Fix MoveOnlyObjectCheckerPImpl::check() changed flag

Extract the special pattern matching logic that is otherwise unrelated to the
check() function. This makes it obvious that the implementation was failing to
set the 'changed' flag whenever needed.

(cherry picked from commit c41715c)

Author: atrick

lib/SILOptimizer/Mandatory/MoveOnlyObjectCheckerUtils.cpp

@@ -185,6 +185,9 @@ struct MoveOnlyObjectCheckerPImpl {
 
   bool
   checkForSameInstMultipleUseErrors(MarkUnresolvedNonCopyableValueInst *base);
+
+  bool eraseMarkWithCopiedOperand(
+    MarkUnresolvedNonCopyableValueInst *markedInst);
 };
 
 } // namespace
@@ -463,9 +466,6 @@ void MoveOnlyObjectCheckerPImpl::check(
   // MarkUnresolvedNonCopyableValueInst in Raw SIL. This ensures we do not
   // miss any.
   //
-  // NOTE: destroys is a separate array that we use to avoid iterator
-  // invalidation when cleaning up destroy_value of guaranteed checked values.
-  SmallVector<DestroyValueInst *, 8> destroys;
   while (!moveIntroducersToProcess.empty()) {
     auto *markedInst = moveIntroducersToProcess.pop_back_val();
 
@@ -475,80 +475,98 @@ void MoveOnlyObjectCheckerPImpl::check(
     if (!diagnosticEmitter.emittedDiagnosticForValue(markedInst)) {
       if (markedInst->getCheckKind() ==
           MarkUnresolvedNonCopyableValueInst::CheckKind::NoConsumeOrAssign) {
-        if (auto *cvi = dyn_cast<CopyValueInst>(markedInst->getOperand())) {
-          auto replacement = cvi->getOperand();
-          auto orig = replacement;
-          if (auto *copyToMoveOnly =
-                  dyn_cast<CopyableToMoveOnlyWrapperValueInst>(orig)) {
-            orig = copyToMoveOnly->getOperand();
-          }
-
-          // TODO: Instead of pattern matching specific code generation patterns,
-          // we should be able to eliminate any `copy_value` whose canonical
-          // lifetime fits within the borrow scope of the borrowed value being
-          // copied from.
-
-          // Handle:
-          //
-          // bb(%arg : @guaranteed $Type):
-          //   %copy = copy_value %arg
-          //   %mark = mark_unresolved_non_copyable_value [no_consume_or_assign] %copy
-          if (auto *arg = dyn_cast<SILArgument>(orig)) {
-            if (arg->getOwnershipKind() == OwnershipKind::Guaranteed) {
-              for (auto *use : markedInst->getConsumingUses()) {
-                destroys.push_back(cast<DestroyValueInst>(use->getUser()));
-              }
-              while (!destroys.empty())
-                destroys.pop_back_val()->eraseFromParent();
-              markedInst->replaceAllUsesWith(replacement);
-              markedInst->eraseFromParent();
-              cvi->eraseFromParent();
-              continue;
-            }
-          }
-
-          // Handle:
-          //
-          //   %1 = load_borrow %0
-          //   %2 = copy_value %1
-          //   %3 = mark_unresolved_non_copyable_value [no_consume_or_assign] %2
-          if (isa<LoadBorrowInst>(orig)) {
-            for (auto *use : markedInst->getConsumingUses()) {
-              destroys.push_back(cast<DestroyValueInst>(use->getUser()));
-            }
-            while (!destroys.empty())
-              destroys.pop_back_val()->eraseFromParent();
-            markedInst->replaceAllUsesWith(replacement);
-            markedInst->eraseFromParent();
-            cvi->eraseFromParent();
-            continue;
-          }
-          
-          // Handle:
-          //   (%yield, ..., %handle) = begin_apply
-          //   %copy = copy_value %yield
-          //   %mark = mark_unresolved_noncopyable_value [no_consume_or_assign] %copy
-          if (isa_and_nonnull<BeginApplyInst>(orig->getDefiningInstruction())) {
-            if (orig->getOwnershipKind() == OwnershipKind::Guaranteed) {
-              for (auto *use : markedInst->getConsumingUses()) {
-                destroys.push_back(cast<DestroyValueInst>(use->getUser()));
-              }
-              while (!destroys.empty())
-                destroys.pop_back_val()->eraseFromParent();
-              markedInst->replaceAllUsesWith(replacement);
-              markedInst->eraseFromParent();
-              cvi->eraseFromParent();
-              continue;
-            }
-          }
+        if (eraseMarkWithCopiedOperand(markedInst)) {
+          changed = true;
+          continue;
         }
       }
+      markedInst->replaceAllUsesWith(markedInst->getOperand());
+      markedInst->eraseFromParent();
+      changed = true;
+    }
+  }
+}
+
+/// Erase a copy_value operand of MarkUnresolvedNonCopyableValueInst.
+bool MoveOnlyObjectCheckerPImpl::eraseMarkWithCopiedOperand(
+  MarkUnresolvedNonCopyableValueInst *markedInst)
+{
+  auto *cvi = dyn_cast<CopyValueInst>(markedInst->getOperand());
+  if (!cvi)
+    return false;
+
+  auto replacement = cvi->getOperand();
+  auto orig = replacement;
+  if (auto *copyToMoveOnly =
+          dyn_cast<CopyableToMoveOnlyWrapperValueInst>(orig)) {
+    orig = copyToMoveOnly->getOperand();
+  }
+
+  // TODO: Instead of pattern matching specific code generation patterns,
+  // we should be able to eliminate any `copy_value` whose canonical
+  // lifetime fits within the borrow scope of the borrowed value being
+  // copied from.
+
+  // NOTE: destroys is a separate array that we use to avoid iterator
+  // invalidation when cleaning up destroy_value of guaranteed checked values.
+  SmallVector<DestroyValueInst *, 8> destroys;
+
+  // Handle:
+  //
+  // bb(%arg : @guaranteed $Type):
+  //   %copy = copy_value %arg
+  //   %mark = mark_unresolved_non_copyable_value [no_consume_or_assign]
+  //   %copy
+  if (auto *arg = dyn_cast<SILArgument>(orig)) {
+    if (arg->getOwnershipKind() == OwnershipKind::Guaranteed) {
+      for (auto *use : markedInst->getConsumingUses()) {
+        destroys.push_back(cast<DestroyValueInst>(use->getUser()));
+      }
+      while (!destroys.empty())
+        destroys.pop_back_val()->eraseFromParent();
+      markedInst->replaceAllUsesWith(replacement);
+      markedInst->eraseFromParent();
+      cvi->eraseFromParent();
+      return true;
     }
+  }
 
