Author: Timm Bäder Date: 2023-01-26T07:07:17+01:00 New Revision: 00e967f6c2d626d1913f5af5763beab7946978ce
URL: https://github.com/llvm/llvm-project/commit/00e967f6c2d626d1913f5af5763beab7946978ce DIFF: https://github.com/llvm/llvm-project/commit/00e967f6c2d626d1913f5af5763beab7946978ce.diff LOG: [clang][Interp] Fix left-/right-shifting more than sizeof(unsigned) We were just casting to `unsigned` before, so that caused problems when shifting more bits than `unsigned` has. Differential Revision: https://reviews.llvm.org/D140845 Added: Modified: clang/lib/AST/Interp/Integral.h clang/lib/AST/Interp/Interp.h clang/test/AST/Interp/shifts.cpp Removed: ################################################################################ diff --git a/clang/lib/AST/Interp/Integral.h b/clang/lib/AST/Interp/Integral.h index d5368167d967..0eb0990a0334 100644 --- a/clang/lib/AST/Interp/Integral.h +++ b/clang/lib/AST/Interp/Integral.h @@ -234,6 +234,18 @@ template <unsigned Bits, bool Signed> class Integral final { return false; } + template <unsigned RHSBits, bool RHSSign> + static void shiftLeft(const Integral A, const Integral<RHSBits, RHSSign> B, + unsigned OpBits, Integral *R) { + *R = Integral::from(A.V << B.V, OpBits); + } + + template <unsigned RHSBits, bool RHSSign> + static void shiftRight(const Integral A, const Integral<RHSBits, RHSSign> B, + unsigned OpBits, Integral *R) { + *R = Integral::from(A.V >> B.V, OpBits); + } + private: template <typename T> static bool CheckAddUB(T A, T B, T &R) { if constexpr (std::is_signed_v<T>) { diff --git a/clang/lib/AST/Interp/Interp.h b/clang/lib/AST/Interp/Interp.h index 466df04ac08d..b36b513c067f 100644 --- a/clang/lib/AST/Interp/Interp.h +++ b/clang/lib/AST/Interp/Interp.h @@ -1334,8 +1334,9 @@ inline bool Shr(InterpState &S, CodePtr OpPC) { if (!CheckShift<RT>(S, OpPC, RHS, Bits)) return false; - unsigned URHS = static_cast<unsigned>(RHS); - S.Stk.push<LT>(LT::from(static_cast<unsigned>(LHS) >> URHS, LHS.bitWidth())); + Integral<LT::bitWidth(), false> R; + Integral<LT::bitWidth(), false>::shiftRight(LHS.toUnsigned(), RHS, Bits, &R); + S.Stk.push<LT>(R); return true; } @@ -1350,9 +1351,9 @@ inline bool Shl(InterpState &S, CodePtr OpPC) { if (!CheckShift<RT>(S, OpPC, RHS, Bits)) return false; - unsigned URHS = static_cast<unsigned>(RHS); - S.Stk.push<LT>(LT::from(static_cast<unsigned>(LHS) << URHS, LHS.bitWidth())); - + Integral<LT::bitWidth(), false> R; + Integral<LT::bitWidth(), false>::shiftLeft(LHS.toUnsigned(), RHS, Bits, &R); + S.Stk.push<LT>(R); return true; } diff --git a/clang/test/AST/Interp/shifts.cpp b/clang/test/AST/Interp/shifts.cpp index 8fa78beb9302..a9193258e6f5 100644 --- a/clang/test/AST/Interp/shifts.cpp +++ b/clang/test/AST/Interp/shifts.cpp @@ -143,4 +143,9 @@ namespace shifts { constexpr char c2 = 1; constexpr int i3 = c2 << (__CHAR_BIT__ + 1); // Not ill-formed + + constexpr signed long int L = 1; + constexpr signed int R = 62; + constexpr decltype(L) M = L << R; + constexpr decltype(L) M2 = L >> R; }; _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
