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#include "Halide.h"
using namespace Halide;
using namespace Halide::Internal;
int main(int argc, char **argv) {
Func f, g;
Var x, y;
Param<bool> p;
// In Stmt IR, if statements can be injected by GuardWithIf, RDom
// predicates, specializations, and uses of undef. There are
// various situations where an if statement can end up further
// inside a loop nest than strictly necessary. Here's one:
f(x, y) = select(p, x + y, undef<int>());
g(x, y) = select(p, f(x, y), undef<int>());
f.compute_at(g, x);
// Both f and g get an if statement for p, which could instead be
// a single combined top-level if statement. Trim-no-ops is
// supposed to lift the if statement out of the loops to the top
// level. Let's check if it worked.
class Checker : public IRMutator {
bool in_loop = false;
Stmt visit(const For *op) override {
ScopedValue<bool> old(in_loop, true);
return IRMutator::visit(op);
}
Stmt visit(const IfThenElse *op) override {
if_in_loop |= in_loop;
return IRMutator::visit(op);
}
public:
bool if_in_loop = false;
} checker;
g.add_custom_lowering_pass(&checker, []() {});
p.set(true);
g.realize({1024, 1024});
if (checker.if_in_loop) {
printf("Found an if statement inside a loop. This was not supposed to happen\n");
return 1;
}
printf("Success!\n");
return 0;
}
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