Enable the CopyPropagation pass.

For now simply run the pass before SemanticARCOpts. This will probably
be called as a utility from within SemanticARCOpts so it can be
iteratively applied after other ARC-related transformations.

Author: atrick

lib/SILOptimizer/PassManager/PassPipeline.cpp

@@ -304,6 +304,7 @@ void addFunctionPasses(SILPassPipelinePlan &P,
 
   // We earlier eliminated ownership if we are not compiling the stdlib. Now
   // handle the stdlib functions, re-simplifying, eliminating ARC as we do.
+  P.addCopyPropagation();
   P.addSemanticARCOpts();
   P.addNonTransparentFunctionOwnershipModelEliminator();
 
@@ -447,6 +448,7 @@ static void addPerfEarlyModulePassPipeline(SILPassPipelinePlan &P) {
   // Cleanup after SILGen: remove trivial copies to temporaries.
   P.addTempRValueOpt();
   // Cleanup after SILGen: remove unneeded borrows/copies.
+  P.addCopyPropagation();
   P.addSemanticARCOpts();
 
   // Devirtualizes differentiability witnesses into functions that reference them.

stdlib/public/core/StringObject.swift

@@ -207,6 +207,7 @@ extension _StringObject {
   internal init(
     object: AnyObject, discriminator: UInt64, countAndFlags: CountAndFlags
   ) {
+    defer { _fixLifetime(object) }
     let builtinRawObject: Builtin.Int64 = Builtin.reinterpretCast(object)
     let builtinDiscrim: Builtin.Int64 = discriminator._value
     self.init(

test/SILOptimizer/OSLogFullOptTest.swift

@@ -140,6 +140,7 @@ func testNSObjectInterpolation(nsArray: NSArray) {
     // CHECK: [[NOT_ENABLED]]:
     // CHECK-NEXT: tail call void @swift_release
     // CHECK-NEXT: tail call void @llvm.objc.release
+    // CHECK-NEXT: tail call void @llvm.objc.release
     // CHECK-NEXT: br label %[[EXIT:[0-9]+]]
 
     // CHECK: [[ENABLED]]:
@@ -170,7 +171,7 @@ func testNSObjectInterpolation(nsArray: NSArray) {
     // CHECK-NEXT: [[BITCASTED_SRC2:%.+]] = bitcast i8* [[NSARRAY_ARG]] to %TSo7NSArrayC*
     // CHECK-64-NEXT: store %TSo7NSArrayC* [[BITCASTED_SRC2]], %TSo7NSArrayC** [[BITCASTED_DEST2]], align 8
     // CHECK-32-NEXT: store %TSo7NSArrayC* [[BITCASTED_SRC2]], %TSo7NSArrayC** [[BITCASTED_DEST2]], align 4
-
+    // CHECK-NEXT: tail call void @llvm.objc.release
     // CHECK-64-NEXT: tail call swiftcc void @"${{.*}}_os_log_impl_test{{.*}}"({{.*}}, {{.*}}, {{.*}}, {{.*}}, i8* getelementptr inbounds ([20 x i8], [20 x i8]* @{{.*}}, i64 0, i64 0), i8* {{(nonnull )?}}[[BUFFER]], i32 12)
     // CHECK-32-NEXT: tail call swiftcc void @"${{.*}}_os_log_impl_test{{.*}}"({{.*}}, {{.*}}, {{.*}}, {{.*}}, i8* getelementptr inbounds ([20 x i8], [20 x i8]* @{{.*}}, i32 0, i32 0), i8* {{(nonnull )?}}[[BUFFER]], i32 8)
     // CHECK-NEXT: [[BITCASTED_OBJ_STORAGE:%.+]] = bitcast i8* [[OBJ_STORAGE]] to %swift.opaque*
@@ -181,7 +182,6 @@ func testNSObjectInterpolation(nsArray: NSArray) {
     // CHECK-NEXT: br label %[[EXIT]]
 
     // CHECK: [[EXIT]]:
-    // CHECK-NEXT: tail call void @llvm.objc.release(i8* [[NSARRAY_ARG]])
     // CHECK-NEXT: ret void
 }
 
@@ -349,7 +349,6 @@ func testMetatypeInterpolation<T>(of type: T.Type) {
 
     // CHECK: [[NOT_ENABLED]]:
     // CHECK-NEXT: call void @swift_release
-    // CHECK-NEXT: br label %[[EXIT:[0-9]+]]
 
     // CHECK: [[ENABLED]]:
     //