Examples of loop hoisting (LICM)

licm.c

#include <stddef.h>

// TODO(dannas): Find examples of loop hoisting. WIP
// https://godbolt.org/z/YWf5c7

// baseline
void f1(int a[], size_t N) {
    for (size_t i = 0; i < N; i++) {
        a[i] = i;
    }
}

// Mult strength-reduced to shift
void f2(int a[], size_t N) {
    for (size_t i = 0; i < N; i++) {
        a[i] = i*2;
    }
}

// x is hoisted outside the loop
void f3(int a[], size_t N) {
    for (size_t i = 0; i < N; i++) {
        int x = N*N;
        a[i] = x + i;
    }
}

// N*N is hoisted outside the loop
void f4(int a[], size_t N) {
    for (size_t i = 0; i < N*N; i++) {
        a[i] = i;
    }
}

// Was hoping for loop unswitching, but doesn't happen
void f5(int a[], size_t N, int x) {
    for (size_t i = 0; i < N; i++) {
        if (x) {
            a[i] = i;
        }
    }
}