Reserve space for PHI nodes when we read them in.  This provides a VERY
tasty 15% speedup on the testcase from Bill.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@8993 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Bytecode/Reader/InstructionReader.cpp b/lib/Bytecode/Reader/InstructionReader.cpp
index a763d66..b415025 100644
--- a/lib/Bytecode/Reader/InstructionReader.cpp
+++ b/lib/Bytecode/Reader/InstructionReader.cpp
@@ -125,6 +125,7 @@
       throw std::string("Invalid phi node encountered!\n");
 
     PHINode *PN = new PHINode(InstTy);
+    PN->op_reserve(Args.size());
     for (unsigned i = 0, e = Args.size(); i != e; i += 2)
       PN->addIncoming(getValue(RI.Type, Args[i]), getBasicBlock(Args[i+1]));
     return PN;