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This article mainly explains "how to understand if-else involves branch prediction". The content of the article is simple and clear, and it is easy to learn and understand. Please follow the editor's train of thought to study and learn "how to understand if-else involves branch prediction".

First, take a look at a classic piece of code and count its execution time:

/ / test_predict.cc # include # include # include int main () {const unsigned ARRAY_SIZE = 50000; int data [array _ SIZE]; const unsigned DATA_STRIDE = 256; for (unsigned c = 0; c

< ARRAY_SIZE; ++c) data[c] = std::rand() % DATA_STRIDE; std::sort(data, data + ARRAY_SIZE); { // 测试部分 clock_t start = clock(); long long sum = 0; for (unsigned i = 0; i < 100000; ++i) { for (unsigned c = 0; c < ARRAY_SIZE; ++c) { if (data[c] >

Sum + = data [c];}} double elapsedTime = static_cast (clock ()-start) / CLOCKS_PER_SEC; std::cout

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