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

[Jakob Stoklund Olesen]

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.

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(),