[PowerPC][NFC] Cleanup PPCCTRLoopsVerify pass

[jsji]

Summary

The PPCCTRLoop pass has been moved to HardwareLoops,
so the comments and some useless code are deprecated now.

[jsji]

Fix the include as well.

[shchenz]

Thanks for clean-up. Some minor comments.

llvm/lib/Target/PowerPC/PPCCTRLoops.cpp

16

Seems now we only need following headers:

#include "MCTargetDesc/PPCMCTargetDesc.h"
#include "PPC.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/InitializePasses.h"
#include "llvm/Pass.h"
#include "llvm/Support/Debug.h"
#include "llvm/CodeGen/MachineDominators.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineFunctionPass.h"

43–44

Since now all the function body is guarded under #ifndef NDEBUG, should we guard other headers as well?

[jsji]

Update the NDEBUG

llvm/lib/Target/PowerPC/PPCCTRLoops.cpp

16

The full include-list for /home/jji/llvm-project/llvm/lib/Target/PowerPC/PPCCTRLoops.cpp:
#include <vector>                                     // for vector
#include "MCTargetDesc/PPCMCTargetDesc.h"             // for CTR, CTR8, BDNZ
#include "PPC.h"                                      // for createPPCCTRLoo...
#include "llvm/ADT/SmallSet.h"                        // for SmallSet
#include "llvm/ADT/SmallVector.h"                     // for SmallVector
#include "llvm/ADT/StringRef.h"                       // for StringRef
#include "llvm/ADT/ilist_iterator.h"                  // for operator!=, ope...
#include "llvm/CodeGen/MachineBasicBlock.h"           // for MachineBasicBlock
#include "llvm/CodeGen/MachineDominators.h"           // for MachineDominato...
#include "llvm/CodeGen/MachineFunction.h"             // for MachineFunction
#include "llvm/CodeGen/MachineFunctionPass.h"         // for MachineFunction...
#include "llvm/CodeGen/MachineInstr.h"                // for operator<<, Mac...
#include "llvm/CodeGen/MachineInstrBundleIterator.h"  // for MachineInstrBun...
#include "llvm/CodeGen/MachineOperand.h"              // for MachineOperand
#include "llvm/CodeGen/Register.h"                    // for Register
#include "llvm/InitializePasses.h"                    // for initializeMachi...
#include "llvm/Pass.h"                                // for AnalysisUsage
#include "llvm/PassRegistry.h"                        // for PassRegistry
#include "llvm/Support/CodeGen.h"                     // for llvm
#include "llvm/Support/Debug.h"  // lines 40-40
#include "llvm/Support/ErrorHandling.h"               // for llvm_unreachable
#include "llvm/Support/GenericDomTreeConstruction.h"  // for dbgs, LLVM_DEBUG
#include "llvm/Support/Printable.h"                   // for operator<<, Pri...
#include "llvm/Support/raw_ostream.h"                 // for raw_ostream
---

This is the output of include what you use, some of the include may have been included in some other headers, I would prefer we keep this as we may want to reduce some include in headers as well later.

[nemanjai]

LGTM.

llvm/lib/Target/PowerPC/PPCCTRLoops.cpp

11

Complete passes that are only defined for non-NDEBUG builds are rare and I think a comment should explain what is going on here. Something like:

CTR loops are produced by the HardwareLoops pass and this pass is simply a verification that no invalid CTR loops are produced. As such, it isn't something that needs to be run (or even defined) for Release builds so the entire file is guarded by NDEBUG.

[jsji]

Add comments about NDEBUG

llvm/lib/Target/PowerPC/PPCCTRLoops.cpp

-//===-- PPCCTRLoops.cpp - Identify and generate CTR loops -----------------===//
+//===-- PPCCTRLoops.cpp - Verify CTR loops -----------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 //
-// This pass identifies loops where we can generate the PPC branch instructions
-// that decrement and test the count register (CTR) (bdnz and friends).
-//
-// The pattern that defines the induction variable can changed depending on
-// prior optimizations.  For example, the IndVarSimplify phase run by 'opt'
-// normalizes induction variables, and the Loop Strength Reduction pass
-// run by 'llc' may also make changes to the induction variable.
-//
-// Criteria for CTR loops:
-//  - Countable loops (w/ ind. var for a trip count)
-//  - Try inner-most loops first
-//  - No nested CTR loops.
-//  - No function calls in loops.
+// This pass verifies that all bdnz/bdz instructions are dominated by a loop
+// mtctr before any other instructions that might clobber the ctr register.
 //
 //===----------------------------------------------------------------------===//
 
