[PATCH] D80360: [PCH] Support writing BuiltinBitCastExprs to PCHs

[Erik Pilkington via Phabricator via cfe-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rG95d7ccb70b9c: [PCH] Support writing BuiltinBitCastExprs to 
PCHs (authored by hyd-dev, committed by erik.pilkington).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D80360/new/

https://reviews.llvm.org/D80360

Files:
  clang/include/clang/AST/ExprCXX.h
  clang/include/clang/Serialization/ASTBitCodes.h
  clang/lib/Serialization/ASTReaderStmt.cpp
  clang/lib/Serialization/ASTWriterStmt.cpp
  clang/test/PCH/builtin-bit-cast.cpp


Index: clang/test/PCH/builtin-bit-cast.cpp
===
--- /dev/null
+++ clang/test/PCH/builtin-bit-cast.cpp
@@ -0,0 +1,19 @@
+// RUN: %clang_cc1 -emit-pch -o %t %s
+// RUN: %clang_cc1 -include-pch %t -fsyntax-only -verify %s
+// expected-no-diagnostics
+
+#ifndef HEADER
+#define HEADER
+
+template 
+constexpr T BuiltinBitCastWrapper(const U ) {
+  return __builtin_bit_cast(T, Arg);
+}
+
+#else
+
+int main() {
+  return BuiltinBitCastWrapper(0);
+}
+
+#endif
Index: clang/lib/Serialization/ASTWriterStmt.cpp
===
--- clang/lib/Serialization/ASTWriterStmt.cpp
+++ clang/lib/Serialization/ASTWriterStmt.cpp
@@ -1655,6 +1655,7 @@
   VisitExplicitCastExpr(E);
   Record.AddSourceLocation(E->getBeginLoc());
   Record.AddSourceLocation(E->getEndLoc());
+  Code = serialization::EXPR_BUILTIN_BIT_CAST;
 }
 
 void ASTStmtWriter::VisitUserDefinedLiteral(UserDefinedLiteral *E) {
Index: clang/lib/Serialization/ASTReaderStmt.cpp
===
--- clang/lib/Serialization/ASTReaderStmt.cpp
+++ clang/lib/Serialization/ASTReaderStmt.cpp
@@ -3618,6 +3618,11 @@
/*PathSize*/ Record[ASTStmtReader::NumExprFields]);
   break;
 
+case EXPR_BUILTIN_BIT_CAST:
+  assert(Record[ASTStmtReader::NumExprFields] == 0 && "Wrong PathSize!");
+  S = new (Context) BuiltinBitCastExpr(Empty);
+  break;
+
 case EXPR_USER_DEFINED_LITERAL:
   S = UserDefinedLiteral::CreateEmpty(
   Context, /*NumArgs=*/Record[ASTStmtReader::NumExprFields], Empty);
Index: clang/include/clang/Serialization/ASTBitCodes.h
===
--- clang/include/clang/Serialization/ASTBitCodes.h
+++ clang/include/clang/Serialization/ASTBitCodes.h
@@ -1812,6 +1812,9 @@
   /// A CXXFunctionalCastExpr record.
   EXPR_CXX_FUNCTIONAL_CAST,
 
+  /// A BuiltinBitCastExpr record.
+  EXPR_BUILTIN_BIT_CAST,
+
   /// A UserDefinedLiteral record.
   EXPR_USER_DEFINED_LITERAL,
 
Index: clang/include/clang/AST/ExprCXX.h
===
--- clang/include/clang/AST/ExprCXX.h
+++ clang/include/clang/AST/ExprCXX.h
@@ -4821,6 +4821,8 @@
   : ExplicitCastExpr(BuiltinBitCastExprClass, T, VK, CK, SrcExpr, 0,
  DstType),
 KWLoc(KWLoc), RParenLoc(RParenLoc) {}
+  BuiltinBitCastExpr(EmptyShell Empty)
+  : ExplicitCastExpr(BuiltinBitCastExprClass, Empty, 0) {}
 
   SourceLocation getBeginLoc() const LLVM_READONLY { return KWLoc; }
   SourceLocation getEndLoc() const LLVM_READONLY { return RParenLoc; }


