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#include "Halide.h"
using namespace Halide;
int main(int argc, char **argv) {
Func f;
Var x;
// Compute the GCD of two numbers using the euclidean algorithm.
Param<int> pa, pb;
// Sort the inputs. We'll maintain the invariant that a >= b.
Expr a = max(pa, pb), b = min(pa, pb);
f() = {a, b, 0};
// The worst-case number of iterations occurs when the smaller
// number is 1. Iterating up to 'a' should suffice.
RDom r(0, a);
a = f()[0];
b = f()[1];
// Stop looping when b hits zero. It would be nice if this created
// an early-exit from the reduction loop, but that doesn't
// currently happen.
r.where(b != 0);
f() = {b, a % b, r};
// Let's unroll it. This originally triggered two bugs:
// 1) There are let statements that get unified, even though they
// include stores with values that change.
// 2) There are if statements with the same condition that get
// unified, even though the value of the condition depends on a
// load whose value may have changed within the body of the first
// if.
f.update().unroll(r, 4);
pa.set(131 * 151 * 2);
pb.set(131 * 157 * 3);
int result = evaluate<int>(f()[0]);
int correct = 131;
if (result != correct) {
printf("Bad GCD: %d != %d\n", result, correct);
return 1;
}
printf("Success!\n");
return 0;
}
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