[HardwareLoops] NFC - move loop with irreducible control flow checking logic to isHardwareLoopProfitable()

[shchenz]

Summary

This is a NFC patch.

Moving the codes to isHardwareLoopProfitable() can avoid duplicated codes for HardwareLoops::TryConvertLoop() and the new added target hook canSaveCmp() in https://reviews.llvm.org/D63477

[samparker]

LGTM, thanks.

[shchenz]

committed in https://reviews.llvm.org/rL364397

[shchenz]

codes moved to class TargetTransformInfo can not be called by both class HardwareLoops and class PPCTargetTransformInfo.
Move the code to class HardwareLoopInfo in NFC patch https://reviews.llvm.org/rL364415. FYI @samparker

llvm/include/llvm/Analysis/TargetTransformInfo.h

public:
   /// Get target-customized preferences for the generic loop unrolling
   /// transformation. The caller will initialize UP with the current
   /// target-independent defaults.
   void getUnrollingPreferences(Loop *L, ScalarEvolution &,
                                UnrollingPreferences &UP) const;
 
   /// Query the target whether it would be profitable to convert the given loop
   /// into a hardware loop.
-  bool isHardwareLoopProfitable(Loop *L, ScalarEvolution &SE,
+  bool isHardwareLoopProfitable(Loop *L, LoopInfo &LI,
+                                ScalarEvolution &SE,
                                 AssumptionCache &AC,
                                 TargetLibraryInfo *LibInfo,
                                 HardwareLoopInfo &HWLoopInfo) const;
 
   /// @}
 
   /// \name Scalar Target Information
   /// @{

llvm/lib/Analysis/TargetTransformInfo.cpp

 #include "llvm/IR/Instruction.h"
 #include "llvm/IR/Instructions.h"
 #include "llvm/IR/IntrinsicInst.h"
 #include "llvm/IR/Module.h"
 #include "llvm/IR/Operator.h"
 #include "llvm/IR/PatternMatch.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/ErrorHandling.h"
+#include "llvm/Analysis/CFG.h"
+#include "llvm/Analysis/LoopIterator.h"
 #include <utility>
 
 using namespace llvm;
 using namespace PatternMatch;
 
 #define DEBUG_TYPE "tti"
 
 static cl::opt<bool> EnableReduxCost("costmodel-reduxcost", cl::init(false),
unsigned TargetTransformInfo::getFlatAddressSpace() const {
   return TTIImpl->getFlatAddressSpace();
 }
 
 bool TargetTransformInfo::isLoweredToCall(const Function *F) const {
   return TTIImpl->isLoweredToCall(F);
 }
 
 bool TargetTransformInfo::isHardwareLoopProfitable(
-  Loop *L, ScalarEvolution &SE, AssumptionCache &AC,
+  Loop *L, LoopInfo &LI, ScalarEvolution &SE, AssumptionCache &AC,
   TargetLibraryInfo *LibInfo, HardwareLoopInfo &HWLoopInfo) const {
+  // If the loop has irreducible control flow, it can not be converted to
+  // Hardware loop.
+  LoopBlocksRPO RPOT(L);  
+  RPOT.perform(&LI);
+  if (containsIrreducibleCFG<const BasicBlock *>(RPOT, LI))
+    return false;
   return TTIImpl->isHardwareLoopProfitable(L, SE, AC, LibInfo, HWLoopInfo);
 }
 
 void TargetTransformInfo::getUnrollingPreferences(
     Loop *L, ScalarEvolution &SE, UnrollingPreferences &UP) const {
   return TTIImpl->getUnrollingPreferences(L, SE, UP);
 }
 

llvm/lib/CodeGen/HardwareLoops.cpp

 ///
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Pass.h"
 #include "llvm/PassRegistry.h"
 #include "llvm/PassSupport.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/Analysis/AssumptionCache.h"
-#include "llvm/Analysis/CFG.h"
 #include "llvm/Analysis/LoopInfo.h"
-#include "llvm/Analysis/LoopIterator.h"
 #include "llvm/Analysis/ScalarEvolution.h"
 #include "llvm/Analysis/ScalarEvolutionExpander.h"
 #include "llvm/Analysis/TargetTransformInfo.h"
 #include "llvm/CodeGen/Passes.h"
 #include "llvm/CodeGen/TargetPassConfig.h"
 #include "llvm/IR/BasicBlock.h"
 #include "llvm/IR/DataLayout.h"
 #include "llvm/IR/Dominators.h"

 // Return true if the search should stop, which will be when an inner loop is
 // converted and the parent loop doesn't support containing a hardware loop.
 bool HardwareLoops::TryConvertLoop(Loop *L) {
   // Process nested loops first.
   for (Loop::iterator I = L->begin(), E = L->end(); I != E; ++I)
     if (TryConvertLoop(*I))
       return true; // Stop search.
 
-  // Bail out if the loop has irreducible control flow.
-  LoopBlocksRPO RPOT(L);
-  RPOT.perform(LI);
-  if (containsIrreducibleCFG<const BasicBlock *>(RPOT, *LI))
-    return false;
-
   HardwareLoopInfo HWLoopInfo(L);
-  if (TTI->isHardwareLoopProfitable(L, *SE, *AC, LibInfo, HWLoopInfo) ||
+  if (TTI->isHardwareLoopProfitable(L, *LI, *SE, *AC, LibInfo, HWLoopInfo) ||
       ForceHardwareLoops) {
 
     // Allow overriding of the counter width and loop decrement value.
     if (CounterBitWidth.getNumOccurrences())
       HWLoopInfo.CountType =
         IntegerType::get(M->getContext(), CounterBitWidth);
 
     if (LoopDecrement.getNumOccurrences())