Merge pull request #4606 from swiftix/master

Author: swift-ci

lib/SILOptimizer/Transforms/CSE.cpp

@@ -681,13 +681,48 @@ bool CSE::processOpenExistentialRef(SILInstruction *Inst, ValueBase *V,
   auto &Builder = Cloner.getBuilder();
   Builder.setOpenedArchetypesTracker(&OpenedArchetypesTracker);
 
+  llvm::SmallPtrSet<SILInstruction *, 16> Processed;
   // Now clone each candidate and replace the opened archetype
   // by a dominating one.
-  for (auto Candidate : Candidates) {
+  while (!Candidates.empty()) {
+    auto Candidate = Candidates.pop_back_val();
+    if (Processed.count(Candidate))
+      continue;
+    // True if a candidate depends on the old opened archetype.
+    bool DependsOnOldOpenedArchetype = !Candidate->getTypeDependentOperands().empty();
+    if (!Candidate->use_empty() &&
+        Candidate->getType().getSwiftRValueType()->hasOpenedExistential()) {
+      // Check if the result type of the candidate depends on the opened
+      // existential in question.
+      auto ResultDependsOnOldOpenedArchetype =
+          Candidate->getType().getSwiftRValueType().findIf(
+              [&OldOpenedArchetype](Type t) -> bool {
+                if (t.getCanonicalTypeOrNull() == OldOpenedArchetype)
+                  return true;
+                return false;
+              });
+      if (ResultDependsOnOldOpenedArchetype) {
+        DependsOnOldOpenedArchetype |= ResultDependsOnOldOpenedArchetype;
+        // We need to update uses of this candidate, because their types
+        // may be affected.
+        for (auto Use : Candidate->getUses()) {
+          Candidates.insert(Use->getUser());
+        }
+      }
+    }
+    // Remember that this candidate was processed already.
+    Processed.insert(Candidate);
+
+    // No need to clone if there is no dependency on the old opened archetype.
+    if (!DependsOnOldOpenedArchetype)
+      continue;
+
     Builder.getOpenedArchetypes().addOpenedArchetypeOperands(
         Candidate->getTypeDependentOperands());
     Builder.setInsertionPoint(Candidate);
     auto NewI = Cloner.clone(Candidate);
+    // Result types of candidate's uses instructions may be using this archetype.
+    // Thus, we need to try to replace it there.
     Candidate->replaceAllUsesWith(NewI);
     if (I == Candidate->getIterator())
       I = NewI->getIterator();

test/SILOptimizer/cse.sil

@@ -1325,6 +1325,8 @@ protocol Proto : class {
 }
 
 // Check that all open_existential_ref instructions are CSEd 
+// Any reference to the $@opened("1B685052-4796-11E6-B7DF-B8E856428C60") Proto should be replaced by
+// references to $@opened("1B68354A-4796-11E6-B7DF-B8E856428C60") Proto.
 // CHECK-LABEL: sil @cse_open_existential : $@convention(thin) (@guaranteed Proto, Bool) -> ()
 // CHECK: bb0
 // CHECK: %[[OPENED_EXISTENTIAL:[0-9]+]] = open_existential_ref %{{[0-9]+}} : $Proto to $@opened("1B68354A-4796-11E6-B7DF-B8E856428C60") Proto
@@ -1334,10 +1336,12 @@ protocol Proto : class {
 // CHECK: bb1:
 // CHECK-NEXT: %[[WM2:[0-9]+]] = witness_method $@opened("1B68354A-4796-11E6-B7DF-B8E856428C60") Proto, #Proto.doThat!1
 // CHECK-NEXT: apply %[[WM2]]{{.*}}(%[[OPENED_EXISTENTIAL]])
-// CHECK-NEXT: br bb
+// CHECK-NOT: 1B6851A6-4796-11E6-B7DF-B8E856428C60
+// CHECK: br bb
 // CHECK: bb2:
 // CHECK-NEXT: apply %[[WM1]]{{.*}}(%[[OPENED_EXISTENTIAL]])
-// CHECK-NEXT: br bb
+// CHECK-NOT: 1B6851A6-4796-11E6-B7DF-B8E856428C60
+// CHECK: br bb
 // CHECK: bb3:
 // CHECK-NEXT: tuple
 // CHECK-NEXT: return
@@ -1359,10 +1363,16 @@ bb2:                                              // Preds: bb0
   %13 = open_existential_ref %0 : $Proto to $@opened("1B6851A6-4796-11E6-B7DF-B8E856428C60") Proto
   %14 = witness_method $@opened("1B6851A6-4796-11E6-B7DF-B8E856428C60") Proto, #Proto.doThis!1, %13 : $@opened("1B6851A6-4796-11E6-B7DF-B8E856428C60") Proto : $@convention(witness_method) <τ_0_0 where τ_0_0 : Proto> (@guaranteed τ_0_0) -> ()
   %15 = apply %14<@opened("1B6851A6-4796-11E6-B7DF-B8E856428C60") Proto>(%13) : $@convention(witness_method) <τ_0_0 where τ_0_0 : Proto> (@guaranteed τ_0_0) -> ()
+  %16 = alloc_stack $@opened("1B6851A6-4796-11E6-B7DF-B8E856428C60") Proto
+  store %13 to %16 : $*@opened("1B6851A6-4796-11E6-B7DF-B8E856428C60") Proto
+  // This is to check that result types of instructions are updated by CSE as well.
+  %17 = load %16 : $*@opened("1B6851A6-4796-11E6-B7DF-B8E856428C60") Proto
+  strong_release %17 : $@opened("1B6851A6-4796-11E6-B7DF-B8E856428C60") Proto
+  dealloc_stack %16 : $*@opened("1B6851A6-4796-11E6-B7DF-B8E856428C60") Proto
   br bb3
 
 bb3:
-  %17 = tuple ()
-  return %17 : $()
+  %20 = tuple ()
+  return %20 : $()
 }