{"id":45425,"date":"2023-04-02T20:59:59","date_gmt":"2022-12-11T06:11:24","guid":{"rendered":"https:\/\/www.silicloud.com\/zh\/blog\/45425-2\/"},"modified":"2024-04-29T21:39:30","modified_gmt":"2024-04-29T13:39:30","slug":"45425-2","status":"publish","type":"post","link":"https:\/\/www.silicloud.com\/zh\/blog\/45425-2\/","title":{"rendered":""},"content":{"rendered":"

\u306f\u3058\u3081\u306b<\/h1>\n

\u3053\u306eC++ Qiita Advent Calendar\u306e\u8a18\u4e8b\u3092\u8aad\u3093\u3067\u3044\u305f\u3060\u3044\u3066\u3001\u672c\u5f53\u306b\u3042\u308a\u304c\u3068\u3046\u3054\u3056\u3044\u307e\u3059\u3002\u4eca\u56de\u306f\u521d\u3081\u3066\u306e\u6295\u7a3f\u306b\u306a\u308a\u307e\u3059\u3002\u4eca\u5e74\u306e6 \u6708\u306bTokyo C++ Meetup\u3067\u4f1a\u3063\u305f\u65b9\u306b\u30a2\u30c9\u30d9\u30f3\u30c8\u30ab\u30ec\u30f3\u30c0\u30fc\u30a4\u30d9\u30f3\u30c8\u3092\u7d39\u4ecb\u3057\u3066\u3082\u3089\u3044\u307e\u3057\u305f\u3002\u3053\u306e\u5834\u3092\u501f\u308a\u3066\u3042\u308a\u304c\u3068\u3046\u3092\u4f1d\u308f\u305b\u3066\u3044\u305f\u3060\u304d\u307e\u3059\u3002<\/p>\n

\u79c1\u306eC++\u6b74\u306f10\u5e74\u4ee5\u4e0a\u3067\u3001\u305d\u306e\u5185\u306e\u7d045\u5e74\u306f\u4ed5\u4e8b\u3068\u3057\u3066\u4f7f\u3063\u3066\u3044\u307e\u3059\u3002\u4eca\u306e\u4ed5\u4e8b\u3067\u306fPython\u3068Rust\u3082\u3088\u304f\u4f7f\u3044\u307e\u3059\u3002C++\u4ee5\u5916\u3067\u6c17\u306b\u5165\u3063\u305f\u8a00\u8a9e\u306fScheme\u3001\u5177\u4f53\u7684\u306bShiro Kawai\u3055\u3093\u304c\u4f5c\u3063\u305fGauche\u3068\u3044\u3046Scheme\u306e\u65b9\u8a00\u3067\u3059\u30021<\/p>\n

\u3053\u306e\u8a18\u4e8b\u3067\u306f\u6d6e\u52d5\u5c0f\u6570\u70b9\u6570\u578b\uff08floating-point number\uff09\u306e\u5024\u3092\u6301\u3064\u5909\u6570\u3092\u6574\u6570\u578b\uff08integral number\uff09\u5909\u6570\u306b\u5909\u63db\u3059\u308b\u65b9\u6cd5\u306b\u3064\u3044\u3066\u304a\u8a71\u3057\u3057\u305f\u3044\u3067\u3059\u3002\u305f\u3060\u3057\u3001\u4e38\u3081\uff08\u30e9\u30a6\u30f3\u30c7\u30a3\u30f3\u30b0\uff09\u306e\u4e8b\u306b\u3064\u3044\u3066\u306f\u8a71\u3057\u307e\u305b\u3093\u3002\u4e38\u3081\u306e\u5f8c\u306b\u3001\u5b9b\u5148\u306e\u5909\u6570\u304c\u53ce\u307e\u308c\u306a\u3044\u5834\u5408\u306b\u3064\u3044\u3066\u8a71\u3057\u307e\u3059\u3002<\/p>\n