+// CTR loops are produced by the HardwareLoops pass and this pass is simply a
+// verification that no invalid CTR loops are produced. As such, it isn't
+// something that needs to be run (or even defined) for Release builds so the
+// entire file is guarded by NDEBUG.
+#ifndef NDEBUG
+#include <vector>
+
+#include "MCTargetDesc/PPCMCTargetDesc.h"
 #include "PPC.h"
-#include "PPCSubtarget.h"
-#include "PPCTargetMachine.h"
-#include "PPCTargetTransformInfo.h"
-#include "llvm/ADT/STLExtras.h"
-#include "llvm/ADT/Statistic.h"
-#include "llvm/Analysis/AssumptionCache.h"
-#include "llvm/Analysis/CFG.h"
-#include "llvm/Analysis/CodeMetrics.h"
-#include "llvm/Analysis/LoopInfo.h"
-#include "llvm/Analysis/LoopIterator.h"
-#include "llvm/Analysis/TargetLibraryInfo.h"
-#include "llvm/Analysis/TargetTransformInfo.h"
-#include "llvm/CodeGen/TargetPassConfig.h"
-#include "llvm/CodeGen/TargetSchedule.h"
-#include "llvm/IR/Constants.h"
-#include "llvm/IR/DerivedTypes.h"
-#include "llvm/IR/Dominators.h"
-#include "llvm/IR/InlineAsm.h"
-#include "llvm/IR/Instructions.h"
-#include "llvm/IR/IntrinsicInst.h"
-#include "llvm/IR/Module.h"
-#include "llvm/IR/ValueHandle.h"
+#include "llvm/ADT/SmallSet.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/ilist_iterator.h"
+#include "llvm/CodeGen/MachineBasicBlock.h"
+#include "llvm/CodeGen/MachineDominators.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/CodeGen/MachineInstr.h"
+#include "llvm/CodeGen/MachineInstrBundleIterator.h"
+#include "llvm/CodeGen/MachineOperand.h"
+#include "llvm/CodeGen/Register.h"
 #include "llvm/InitializePasses.h"
 #include "llvm/Pass.h"
-#include "llvm/Support/CommandLine.h"
+#include "llvm/PassRegistry.h"
+#include "llvm/Support/CodeGen.h"
 #include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/GenericDomTreeConstruction.h"
+#include "llvm/Support/Printable.h"
 #include "llvm/Support/raw_ostream.h"
-#include "llvm/Transforms/Scalar.h"
-#include "llvm/Transforms/Utils.h"
-#include "llvm/Transforms/Utils/BasicBlockUtils.h"
-#include "llvm/Transforms/Utils/Local.h"
-#include "llvm/Transforms/Utils/LoopUtils.h"
-
-#ifndef NDEBUG
-#include "llvm/CodeGen/MachineDominators.h"
-#include "llvm/CodeGen/MachineFunction.h"
-#include "llvm/CodeGen/MachineFunctionPass.h"
-#include "llvm/CodeGen/MachineRegisterInfo.h"
-#endif
 
 using namespace llvm;
 
-#define DEBUG_TYPE "ctrloops"
-
-#ifndef NDEBUG
-static cl::opt<int> CTRLoopLimit("ppc-max-ctrloop", cl::Hidden, cl::init(-1));
-#endif
+#define DEBUG_TYPE "ppc-ctrloops-verify"
 
 namespace {
 
-#ifndef NDEBUG
   struct PPCCTRLoopsVerify : public MachineFunctionPass {
   public:
     static char ID;
 
     PPCCTRLoopsVerify() : MachineFunctionPass(ID) {
       initializePPCCTRLoopsVerifyPass(*PassRegistry::getPassRegistry());
     }
 
     void getAnalysisUsage(AnalysisUsage &AU) const override {
       AU.addRequired<MachineDominatorTree>();
       MachineFunctionPass::getAnalysisUsage(AU);
     }
 
     bool runOnMachineFunction(MachineFunction &MF) override;
 
   private:
     MachineDominatorTree *MDT;
   };
 
   char PPCCTRLoopsVerify::ID = 0;
-#endif // NDEBUG
 } // end anonymous namespace
 
-#ifndef NDEBUG
 INITIALIZE_PASS_BEGIN(PPCCTRLoopsVerify, "ppc-ctr-loops-verify",
                       "PowerPC CTR Loops Verify", false, false)
 INITIALIZE_PASS_DEPENDENCY(MachineDominatorTree)
 INITIALIZE_PASS_END(PPCCTRLoopsVerify, "ppc-ctr-loops-verify",
                     "PowerPC CTR Loops Verify", false, false)
 
 FunctionPass *llvm::createPPCCTRLoopsVerify() {
   return new PPCCTRLoopsVerify();
 }
-#endif // NDEBUG
 
-#ifndef NDEBUG
 static bool clobbersCTR(const MachineInstr &MI) {
   for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) {
     const MachineOperand &MO = MI.getOperand(i);
     if (MO.isReg()) {
       if (MO.isDef() && (MO.getReg() == PPC::CTR || MO.getReg() == PPC::CTR8))
         return true;
     } else if (MO.isRegMask()) {
       if (MO.clobbersPhysReg(PPC::CTR) || MO.clobbersPhysReg(PPC::CTR8))