Apply clang-tidy's modernize-loop-convert to most of lib/Transforms.

Only minor manual fixes. No functionality change intended.

llvm-svn: 273808
diff --git a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
index a02d8ea..2d3ff83 100644
--- a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -3046,11 +3046,11 @@
   // Do a quick scan over the function.  If we find any blocks that are
   // unreachable, remove any instructions inside of them.  This prevents
   // the instcombine code from having to deal with some bad special cases.
-  for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) {
-    if (Visited.count(&*BB))
+  for (BasicBlock &BB : F) {
+    if (Visited.count(&BB))
       continue;
 
-    unsigned NumDeadInstInBB = removeAllNonTerminatorAndEHPadInstructions(&*BB);
+    unsigned NumDeadInstInBB = removeAllNonTerminatorAndEHPadInstructions(&BB);
     MadeIRChange |= NumDeadInstInBB > 0;
     NumDeadInst += NumDeadInstInBB;
   }