[sil-combine] Enable classify_bridge_object folding when ownership is enabled.

From an ownership perspective, this is just eliminating a non-lifetime ending
use. The new instructions we create are not connecting to the underlying object
anymore.

Author: gottesmm

lib/SILOptimizer/SILCombiner/SILCombinerMiscVisitors.cpp

@@ -2027,26 +2027,20 @@ SILInstruction *SILCombiner::visitMarkDependenceInst(MarkDependenceInst *mdi) {
   return nullptr;
 }
 
-
-SILInstruction *SILCombiner::
-visitClassifyBridgeObjectInst(ClassifyBridgeObjectInst *CBOI) {
-  if (CBOI->getFunction()->hasOwnership())
-    return nullptr;
-
-  auto *URC = dyn_cast<UncheckedRefCastInst>(CBOI->getOperand());
-  if (!URC)
+SILInstruction *
+SILCombiner::visitClassifyBridgeObjectInst(ClassifyBridgeObjectInst *cboi) {
+  auto *urc = dyn_cast<UncheckedRefCastInst>(cboi->getOperand());
+  if (!urc)
     return nullptr;
 
-  auto type = URC->getOperand()->getType().getASTType();
+  auto type = urc->getOperand()->getType().getASTType();
   if (ClassDecl *cd = type->getClassOrBoundGenericClass()) {
     if (!cd->isObjC()) {
       auto int1Ty = SILType::getBuiltinIntegerType(1, Builder.getASTContext());
-      SILValue zero = Builder.createIntegerLiteral(CBOI->getLoc(),
-                                                   int1Ty, 0);
-      return Builder.createTuple(CBOI->getLoc(), { zero, zero });
+      SILValue zero = Builder.createIntegerLiteral(cboi->getLoc(), int1Ty, 0);
+      return Builder.createTuple(cboi->getLoc(), {zero, zero});
     }
   }
 
   return nullptr;
 }
-

test/SILOptimizer/sil_combine_ossa.sil

@@ -4080,11 +4080,12 @@ bb0(%0 : $*Builtin.Int64, %1 : @owned $B):
 
 // Test to see if we can constant fold a classify_bridge_object on a Swift class
 // to false.
-// CHECK-LABEL: sil [ossa] @test_classify_fold
-// XHECK-NOT: classify_bridge_object
-// XHECK: integer_literal $Builtin.Int1, 0
-// XHECK-NEXT: destroy_value
-// XHECK-NEXT: return
+// CHECK-LABEL: sil [ossa] @test_classify_fold :
+// CHECK-NOT: classify_bridge_object
+// CHECK: destroy_value
+// CHECK: [[LITERAL:%.*]] = integer_literal $Builtin.Int1, 0
+// CHECK: return [[LITERAL]]
+// CHECK: } // end sil function 'test_classify_fold'
 sil [ossa] @test_classify_fold : $@convention(thin) (@owned _ContiguousArrayStorage<B>) -> Builtin.Int1 {
 bb0(%0 : @owned $_ContiguousArrayStorage<B>):
   %1 = unchecked_ref_cast %0 : $_ContiguousArrayStorage<B> to $Builtin.BridgeObject
@@ -4094,10 +4095,11 @@ bb0(%0 : @owned $_ContiguousArrayStorage<B>):
   return %3 : $Builtin.Int1
 }
 
-// CHECK-LABEL: sil [ossa] @bridge_cast_noop_fold
-// XHECK: bb0(%0
-// XHECK-NEXT: %1 = upcast %0
-// XHECK-NEXT: return %1
+// CHECK-LABEL: sil [ossa] @bridge_cast_noop_fold :
+// CHECK: bb0(%0
+// CHECK-NEXT: %1 = upcast %0
+// CHECK-NEXT: return %1
+// CHECK: } // end sil function 'bridge_cast_noop_fold'
 sil [ossa] @bridge_cast_noop_fold : $@convention(thin) (@owned _ContiguousArrayStorage<B>) -> @owned __ContiguousArrayStorageBase {
 bb0(%0 : @owned $_ContiguousArrayStorage<B>):
   %1 = unchecked_ref_cast %0 : $_ContiguousArrayStorage<B> to $Builtin.BridgeObject