Index: clang/test/PCH/builtin-bit-cast.cpp
===
--- /dev/null
+++ clang/test/PCH/builtin-bit-cast.cpp
@@ -0,0 +1,19 @@
+// RUN: %clang_cc1 -emit-pch -o %t %s
+// RUN: %clang_cc1 -include-pch %t -fsyntax-only -verify %s
+// expected-no-diagnostics
+
+#ifndef HEADER
+#define HEADER
+
+template 
+constexpr T BuiltinBitCastWrapper(const U ) {
+  return __builtin_bit_cast(T, Arg);
+}
+
+#else
+
+int main() {
+  return BuiltinBitCastWrapper(0);
+}
+
+#endif
Index: clang/lib/Serialization/ASTWriterStmt.cpp
===
--- clang/lib/Serialization/ASTWriterStmt.cpp
+++ clang/lib/Serialization/ASTWriterStmt.cpp
@@ -1655,6 +1655,7 @@
   VisitExplicitCastExpr(E);
   Record.AddSourceLocation(E->getBeginLoc());
   Record.AddSourceLocation(E->getEndLoc());
+  Code = serialization::EXPR_BUILTIN_BIT_CAST;
 }
 
 void ASTStmtWriter::VisitUserDefinedLiteral(UserDefinedLiteral *E) {
Index: clang/lib/Serialization/ASTReaderStmt.cpp
===
--- clang/lib/Serialization/ASTReaderStmt.cpp
+++ clang/lib/Serialization/ASTReaderStmt.cpp
@@ -3618,6 +3618,11 @@
/*PathSize*/ Record[ASTStmtReader::NumExprFields]);
   break;
 
+case EXPR_BUILTIN_BIT_CAST:
+  assert(Record[ASTStmtReader::NumExprFields] == 0 && "Wrong PathSize!");
+  S = new (Context) BuiltinBitCastExpr(Empty);
+  break;
+
 case EXPR_USER_DEFINED_LITERAL:
   S = UserDefinedLiteral::CreateEmpty(
   Context, /*NumArgs=*/Record[ASTStmtReader::NumExprFields], Empty);
Index: 

[PATCH] D80360: [PCH] Support writing BuiltinBitCastExprs to PCHs

[hyd-dev via Phabricator via cfe-commits]

hyd-dev updated this revision to Diff 269765.
hyd-dev marked an inline comment as done.
hyd-dev added a comment.

Address the comment: remove `PathSize` from `BuiltinBitCastExpr`'s constructor 
and `assert()` it `== 0`.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D80360/new/

https://reviews.llvm.org/D80360

Files:
  clang/include/clang/AST/ExprCXX.h
  clang/include/clang/Serialization/ASTBitCodes.h
  clang/lib/Serialization/ASTReaderStmt.cpp
  clang/lib/Serialization/ASTWriterStmt.cpp
  clang/test/PCH/builtin-bit-cast.cpp


Index: clang/test/PCH/builtin-bit-cast.cpp
===
--- /dev/null
+++ clang/test/PCH/builtin-bit-cast.cpp
@@ -0,0 +1,19 @@
+// RUN: %clang_cc1 -emit-pch -o %t %s
+// RUN: %clang_cc1 -include-pch %t -fsyntax-only -verify %s
+// expected-no-diagnostics
+
+#ifndef HEADER
+#define HEADER
+
+template 
+constexpr T BuiltinBitCastWrapper(const U ) {
+  return __builtin_bit_cast(T, Arg);
+}
+
+#else
+
+int main() {
+  return BuiltinBitCastWrapper(0);
+}
+
+#endif
Index: clang/lib/Serialization/ASTWriterStmt.cpp
===
--- clang/lib/Serialization/ASTWriterStmt.cpp
+++ clang/lib/Serialization/ASTWriterStmt.cpp
@@ -1646,6 +1646,7 @@
   VisitExplicitCastExpr(E);
   Record.AddSourceLocation(E->getBeginLoc());
   Record.AddSourceLocation(E->getEndLoc());
+  Code = serialization::EXPR_BUILTIN_BIT_CAST;
 }
 
 void ASTStmtWriter::VisitUserDefinedLiteral(UserDefinedLiteral *E) {
Index: clang/lib/Serialization/ASTReaderStmt.cpp
===
--- clang/lib/Serialization/ASTReaderStmt.cpp
+++ clang/lib/Serialization/ASTReaderStmt.cpp
@@ -3606,6 +3606,11 @@
/*PathSize*/ Record[ASTStmtReader::NumExprFields]);
   break;
 
