Merge pull request swiftlang#23089 from gottesmm/pr-71f5c35dee085d55e543277b2c59a6e48f16840b

Author: swift-ci

include/swift/SIL/SILBuilder.h

@@ -2257,18 +2257,45 @@ class SILBuilderWithScope : public SILBuilder {
 };
 
 class SavedInsertionPointRAII {
-  SILBuilder &Builder;
-  PointerUnion<SILInstruction *, SILBasicBlock *> SavedIP;
+  SILBuilder &builder;
+  PointerUnion<SILInstruction *, SILBasicBlock *> savedInsertionPoint;
 
 public:
-  SavedInsertionPointRAII(SILBuilder &B, SILInstruction *NewIP)
-      : Builder(B), SavedIP(&*B.getInsertionPoint()) {
-    Builder.setInsertionPoint(NewIP);
+  /// Constructor that saves a Builder's insertion point without changing the
+  /// builder's underlying insertion point.
+  SavedInsertionPointRAII(SILBuilder &B) : builder(B), savedInsertionPoint() {
+    // If our builder does not have a valid insertion point, just put nullptr
+    // into SavedIP.
+    if (!builder.hasValidInsertionPoint()) {
+      savedInsertionPoint = static_cast<SILBasicBlock *>(nullptr);
+      return;
+    }
+
+    // If we are inserting into the end of the block, stash the insertion block.
+    if (builder.insertingAtEndOfBlock()) {
+      savedInsertionPoint = builder.getInsertionBB();
+      return;
+    }
+
+    // Otherwise, stash the instruction.
+    SILInstruction *i = &*builder.getInsertionPoint();
+    savedInsertionPoint = i;
+  }
+
+  SavedInsertionPointRAII(SILBuilder &b, SILInstruction *insertionPoint)
+      : SavedInsertionPointRAII(b) {
+    builder.setInsertionPoint(insertionPoint);
+  }
+
+  SavedInsertionPointRAII(SILBuilder &b, SILBasicBlock *block,
+                          SILBasicBlock::iterator iter)
+      : SavedInsertionPointRAII(b) {
+    builder.setInsertionPoint(block, iter);
   }
 
-  SavedInsertionPointRAII(SILBuilder &B, SILBasicBlock *NewIP)
-      : Builder(B), SavedIP(B.getInsertionBB()) {
-    Builder.setInsertionPoint(NewIP);
+  SavedInsertionPointRAII(SILBuilder &b, SILBasicBlock *insertionBlock)
+      : SavedInsertionPointRAII(b) {
+    builder.setInsertionPoint(insertionBlock);
   }
 
   SavedInsertionPointRAII(const SavedInsertionPointRAII &) = delete;
@@ -2277,12 +2304,12 @@ class SavedInsertionPointRAII {
   SavedInsertionPointRAII &operator=(SavedInsertionPointRAII &&) = delete;
 
   ~SavedInsertionPointRAII() {
-    if (SavedIP.isNull()) {
-      Builder.clearInsertionPoint();
-    } else if (SavedIP.is<SILInstruction *>()) {
-      Builder.setInsertionPoint(SavedIP.get<SILInstruction *>());
+    if (savedInsertionPoint.isNull()) {
+      builder.clearInsertionPoint();
+    } else if (savedInsertionPoint.is<SILInstruction *>()) {
+      builder.setInsertionPoint(savedInsertionPoint.get<SILInstruction *>());
     } else {
-      Builder.setInsertionPoint(SavedIP.get<SILBasicBlock *>());
+      builder.setInsertionPoint(savedInsertionPoint.get<SILBasicBlock *>());
     }
   }
 };