Merge pull request #64881 from nate-chandler/copy-propagation/forward-owned-lexical-values

[CanonicalizeOSSALifetime] Transfer lexical value into callee.

Author: nate-chandler

lib/SILOptimizer/Utils/CanonicalizeOSSALifetime.cpp

@@ -257,7 +257,23 @@ void CanonicalizeOSSALifetime::extendLivenessToDeinitBarriers() {
                        [&](auto *inst) {
                          if (inst == def)
                            return true;
-                         return isDeinitBarrier(inst, calleeAnalysis);
+                         if (!isDeinitBarrier(inst, calleeAnalysis))
+                           return false;
+                         // For the most part, instructions that are deinit
+                         // barriers in the abstract are also deinit barriers
+                         // for the purposes of canonicalizing def's lifetime.
+                         //
+                         // There is an important exception: transferring an
+                         // owned lexical lifetime into a callee.  If the
+                         // instruction is a full apply which consumes def,
+                         // then it isn't a deinit barrier.  Keep looking for
+                         // barriers above it.
+                         auto apply = FullApplySite::isa(inst);
+                         if (!apply)
+                           return true;
+                         return liveness->isInterestingUser(inst) !=
+                                PrunedLiveness::IsInterestingUser::
+                                    LifetimeEndingUse;
                        });
   for (auto *barrier : barriers.instructions) {
     liveness->updateForUse(barrier, /*lifetimeEnding*/ false);

test/SILOptimizer/copy_propagation.sil

@@ -22,6 +22,7 @@ sil [ossa] @getOwnedC : $@convention(thin) () -> (@owned C)
 sil [ossa] @getOwnedB : $@convention(thin) () -> (@owned B)
 sil [ossa] @takeOwnedC : $@convention(thin) (@owned C) -> ()
 sil [ossa] @takeOwnedCTwice : $@convention(thin) (@owned C, @owned C) -> ()
+sil [ossa] @takeOwnedCAndGuaranteedC : $@convention(thin) (@owned C, @guaranteed C) -> ()
 sil [ossa] @takeGuaranteedC : $@convention(thin) (@guaranteed C) -> ()
 sil [ossa] @borrowB : $@convention(thin) (@guaranteed B) -> ()
 sil [ossa] @takeGuaranteedAnyObject : $@convention(thin) (@guaranteed AnyObject) -> ()
@@ -1016,3 +1017,33 @@ entry(%instance : @owned $C):
   %retval = tuple ()
   return %retval : $()
 }
+
+// CHECK-LABEL: sil [ossa] @forward_owned_lexical_value_to_callee : {{.*}} {
+// CHECK-NOT:     copy_value
+// CHECK-LABEL: } // end sil function 'forward_owned_lexical_value_to_callee'
+sil [ossa] @forward_owned_lexical_value_to_callee : $@convention(thin) (@owned C) -> () {
+entry(%instance : @owned $C):
+  %copy = copy_value %instance : $C
+  %consume = function_ref @takeOwnedC : $@convention(thin) (@owned C) -> ()
+  apply %consume(%copy) : $@convention(thin) (@owned C) -> ()
+  destroy_value %instance : $C
+  %retval = tuple ()
+  return %retval : $()
+}
+
+// CHECK-LABEL: sil [ossa] @cantForwardBecauseBorrowing : {{.*}} {
+// CHECK:       {{bb[0-9]+}}([[INSTANCE:%[^,]+]] :
+// CHECK:         [[COPY:%[^,]+]] = copy_value [[INSTANCE]]
+// CHECK:         [[CONSUME_AND_BORROW:%[^,]+]] = function_ref @takeOwnedCAndGuaranteedC
+// CHECK:         apply [[CONSUME_AND_BORROW]]([[COPY]], [[INSTANCE]])
+// CHECK:         destroy_value [[INSTANCE]]
+// CHECK-LABEL: } // end sil function 'cantForwardBecauseBorrowing'
+sil [ossa] @cantForwardBecauseBorrowing :$@convention(thin) (@owned C) -> () {
+entry(%instance : @owned $C):
+  %copy = copy_value %instance : $C
+  %consumeAndBorrow = function_ref @takeOwnedCAndGuaranteedC : $@convention(thin) (@owned C, @guaranteed C) -> ()
+  apply %consumeAndBorrow(%copy, %instance) : $@convention(thin) (@owned C, @guaranteed C) -> ()
+  destroy_value %instance : $C
+  %retval = tuple ()
+  return %retval : $()
+}