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

[Jakob Stoklund Olesen]

On Feb 10, 2010, at 4:48 PM, Chris Lattner wrote:

> 
> 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

Why SmallVector? The number of successors on an indirectbr varies a lot - I don't expect most of them to be less than some small integer size.

> and array_pod_sort

Will do.

> 
> -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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>