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\u79c1\u306f\u4fe1\u53f7\u51e6\u7406\u306e\u5206\u91ce\u306e\u4ed5\u4e8b\u3092\u3057\u3066\u3044\u3066\u3001\u6700\u3082\u3088\u304f\u4f7f\u7528\u3057\u3066\u3044\u308b\u306e\u306fC++\u3067\u3059\u3002\u79c1\u306b\u3068\u3063\u3066\u6d6e\u52d5\u5c0f\u6570\u70b9\u578b\u304b\u3089\u6574\u6570\u578b\u3078\u306e\u5909\u63db\u306f\u751f\u6d3b\u306e\u4e00\u90e8\u3067\u3042\u308a\u3001\u3042\u307e\u308a\u610f\u8b58\u3057\u3066\u3044\u307e\u305b\u3093\u3067\u3057\u305f\u3001\u5148\u65e5\u79c1\u304c\u3042\u308b\u51e6\u7406\u3092\u30c7\u30d0\u30c3\u30b0\u3057\u3066\u3044\u305f\u6642\u306b\u7a81\u7136\u4ee5\u4e0b\u306e\u30a8\u30e9\u30fc\u30e1\u30c3\u30bb\u30fc\u30b8\u304c\u8868\u793a\u3055\u308c\u308b\u307e\u3067\u306f\u3002<\/p>\n

main.cpp:2:26: runtime error: -5 is outside the range of representable values of type 'unsigned short'\r\nSUMMARY: UndefinedBehaviorSanitizer: undefined-behavior main.cpp:2:26 in\r\n<\/code><\/pre>\n
\u3053\u306e\u30a8\u30e9\u30fc\u306f\u306a\u304b\u306a\u304b\u8208\u5473\u3092\u5f15\u304d\u307e\u3057\u305f\u3002\u6d6e\u52d5\u5c0f\u6570\u70b9\u6570\u578b\u304b\u3089\u6574\u6570\u578b\u3078\u306e\u5909\u63db\u306f\u5fc5\u305a\u3057\u3082\u6210\u529f\u3059\u308b\u308f\u3051\u3067\u306f\u306a\u3044\u3053\u3068\u306f\u308f\u304b\u3063\u3066\u3044\u305f\u306e\u306b\u3001\u3053\u306e\u30a8\u30e9\u30fc\u3092\u898b\u308b\u307e\u3067\u3053\u306e\u72b6\u614b\u304b\u3089\u4f55\u3092\u3059\u308c\u3070\u3044\u3044\u306e\u304b\u3068\u771f\u5263\u306b\u8003\u3048\u305f\u3053\u3068\u306f\u3042\u308a\u307e\u305b\u3093\u3067\u3057\u305f\u3002<\/p>\n
\u4f55\u304c\u8d77\u304d\u305f\u306e\u304b\uff1f<\/h1>\n
C++\u6a19\u6e96\u898f\u683c\u3067\u306f\u3053\u306e\u3088\u3046\u306a\u30b1\u30fc\u30b9\u306b\u3064\u3044\u3066\u3069\u3046\u8a00\u53ca\u3057\u3066\u3044\u308b\u3067\u3057\u3087\u3046\u304b\uff1f2<\/p>\n
A prvalue of a floating-point type can be converted to a prvalue of an integer type. The conversion truncates; that is, the fractional part is discarded. The behavior is undefined if the truncated value cannot be represented in the destination type.<\/p><\/blockquote>\n
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\u3067\u306f\u3001\u3053\u306e\u554f\u984c\u306b\u5bfe\u3057\u3066\u3069\u3046\u5bfe\u51e6\u3059\u3079\u304d\u3067\u3057\u3087\u3046\u304b\uff1f\u672a\u5b9a\u7fa9\u52d5\u4f5c\u304c\u767a\u751f\u3057\u5f97\u308b\u306e\u3067\u3001\u305d\u308c\u3092\u907f\u3051\u305f\u3044\u5834\u5408\u3001\u81ea\u5206\u3067\u305d\u308c\u3092\u691c\u51fa\u3057\u56de\u907f\u3059\u308b\u305f\u3081\u306e\u4e88\u3081\u306b\u30c1\u30a7\u30c3\u30af\u3092\u66f8\u304b\u306a\u3051\u308c\u3070\u306a\u308a\u307e\u305b\u3093\u3002\u300c\u4e88\u3081\u300d\u306e\u30dd\u30a4\u30f3\u30c8\u306f\u91cd\u8981\u3067\u3059\u3002\u306a\u305c\u304b\u3068\u3044\u3046\u3068\u3001\u672a\u5b9a\u7fa9\u306e\u52d5\u4f5c\u306f\u4e8b\u5f8c\u306b\u691c\u51fa\u304c\u99c4\u76ee\u3067\u3059\u304b\u3089\u3002 \u524d\u306bJeanHeyd Meneide\u304c\u66f8\u3044\u305fSledgehammer Principle\u306f\u53c2\u8003\u306b\u306a\u308a\u307e\u3059\u30023<\/p>\n
