DocBohn

#include <stdint.h>

int switch_lg(uint32_t power_of_two) {
    switch (power_of_two) {
        case 0x1 :
            return 0;
        case 0x2 :
            return 1;
        case 0x4 :
            return 2;

DocBohn

#include <string.h>

int trim_k_and_r(char s[]) {
    int n;
    for (n = strlen(s) - 1; n >= 0; n--) {
        if (s[n] != ' ' && s[n] != '\t' && s[n] != '\n') {
            break;
        }
    }
    s[n + 1] = '\0';

DocBohn

void multiply_add(int *accumulator, int multiplier, int addend) {
    *accumulator *= multiplier;
    *accumulator += addend;
}

DocBohn

// The ternary operator version and the bit manipuation version is *not* equivalent to the "if" version
// since they'll have a memory access regardless of array[i]'s value

void clamp_if(int *array, int length) {
    for (int i = 0; i < length; i++) {
        if (array[i] < 0) {
            array[i] = 0;
        }
    }
}

DocBohn

// extracting the load in each conditional path or each half of the conditional assignment was necessary for vectorization
// duplicate loads is the impediment to vectorization, not if/else statements

void loop_feedback_if(int *restrict levels, int *restrict deviations, int length, int feedback) {
    for (int i = 0; i < length; i++) {
        int level = levels[i];
        if (deviations[i] < 0) {
            levels[i] = level + feedback;
        } else {
            levels[i] = level - feedback;

DocBohn

int apply_feedback_if(int level, int feedback, int deviation) {
    if (deviation < 0) {
        return level + feedback;
    } else {
        return level - feedback;
    }
}

int apply_feedback_ternary(int level, int feedback, int deviation) {
    return deviation < 0 ? level + feedback : level - feedback;

DocBohn

static int values[] = {5, 6, 2, 9, 8, 2, 9, 7};

long basic_loop(unsigned int count) {
    long sum = 0;
    for(unsigned int i = 0; i < count; i++) {
        sum += values[i % 8];
    }
    return sum;
}

DocBohn

void simple_memory_copy(char *restrict destination, char const *restrict source, unsigned int length) {
    for (unsigned int i = 0; i < length; i++) {
        destination[i] = source[i];
    }
}

DocBohn

void nonoptimizable_accumulate(int *accumulator, int const *array, int length) {
    for (int i = 0; i < length; i++) {
        *accumulator += array[i];
    }
}

void optimizable_accumulate(int *restrict accumulator, int const *restrict array, int length) {
    for (int i = 0; i < length; i++) {
        *accumulator += array[i];
    }

DocBohn

static int compute_triangle_number(int base) {
    int base_incremented = base + 1;
    int numerator = base * base_incremented;
    return numerator/2;
}

long simple_bonus_threshold(unsigned int number) {
    int triangle_number = compute_triangle_number(number);
    return 3 * triangle_number;
}