TempLValue opt: don't insert destroy_addr too early due to ignoring deinit barriers

This can happen for inout arguments. It fixes a potential miscompile, e.g. observable by a weak reference being nil where it shouldn't.

rdar://116335089

Author: eeckstein

lib/SILOptimizer/Transforms/TempLValueOpt.cpp

@@ -18,6 +18,7 @@
 
 #include "swift/SILOptimizer/PassManager/Transforms.h"
 #include "swift/SILOptimizer/Analysis/AliasAnalysis.h"
+#include "swift/SILOptimizer/Analysis/BasicCalleeAnalysis.h"
 #include "swift/SIL/NodeBits.h"
 #include "swift/SIL/SILFunction.h"
 #include "swift/SIL/SILBasicBlock.h"
@@ -176,6 +177,13 @@ void TempLValueOptPass::tempLValueOpt(CopyAddrInst *copyInst) {
   // but a block argument.
   SILInstruction *destRootInst = destRootAddr->getDefiningInstruction();
 
+  bool needDestroyEarly = false;
+  BasicCalleeAnalysis *bca = nullptr;
+  if (!copyInst->isInitializationOfDest()) {
+    needDestroyEarly = true;
+    bca = PM->getAnalysis<BasicCalleeAnalysis>();
+  }
+
   // Iterate over the liferange of the temporary and make some validity checks.
   AliasAnalysis *AA = nullptr;
   SILInstruction *beginOfLiferange = nullptr;
@@ -220,6 +228,9 @@ void TempLValueOptPass::tempLValueOpt(CopyAddrInst *copyInst) {
           // Needed to treat init_existential_addr as not-writing projection.
           projections.contains(inst) == 0)
         return;
+
+      if (needDestroyEarly && isDeinitBarrier(inst, bca))
+        return;
     }
   }
   assert(endOfLiferangeReached);

test/SILOptimizer/templvalueopt_ossa.sil

@@ -1,5 +1,7 @@
 // RUN: %target-sil-opt -enable-sil-verify-all %s -temp-lvalue-opt | %FileCheck %s
 
+// REQUIRES: swift_in_compiler
+
 import Swift
 import Builtin
 
@@ -300,3 +302,35 @@ bb0(%0 : $*T):
   return %78 : $()
 }
 
+sil @createAny : $@convention(thin) () -> @out Any
+sil @createAny_no_barrier : $@convention(thin) () -> @out Any {
+ [global:]
+}
+
+// CHECK-LABEL: sil [ossa] @test_deinit_barrier :
+// CHECK:         copy_addr [take]
+// CHECK-LABEL: } // end sil function 'test_deinit_barrier'
+sil [ossa] @test_deinit_barrier : $@convention(thin) (@guaranteed Any, @inout Any) -> () {
+bb0(%0 : @guaranteed $Any, %1 : $*Any):
+  %2 = alloc_stack $Any
+  %4 = function_ref @createAny : $@convention(thin) () -> @out Any
+  %5 = apply %4(%2) : $@convention(thin) () -> @out Any
+  copy_addr [take] %2 to %1 : $*Any
+  dealloc_stack %2 : $*Any
+  %11 = tuple ()
+  return %11 : $()
+}
+
+// CHECK-LABEL: sil [ossa] @test_no_deinit_barrier :
+// CHECK-NOT:     copy_addr
+// CHECK-LABEL: } // end sil function 'test_no_deinit_barrier'
+sil [ossa] @test_no_deinit_barrier : $@convention(thin) (@guaranteed Any, @inout Any) -> () {
+bb0(%0 : @guaranteed $Any, %1 : $*Any):
+  %2 = alloc_stack $Any
+  %4 = function_ref @createAny_no_barrier : $@convention(thin) () -> @out Any
+  %5 = apply %4(%2) : $@convention(thin) () -> @out Any
+  copy_addr [take] %2 to %1 : $*Any
+  dealloc_stack %2 : $*Any
+  %11 = tuple ()
+  return %11 : $()
+}