Test and fix GCC -Wpadded and MSVC 4324

Author: mborland

include/boost/decimal/cstdio.hpp

@@ -43,6 +43,12 @@ enum class decimal_type : unsigned
     decimal128_t = 1 << 2
 };
 
+// Internal use only
+#ifdef __GNUC__
+#  pragma GCC diagnostic push
+#  pragma GCC diagnostic ignored "-Wpadded"
+#endif
+
 struct parameters
 {
     int precision;
@@ -51,6 +57,10 @@ struct parameters
     bool upper_case;
 };
 
+#ifdef __GNUC__
+#  pragma GCC diagnostic pop
+#endif
+
 inline auto parse_format(const char* format) -> parameters
 {
     // If the format is unspecified or incorrect, we will use this as the default values

include/boost/decimal/decimal_fast128_t.hpp

@@ -85,7 +85,7 @@ constexpr auto write_payload(typename TargetDecimalType::significand_type payloa
 #  pragma warning(disable : 4324) // Structure was padded due to alignment specifier
 #endif
 
-BOOST_DECIMAL_EXPORT class decimal_fast128_t final
+BOOST_DECIMAL_EXPORT class alignas(16) decimal_fast128_t final
 {
 public:
     using significand_type = int128::uint128_t;
@@ -99,6 +99,7 @@ BOOST_DECIMAL_EXPORT class decimal_fast128_t final
     significand_type significand_ {};
     exponent_type exponent_ {};
     bool sign_ {};
+    char pad_[11] {};
 
     constexpr auto isneg() const noexcept -> bool
     {

include/boost/decimal/decimal_fast32_t.hpp

@@ -78,7 +78,12 @@ constexpr auto write_payload(typename TargetDecimalType::significand_type payloa
 
 } // namespace detail
 
-BOOST_DECIMAL_EXPORT class decimal_fast32_t final
+#ifdef _MSC_VER
+#  pragma warning(push)
+#  pragma warning(disable : 4324) // Structure was padded due to alignment specifier
+#endif
+
+BOOST_DECIMAL_EXPORT class alignas(4) decimal_fast32_t final
 {
 public:
     using significand_type = std::uint32_t;
@@ -93,6 +98,7 @@ BOOST_DECIMAL_EXPORT class decimal_fast32_t final
     significand_type significand_ {};
     exponent_type exponent_ {};
     bool sign_ {};
+    char pad_[2] {};
 
     constexpr auto isneg() const noexcept -> bool
     {
@@ -495,6 +501,10 @@ BOOST_DECIMAL_EXPORT class decimal_fast32_t final
     friend constexpr auto quantized32f(decimal_fast32_t lhs, decimal_fast32_t rhs) noexcept -> decimal_fast32_t;
 };
 
+#ifdef _MSC_VER
+#  pragma warning(pop)
+#endif
+
 template <typename T1, typename T2, std::enable_if_t<detail::is_unsigned_v<T1> && detail::is_integral_v<T2>, bool>>
 constexpr decimal_fast32_t::decimal_fast32_t(T1 coeff, T2 exp, const detail::construction_sign_wrapper resultant_sign) noexcept
 {

include/boost/decimal/decimal_fast64_t.hpp

@@ -80,7 +80,12 @@ constexpr auto write_payload(typename TargetDecimalType::significand_type payloa
 
 } // namespace detail
 
-BOOST_DECIMAL_EXPORT class decimal_fast64_t final
+#ifdef _MSC_VER
+#  pragma warning(push)
+#  pragma warning(disable : 4324) // Structure was padded due to alignment specifier
+#endif
+
+BOOST_DECIMAL_EXPORT class alignas(8) decimal_fast64_t final
 {
 public:
     using significand_type = std::uint64_t;
@@ -94,6 +99,7 @@ BOOST_DECIMAL_EXPORT class decimal_fast64_t final
     significand_type significand_ {};
     exponent_type exponent_ {};
     bool sign_ {};
+    char pad_[5] {};
 
     constexpr auto isneg() const noexcept -> bool
     {
@@ -496,6 +502,10 @@ BOOST_DECIMAL_EXPORT class decimal_fast64_t final
     friend constexpr auto quantexpd64f(decimal_fast64_t x) noexcept -> int;
 };
 
+#ifdef _MSC_VER
+#  pragma warning(pop)
+#endif
+
 #ifdef BOOST_DECIMAL_HAS_CONCEPTS
 template <BOOST_DECIMAL_UNSIGNED_INTEGRAL T1, BOOST_DECIMAL_INTEGRAL T2>
 #else

include/boost/decimal/detail/components.hpp

@@ -23,6 +23,13 @@ namespace impl {
 #  pragma warning(disable : 4324) // Structure was padded due to alignment specifier
 #endif
 
