Remove getNumUses() comparisons (NFC)

getNumUses() scans the full use list. Don't use it is we only want
to check if there's zero or one uses.

llvm/include/llvm/IR/AbstractCallSite.h

@@ -144,7 +144,7 @@ public:
     // If the use is actually in a constant cast expression which itself
     // has only one use, we look through the constant cast expression.
     if (auto *CE = dyn_cast<ConstantExpr>(U->getUser()))
-      if (CE->getNumUses() == 1 && CE->isCast())
+      if (CE->hasOneUse() && CE->isCast())
         U = &*CE->use_begin();
 
     return (int)CB->getArgOperandNo(U) == CI.ParameterEncoding[0];

llvm/lib/IR/AbstractCallSite.cpp

@@ -64,7 +64,7 @@ AbstractCallSite::AbstractCallSite(const Use *U)
     // This happens by updating the use @p U to the use of the constant
     // cast expression and afterwards re-initializing CB accordingly.
     if (ConstantExpr *CE = dyn_cast<ConstantExpr>(U->getUser()))
-      if (CE->getNumUses() == 1 && CE->isCast()) {
+      if (CE->hasOneUse() && CE->isCast()) {
         U = &*CE->use_begin();
         CB = dyn_cast<CallBase>(U->getUser());
       }

llvm/lib/Transforms/Coroutines/CoroSplit.cpp

@@ -584,7 +584,7 @@ void CoroCloner::replaceEntryBlock() {
   // Move any allocas into Entry that weren't moved into the frame.
   for (auto IT = OldEntry->begin(), End = OldEntry->end(); IT != End;) {
     Instruction &I = *IT++;
-    if (!isa<AllocaInst>(&I) || I.getNumUses() == 0)
+    if (!isa<AllocaInst>(&I) || I.use_empty())
       continue;
 
     I.moveBefore(*Entry, Entry->getFirstInsertionPt());

llvm/lib/Transforms/IPO/Attributor.cpp

@@ -1293,7 +1293,7 @@ static void createShallowWrapper(Function &F) {
   F.setLinkage(GlobalValue::InternalLinkage);
 
   F.replaceAllUsesWith(Wrapper);
-  assert(F.getNumUses() == 0 && "Uses remained after wrapper was created!");
+  assert(F.use_empty() && "Uses remained after wrapper was created!");
 
   // Move the COMDAT section to the wrapper.
   // TODO: Check if we need to keep it for F as well.

llvm/lib/Transforms/IPO/AttributorAttributes.cpp

@@ -897,7 +897,7 @@ ChangeStatus AAReturnedValuesImpl::manifest(Attributor &A) {
 
   // Callback to replace the uses of CB with the constant C.
   auto ReplaceCallSiteUsersWith = [&A](CallBase &CB, Constant &C) {
-    if (CB.getNumUses() == 0)
+    if (CB.use_empty())
       return ChangeStatus::UNCHANGED;
     if (A.changeValueAfterManifest(CB, C))
       return ChangeStatus::CHANGED;
@@ -2267,7 +2267,7 @@ struct AANoAliasFloating final : AANoAliasImpl {
       if (!CI)
         break;
       Value *Base = CI->getOperand(0);
-      if (Base->getNumUses() != 1)
+      if (!Base->hasOneUse())
         break;
       Val = Base;
     } while (true);
@@ -2451,7 +2451,7 @@ struct AANoAliasCallSiteArgument final : AANoAliasImpl {
       Instruction *UserI = cast<Instruction>(U.getUser());
 
       // If user if curr instr and only use.
-      if ((UserI == getCtxI()) && (UserI->getNumUses() == 1))
+      if (UserI == getCtxI() && UserI->hasOneUse())
         return true;
 
       const Function *ScopeFn = VIRP.getAnchorScope();

llvm/lib/Transforms/Scalar/SeparateConstOffsetFromGEP.cpp

@@ -704,7 +704,7 @@ Value *ConstantOffsetExtractor::removeConstOffset(unsigned ChainIndex) {
   }
 
   BinaryOperator *BO = cast<BinaryOperator>(UserChain[ChainIndex]);
-  assert(BO->getNumUses() <= 1 &&
+  assert((BO->use_empty() || BO->hasOneUse()) &&
          "distributeExtsAndCloneChain clones each BinaryOperator in "
          "UserChain, so no one should be used more than "
          "once");