[NFC] fix trivial typos in comments and documents

"to to" -> "to"

llvm-svn: 323628
diff --git a/llvm/lib/Target/X86/X86FastISel.cpp b/llvm/lib/Target/X86/X86FastISel.cpp
index faeda19..7e88304 100644
--- a/llvm/lib/Target/X86/X86FastISel.cpp
+++ b/llvm/lib/Target/X86/X86FastISel.cpp
@@ -2675,7 +2675,7 @@
             (FrameReg == X86::EBP && VT == MVT::i32)) &&
            "Invalid Frame Register!");
 
-    // Always make a copy of the frame register to to a vreg first, so that we
+    // Always make a copy of the frame register to a vreg first, so that we
     // never directly reference the frame register (the TwoAddressInstruction-
     // Pass doesn't like that).
     unsigned SrcReg = createResultReg(RC);