+case EXPR_BUILTIN_BIT_CAST:
+  assert(Record[ASTStmtReader::NumExprFields] == 0 && "Wrong PathSize!");
+  S = new (Context) BuiltinBitCastExpr(Empty);
+  break;
+
 case EXPR_USER_DEFINED_LITERAL:
   S = UserDefinedLiteral::CreateEmpty(
   Context, /*NumArgs=*/Record[ASTStmtReader::NumExprFields], Empty);
Index: clang/include/clang/Serialization/ASTBitCodes.h
===
--- clang/include/clang/Serialization/ASTBitCodes.h
+++ clang/include/clang/Serialization/ASTBitCodes.h
@@ -1797,6 +1797,9 @@
   /// A CXXFunctionalCastExpr record.
   EXPR_CXX_FUNCTIONAL_CAST,
 
+  /// A BuiltinBitCastExpr record.
+  EXPR_BUILTIN_BIT_CAST,
+
   /// A UserDefinedLiteral record.
   EXPR_USER_DEFINED_LITERAL,
 
Index: clang/include/clang/AST/ExprCXX.h
===
--- clang/include/clang/AST/ExprCXX.h
+++ clang/include/clang/AST/ExprCXX.h
@@ -4822,6 +4822,8 @@
   : ExplicitCastExpr(BuiltinBitCastExprClass, T, VK, CK, SrcExpr, 0,
  DstType),
 KWLoc(KWLoc), RParenLoc(RParenLoc) {}
+  BuiltinBitCastExpr(EmptyShell Empty)
+  : ExplicitCastExpr(BuiltinBitCastExprClass, Empty, 0) {}
 
   SourceLocation getBeginLoc() const LLVM_READONLY { return KWLoc; }
   SourceLocation getEndLoc() const LLVM_READONLY { return RParenLoc; }


Index: clang/test/PCH/builtin-bit-cast.cpp
===
--- /dev/null
+++ clang/test/PCH/builtin-bit-cast.cpp
@@ -0,0 +1,19 @@
+// RUN: %clang_cc1 -emit-pch -o %t %s
+// RUN: %clang_cc1 -include-pch %t -fsyntax-only -verify %s
+// expected-no-diagnostics
+
+#ifndef HEADER
+#define HEADER
+
+template 
+constexpr T BuiltinBitCastWrapper(const U ) {
+  return __builtin_bit_cast(T, Arg);
+}
+
+#else
+
+int main() {
+  return BuiltinBitCastWrapper(0);
+}
+
+#endif
Index: clang/lib/Serialization/ASTWriterStmt.cpp
===
--- clang/lib/Serialization/ASTWriterStmt.cpp
+++ clang/lib/Serialization/ASTWriterStmt.cpp
@@ -1646,6 +1646,7 @@
   VisitExplicitCastExpr(E);
   Record.AddSourceLocation(E->getBeginLoc());
   Record.AddSourceLocation(E->getEndLoc());
+  Code = serialization::EXPR_BUILTIN_BIT_CAST;
 }
 
 void ASTStmtWriter::VisitUserDefinedLiteral(UserDefinedLiteral *E) {
Index: clang/lib/Serialization/ASTReaderStmt.cpp
===
--- clang/lib/Serialization/ASTReaderStmt.cpp
+++ clang/lib/Serialization/ASTReaderStmt.cpp
@@ -3606,6 +3606,11 @@
/*PathSize*/ Record[ASTStmtReader::NumExprFields]);
   break;
 
+case EXPR_BUILTIN_BIT_CAST:
+  assert(Record[ASTStmtReader::NumExprFields] == 0 && "Wrong PathSize!");
+  S = new (Context) BuiltinBitCastExpr(Empty);
+  break;
+
 case EXPR_USER_DEFINED_LITERAL:
   S = UserDefinedLiteral::CreateEmpty(
   Context, /*NumArgs=*/Record[ASTStmtReader::NumExprFields], Empty);
Index: 

[PATCH] D80360: [PCH] Support writing BuiltinBitCastExprs to PCHs

[hyd-dev via Phabricator via cfe-commits]

hyd-dev added a comment.

If this is OK, please commit it with `--author "hyd-dev 
"`.


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[PATCH] D80360: [PCH] Support writing BuiltinBitCastExprs to PCHs

[Erik Pilkington via Phabricator via cfe-commits]

erik.pilkington accepted this revision.
erik.pilkington added a comment.
This revision is now accepted and ready to land.

LGTM (after a minor comment), thank you for fixing this!




Comment at: clang/lib/Serialization/ASTReaderStmt.cpp:3598
+  S = new (Context) BuiltinBitCastExpr(
+  Empty, /*PathSize*/ Record[ASTStmtReader::NumExprFields]);
+  break;

PathSize should always be zero, so I think it makes more sense to 
`assert(Record[ASTStmtReader::NumExprFields] == 0);` here and remove the 
PathSize parameter from the BuiltinBitCastExpr constructor. 


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[PATCH] D80360: [PCH] Support writing BuiltinBitCastExprs to PCHs

[hyd-dev via Phabricator via cfe-commits]

hyd-dev added a comment.

**Ping?**


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[PATCH] D80360: [PCH] Support writing BuiltinBitCastExprs to PCHs

[hyd-dev via Phabricator via cfe-commits]

hyd-dev updated this revision to Diff 265436.
hyd-dev added a comment.

Format the test `builtin-bit-cast.cpp`.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D80360/new/

https://reviews.llvm.org/D80360

Files:
  clang/include/clang/AST/ExprCXX.h
  clang/include/clang/Serialization/ASTBitCodes.h
  clang/lib/Serialization/ASTReaderStmt.cpp
  clang/lib/Serialization/ASTWriterStmt.cpp
  clang/test/PCH/builtin-bit-cast.cpp


Index: clang/test/PCH/builtin-bit-cast.cpp
===
--- /dev/null
+++ clang/test/PCH/builtin-bit-cast.cpp
@@ -0,0 +1,19 @@
+// RUN: %clang_cc1 -emit-pch -o %t %s
+// RUN: %clang_cc1 -include-pch %t -fsyntax-only -verify %s
+// expected-no-diagnostics
+
+#ifndef HEADER
+#define HEADER
+
+template 
+constexpr T BuiltinBitCastWrapper(const U ) {
+  return __builtin_bit_cast(T, Arg);
+}
+
+#else
+
+int main() {
+  return BuiltinBitCastWrapper(0);
+}
+
+#endif
Index: clang/lib/Serialization/ASTWriterStmt.cpp
===
--- clang/lib/Serialization/ASTWriterStmt.cpp
+++ clang/lib/Serialization/ASTWriterStmt.cpp
@@ -1635,6 +1635,7 @@
   VisitExplicitCastExpr(E);
   Record.AddSourceLocation(E->getBeginLoc());
   Record.AddSourceLocation(E->getEndLoc());
+  Code = serialization::EXPR_BUILTIN_BIT_CAST;
 }
 
 void ASTStmtWriter::VisitUserDefinedLiteral(UserDefinedLiteral *E) {
Index: clang/lib/Serialization/ASTReaderStmt.cpp
===
--- clang/lib/Serialization/ASTReaderStmt.cpp
+++ clang/lib/Serialization/ASTReaderStmt.cpp
@@ -3593,6 +3593,11 @@
/*PathSize*/ Record[ASTStmtReader::NumExprFields]);
   break;
 
+case EXPR_BUILTIN_BIT_CAST:
+  S = new (Context) BuiltinBitCastExpr(
+  Empty, /*PathSize*/ Record[ASTStmtReader::NumExprFields]);
+  break;
+
 case EXPR_USER_DEFINED_LITERAL:
   S = UserDefinedLiteral::CreateEmpty(
   Context, /*NumArgs=*/Record[ASTStmtReader::NumExprFields], Empty);
Index: clang/include/clang/Serialization/ASTBitCodes.h
===
--- clang/include/clang/Serialization/ASTBitCodes.h
+++ clang/include/clang/Serialization/ASTBitCodes.h
@@ -1791,6 +1791,9 @@
   /// A CXXFunctionalCastExpr record.
   EXPR_CXX_FUNCTIONAL_CAST,
 
+  /// A BuiltinBitCastExpr record.
+  EXPR_BUILTIN_BIT_CAST,
+
   /// A UserDefinedLiteral record.
   EXPR_USER_DEFINED_LITERAL,
 
Index: clang/include/clang/AST/ExprCXX.h
===
--- clang/include/clang/AST/ExprCXX.h
+++ clang/include/clang/AST/ExprCXX.h
@@ -4785,6 +4785,8 @@
   : ExplicitCastExpr(BuiltinBitCastExprClass, T, VK, CK, SrcExpr, 0,
  DstType),
 KWLoc(KWLoc), RParenLoc(RParenLoc) {}
+  BuiltinBitCastExpr(EmptyShell Empty, unsigned PathSize)
+  : ExplicitCastExpr(BuiltinBitCastExprClass, Empty, PathSize) {}
 
   SourceLocation getBeginLoc() const LLVM_READONLY { return KWLoc; }
   SourceLocation getEndLoc() const LLVM_READONLY { return RParenLoc; }


Index: clang/test/PCH/builtin-bit-cast.cpp
===
--- /dev/null
+++ clang/test/PCH/builtin-bit-cast.cpp
@@ -0,0 +1,19 @@
+// RUN: %clang_cc1 -emit-pch -o %t %s
+// RUN: %clang_cc1 -include-pch %t -fsyntax-only -verify %s
+// expected-no-diagnostics
+
+#ifndef HEADER
+#define HEADER
+
+template 
+constexpr T BuiltinBitCastWrapper(const U ) {
+  return __builtin_bit_cast(T, Arg);
+}
+
+#else
+
+int main() {
+  return BuiltinBitCastWrapper(0);
+}
+
+#endif
Index: clang/lib/Serialization/ASTWriterStmt.cpp
===
--- clang/lib/Serialization/ASTWriterStmt.cpp
+++ clang/lib/Serialization/ASTWriterStmt.cpp
@@ -1635,6 +1635,7 @@
   VisitExplicitCastExpr(E);
   Record.AddSourceLocation(E->getBeginLoc());
   Record.AddSourceLocation(E->getEndLoc());
+  Code = serialization::EXPR_BUILTIN_BIT_CAST;
 }
 
 void ASTStmtWriter::VisitUserDefinedLiteral(UserDefinedLiteral *E) {
Index: clang/lib/Serialization/ASTReaderStmt.cpp
===
--- clang/lib/Serialization/ASTReaderStmt.cpp
+++ clang/lib/Serialization/ASTReaderStmt.cpp
@@ -3593,6 +3593,11 @@
/*PathSize*/ Record[ASTStmtReader::NumExprFields]);
   break;
 
+case EXPR_BUILTIN_BIT_CAST:
+  S = new (Context) BuiltinBitCastExpr(
+  Empty, /*PathSize*/ Record[ASTStmtReader::NumExprFields]);
+  break;
+
 case EXPR_USER_DEFINED_LITERAL:
   S = UserDefinedLiteral::CreateEmpty(
   Context, /*NumArgs=*/Record[ASTStmtReader::NumExprFields], Empty);
Index: clang/include/clang/Serialization/ASTBitCodes.h
===
--- 

[PATCH] D80360: [PCH] Support writing BuiltinBitCastExprs to PCHs

[hyd-dev via Phabricator via cfe-commits]

hyd-dev created this revision.
hyd-dev added reviewers: erik.pilkington, rsmith.
hyd-dev added a project: clang.
Herald added subscribers: cfe-commits, dexonsmith.
hyd-dev edited the summary of this revision.
hyd-dev edited the summary of this revision.

D62825  adds the new `BuiltinBitCastExpr`, but 
does not set the `Code` member of `ASTStmtWriter`. This is not correct and 
causes an assertion failue (`assert(Code != serialization::STMT_NULL_PTR && 
"unhandled sub-statement writing AST file")`) in `ASTStmtWriter::emit()` when 
building PCHs which contain `__builtin_bit_cast`. This patch adds 
`serialization::EXPR_BUILTIN_BIT_CAST` and handles `ASTStmtWriter::Code` 
properly.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D80360

Files:
  clang/include/clang/AST/ExprCXX.h
  clang/include/clang/Serialization/ASTBitCodes.h
  clang/lib/Serialization/ASTReaderStmt.cpp
  clang/lib/Serialization/ASTWriterStmt.cpp
  clang/test/PCH/builtin-bit-cast.cpp


Index: clang/test/PCH/builtin-bit-cast.cpp
===
--- /dev/null
+++ clang/test/PCH/builtin-bit-cast.cpp
@@ -0,0 +1,20 @@
+// RUN: %clang_cc1 -emit-pch -o %t %s
+// RUN: %clang_cc1 -include-pch %t -fsyntax-only -verify %s
+// expected-no-diagnostics
+
+#ifndef HEADER
+#define HEADER
+
+template
+constexpr T builtin_bit_cast_wrapper(const U& arg) {
+  return __builtin_bit_cast(T, arg);
+}
+
+#else
+
+int main() {
+  builtin_bit_cast_wrapper(0);
+  return 0;
+}
+
+#endif
Index: clang/lib/Serialization/ASTWriterStmt.cpp
===
--- clang/lib/Serialization/ASTWriterStmt.cpp
+++ clang/lib/Serialization/ASTWriterStmt.cpp
@@ -1635,6 +1635,7 @@
   VisitExplicitCastExpr(E);
   Record.AddSourceLocation(E->getBeginLoc());
   Record.AddSourceLocation(E->getEndLoc());
+  Code = serialization::EXPR_BUILTIN_BIT_CAST;
 }
 
 void ASTStmtWriter::VisitUserDefinedLiteral(UserDefinedLiteral *E) {
Index: clang/lib/Serialization/ASTReaderStmt.cpp
===
--- clang/lib/Serialization/ASTReaderStmt.cpp
+++ clang/lib/Serialization/ASTReaderStmt.cpp
@@ -3593,6 +3593,11 @@
/*PathSize*/ Record[ASTStmtReader::NumExprFields]);
   break;
 
+case EXPR_BUILTIN_BIT_CAST:
+  S = new (Context) BuiltinBitCastExpr(
+  Empty, /*PathSize*/ Record[ASTStmtReader::NumExprFields]);
+  break;
+
 case EXPR_USER_DEFINED_LITERAL:
   S = UserDefinedLiteral::CreateEmpty(
   Context, /*NumArgs=*/Record[ASTStmtReader::NumExprFields], Empty);
Index: clang/include/clang/Serialization/ASTBitCodes.h
===
--- clang/include/clang/Serialization/ASTBitCodes.h
+++ clang/include/clang/Serialization/ASTBitCodes.h
@@ -1791,6 +1791,9 @@
   /// A CXXFunctionalCastExpr record.
   EXPR_CXX_FUNCTIONAL_CAST,
 
+  /// A BuiltinBitCastExpr record.
+  EXPR_BUILTIN_BIT_CAST,
+
   /// A UserDefinedLiteral record.
   EXPR_USER_DEFINED_LITERAL,
 
Index: clang/include/clang/AST/ExprCXX.h
===
--- clang/include/clang/AST/ExprCXX.h
+++ clang/include/clang/AST/ExprCXX.h
@@ -4785,6 +4785,8 @@
   : ExplicitCastExpr(BuiltinBitCastExprClass, T, VK, CK, SrcExpr, 0,
  DstType),
 KWLoc(KWLoc), RParenLoc(RParenLoc) {}
+  BuiltinBitCastExpr(EmptyShell Empty, unsigned PathSize)
+  : ExplicitCastExpr(BuiltinBitCastExprClass, Empty, PathSize) {}
 
   SourceLocation getBeginLoc() const LLVM_READONLY { return KWLoc; }
   SourceLocation getEndLoc() const LLVM_READONLY { return RParenLoc; }


Index: clang/test/PCH/builtin-bit-cast.cpp
===
--- /dev/null
+++ clang/test/PCH/builtin-bit-cast.cpp
@@ -0,0 +1,20 @@
+// RUN: %clang_cc1 -emit-pch -o %t %s
+// RUN: %clang_cc1 -include-pch %t -fsyntax-only -verify %s
+// expected-no-diagnostics
+
+#ifndef HEADER
+#define HEADER
+
+template
+constexpr T builtin_bit_cast_wrapper(const U& arg) {
+  return __builtin_bit_cast(T, arg);
+}
+
+#else
+
+int main() {
+  builtin_bit_cast_wrapper(0);
+  return 0;
+}
+
+#endif
Index: clang/lib/Serialization/ASTWriterStmt.cpp
===
--- clang/lib/Serialization/ASTWriterStmt.cpp
+++ clang/lib/Serialization/ASTWriterStmt.cpp
@@ -1635,6 +1635,7 @@
   VisitExplicitCastExpr(E);
   Record.AddSourceLocation(E->getBeginLoc());
   Record.AddSourceLocation(E->getEndLoc());
+  Code = serialization::EXPR_BUILTIN_BIT_CAST;
 }
 
 void ASTStmtWriter::VisitUserDefinedLiteral(UserDefinedLiteral *E) {
Index: clang/lib/Serialization/ASTReaderStmt.cpp
===
--- clang/lib/Serialization/ASTReaderStmt.cpp
+++