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.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@95831 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index de17f90..477c1c7 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -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(),