(Almost) always call reserveOperandSpace() on newly created PHINodes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128535 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/examples/Kaleidoscope/Chapter5/toy.cpp b/examples/Kaleidoscope/Chapter5/toy.cpp
index 26b3db6..e3f7565 100644
--- a/examples/Kaleidoscope/Chapter5/toy.cpp
+++ b/examples/Kaleidoscope/Chapter5/toy.cpp
@@ -552,6 +552,7 @@
   Builder.SetInsertPoint(MergeBB);
   PHINode *PN = Builder.CreatePHI(Type::getDoubleTy(getGlobalContext()),
                                   "iftmp");
+  PN->reserveOperandSpace(2);
   
   PN->addIncoming(ThenV, ThenBB);
   PN->addIncoming(ElseV, ElseBB);
@@ -593,6 +594,7 @@
   
   // Start the PHI node with an entry for Start.
   PHINode *Variable = Builder.CreatePHI(Type::getDoubleTy(getGlobalContext()), VarName.c_str());
+  Variable->reserveOperandSpace(2);
   Variable->addIncoming(StartVal, PreheaderBB);
   
   // Within the loop, the variable is defined equal to the PHI node.  If it