Replace some instances of UniqueVector with SetVector, which is slightly cheaper.

No functionality change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167116 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 7ac0af7..2b34e56 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -850,9 +850,9 @@
   Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("data_end"));
 
   // End text sections.
-  for (unsigned i = 1, N = SectionMap.size(); i <= N; ++i) {
-    Asm->OutStreamer.SwitchSection(SectionMap[i]);
-    Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("section_end", i));
+  for (unsigned I = 0, E = SectionMap.size(); I != E; ++I) {
+    Asm->OutStreamer.SwitchSection(SectionMap[I]);
+    Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("section_end", I+1));
   }
 
   // Compute DIE offsets and sizes.