-    markedInst->replaceAllUsesWith(markedInst->getOperand());
+  // Handle:
+  //
+  //   %1 = load_borrow %0
+  //   %2 = copy_value %1
+  //   %3 = mark_unresolved_non_copyable_value [no_consume_or_assign] %2
+  if (isa<LoadBorrowInst>(orig)) {
+    for (auto *use : markedInst->getConsumingUses()) {
+      destroys.push_back(cast<DestroyValueInst>(use->getUser()));
+    }
+    while (!destroys.empty())
+      destroys.pop_back_val()->eraseFromParent();
+    markedInst->replaceAllUsesWith(replacement);
     markedInst->eraseFromParent();
-    changed = true;
+    cvi->eraseFromParent();
+    return true;
+  }
+
+  // Handle:
+  //   (%yield, ..., %handle) = begin_apply
+  //   %copy = copy_value %yield
+  //   %mark = mark_unresolved_noncopyable_value [no_consume_or_assign]
+  //   %copy
+  if (isa_and_nonnull<BeginApplyInst>(orig->getDefiningInstruction())) {
+    if (orig->getOwnershipKind() == OwnershipKind::Guaranteed) {
+      for (auto *use : markedInst->getConsumingUses()) {
+        destroys.push_back(cast<DestroyValueInst>(use->getUser()));
+      }
+      while (!destroys.empty())
+        destroys.pop_back_val()->eraseFromParent();
+      markedInst->replaceAllUsesWith(replacement);
+      markedInst->eraseFromParent();
+      cvi->eraseFromParent();
+      return true;
+    }
   }
+  return false;
 }
 
 //===----------------------------------------------------------------------===//