[LLVMdev] Questions on Parallelism and Data Dependence Analysis

[tanmingxing at mprc.pku.edu.cn]

> Hi, I have two questions about llvm, and expect your reply very much.
>
> 1. Is there any plan of llvm to support Thread-Level Parallelism by using
> OpenMP, MPI, pthread or llvm-defined directives?
>     If automatic parallelism exploring is very hard, what is the key
> problem? We can't get the precise data dependence
>     information at compile-time?
llvm-gcc uses gcc as the front-end. OpenMP, MPI and pthread are all OK in
llvm, no additional directives are used in llvm now.

> 2. Can I use the functions provided by llvm to get the real data
> dependence(Read After Write) info on basic block level directly?
>    In other words, can I get the task graph(node: task viewed as basic
> block or more coarse grain, edge: real data dependence)
>    from sequential program using llvm to explore task-level parallelism by
> some proposed task scheduling algorithm?

Waht is the exact values you mean? If you means oridinary "values" in llvm
, you can construct the task graph in a straightforward way with Use-def
chains.

>
> thanks.
>
> 2008-12-25
>
>
>
> Wenzhi Tao
>