[NFC] fix trivial typos in comments and documents

"in in" -> "in", "on on" -> "on" etc.

llvm-svn: 323508
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyFixIrreducibleControlFlow.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyFixIrreducibleControlFlow.cpp
index 88daea7..89018e2 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyFixIrreducibleControlFlow.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyFixIrreducibleControlFlow.cpp
@@ -136,7 +136,7 @@
   MachineBasicBlock *Header = Loop ? Loop->getHeader() : &*MF.begin();
   SetVector<MachineBasicBlock *> RewriteSuccs;
 
-  // DFS through Loop's body, looking for for irreducible control flow. Loop is
+  // DFS through Loop's body, looking for irreducible control flow. Loop is
   // natural, and we stay in its body, and we treat any nested loops
   // monolithically, so any cycles we encounter indicate irreducibility.
   SmallPtrSet<MachineBasicBlock *, 8> OnStack;