[SIL] NFC: Removed visitBorrowIntroUserResults.

It's equivalent to getBorrowIntroducingUserResult except that it's less
convenient to use.  There's only ever one result, so there's no need for
a visitor.  Updated all users to call getBorrowIntroducingUserResult
instead.

Author: nate-chandler

Diff for: include/swift/SIL/OwnershipUtils.h

@@ -440,8 +440,8 @@ struct BorrowingOperand {
   /// values do not themselves introduce a borrow scope. In other words, they
   /// cannot be reborrowed.
   ///
-  /// If true, the visitBorrowIntroducingUserResults() can be called to acquire
-  /// each BorrowedValue that introduces a new borrow scopes.
+  /// If true, getBorrowIntroducingUserResult() can be called to acquire the
+  /// BorrowedValue that introduces a new borrow scope.
   bool hasBorrowIntroducingUser() const {
     // TODO: Can we derive this by running a borrow introducer check ourselves?
     switch (kind) {
@@ -461,16 +461,6 @@ struct BorrowingOperand {
     llvm_unreachable("Covered switch isn't covered?!");
   }
 
-  /// Visit all of the "results" of the user of this operand that are borrow
-  /// scope introducers for the specific scope that this borrow scope operand
-  /// summarizes.
-  ///
-  /// Precondition: hasBorrowIntroducingUser() is true
-  ///
-  /// Returns false and early exits if \p visitor returns false.
-  bool visitBorrowIntroducingUserResults(
-      function_ref<bool(BorrowedValue)> visitor) const;
-
   /// If this operand's user has a single borrowed value result return a
   /// valid BorrowedValue instance.
   BorrowedValue getBorrowIntroducingUserResult() const;

Diff for: lib/SIL/Utils/OwnershipUtils.cpp

@@ -693,42 +693,12 @@ bool BorrowingOperand::visitExtendedScopeEndingUses(
     function_ref<bool(Operand *)> visitor) const {
 
   if (hasBorrowIntroducingUser()) {
-    return visitBorrowIntroducingUserResults(
-        [visitor](BorrowedValue borrowedValue) {
-          return borrowedValue.visitExtendedScopeEndingUses(visitor);
-        });
+    auto borrowedValue = getBorrowIntroducingUserResult();
+    return borrowedValue.visitExtendedScopeEndingUses(visitor);
   }
   return visitScopeEndingUses(visitor);
 }
 
-bool BorrowingOperand::visitBorrowIntroducingUserResults(
-    function_ref<bool(BorrowedValue)> visitor) const {
-  switch (kind) {
-  case BorrowingOperandKind::Invalid:
-    llvm_unreachable("Using invalid case");
-  case BorrowingOperandKind::Apply:
-  case BorrowingOperandKind::TryApply:
-  case BorrowingOperandKind::BeginApply:
-  case BorrowingOperandKind::Yield:
-  case BorrowingOperandKind::PartialApplyStack:
-  case BorrowingOperandKind::BeginAsyncLet:
-    llvm_unreachable("Never has borrow introducer results!");
-  case BorrowingOperandKind::BeginBorrow: {
-    auto value = BorrowedValue(cast<BeginBorrowInst>(op->getUser()));
-    assert(value);
-    return visitor(value);
-  }
-  case BorrowingOperandKind::Branch: {
-    auto *bi = cast<BranchInst>(op->getUser());
-    auto value = BorrowedValue(
-        bi->getDestBB()->getArgument(op->getOperandNumber()));
-    assert(value && "guaranteed-to-unowned conversion not allowed on branches");
-    return visitor(value);
-  }
-  }
-  llvm_unreachable("Covered switch isn't covered?!");
-}
-
 BorrowedValue BorrowingOperand::getBorrowIntroducingUserResult() const {
   switch (kind) {
   case BorrowingOperandKind::Invalid:
@@ -900,11 +870,9 @@ bool BorrowedValue::visitExtendedScopeEndingUses(
 
   auto visitEnd = [&](Operand *scopeEndingUse) {
     if (scopeEndingUse->getOperandOwnership() == OperandOwnership::Reborrow) {
-      BorrowingOperand(scopeEndingUse).visitBorrowIntroducingUserResults(
-        [&](BorrowedValue borrowedValue) {
-          reborrows.insert(borrowedValue.value);
-          return true;
-        });
+      auto borrowedValue =
+          BorrowingOperand(scopeEndingUse).getBorrowIntroducingUserResult();
+      reborrows.insert(borrowedValue.value);
       return true;
     }
     return visitor(scopeEndingUse);
@@ -929,11 +897,9 @@ bool BorrowedValue::visitTransitiveLifetimeEndingUses(
 
   auto visitEnd = [&](Operand *scopeEndingUse) {
     if (scopeEndingUse->getOperandOwnership() == OperandOwnership::Reborrow) {
-      BorrowingOperand(scopeEndingUse)
-          .visitBorrowIntroducingUserResults([&](BorrowedValue borrowedValue) {
-            reborrows.insert(borrowedValue.value);
-            return true;
-          });
+      auto borrowedValue =
+          BorrowingOperand(scopeEndingUse).getBorrowIntroducingUserResult();
+      reborrows.insert(borrowedValue.value);
       // visitor on the reborrow
       return visitor(scopeEndingUse);
     }
@@ -984,16 +950,14 @@ bool BorrowedValue::visitInteriorPointerOperandHelper(
         break;
       }
 
-      borrowingOperand.visitBorrowIntroducingUserResults([&](auto bv) {
-        for (auto *use : bv->getUses()) {
-          if (auto intPtrOperand = InteriorPointerOperand(use)) {
-            func(intPtrOperand);
-            continue;
-          }
-          worklist.push_back(use);
+      auto bv = borrowingOperand.getBorrowIntroducingUserResult();
+      for (auto *use : bv->getUses()) {
+        if (auto intPtrOperand = InteriorPointerOperand(use)) {
+          func(intPtrOperand);
+          continue;
         }
-        return true;
-      });
+        worklist.push_back(use);
+      }
       continue;
     }
 

Diff for: lib/SILOptimizer/SILCombiner/SILCombinerBuiltinVisitors.cpp

@@ -118,10 +118,8 @@ SILCombiner::optimizeBuiltinCOWBufferForReadingOSSA(BuiltinInst *bi) {
     if (auto operand = BorrowingOperand(use)) {
       if (operand.isReborrow())
         return nullptr;
-      operand.visitBorrowIntroducingUserResults([&](BorrowedValue bv) {
-        accumulatedBorrowedValues.push_back(bv);
-        return true;
-      });
+      auto bv = operand.getBorrowIntroducingUserResult();
+      accumulatedBorrowedValues.push_back(bv);
       continue;
     }