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/Scalar/RewriteStatepointsForGC.cpp b/llvm/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp
index a4b8519..bab39a3 100644
--- a/llvm/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp
+++ b/llvm/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp
@@ -1553,9 +1553,8 @@
   // record initial number of (static) allocas; we'll check we have the same
   // number when we get done.
   int InitialAllocaNum = 0;
-  for (auto I = F.getEntryBlock().begin(), E = F.getEntryBlock().end(); I != E;
-       I++)
-    if (isa<AllocaInst>(*I))
+  for (Instruction &I : F.getEntryBlock())
+    if (isa<AllocaInst>(I))
       InitialAllocaNum++;
 #endif