Whenever you commit undefined behavior, you have to imagine that you\u2019ve taken a sledgehammer and smashed it into a large, very expensive vase your mother (or father, or grandmother, or whoever happens to be closest to you) owns. … This means that, before you swing your sledgehammer around, you check before you commit the undefined behavior, not afterwards.<\/p><\/blockquote>\n
\u4e00\u5fdc\u6982\u5ff5\u5b9f\u8a3c\u3092\u8f09\u305b\u3066\u307f\u307e\u3057\u305f\u304c\u3001\u5468\u8fba\u6761\u4ef6\u3092\u4e00\u3064\u4e00\u3064\u4e01\u5be7\u306b\u30ad\u30e3\u30c3\u30c1\u3057\u306a\u3044\u3068\u3044\u3051\u306a\u3044\u3068\u306f\u3044\u3044\u611f\u3058\u3068\u8a00\u3048\u307e\u305b\u3093\u3002\u57fa\u6e96\u30e9\u30a4\u30d6\u30e9\u30ea\u304c\u3053\u3046\u3044\u3046\u6a5f\u80fd\u3092\u5b9f\u88c5\u3057\u3066\u304f\u308c\u308c\u3070\u3088\u304b\u3063\u305f\u3067\u306f\u306a\u3044\u3060\u308d\u3046\u304b\u2026 \uff08\u6b7b\u4ea1\u30d5\u30e9\u30b0\uff094<\/p>\n
#include<\/span> <cmath><\/span>\r\n#include<\/span> <cstdint><\/span>\r\n#include<\/span> <limits><\/span>\r\n#include<\/span> <type_traits><\/span>\r\n\r\ntemplate<\/span> <<\/span>typename<\/span> Unsigned<\/span>><\/span>\r\nUnsigned<\/span> __attribute__<\/span>((<\/span>noinline<\/span>))<\/span> safe_cast<\/span>(<\/span>auto<\/span> in<\/span>)<\/span> {<\/span>\r\n  static_assert<\/span>(<\/span>std<\/span>::<\/span>is_unsigned_v<\/span><<\/span>Unsigned<\/span>><\/span>,<\/span> \"Output type must be unsigned\"<\/span>);<\/span>\r\n\r\n  if<\/span> constexpr<\/span> (<\/span>std<\/span>::<\/span>numeric_limits<\/span><<\/span>decltype<\/span>(<\/span>in<\/span>)<\/span>>::<\/span>has_quiet_NaN<\/span> ||<\/span>\r\n                std<\/span>::<\/span>numeric_limits<\/span><<\/span>decltype<\/span>(<\/span>in<\/span>)<\/span>>::<\/span>has_signaling_NaN<\/span>)<\/span> {<\/span>\r\n    if<\/span> (<\/span>std<\/span>::<\/span>isnan<\/span>(<\/span>in<\/span>))<\/span> {<\/span>\r\n      return<\/span> std<\/span>::<\/span>numeric_limits<\/span><<\/span>Unsigned<\/span>>::<\/span>min<\/span>();<\/span> \/\/ \u5927\u4e08\u592b\u304b\u306a\uff1f<\/span>\r\n    }<\/span>\r\n  }<\/span>\r\n  if<\/span> (<\/span>in<\/span> ><\/span> std<\/span>::<\/span>numeric_limits<\/span><<\/span>Unsigned<\/span>>::<\/span>max<\/span>())<\/span> {<\/span>\r\n    return<\/span> std<\/span>::<\/span>numeric_limits<\/span><<\/span>Unsigned<\/span>>::<\/span>max<\/span>();<\/span>\r\n  }<\/span> else<\/span> if<\/span> (<\/span>in<\/span> <<\/span> std<\/span>::<\/span>numeric_limits<\/span><<\/span>Unsigned<\/span>>::<\/span>min<\/span>())<\/span> {<\/span>\r\n    return<\/span> std<\/span>::<\/span>numeric_limits<\/span><<\/span>Unsigned<\/span>>::<\/span>min<\/span>();<\/span>\r\n  }<\/span>\r\n  return<\/span> static_cast<\/span><<\/span>Unsigned<\/span>><\/span>(<\/span>in<\/span>);<\/span>\r\n}<\/span>\r\n\r\n#include<\/span> <iostream><\/span>\r\n\r\nint<\/span> main<\/span>()<\/span> {<\/span>\r\n    std<\/span>::<\/span>cout<\/span> <<<\/span> safe_cast<\/span><<\/span>uint64_t<\/span>><\/span>(<\/span>std<\/span>::<\/span>nan<\/span>(<\/span>\"1\"<\/span>))<\/span> <<<\/span> std<\/span>::<\/span>endl<\/span>;<\/span>\r\n    std<\/span>::<\/span>cout<\/span> <<<\/span> safe_cast<\/span><<\/span>uint64_t<\/span>><\/span>(<\/span>std<\/span>::<\/span>numeric_limits<\/span><<\/span>double<\/span>>::<\/span>infinity<\/span>())<\/span> <<<\/span> std<\/span>::<\/span>endl<\/span>;<\/span>\r\n    std<\/span>::<\/span>cout<\/span> <<<\/span> safe_cast<\/span><<\/span>uint64_t<\/span>><\/span>(<\/span>-<\/span>std<\/span>::<\/span>numeric_limits<\/span><<\/span>double<\/span>>::<\/span>infinity<\/span>())<\/span> <<<\/span> std<\/span>::<\/span>endl<\/span>;<\/span>\r\n    std<\/span>::<\/span>cout<\/span> <<<\/span> safe_cast<\/span><<\/span>uint64_t<\/span>><\/span>(<\/span>NAN<\/span>)<\/span> <<<\/span> std<\/span>::<\/span>endl<\/span>;<\/span>\r\n\r\n    return<\/span> 0<\/span>;<\/span>\r\n}<\/span>\r\n<\/code><\/pre>\n
\u3061\u306a\u307f\u306b\u3053\u308c\u3001\u7121\u52b9\u5165\u529b\u3092\u51e6\u7406\u3059\u308b\u3068\u98fd\u548c\u6f14\u7b97\u3092\u65bd\u884c\u3057\u307e\u3059\u3002\u5f8c\u306b\u8a71\u3057\u307e\u3059\u304c\u3001\u98fd\u548c\u30ad\u30e3\u30b9\u30c8\u304c\u6570\u70b9\u306e\u3044\u3044\u3068\u3053\u308d\u3042\u308a\u307e\u3059\u3002\u9055\u3046\u884c\u70ba\u304c\u6b32\u3057\u3044\u969b\u306freturn\u547d\u4ee4\u3092\u7de8\u96c6\u3059\u308b\u304c\u3067\u304d\u307e\u3059\u3002<\/p>\n
CPU\u547d\u4ee4\u3067\u306f\u4f55\u304c\u8d77\u3053\u308a\u307e\u3059\u304b\uff1f<\/h1>\n
\u5c11\u3057\u3060\u3051\u8a71\u3057\u307e\u3059\u304c\u3001\u597d\u5947\u5fc3\u3092\u6301\u3063\u3066\u3044\u308b\u8aad\u8005\u306b\u306f\u3053\u306e\u4e00\u4f8b\u304c\u8208\u5473\u3042\u308b\u3068\u601d\u3063\u3066\u3044\u307e\u3059\u30025<\/p>\n
