From 2dea3ca3fc77533c28dead0e25fd76cc37b453f6 Mon Sep 17 00:00:00 2001
From: Kavon Farvardin <kfarvardin@apple.com>
Date: Tue, 16 Sep 2025 14:33:43 -0700
Subject: [PATCH] sil: load [copy] affects reference counting

Based on what I see from OwnershipModelEliminator,
`%x = load [copy] %y` can turn into a plain load
followed by a retain of the loaded value.

See `NonTrivialLoadableTypeLowering::emitLoad`
---
 docs/SIL/Instructions.md           | 6 +++---
 lib/SIL/Utils/InstructionUtils.cpp | 9 ++++++++-
 2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/docs/SIL/Instructions.md b/docs/SIL/Instructions.md
index d9fd4a00ceb7c..e4bbe28a3b072 100644
--- a/docs/SIL/Instructions.md
+++ b/docs/SIL/Instructions.md
@@ -832,7 +832,7 @@ load-ownership-kind ::= 'take'
 ```
 
 Loads the value at address `%0` from memory. `T` must be a loadable
-type. This does not affect the reference count, if any, of the loaded
+type. An unqualified load does not affect the reference count, if any, of the loaded
 value; the value must be retained explicitly if necessary. It is
 undefined behavior to load from uninitialized memory or to load from an
 address that points to deallocated storage.
@@ -840,8 +840,8 @@ address that points to deallocated storage.
 In OSSA the ownership kind specifies how to handle ownership:
 -  **trivial**: the loaded value is trivial and no further action must be taken
                 than to load the raw bits of the value
--  **copy**: the loaded value is copied and the original value stays in the
-             memory location.
+-  **copy**: the loaded value is copied (e.g., retained) and the original value
+                stays in the memory location.
 -  **take**: the value is _moved_ from the memory location without copying.
              After the `load`, the memory location remains uninitialized.
 
diff --git a/lib/SIL/Utils/InstructionUtils.cpp b/lib/SIL/Utils/InstructionUtils.cpp
index c4c569b79a10f..60e73bf267ee6 100644
--- a/lib/SIL/Utils/InstructionUtils.cpp
+++ b/lib/SIL/Utils/InstructionUtils.cpp
@@ -552,7 +552,6 @@ RuntimeEffect swift::getRuntimeEffect(SILInstruction *inst, SILType &impactType)
   case SILInstructionKind::CopyableToMoveOnlyWrapperValueInst:
   case SILInstructionKind::MoveOnlyWrapperToCopyableValueInst:
   case SILInstructionKind::UncheckedOwnershipConversionInst:
-  case SILInstructionKind::LoadInst:
   case SILInstructionKind::LoadBorrowInst:
   case SILInstructionKind::BeginBorrowInst:
   case SILInstructionKind::BorrowedFromInst:
@@ -626,6 +625,14 @@ RuntimeEffect swift::getRuntimeEffect(SILInstruction *inst, SILType &impactType)
   case SILInstructionKind::TypeValueInst:
   case SILInstructionKind::IgnoredUseInst:
     return RuntimeEffect::NoEffect;
+
+  case SILInstructionKind::LoadInst: {
+    if (cast<LoadInst>(inst)->getOwnershipQualifier() == LoadOwnershipQualifier::Copy) {
+      return ifNonTrivial(inst->getOperand(0)->getType(),
+                          RuntimeEffect::RefCounting);
+    }
+    return RuntimeEffect::NoEffect;
+  }
       
   case SILInstructionKind::OpenExistentialMetatypeInst:
   case SILInstructionKind::OpenExistentialBoxInst: