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/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/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/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/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 &Arg) { + return __builtin_bit_cast(T, Arg); +} + +#else + +int main() { + return BuiltinBitCastWrapper(0); +} + +#endif