#include<\/span> <cstdint><\/span>\r\n\r\ntemplate<\/span><<\/span>typename<\/span> Out<\/span>><\/span>\r\nOut<\/span> __attribute__<\/span> ((<\/span>noinline<\/span>))<\/span> yolo_cast<\/span>(<\/span>float<\/span> in<\/span>)<\/span> {<\/span>\r\n    return<\/span> static_cast<\/span><<\/span>Out<\/span>><\/span>(<\/span>in<\/span>);<\/span>\r\n}<\/span>\r\n\r\nint<\/span> main<\/span>()<\/span> {<\/span>\r\n    return<\/span> yolo_cast<\/span><<\/span>uint16_t<\/span>><\/span>(<\/span>-<\/span>6.<\/span>f<\/span>);<\/span>\r\n}<\/span>\r\n<\/code><\/pre>\n
\u5099\u8003:\u300c\u4f55\u304c\u8d77\u3053\u3063\u305f\u304b\u300d\u306f\u540c\u3058\u30b3\u30f3\u30d1\u30a4\u30e9\u3001\u540c\u3058\u30d7\u30e9\u30c3\u30c8\u30d5\u30a9\u30fc\u30e0\u3001\u540c\u3058\u30b3\u30f3\u30d1\u30a4\u30e9\u30aa\u30d7\u30b7\u30e7\u30f3\u7b49\u306e\u5834\u5408\u306b\u9650\u308a\u6709\u610f\u7fa9\u3067\u3042\u308a\u307e\u3059\u3002\u305d\u308c\u306f\u672a\u5b9a\u7fa9\u52d5\u4f5c\u3060\u304b\u3089\u3067\u3059\u3002\u3053\u308c\u306f\u8a00\u8a9e\u306e\u884c\u52d5\u3088\u308a\u3001\u30b3\u30f3\u30d1\u30a4\u30e9\u5b9f\u88c5\u8a73\u7d30\u3092\u52c9\u5f37\u306b\u306a\u308b\u3053\u3068\u3067\u3059\u3002<\/p>\n
Rust\u306e\u5834\u5408\u306f\u3069\u3046\u3055\u308c\u307e\u3059\u304b\uff1f<\/h1>\n
\u3053\u306e\u8208\u5473\u6df1\u3044\u7591\u554f\u306b\u3064\u3044\u3066\u8abf\u3079\u3066\u3044\u308b\u3046\u3061\u306b\u3001Rust\u306e\u6c11\u306f\u3069\u3046\u3084\u3063\u3066\u3053\u306e\u554f\u984c\u3092\u6271\u3048\u308b\u306e\u3060\u308d\u3046\u3068\u601d\u3044\u59cb\u3081\u307e\u3057\u305f\u3002\u6d6e\u52d5\u5c0f\u6570\u70b9\u578b\u3068\u7a4d\u5206\u578b\u306fRust\u306b\u5185\u8535\u3055\u308c\u3066\u304a\u308a\u3001\u5909\u63db\u6f14\u7b97\u5b50as\u306fOption\u3084Result\u3067\u30e9\u30c3\u30d7\u3055\u308c\u304a\u3089\u305a\u3001\u305d\u306e\u578b\u306e\u6709\u52b9\u306a\u7d50\u679c\u3092\u8fd4\u3055\u306a\u3051\u308c\u3070\u306a\u3089\u306a\u3044\u8a00\u8a9e\u30ad\u30fc\u30ef\u30fc\u30c9\u3067\u3059\u3002<\/p>\n
\u305d\u306e\u7b54\u3048\u306f\u3001\u8868\u73fe\u4e0d\u53ef\u80fd\u306a\u5024\u306f\u51fa\u529b\u306e\u8868\u73fe\u53ef\u80fd\u306a\u6700\u5c0f\u5024\u3042\u308b\u3044\u306f\u6700\u5927\u5024\u306b\u98fd\u548c\u3055\u308c\u308b\u3068\u3044\u3046\u3053\u3068\u3067\u3059\u3002\u4e88\u60f3\u4ee5\u4e0a\u306b\u610f\u898b\u304c\u5206\u304b\u308c\u3066\u3044\u308b\u3088\u3046\u306b\u601d\u3048\u305f\u306e\u3067\u3001\u3053\u308c\u306b\u306f\u5c11\u3005\u9a5a\u3044\u305f\u304c\u3001\u305d\u308c\u3067\u3082\u30bb\u30de\u30f3\u30c6\u30a3\u30af\u30b9\u306f\u304d\u3061\u3093\u3068\u5b9a\u7fa9\u3055\u308c\u3066\u304a\u308a\u3001\u4e00\u8cab\u3057\u3066\u3044\u305f\u3002\u3057\u304b\u3057\u30b3\u30f3\u30d1\u30a4\u30e9\u3068\u30b3\u30fc\u30c9\u30b8\u30a7\u30cd\u30ec\u30fc\u30b7\u30e7\u30f3\u306e\u8996\u7dda\u304b\u3089\u4f55\u304c\u8d77\u3053\u3063\u3066\u3044\u308b\u306e\u304b\u3092\u7406\u89e3\u3059\u308b\u305f\u3081\u306b\u3001\u3082\u3046\u5c11\u3057\u8abf\u3079\u305f\u3044\u3068\u601d\u3044\u307e\u3057\u305f\u3002<\/p>\n
