1#include <Functions/FunctionFactory.h>
2#include <Functions/FunctionBinaryArithmetic.h>
3#include <Core/AccurateComparison.h>
4
5namespace DB
6{
7
8template <typename A, typename B>
9struct LeastBaseImpl
10{
11 using ResultType = NumberTraits::ResultOfLeast<A, B>;
12
13 template <typename Result = ResultType>
14 static inline Result apply(A a, B b)
15 {
16 /** gcc 4.9.2 successfully vectorizes a loop from this function. */
17 return static_cast<Result>(a) < static_cast<Result>(b) ? static_cast<Result>(a) : static_cast<Result>(b);
18 }
19
20#if USE_EMBEDDED_COMPILER
21 static constexpr bool compilable = true;
22
23 static inline llvm::Value * compile(llvm::IRBuilder<> & b, llvm::Value * left, llvm::Value * right, bool is_signed)
24 {
25 if (!left->getType()->isIntegerTy())
26 /// XXX minnum is basically fmin(), it may or may not match whatever apply() does
27 return b.CreateMinNum(left, right);
28 return b.CreateSelect(is_signed ? b.CreateICmpSLT(left, right) : b.CreateICmpULT(left, right), left, right);
29 }
30#endif
31};
32
33template <typename A, typename B>
34struct LeastSpecialImpl
35{
36 using ResultType = std::make_signed_t<A>;
37
38 template <typename Result = ResultType>
39 static inline Result apply(A a, B b)
40 {
41 static_assert(std::is_same_v<Result, ResultType>, "ResultType != Result");
42 return accurate::lessOp(a, b) ? static_cast<Result>(a) : static_cast<Result>(b);
43 }
44
45#if USE_EMBEDDED_COMPILER
46 static constexpr bool compilable = false; /// ???
47#endif
48};
49
50template <typename A, typename B>
51using LeastImpl = std::conditional_t<!NumberTraits::LeastGreatestSpecialCase<A, B>, LeastBaseImpl<A, B>, LeastSpecialImpl<A, B>>;
52
53struct NameLeast { static constexpr auto name = "least"; };
54using FunctionLeast = FunctionBinaryArithmetic<LeastImpl, NameLeast>;
55
56void registerFunctionLeast(FunctionFactory & factory)
57{
58 factory.registerFunction<FunctionLeast>();
59}
60
61}
62