https://github.com/unterumarmung created https://github.com/llvm/llvm-project/pull/201363
Fixes #201115 >From c201e710c4b75832e35f921347c1985f4e834c8f Mon Sep 17 00:00:00 2001 From: Daniil Dudkin <[email protected]> Date: Wed, 3 Jun 2026 16:52:07 +0300 Subject: [PATCH] [clang-tidy] avoid 64-bit truncation in redundant bitwise checks Fixes #201115 --- .../misc/RedundantExpressionCheck.cpp | 6 ++- .../checkers/misc/redundant-expression.cpp | 45 +++++++++++++++++++ 2 files changed, 49 insertions(+), 2 deletions(-) diff --git a/clang-tools-extra/clang-tidy/misc/RedundantExpressionCheck.cpp b/clang-tools-extra/clang-tidy/misc/RedundantExpressionCheck.cpp index 9db297990b274..de489da96de3b 100644 --- a/clang-tools-extra/clang-tidy/misc/RedundantExpressionCheck.cpp +++ b/clang-tools-extra/clang-tidy/misc/RedundantExpressionCheck.cpp @@ -1178,8 +1178,10 @@ void RedundantExpressionCheck::checkBitwiseExpr( !retrieveIntegerConstantExpr(Result, "rhs", RhsValue)) return; - const uint64_t LhsConstant = LhsValue.getZExtValue(); - const uint64_t RhsConstant = RhsValue.getZExtValue(); + const unsigned ConstantWidth = + std::max(LhsValue.getBitWidth(), RhsValue.getBitWidth()); + const llvm::APInt LhsConstant = LhsValue.extOrTrunc(ConstantWidth); + const llvm::APInt RhsConstant = RhsValue.extOrTrunc(ConstantWidth); const SourceLocation Loc = ComparisonOperator->getOperatorLoc(); // Check expression: x & k1 == k2 (i.e. x & 0xFF == 0xF00) diff --git a/clang-tools-extra/test/clang-tidy/checkers/misc/redundant-expression.cpp b/clang-tools-extra/test/clang-tidy/checkers/misc/redundant-expression.cpp index 4ff0ba867ebb9..4bd2d2df343dc 100644 --- a/clang-tools-extra/test/clang-tidy/checkers/misc/redundant-expression.cpp +++ b/clang-tools-extra/test/clang-tidy/checkers/misc/redundant-expression.cpp @@ -572,6 +572,51 @@ int TestBitwise(int X, int Y) { return 0; } +bool TestBitwiseUInt128(unsigned __int128 Value) { + constexpr unsigned __int128 BigBit = + static_cast<unsigned __int128>(1) << 100; + + if ((Value & BigBit) == BigBit) return true; + + constexpr unsigned __int128 LowMask = static_cast<unsigned __int128>(0xFF); + + if ((Value & LowMask) == BigBit) return true; + // CHECK-MESSAGES: :[[@LINE-1]]:25: warning: logical expression is always false + if ((Value & LowMask) != BigBit) return true; + // CHECK-MESSAGES: :[[@LINE-1]]:25: warning: logical expression is always true + if ((Value | BigBit) == LowMask) return true; + // CHECK-MESSAGES: :[[@LINE-1]]:24: warning: logical expression is always false + if ((Value | BigBit) != LowMask) return true; + // CHECK-MESSAGES: :[[@LINE-1]]:24: warning: logical expression is always true + + return false; +} + +#define UINT128_BIG_BIT (static_cast<unsigned __int128>(1) << 100) + +bool TestBitwiseUInt128Macro(unsigned __int128 Value) { + return (Value & UINT128_BIG_BIT) == UINT128_BIG_BIT; +} + +template <int N> +bool TestBitwiseUInt128Template(unsigned __int128 Value) { + constexpr unsigned __int128 Mask = static_cast<unsigned __int128>(1) << N; + return (Value & Mask) == Mask; +} + +bool UseBitwiseUInt128Template(unsigned __int128 Value) { + return TestBitwiseUInt128Template<100>(Value); +} + +using RedundantExpressionU128 = unsigned __int128; +typedef unsigned __int128 RedundantExpressionTypedefU128; + +bool TestBitwiseUInt128AliasCvRef(const RedundantExpressionU128 &Value) { + constexpr RedundantExpressionTypedefU128 Mask = + static_cast<RedundantExpressionU128>(1) << 100; + return (Value & Mask) == Mask; +} + // Overloaded operators that compare an instance of a struct and an integer // constant. struct S { _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