Rust\u30b3\u30f3\u30d1\u30a4\u30e9\u3068\u30d5\u30ed\u30f3\u30c8\u30a8\u30f3\u30c9\u304c\u6d6e\u52d5\u5c0f\u6570\u70b9\u578b\u3092\u6574\u6570\u578b\u306b\u5909\u63db\u3059\u308b\u5fc5\u8981\u304c\u3042\u308b\u3068\u304d\u306b\u767a\u884c\u3059\u308b\u547d\u4ee4\u306f\u3001llvm.fptosi.sat\u3068llvm.fptoui.sat\u3068\u3044\u3046\u7279\u5225\u306aLLVM IR\u547d\u4ee4\u3067\u3059\u30026\u3053\u306e\u547d\u4ee4\u306f\u4e0d\u601d\u8b70\u306a\u3053\u3068\u306bRust\u8a00\u8a9e\u306e\u6a19\u6e96\u30eb\u30fc\u30eb\u306b\u4f3c\u305f\u30bb\u30de\u30f3\u30c6\u30a3\u30af\u30b9\u3092\u6301\u3063\u3066\u3044\u307e\u3059\u3002\u5b9f\u306f\u3001Rust\u8a00\u8a9e\u59d4\u54e1\u4f1a\u304c\u3053\u306e\u30eb\u30fc\u30eb\u306e\u3042\u308a\u65b9\u3092\u6c7a\u5b9a\u3057\u305f\u4e0a\u3067\u8ffd\u52a0\u3055\u308c\u305f\u3082\u306e\u3067\u3059\u3002\u6570\u5e74\u9593\u3001\u3053\u308c\u306f\u78ba\u304b\u306bRust\u8a00\u8a9e\u306e\u672a\u5b9a\u7fa9\u306e\u52d5\u4f5c\u3067\u3042\u308a\u3001\u6a19\u6e96\u5316\u59d4\u54e1\u4f1a\u306f\u3053\u308c\u3092\u300c\u5065\u5168\u6027\u306e\u7a74\u300d(“soundness hole”)\u3068\u307f\u306a\u3057\u3066\u3044\u305f\u3088\u3046\u3067\u3059\u30027\u3057\u304b\u3057\u3001\u3053\u308c\u307e\u3067\u8003\u3048\u3066\u304d\u305f\u3088\u3046\u306a\u5236\u7d04\u304c\u3042\u308b\u305f\u3081\u3001\u3053\u308c\u3092\u3069\u3046\u3059\u3079\u304d\u304b\u306b\u3064\u3044\u3066\u660e\u78ba\u306a\u6c7a\u5b9a\u306f\u4e0b\u305b\u307e\u305b\u3093\u3067\u3057\u305f\u3002\u6700\u7d42\u7684\u306b\u3001\u300c\u30de\u30b7\u300d\u306a\u89e3\u6c7a\u7b56\u3068\u3057\u3066\u98fd\u548c\u5909\u63db\u306b\u843d\u3061\u7740\u304d\u3001\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u958b\u767a\u8005\u304c\u3053\u306e\u6a5f\u80fd\u3092\u30aa\u30f3\u306b\u3057\u305f\u30b3\u30fc\u30c9\u3092\u30d9\u30f3\u30c1\u30de\u30fc\u30af\u3059\u308b\u3088\u3046\u516c\u52df\u3057\u305f\u5f8c\u3001\u8a00\u8a9e\u6a19\u6e96\u306b\u6210\u6587\u5316\u3055\u308c\u307e\u3057\u305f\u30028<\/p>\n
(GCC\u306eRust\u30d5\u30ed\u30f3\u30c8\u30a8\u30f3\u30c9\u3067\u3042\u308bgccrs\u304c\u3053\u308c\u3092\u3069\u306e\u3088\u3046\u306b\u51e6\u7406\u3059\u308b\u306e\u304b\u4e0d\u601d\u8b70\u306b\u601d\u3046\u304b\u3082\u3057\u308c\u306a\u3044\u304c\u3001\u305d\u306e\u7b54\u3048\u306f\u4eca\u306e\u3068\u3053\u308d\u51e6\u7406\u3057\u306a\u3044\u3053\u3068\u3060\u3002)9<\/p>\n
\u6d6e\u52d5\u5c0f\u6570\u70b9\u4f8b\u5916\u3092\u4f7f\u3063\u305f\u3089\uff1f<\/h1>\n
\u6b8b\u5ff5\u306a\u304c\u3089\u3001\u3053\u306e\u8a71\u984c\u3092\u8a73\u3057\u304f\u53d6\u308a\u4e0a\u3052\u308b\u306b\u306f\u5341\u5206\u306a\u6642\u9593\u304c\u3042\u308a\u307e\u305b\u3093\u3067\u3057\u305f\u304c\u3001\u6307\u6458\u3057\u3066\u304a\u304b\u306a\u3051\u308c\u3070\u640d\u3067\u3059\u3002C++\u6a19\u6e96\u30e9\u30a4\u30d6\u30e9\u30ea\u306b\u306f\u3001CPU\u306e\u6d6e\u52d5\u5c0f\u6570\u70b9\u4f8b\u5916\u30ec\u30b8\u30b9\u30bf\u306e\u72b6\u614b\u3092\u30c1\u30a7\u30c3\u30af\u3059\u308b\u305f\u3081\u306e\u30e6\u30fc\u30c6\u30a3\u30ea\u30c6\u30a3\u95a2\u6570\u304c\u591a\u6570\u7d99\u627f\u3055\u308c\u3066\u3044\u307e\u3059\u3002\u3053\u306e\u95a2\u6570\u306f\u3082\u3068\u3082\u3068C\u6a19\u6e96\u306b\u898f\u5b9a\u3055\u308c\u3066\u3044\u305f\u3082\u306e\u3067\u3001\u307b\u3068\u3093\u3069\u5909\u66f4\u3055\u308c\u308b\u3053\u3068\u306a\u304fC++\u306b\u5f15\u304d\u7d99\u304c\u308c\u305f\u3002\u3053\u308c\u3089\u306e\u95a2\u6570\u3092\u4e0a\u8a18\u306e\u89e3\u6c7a\u7b56\u306b\u9069\u5fdc\u3055\u305b\u308b\u306e\u306f\u9b45\u529b\u7684\u304b\u3082\u3057\u308c\u307e\u305b\u3093\u304c\u3001\u3053\u308c\u3089\u306f\u6700\u5f8c\u306e\u6d6e\u52d5\u5c0f\u6570\u70b9\u6f14\u7b97\u306e\u72b6\u614b\u3057\u304b\u30c1\u30a7\u30c3\u30af\u3067\u304d\u306a\u3044\u305f\u3081\u3001\u305d\u306e\u6f14\u7b97\u304c\u672a\u5b9a\u7fa9\u306e\u52d5\u4f5c\u3067\u3082\u3042\u3063\u305f\u5834\u5408\u306b\u306f\u5f79\u306b\u7acb\u3061\u307e\u305b\u3093\u3002\u30d7\u30e9\u30c3\u30c8\u30d5\u30a9\u30fc\u30e0\u306b\u3088\u3063\u3066\u306f\u52d5\u4f5c\u3059\u308b\u304b\u3082\u3057\u308c\u307e\u305b\u3093\u304c\u3001\u30dd\u30fc\u30bf\u30d6\u30eb\u3068\u3055\u308c\u3066\u3044\u306a\u3044\u3002<\/p>\n
\u53c2\u8003\u6587\u732e:fenv.h10<\/p>\n
\u307e\u3068\u3081<\/h1>\n
\u52c9\u5f37\u306b\u306a\u308a\u307e\u3057\u305f\u30dd\u30a4\u30f3\u30c8\u3067\u3059\u3002<\/p>\n
    \n
  • \n
      UBSan11\u3092\u6709\u52b9\u306b\u3059\u308b\u3002UBSan\u3092\u6709\u52b9\u306b\u3057\u3066\u3044\u306a\u3051\u308c\u3070\u79c1\u9054\u306e\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u306b\u3053\u308c\u304c\u3042\u308b\u3053\u3068\u3092\u77e5\u308b\u3053\u3068\u306f\u306a\u304b\u3063\u305f\u3067\u3057\u3087\u3046\u3002<\/ul>\n<\/li>\n<\/ul>\n
       <\/p>\n
        \n
      • \n
          \u6d6e\u52d5\u5c0f\u6570\u70b9\u6570\u578b\u3068\u6574\u6570\u578b\u306f\u975e\u5e38\u306b\u7570\u306a\u308a\u3001\u53ef\u80fd\u306a\u9650\u308a\u3001\u3053\u308c\u3089\u306e\u9593\u306e\u5883\u754c\u3092\u975e\u5e38\u306b\u660e\u78ba\u306b\u3059\u308b\u3088\u3046\u306b\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u3092\u69cb\u7bc9\u3059\u3079\u304d\u3067\u3059\u3002<\/ul>\n<\/li>\n<\/ul>\n
           <\/p>\n
            C++\u6a19\u6e96\u898f\u683c\u306f\u672a\u5b9a\u7fa9\u306e\u52d5\u4f5c\u304c\u591a\u3059\u304e\u308b\u3053\u3068\u3002\u591a\u304f\u306e\u5834\u5408\u3001\u672a\u5b9a\u7fa9\u52d5\u4f5c\u306e\u307e\u307e\u306b\u3057\u3066\u304a\u304f\u3088\u308a\u3082\u4ed5\u69d8\u3092\u6c7a\u3081\u305f\u307b\u3046\u304c\u826f\u3044\u3067\u3059\u3002\u4e00\u65b9\u3001\u4ed6\u306e\u5b9f\u88c5\u306e\u53ef\u80fd\u6027\u3092\u6392\u9664\u3059\u308b\u3053\u3068\u3082\u554f\u984c\u3067\u3059\u3002<\/ul>\n
            https:\/\/practical-scheme.net\/gauche\/index.html \u21a9<\/p>\n
            https:\/\/eel.is\/c++draft\/conv#fpint \u21a9<\/p>\n
            https:\/\/thephd.dev\/c-undefined-behavior-and-the-sledgehammer-guideline \u21a9<\/p>\n
            https:\/\/godbolt.org\/z\/arT7cf76x \u21a9<\/p>\n
            https:\/\/godbolt.org\/z\/35MjY5GP5 \u21a9<\/p>\n
            https:\/\/llvm.org\/docs\/LangRef.html#saturating-floating-point-to-integer-conversions \u21a9<\/p>\n
            https:\/\/github.com\/rust-lang\/rust\/pull\/71269 \u21a9<\/p>\n
            https:\/\/internals.rust-lang.org\/t\/help-us-benchmark-saturating-float-casts\/6231 \u21a9<\/p>\n
            https:\/\/godbolt.org\/z\/T378jcead \u21a9<\/p>\n
            https:\/\/ja.cppreference.com\/w\/c\/numeric\/fenv \u21a9<\/p>\n
            https:\/\/clang.llvm.org\/docs\/UndefinedBehaviorSanitizer.html \u21a9<\/p>\n<\/section>\n","protected":false},"excerpt":{"rendered":"
            \u306f\u3058\u3081\u306b \u3053\u306eC++ Qiita Advent Calendar\u306e\u8a18\u4e8b\u3092\u8aad\u3093\u3067\u3044\u305f\u3060\u3044\u3066\u3001\u672c\u5f53\u306b\u3042\u308a\u304c\u3068\u3046\u3054\u3056 […]<\/p>\n","protected":false},"author":8,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-45425","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"yoast_head":"\n- Blog - Silicon Cloud<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.silicloud.com\/zh\/blog\/45425-2\/\" \/>\n<meta property=\"og:locale\" content=\"zh_CN\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:description\" content=\"\u306f\u3058\u3081\u306b \u3053\u306eC++ Qiita Advent Calendar\u306e\u8a18\u4e8b\u3092\u8aad\u3093\u3067\u3044\u305f\u3060\u3044\u3066\u3001\u672c\u5f53\u306b\u3042\u308a\u304c\u3068\u3046\u3054\u3056 […]\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.silicloud.com\/zh\/blog\/45425-2\/\" \/>\n<meta property=\"og:site_name\" content=\"Blog - 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