Bailout of DestroyHoisting if there were no hoistable destroys

Otherwise, DestroyHoisting attemps to compute interior liveness
and inserts destoys at the ends. CanonicalizeOSSALifetimes is
designed to do this and not DestroyHoisting.

Author: meg-gupta

SwiftCompilerSources/Sources/Optimizer/FunctionPasses/DestroyHoisting.swift

@@ -88,9 +88,13 @@ private func optimize(value: Value, _ context: FunctionPassContext) {
     return
   }
 
-  var hoistableDestroys = selectHoistableDestroys(of: value, context)
+  var (foundDestroys, hoistableDestroys) = selectHoistableDestroys(of: value, context)
   defer { hoistableDestroys.deinitialize() }
 
+  guard foundDestroys else {
+    return
+  }
+
   guard var minimalLiverange = InstructionRange(withLiverangeOf: value, ignoring: hoistableDestroys, context) else {
     return
   }
@@ -99,12 +103,13 @@ private func optimize(value: Value, _ context: FunctionPassContext) {
   hoistDestroys(of: value, toEndOf: minimalLiverange, restrictingTo: &hoistableDestroys, context)
 }
 
-private func selectHoistableDestroys(of value: Value, _ context: FunctionPassContext) -> InstructionSet {
+private func selectHoistableDestroys(of value: Value, _ context: FunctionPassContext) -> (Bool, InstructionSet) {
   // Also includes liveranges of copied values and values stored to memory.
   var forwardExtendedLiverange = InstructionRange(withForwardExtendedLiverangeOf: value, context)
   defer { forwardExtendedLiverange.deinitialize() }
 
   let deadEndBlocks = context.deadEndBlocks
+  var foundDestroys = false
   var hoistableDestroys = InstructionSet(context)
 
   for use in value.uses {
@@ -114,10 +119,11 @@ private func selectHoistableDestroys(of value: Value, _ context: FunctionPassCon
        // TODO: once we have complete OSSA lifetimes we don't need to handle dead-end blocks.
        !deadEndBlocks.isDeadEnd(destroy.parentBlock)
     {
+      foundDestroys = true
       hoistableDestroys.insert(destroy)
     }
   }
-  return hoistableDestroys
+  return (foundDestroys, hoistableDestroys)
 }
 
 private func hoistDestroys(of value: Value,

test/SILOptimizer/rdar146142041.sil

@@ -1,4 +1,4 @@
-// RUN: %target-sil-opt -enable-sil-verify-all %s -semantic-arc-opts | %FileCheck %s
+// RUN: %target-sil-opt -enable-sil-verify-all %s -semantic-arc-opts -destroy-hoisting | %FileCheck %s
 
 import Swift
 
@@ -13,6 +13,7 @@ struct NonTrivial {
 
 sil @foo : $@convention(thin) (@inout_aliasable Optional<NonTrivial>) -> ()
 
+// test1 is the reduction from rdar://146142041. test2 and test3 are mutations of test1 and may not be created from swift code in practice
 // CHECK-LABEL: sil [ossa] @test1 :
 // CHECK: [[PA:%.*]] = partial_apply
 // CHECK: [[COPY:%.*]] = copy_value [[PA]] 
@@ -111,3 +112,48 @@ bb8:
   return %24
 }
 
+// Ensure no ownership verification error 
+sil [ossa] @test3 : $@convention(thin) () -> () {
+bb0:
+  cond_br undef, bb2, bb1
+
+bb1:
+  %1 = enum $Optional<@callee_guaranteed () -> ()>, #Optional.none!enumelt
+  br bb7(%1)
+
+bb2:
+  br bb3
+
+bb3:
+  %4 = alloc_box ${ var Optional<NonTrivial> }
+  %5 = begin_borrow [lexical] %4
+  %6 = project_box %5, 0
+  inject_enum_addr %6, #Optional.none!enumelt
+  cond_br undef, bb4, bb5
+
+bb4:
+  unreachable
+
+bb5:
+  br bb6
+
+bb6:
+  %11 = function_ref @foo : $@convention(thin) (@inout_aliasable Optional<NonTrivial>) -> ()
+  %12 = partial_apply [callee_guaranteed] %11(%6) : $@convention(thin) (@inout_aliasable Optional<NonTrivial>) -> ()
+  %13 = copy_value %12
+  %14 = convert_escape_to_noescape %13 to $@noescape @callee_guaranteed () -> ()
+  %15 = enum $Optional<@callee_guaranteed () -> ()>, #Optional.some!enumelt, %13
+  end_borrow %5
+  destroy_value %4
+  destroy_value %12
+  destroy_value %14
+  br bb7(%15)
+
+bb7(%21 : @owned $Optional<@callee_guaranteed () -> ()>):
+  destroy_value %21
+  br bb8
+
+bb8:
+  %24 = tuple ()
+  return %24
+}