[CycleInfo] Support forward declarations

llvm/include/llvm/IR/CycleInfo.h

@@ -20,7 +20,9 @@
 
 namespace llvm {
 
-using CycleInfo = GenericCycleInfo<SSAContext>;
+// Use class instead of using to allow forward declarations.
+class CycleInfo : public GenericCycleInfo<SSAContext> {};
+
 using Cycle = CycleInfo::CycleT;
 
 } // namespace llvm

llvm/include/llvm/Transforms/Utils/BasicBlockUtils.h

@@ -19,14 +19,14 @@
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/SetVector.h"
 #include "llvm/IR/BasicBlock.h"
-#include "llvm/IR/CycleInfo.h"
 #include "llvm/IR/Dominators.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/Printable.h"
 #include <cassert>
 
 namespace llvm {
 class CondBrInst;
+class CycleInfo;
 class LandingPadInst;
 class Loop;
 class PHINode;

llvm/include/llvm/Transforms/Utils/ControlFlowUtils.h

@@ -15,7 +15,6 @@
 
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
-#include "llvm/IR/CycleInfo.h"
 
 namespace llvm {
 

llvm/lib/Transforms/Utils/BasicBlockUtils.cpp

@@ -24,6 +24,7 @@
 #include "llvm/IR/BasicBlock.h"
 #include "llvm/IR/CFG.h"
 #include "llvm/IR/Constants.h"
+#include "llvm/IR/CycleInfo.h"
 #include "llvm/IR/DebugInfo.h"
 #include "llvm/IR/DebugInfoMetadata.h"
 #include "llvm/IR/Dominators.h"