[llvm-dev] Transfer GVN-PRE pass to Machine IR (llvm bug 38917)

Previous Topic Next Topic
 
classic Classic list List threaded Threaded
1 message Options
Reply | Threaded
Open this post in threaded view
|

[llvm-dev] Transfer GVN-PRE pass to Machine IR (llvm bug 38917)

韩玉 via llvm-dev
Hi all,

I'm working on fixing this bug (https://bugs.llvm.org/show_bug.cgi?id=38917, "Failure to hoist repeated vextractf128 from switch cases") -- actually, under-optimization. It's not related to special arch or AVX inst. set, it will arise on many cases when llvm ir instr/intrinsic is splitting to several machine instrs (like vextract128->VEXTRACTF128rr+VPEXTRDmr) on this specific CFG (defined by switch-case structure). To hoist common subexpession successfully on such CFG, one need to use method eliminating partitial redundancy like GVN-PRE. I'm to implement this as separate MIR pass (actually I'm to copy and adopt llvm ir GVN-PRE pass).

Meanwhile I want to consult llvm dev -- is it a good decision? May anyone has pros and cons of it?

  Thanks,
   Anton


_______________________________________________
LLVM Developers mailing list
[hidden email]
http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev