tbaeder added a comment. In D134859#3945709 <https://reviews.llvm.org/D134859#3945709>, @sepavloff wrote:
> In D134859#3943926 <https://reviews.llvm.org/D134859#3943926>, @tbaeder wrote: > >> FYI, I noticed the way the floating values are serialized doesn't work if >> the `APFloat` heap-allocated anything; those values aren't preserved through >> (de)serialization of course. >> >> Reproducer: >> >> constexpr double foo() { >> return __LDBL_MIN__; >> } > > The return statement returns a value of type `long double` while the function > returns `double`. If `long double` is wider than `double`, truncation occurs, > may be this is the reason? It also happens when the function returns a `long double`. I tracked the problem down to the way we emit byte code into a `std::vector`. It's simply `reintepret_cast'`ed to `const char *`, so that won't work for `APFloat`. This change seems to fix the problem: diff --git a/clang/lib/AST/Interp/ByteCodeEmitter.cpp b/clang/lib/AST/Interp/ByteCodeEmitter.cpp index ff2136d34872..61e9662013c3 100644 --- a/clang/lib/AST/Interp/ByteCodeEmitter.cpp +++ b/clang/lib/AST/Interp/ByteCodeEmitter.cpp @@ -163,8 +163,15 @@ static void emit(Program &P, std::vector<char> &Code, const T &Val, } if constexpr (!std::is_pointer_v<T>) { - const char *Data = reinterpret_cast<const char *>(&Val); - Code.insert(Code.end(), Data, Data + Size); + if constexpr (std::is_trivially_copyable_v<T>) { + const char *Data = reinterpret_cast<const char *>(&Val); + Code.insert(Code.end(), Data, Data + Size); + } else { + // Construct the value directly into our storage vector. + size_t ValPos = Code.size(); + Code.resize(Code.size() + Size); + new (Code.data() + ValPos) T(Val); + } } else { uint32_t ID = P.getOrCreateNativePointer(Val); const char *Data = reinterpret_cast<const char *>(&ID); CHANGES SINCE LAST ACTION https://reviews.llvm.org/D134859/new/ https://reviews.llvm.org/D134859 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
