 'select' instruction(am i right?). 
>so is there any compiling option to aviod generate 'select' instruction?
>
>
>
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