LoadableByAddress: Only replace yielded values with a load if required by users

rdar://46372278

Author: aschwaighofer

lib/IRGen/LoadableByAddress.cpp

@@ -2453,8 +2453,10 @@ void LoadableByAddress::recreateSingleApply(SILInstruction *applyInst) {
       SILValue oldValue = oldYieldedValues[i];
       SILValue newValue = newYieldedValues[i];
 
-      // For now, just replace the value with an immediate load.
-      if (oldValue->getType() != newValue->getType()) {
+      // For now, just replace the value with an immediate load if the old value
+      // was direct.
+      if (oldValue->getType() != newValue->getType() &&
+          !oldValue->getType().isAddress()) {
         LoadOwnershipQualifier ownership;
         if (!F->hasQualifiedOwnership()) {
           ownership = LoadOwnershipQualifier::Unqualified;

test/IRGen/big_types_coroutine.sil

@@ -1,4 +1,4 @@
-// RUN: %target-sil-opt -loadable-address -enable-sil-verify-all %s | %FileCheck %s
+// RUN: %target-sil-opt -assume-parsing-unqualified-ownership-sil -loadable-address -enable-sil-verify-all %s | %FileCheck %s
 
 // REQUIRES: CPU=x86_64
 // REQUIRES: OS=macosx
@@ -57,8 +57,8 @@ unwind:
 // CHECK-NEXT:    [[CORO:%.*]] = function_ref @test_yield_big : $@yield_once @convention(thin) () -> @yields @in_constant BigStruct
 // CHECK-NEXT:    ([[ADDR:%.*]], [[TOKEN:%.*]]) = begin_apply [[CORO]]()
 //   TODO: this isn't very efficient
-// CHECK-NEXT:    [[T0:%.*]] = load [trivial] [[ADDR]] : $*BigStruct
-// CHECK-NEXT:    store [[T0]] to [trivial] [[TEMP]] : $*BigStruct
+// CHECK-NEXT:    [[T0:%.*]] = load [[ADDR]] : $*BigStruct
+// CHECK-NEXT:    store [[T0]] to [[TEMP]] : $*BigStruct
 // CHECK-NEXT:    // function_ref
 // CHECK-NEXT:    [[USE:%.*]] = function_ref @use_big_struct : $@convention(thin) (@in_constant BigStruct) -> ()
 // CHECK-NEXT:    apply [[USE]]([[TEMP]])
@@ -76,3 +76,24 @@ entry:
   %ret = tuple ()
   return %ret : $()
 }
+
+sil @yield_fun_ptr2 : $@yield_once @convention(thin) () -> @yields @inout Optional<@callee_guaranteed (@guaranteed BigStruct) -> ()>
+
+// CHECK-LABEL: sil @yield_funptr : $
+// CHECK: (%1, %2) = begin_apply %0() : $@yield_once @convention(thin) () -> @yields @inout Optional<@callee_guaranteed (@in_guaranteed BigStruct) -> ()>
+// CHECK: yield %1
+sil @yield_funptr : $@yield_once @convention(thin) () -> @yields @inout Optional<@callee_guaranteed (@guaranteed BigStruct) -> ()> {
+bb0:
+  %2 = function_ref @yield_fun_ptr2 : $@yield_once @convention(thin) () -> @yields @inout Optional<@callee_guaranteed (@guaranteed BigStruct) -> ()>
+  (%3, %4) = begin_apply %2() : $@yield_once @convention(thin) () -> @yields @inout Optional<@callee_guaranteed (@guaranteed BigStruct) -> ()>
+  yield %3 : $*Optional<@callee_guaranteed (@guaranteed BigStruct) -> ()>, resume bb1, unwind bb2
+
+bb1:
+  end_apply %4
+  %7 = tuple ()
+  return %7 : $()
+
+bb2:
+  abort_apply %4
+  unwind
+}