[llvm-commits] [llvm] r95831 - /llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp

[Chris Lattner]

On Feb 10, 2010, at 4:34 PM, Jakob Stoklund Olesen wrote:

> Author: stoklund
> Date: Wed Feb 10 18:34:18 2010
> New Revision: 95831
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=95831&view=rev
> Log:
> Remove duplicate successors from indirectbr instructions before building the machine CFG.
> 
> This makes early tail duplication run 60 times faster when compiling the Firefox
> JavaScript interpreter, see PR6186.

Nice speedup!  Please use SmallVector and array_pod_sort instead of vector and sort,

-Chris

> 
> Modified:
>    llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
> 
> Modified: llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp?rev=95831&r1=95830&r2=95831&view=diff
> 
> ==============================================================================
> --- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp (original)
> +++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp Wed Feb 10 18:34:18 2010
> @@ -2062,9 +2062,15 @@
> }
> 
> void SelectionDAGBuilder::visitIndirectBr(IndirectBrInst &I) {
> -  // Update machine-CFG edges.
> +  // Update machine-CFG edges with unique successors.
> +  std::vector<BasicBlock*> succs;
> +  succs.reserve(I.getNumSuccessors());
>   for (unsigned i = 0, e = I.getNumSuccessors(); i != e; ++i)
> -    CurMBB->addSuccessor(FuncInfo.MBBMap[I.getSuccessor(i)]);
> +    succs.push_back(I.getSuccessor(i));
> +  std::sort(succs.begin(), succs.end());
> +  succs.erase(std::unique(succs.begin(), succs.end()), succs.end());
> +  for (unsigned i = 0, e = succs.size(); i != e; ++i)
> +    CurMBB->addSuccessor(FuncInfo.MBBMap[succs[i]]);
> 
>   DAG.setRoot(DAG.getNode(ISD::BRIND, getCurDebugLoc(),
>                           MVT::Other, getControlRoot(),
> 
> 
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