Author: Timm Baeder Date: 2023-10-03T06:05:39+02:00 New Revision: ef9666aa81abdbcff54448446ba1f6fffe5fa45c
URL: https://github.com/llvm/llvm-project/commit/ef9666aa81abdbcff54448446ba1f6fffe5fa45c DIFF: https://github.com/llvm/llvm-project/commit/ef9666aa81abdbcff54448446ba1f6fffe5fa45c.diff LOG: [clang][Interp] Fix value truncation when casting int128 to smaller size (#67961) Before this patch, we would run into an assertion in `APInt::get{S,Z}ExtValue()` because the `AllOnes` value had more than 64 active bits. Added: Modified: clang/lib/AST/Interp/IntegralAP.h clang/test/AST/Interp/literals.cpp Removed: ################################################################################ diff --git a/clang/lib/AST/Interp/IntegralAP.h b/clang/lib/AST/Interp/IntegralAP.h index 42f44354cbd2599..0876d7fae958a54 100644 --- a/clang/lib/AST/Interp/IntegralAP.h +++ b/clang/lib/AST/Interp/IntegralAP.h @@ -32,6 +32,12 @@ template <unsigned Bits, bool Signed> class Integral; class Boolean; template <bool Signed> class IntegralAP final { +private: + template <typename T> static T truncateCast(const APSInt &V) { + return std::is_signed_v<T> ? V.trunc(sizeof(T) * 8).getSExtValue() + : V.trunc(sizeof(T) * 8).getZExtValue(); + } + public: APSInt V; @@ -55,14 +61,14 @@ template <bool Signed> class IntegralAP final { bool operator<=(IntegralAP RHS) const { return V <= RHS.V; } explicit operator bool() const { return !V.isZero(); } - explicit operator int8_t() const { return V.getSExtValue(); } - explicit operator uint8_t() const { return V.getZExtValue(); } - explicit operator int16_t() const { return V.getSExtValue(); } - explicit operator uint16_t() const { return V.getZExtValue(); } - explicit operator int32_t() const { return V.getSExtValue(); } - explicit operator uint32_t() const { return V.getZExtValue(); } - explicit operator int64_t() const { return V.getSExtValue(); } - explicit operator uint64_t() const { return V.getZExtValue(); } + explicit operator int8_t() const { return truncateCast<int8_t>(V); } + explicit operator uint8_t() const { return truncateCast<uint8_t>(V); } + explicit operator int16_t() const { return truncateCast<int16_t>(V); } + explicit operator uint16_t() const { return truncateCast<uint16_t>(V); } + explicit operator int32_t() const { return truncateCast<int32_t>(V); } + explicit operator uint32_t() const { return truncateCast<uint32_t>(V); } + explicit operator int64_t() const { return truncateCast<int64_t>(V); } + explicit operator uint64_t() const { return truncateCast<uint64_t>(V); } template <typename T> static IntegralAP from(T Value, unsigned NumBits = 0) { assert(NumBits > 0); diff --git a/clang/test/AST/Interp/literals.cpp b/clang/test/AST/Interp/literals.cpp index 00182ba4ab1d918..00875bcf44dc8e6 100644 --- a/clang/test/AST/Interp/literals.cpp +++ b/clang/test/AST/Interp/literals.cpp @@ -53,7 +53,7 @@ namespace i128 { static_assert(Two == 2, ""); constexpr uint128_t AllOnes = ~static_cast<uint128_t>(0); - static_assert(AllOnes == static_cast<uint128_t>(-1), ""); + static_assert(AllOnes == UINT128_MAX, ""); #if __cplusplus >= 201402L template <typename T> @@ -70,6 +70,14 @@ namespace i128 { static_assert(CastFrom<double>(12) == 12, ""); static_assert(CastFrom<long double>(12) == 12, ""); + static_assert(CastFrom<char>(AllOnes) == -1, ""); + static_assert(CastFrom<unsigned char>(AllOnes) == 0xFF, ""); + static_assert(CastFrom<long>(AllOnes) == -1, ""); + static_assert(CastFrom<unsigned short>(AllOnes) == 0xFFFF, ""); + static_assert(CastFrom<int>(AllOnes) == -1, ""); + static_assert(CastFrom<int128_t>(AllOnes) == -1, ""); + static_assert(CastFrom<uint128_t>(AllOnes) == AllOnes, ""); + template <typename T> constexpr __int128 CastTo(T A) { int128_t B = (int128_t)A; _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
