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70 lines
2.2 KiB
C++
70 lines
2.2 KiB
C++
#include <Functions/FunctionFactory.h>
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#include <Functions/FunctionBinaryArithmetic.h>
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#include <Core/AccurateComparison.h>
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#include <Functions/LeastGreatestGeneric.h>
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namespace DB
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{
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template <typename A, typename B>
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struct LeastBaseImpl
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{
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using ResultType = NumberTraits::ResultOfLeast<A, B>;
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static const constexpr bool allow_fixed_string = false;
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template <typename Result = ResultType>
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static inline Result apply(A a, B b)
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{
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/** gcc 4.9.2 successfully vectorizes a loop from this function. */
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return static_cast<Result>(a) < static_cast<Result>(b) ? static_cast<Result>(a) : static_cast<Result>(b);
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}
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#if USE_EMBEDDED_COMPILER
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static constexpr bool compilable = true;
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static inline llvm::Value * compile(llvm::IRBuilder<> & b, llvm::Value * left, llvm::Value * right, bool is_signed)
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{
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if (!left->getType()->isIntegerTy())
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{
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/// Follows the IEEE-754 semantics for minNum, except for handling of signaling NaNs. This match’s the behavior of libc fmin.
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return b.CreateMinNum(left, right);
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}
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auto * compare_value = is_signed ? b.CreateICmpSLT(left, right) : b.CreateICmpULT(left, right);
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return b.CreateSelect(compare_value, left, right);
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}
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#endif
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};
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template <typename A, typename B>
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struct LeastSpecialImpl
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{
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using ResultType = std::make_signed_t<A>;
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static const constexpr bool allow_fixed_string = false;
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template <typename Result = ResultType>
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static inline Result apply(A a, B b)
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{
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static_assert(std::is_same_v<Result, ResultType>, "ResultType != Result");
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return accurate::lessOp(a, b) ? static_cast<Result>(a) : static_cast<Result>(b);
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}
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#if USE_EMBEDDED_COMPILER
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static constexpr bool compilable = false; /// ???
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#endif
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};
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template <typename A, typename B>
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using LeastImpl = std::conditional_t<!NumberTraits::LeastGreatestSpecialCase<A, B>, LeastBaseImpl<A, B>, LeastSpecialImpl<A, B>>;
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struct NameLeast { static constexpr auto name = "least"; };
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using FunctionLeast = FunctionBinaryArithmetic<LeastImpl, NameLeast>;
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void registerFunctionLeast(FunctionFactory & factory)
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{
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factory.registerFunction<LeastGreatestOverloadResolver<LeastGreatest::Least, FunctionLeast>>(FunctionFactory::CaseInsensitive);
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}
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}
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