---

yaml
---
r: 340969
b: refs/heads/rxwei-patch-1
c: d788bba
h: refs/heads/master
i:
  340967: 2aedf0e

Author: dan-zheng

[refs]

@@ -1015,7 +1015,7 @@ refs/tags/swift-DEVELOPMENT-SNAPSHOT-2018-08-18-a: b10b1fce14385faa6d44f6b933e95
 refs/heads/rdar-43033749-fix-batch-mode-no-diags-swift-5.0-branch: a14e64eaad30de89f0f5f0b2a782eed7ecdcb255
 refs/heads/revert-19006-error-bridging-integer-type: 8a9065a3696535305ea53fe9b71f91cbe6702019
 refs/heads/revert-19050-revert-19006-error-bridging-integer-type: ecf752d54b05dd0a20f510f0bfa54a3fec3bcaca
-refs/heads/rxwei-patch-1: b4483dac64121a60ee46a8f28f3c29ddf1c1abf5
+refs/heads/rxwei-patch-1: d788bba41ec71f7d42bf61d1f080c5e79a211172
 refs/heads/shahmishal-patch-1: e58ec0f7488258d42bef51bc3e6d7b3dc74d7b2a
 refs/heads/typelist-existential: 4046359efd541fb5c72d69a92eefc0a784df8f5e
 refs/tags/swift-4.2-DEVELOPMENT-SNAPSHOT-2018-08-20-a: 4319ba09e4fb8650ee86061075c74a016b6baab9

branches/rxwei-patch-1/lib/Serialization/Serialization.cpp

@@ -2040,7 +2040,24 @@ bool Serializer::isDeclXRef(const Decl *D) const {
   // Special-case for SIL generic parameter decls, which don't have a real
   // DeclContext.
   if (!isa<FileUnit>(topLevel)) {
-    assert(isa<GenericTypeParamDecl>(D) && "unexpected decl kind");
+    // SWIFT_ENABLE_TENSORFLOW
+    // FIXME(TF-623): Find a robust way to special-casing structs/enums
+    // synthesized during SIL differentiation transform.
+    auto isDifferentiationDataStructure = [](const Decl *D) {
+      auto *valueDecl = dyn_cast<ValueDecl>(D);
+      if (!valueDecl)
+        return false;
+      if (auto *structDecl =
+              valueDecl->getInterfaceType()->getStructOrBoundGenericStruct())
+        return structDecl->getNameStr().contains("__PB__");
+      if (auto *enumDecl =
+              valueDecl->getInterfaceType()->getEnumOrBoundGenericEnum())
+        return enumDecl->getNameStr().contains("__Pred__");
+      return false;
+    };
+    assert(
+        (isa<GenericTypeParamDecl>(D) || isDifferentiationDataStructure(D)) &&
+        "unexpected decl kind");
     return false;
   }
   return true;

branches/rxwei-patch-1/test/AutoDiff/ast_serialization.swift

@@ -0,0 +1,8 @@
+// RUN: %target-swift-frontend -emit-sib -primary-file %s
+
+// Test AST serialization of differentiation generated structs/enums.
+@differentiable
+func TF_623(_ x: Float) -> Float {
+   if x > 0 {}
+   return x
+}