[region-isolation] Just iterate directly over a block state's partition ops rather than use a callback.

There isn't a strong reason to use a callback here since we aren't ever
composing transformations on partition ops. Better instead to go for simplicity
and just iterate directly. If we start doing complex transformations over
partition ops with composable APIs, we can always add this back in later. As a
nice benefit, one doesn't need to worry that the callback API is hiding actual
complexity... since just by using a for loop we communicate that nothing
interesting is happening here.

Just reducing the amount of code surface area in the pass.

Author: gottesmm

lib/SILOptimizer/Mandatory/TransferNonSendable.cpp

@@ -1398,15 +1398,6 @@ class BlockPartitionState {
   }
 
 public:
-  /// Run the passed action on each partitionOp in this block. Action should
-  /// return true iff iteration should continue.
-  void forEachPartitionOp(
-      llvm::function_ref<bool(const PartitionOp &)> action) const {
-    for (const PartitionOp &partitionOp : blockPartitionOps)
-      if (!action(partitionOp))
-        break;
-  }
-
   ArrayRef<PartitionOp> getPartitionOps() const { return blockPartitionOps; }
 
   const Partition &getEntryPartition() const { return entryPartition; }
@@ -1831,15 +1822,15 @@ class RaceTracer {
     if (!targetOp && transferredAtExitReasons.count({SILBlock, transferredVal}))
       return transferredAtExitReasons.at({SILBlock, transferredVal});
 
-    const BlockPartitionState &block = blockStates[SILBlock];
+    const BlockPartitionState &blockState = blockStates[SILBlock];
 
     // If targetOp is null, we're checking why the value is transferred at exit,
     // so assert that it's actually transferred at exit
-    assert(targetOp || block.getExitPartition().isTransferred(transferredVal));
+    assert(targetOp || blockState.getExitPartition().isTransferred(transferredVal));
 
     std::optional<LocalTransferredReason> transferredReason;
 
-    Partition workingPartition = block.getEntryPartition();
+    Partition workingPartition = blockState.getEntryPartition();
 
     // We are looking for a local reason, so if the value is transferred at
     // entry, revive it for the sake of this search.
@@ -1849,10 +1840,10 @@ class RaceTracer {
       eval.apply(PartitionOp::AssignFresh(transferredVal));
     }
 
-    int i = 0;
-    block.forEachPartitionOp([&](const PartitionOp &partitionOp) {
+    for (const auto &partitionOp : blockState.getPartitionOps()) {
       if (targetOp == partitionOp)
-        return false; // break
+        break;
+
       PartitionOpEvaluator eval(workingPartition);
       eval.emitLog = false;
       eval.apply(partitionOp);
@@ -1869,16 +1860,12 @@ class RaceTracer {
       if (!workingPartition.isTransferred(transferredVal) && transferredReason)
         // Value is no longer transferred - e.g. reassigned or assigned fresh.
         transferredReason = llvm::None;
-
-      // continue walking block
-      i++;
-      return true;
-    });
+    }
 
     // If we failed to find a local transfer reason, but the value was
     // transferred at entry to the block, then the reason is "NonLocal".
     if (!transferredReason &&
-        block.getEntryPartition().isTransferred(transferredVal))
+        blockState.getEntryPartition().isTransferred(transferredVal))
       transferredReason = LocalTransferredReason::NonLocal();
 
     // If transferredReason is none, then transferredVal was not actually
@@ -1902,13 +1889,14 @@ class RaceTracer {
 
   bool printBlockSearch(raw_ostream &os, SILBasicBlock *SILBlock,
                         TrackableValueID transferredVal) const {
-    unsigned i = 0;
-    const BlockPartitionState &block = blockStates[SILBlock];
-    Partition working = block.getEntryPartition();
+    const BlockPartitionState &blockState = blockStates[SILBlock];
+    Partition working = blockState.getEntryPartition();
     PartitionOpEvaluator eval(working);
     os << "┌──────────╼\n│ ";
     working.print(os);
-    block.forEachPartitionOp([&](const PartitionOp &op) {
+
+    unsigned i = 0;
+    for (const auto &op : blockState.getPartitionOps()) {
       os << "├[" << i++ << "] ";
       op.print(os);
       eval.apply(op);
@@ -1917,8 +1905,7 @@ class RaceTracer {
         os << "(" << transferredVal << " TRANSFERRED) ";
       }
       working.print(os);
-      return true;
-    });
+    }
     os << "└──────────╼\n";
     return false;
   }