[LegacyPM] Remove LowerWidenableConditionLegacyPass

[nikic]

This sounds like a backend pass for out-of-tree usage, so we might have to keep the legacy version.

[anna]

This sounds like a backend pass for out-of-tree usage, so we might have to keep the legacy version

In our custom pipeline downstream, we enable this pass late in our opt pipeline So, this change wouldn't affect us. However, in the LangRef, we state it can be lowered pretty late - which means someone (any other downstream users, if any?) can lower it under TargetPassConfig::addIRPasses for example.

llvm/include/llvm/InitializePasses.h

 void initializeLoopStrengthReducePass(PassRegistry&);
 void initializeLoopUnrollPass(PassRegistry&);
 void initializeLowerAtomicLegacyPassPass(PassRegistry&);
 void initializeLowerConstantIntrinsicsPass(PassRegistry&);
 void initializeLowerEmuTLSPass(PassRegistry&);
 void initializeLowerExpectIntrinsicPass(PassRegistry&);
 void initializeLowerGlobalDtorsLegacyPassPass(PassRegistry &);
 void initializeLowerGuardIntrinsicLegacyPassPass(PassRegistry&);
-void initializeLowerWidenableConditionLegacyPassPass(PassRegistry&);
 void initializeLowerIntrinsicsPass(PassRegistry&);
 void initializeLowerInvokeLegacyPassPass(PassRegistry&);
 void initializeLowerSwitchLegacyPassPass(PassRegistry &);
 void initializeKCFIPass(PassRegistry &);
 void initializeMIRAddFSDiscriminatorsPass(PassRegistry &);
 void initializeMIRCanonicalizerPass(PassRegistry &);
 void initializeMIRNamerPass(PassRegistry &);
 void initializeMIRPrintingPassPass(PassRegistry&);

llvm/include/llvm/Transforms/Scalar.h

 //===----------------------------------------------------------------------===//
 //
 // LowerGuardIntrinsic - Lower guard intrinsics to normal control flow.
 //
 Pass *createLowerGuardIntrinsicPass();
 
 //===----------------------------------------------------------------------===//
 //
-// LowerWidenableCondition - Lower widenable condition to i1 true.
-//
-Pass *createLowerWidenableConditionPass();
-
-//===----------------------------------------------------------------------===//
-//
 // MergeICmps - Merge integer comparison chains into a memcmp
 //
 Pass *createMergeICmpsLegacyPass();
 
 //===----------------------------------------------------------------------===//
 //
 // InferAddressSpaces - Modify users of addrspacecast instructions with values
 // in the source address space if using the destination address space is slower

llvm/lib/Transforms/Scalar/LowerWidenableCondition.cpp

 #include "llvm/IR/Module.h"
 #include "llvm/IR/PatternMatch.h"
 #include "llvm/InitializePasses.h"
 #include "llvm/Pass.h"
 #include "llvm/Transforms/Scalar.h"
 
 using namespace llvm;
 
-namespace {
-struct LowerWidenableConditionLegacyPass : public FunctionPass {
-  static char ID;
-  LowerWidenableConditionLegacyPass() : FunctionPass(ID) {
-    initializeLowerWidenableConditionLegacyPassPass(
-        *PassRegistry::getPassRegistry());
-  }
-
-  bool runOnFunction(Function &F) override;
-};
-}
-
 static bool lowerWidenableCondition(Function &F) {
   // Check if we can cheaply rule out the possibility of not having any work to
   // do.
   auto *WCDecl = F.getParent()->getFunction(
       Intrinsic::getName(Intrinsic::experimental_widenable_condition));
   if (!WCDecl || WCDecl->use_empty())
     return false;
 
static bool lowerWidenableCondition(Function &F) {
 
   for (auto *CI : ToLower) {
     CI->replaceAllUsesWith(ConstantInt::getTrue(CI->getContext()));
     CI->eraseFromParent();
   }
   return true;
 }
 
-bool LowerWidenableConditionLegacyPass::runOnFunction(Function &F) {
-  return lowerWidenableCondition(F);
-}
-
-char LowerWidenableConditionLegacyPass::ID = 0;
-INITIALIZE_PASS(LowerWidenableConditionLegacyPass, "lower-widenable-condition",
-                "Lower the widenable condition to default true value", false,
-                false)
-
-Pass *llvm::createLowerWidenableConditionPass() {
-  return new LowerWidenableConditionLegacyPass();
-}
-
 PreservedAnalyses LowerWidenableConditionPass::run(Function &F,
                                                FunctionAnalysisManager &AM) {
   if (lowerWidenableCondition(F))
     return PreservedAnalyses::none();
 
   return PreservedAnalyses::all();
 }

llvm/lib/Transforms/Scalar/Scalar.cpp

void llvm::initializeScalarOpts(PassRegistry &Registry) {
   initializeLoopPredicationLegacyPassPass(Registry);
   initializeLoopRotateLegacyPassPass(Registry);
   initializeLoopStrengthReducePass(Registry);
   initializeLoopUnrollPass(Registry);
   initializeLowerAtomicLegacyPassPass(Registry);
   initializeLowerConstantIntrinsicsPass(Registry);
   initializeLowerExpectIntrinsicPass(Registry);
   initializeLowerGuardIntrinsicLegacyPassPass(Registry);
-  initializeLowerWidenableConditionLegacyPassPass(Registry);
   initializeMergeICmpsLegacyPassPass(Registry);
   initializeMergedLoadStoreMotionLegacyPassPass(Registry);
   initializeNaryReassociateLegacyPassPass(Registry);
   initializePartiallyInlineLibCallsLegacyPassPass(Registry);
   initializeReassociateLegacyPassPass(Registry);
   initializeRedundantDbgInstEliminationPass(Registry);
   initializeRegToMemLegacyPass(Registry);
   initializeScalarizeMaskedMemIntrinLegacyPassPass(Registry);