+
+// Internal use only, and changes based on the types
+#ifdef __GNUC__
+#  pragma GCC diagnostic push
+#  pragma GCC diagnostic ignored "-Wpadded"
+#endif
+
 template <typename SigType, typename BiasedExpType>
 struct decimal_components
 {
@@ -74,6 +81,10 @@ using decimal128_t_components = impl::decimal_components<boost::int128::uint128_
 
 using decimal_fast128_t_components = impl::decimal_components<boost::int128::uint128_t, std::int32_t>;
 
+#ifdef __GNUC__
+#  pragma GCC diagnostic pop
+#endif
+
 #ifdef _MSC_VER
 #  pragma warning(pop)
 #endif

include/boost/decimal/detail/fenv_rounding.hpp

@@ -19,6 +19,12 @@ namespace detail {
 
 namespace impl {
 
+// These structs are for internal use only and change based on the type of T
+#ifdef __GNUC__
+#  pragma GCC diagnostic push
+#  pragma GCC diagnostic ignored "-Wpadded"
+#endif
+
 template <typename T>
 struct divmod_result
 {
@@ -33,6 +39,10 @@ struct divmod10_result
     std::uint64_t remainder;
 };
 
+#ifdef __GNUC__
+#  pragma GCC diagnostic pop
+#endif
+
 template <typename T, std::enable_if_t<std::is_integral<T>::value, bool> = true>
 constexpr auto divmod(T dividend, T divisor) noexcept -> divmod_result<T>
 {

include/boost/decimal/detail/from_chars_result.hpp

@@ -18,6 +18,12 @@ namespace decimal {
 
 // 22.13.3, Primitive numerical input conversion
 
+// This is how the STL says to implement
+#ifdef __GNUC__
+#  pragma GCC diagnostic push
+#  pragma GCC diagnostic ignored "-Wpadded"
+#endif
+
 BOOST_DECIMAL_EXPORT struct from_chars_result
 {
     const char* ptr;
@@ -41,6 +47,10 @@ BOOST_DECIMAL_EXPORT struct from_chars_result
     constexpr explicit operator bool() const noexcept { return ec == std::errc{}; }
 };
 
+#ifdef __GNUC__
+#  pragma GCC diagnostic pop
+#endif
+
 } // namespace decimal
 } // namespace boost
 

include/boost/decimal/detail/remove_trailing_zeros.hpp

@@ -29,13 +29,23 @@ constexpr auto rotr(UInt n, unsigned int r) noexcept
     return (n >> r) | (n << ((bit_width - r) & (bit_width - 1)));
 }
 
+// For internal use only and changes based on the type of T
+#ifdef __GNUC__
+#  pragma GCC diagnostic push
+#  pragma GCC diagnostic ignored "-Wpadded"
+#endif
+
 template <typename T>
 struct remove_trailing_zeros_return
 {
     T trimmed_number;
     std::size_t number_of_removed_zeros;
 };
 
+#ifdef __GNUC__
+#  pragma GCC diagnostic pop
+#endif
+
 constexpr auto remove_trailing_zeros(std::uint32_t n) noexcept -> remove_trailing_zeros_return<std::uint32_t>
 {
     std::size_t s {};

include/boost/decimal/detail/ryu/ryu_generic_128.hpp

@@ -36,13 +36,23 @@ BOOST_DECIMAL_INLINE_CONSTEXPR_VARIABLE unsigned_128_type one = 1;
 #  pragma warning(disable : 4324) // Structure was padded due to alignment specifier
 #endif
 
+// Internal use only
+#ifdef __GNUC__
+#  pragma GCC diagnostic push
+#  pragma GCC diagnostic ignored "-Wpadded"
+#endif
+
 struct floating_decimal_128
 {
     unsigned_128_type mantissa;
     int32_t exponent;
     bool sign;
 };
 
+#ifdef __GNUC__
+#  pragma GCC diagnostic pop
+#endif
+
 #ifdef _MSC_VER
 #  pragma warning(pop)
 #endif

include/boost/decimal/detail/to_chars_result.hpp

@@ -16,6 +16,12 @@
 namespace boost {
 namespace decimal {
 
+// This is how the STL says to implement
+#ifdef __GNUC__
+#  pragma GCC diagnostic push
+#  pragma GCC diagnostic ignored "-Wpadded"
+#endif
+
 BOOST_DECIMAL_EXPORT struct to_chars_result
 {
     char *ptr;
@@ -34,6 +40,10 @@ BOOST_DECIMAL_EXPORT struct to_chars_result
     constexpr explicit operator bool() const noexcept { return ec == std::errc{}; }
 };
 
+#ifdef __GNUC__
+#  pragma GCC diagnostic pop
+#endif
+
 } // namespace decimal
 } // namespace boost