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[Arith][Refactor] Extract And/Or/Not handling from RewriteSimplifier #12942

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[Arith][Refactor] Extract And/Or/Not handling from RewriteSimplifier #12942

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2cda4c3
[Arith][Refactor] Extract And/Or/Not handling from RewriteSimplifier
Lunderberg Sep 29, 2022
ffad69c
lint fix, include <utility>
Lunderberg Sep 29, 2022
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261 changes: 171 additions & 90 deletions src/arith/rewrite_simplify.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -29,6 +29,7 @@
#include <tvm/tir/op.h>

#include <algorithm>
#include <utility>

#include "../target/datatype/registry.h"
#include "const_fold.h"
Expand Down Expand Up @@ -232,17 +233,17 @@ std::function<void()> RewriteSimplifier::Impl::EnterConstraint(const PrimExpr& c
for (const PrimExpr& subconstraint : ExtractConstraints(new_constraint)) {
if (SideEffect(subconstraint) <= CallEffectKind::kPure) {
literal_constraints_.push_back(subconstraint);
// We could apply this during TryMatchLiteralConstraint, but
// that would require performing a rewrite of each expression
// being checked. This way, we only apply a rewrite for each
// constraint being applied.
PrimExpr negation;
if (subconstraint.dtype().is_bool()) {
negation = Not(subconstraint);
// We could apply RewriteBooleanOperators during
// TryMatchLiteralConstraint, but that would require
// performing a rewrite of each expression being checked.
// This way, we only apply a rewrite for each constraint being
// applied.
negation = RewriteBooleanOperators(Not(subconstraint));
} else {
negation = subconstraint == make_zero(subconstraint.dtype());
}
negation = operator()(negation);
literal_constraints_.push_back(Not(negation));
}
}
Expand Down Expand Up @@ -1301,7 +1302,7 @@ PrimExpr RewriteSimplifier::Impl::VisitExpr_(const MaxNode* op) {
}

Optional<PrimExpr> RewriteSimplifier::Impl::TryMatchLiteralConstraint(const PrimExpr& expr) const {
PrimExpr negation = Not(expr);
PrimExpr negation = RewriteBooleanOperators(Not(expr));

ExprDeepEqual expr_equal;
for (const auto& constraint : literal_constraints_) {
Expand Down Expand Up @@ -1497,105 +1498,26 @@ PrimExpr RewriteSimplifier::Impl::VisitExpr_(const LTNode* op) {
PrimExpr RewriteSimplifier::Impl::VisitExpr_(const NotNode* op) {
PrimExpr ret = IRMutatorWithAnalyzer::VisitExpr_(op);
op = ret.as<NotNode>();
if (auto const_res = TryConstFold<Not>(op->a)) return const_res.value();
if (auto match = TryMatchLiteralConstraint(ret)) return match.value();

// Pattern var to match any expression
PVar<PrimExpr> x, y;
PVar<int> lanes;
if (op->dtype.lanes() != 1) {
TVM_TRY_REWRITE(!broadcast(x, lanes), broadcast(!x, lanes));
}
if (auto match = TryMatchLiteralConstraint(ret)) return match.value();

TVM_TRY_REWRITE(!(!x), x);
TVM_TRY_REWRITE(!(x <= y), y < x);
TVM_TRY_REWRITE(!(x >= y), x < y);
TVM_TRY_REWRITE(!(x < y), y <= x);
TVM_TRY_REWRITE(!(x > y), x <= y);
TVM_TRY_REWRITE(!(x == y), x != y);
TVM_TRY_REWRITE(!(x != y), x == y);
TVM_TRY_RECURSIVE_REWRITE(!(x || y), (!x) && (!y));
TVM_TRY_RECURSIVE_REWRITE(!(x && y), (!x) || (!y));
return ret;
return RewriteBooleanOperators(ret);
}

PrimExpr RewriteSimplifier::Impl::VisitExpr_(const AndNode* op) {
PrimExpr ret = IRMutatorWithAnalyzer::VisitExpr_(op);
op = ret.as<AndNode>();
if (auto const_res = TryConstFold<And>(op->a, op->b)) return const_res.value();
if (auto match = TryMatchLiteralConstraint(ret)) return match.value();

// Pattern var to match any expression
PVar<PrimExpr> x, y;
// Pattern var match IntImm
PVar<IntImm> c1, c2;
PVar<int> lanes;

if (op->dtype.lanes() != 1) {
TVM_TRY_REWRITE(broadcast(x, lanes) && broadcast(y, lanes), broadcast(x && y, lanes));
}

auto cfalse = PConst<PrimExpr>(make_const(op->dtype, false));
TVM_TRY_REWRITE(x == y && x != y, cfalse);
TVM_TRY_REWRITE(x != y && x == y, cfalse);
TVM_TRY_REWRITE(x && !x, cfalse);
TVM_TRY_REWRITE(x <= y && y < x, cfalse);
TVM_TRY_REWRITE(y < x && x <= y, cfalse);

TVM_TRY_REWRITE_IF(x < c1 && c2 < x, cfalse, c2.Eval()->value + 1 >= c1.Eval()->value);
TVM_TRY_REWRITE_IF(c2 < x && x < c1, cfalse, c2.Eval()->value + 1 >= c1.Eval()->value);

TVM_TRY_REWRITE_IF(x < c1 && c2 <= x, cfalse, c2.Eval()->value >= c1.Eval()->value);
TVM_TRY_REWRITE_IF(c2 <= x && x < c1, cfalse, c2.Eval()->value >= c1.Eval()->value);
TVM_TRY_REWRITE_IF(x <= c1 && c2 < x, cfalse, c2.Eval()->value >= c1.Eval()->value);
TVM_TRY_REWRITE_IF(c2 < x && x <= c1, cfalse, c2.Eval()->value >= c1.Eval()->value);

TVM_TRY_REWRITE_IF(x <= c1 && c2 <= x, cfalse, c2.Eval()->value > c1.Eval()->value);
TVM_TRY_REWRITE_IF(c2 <= x && x <= c1, cfalse, c2.Eval()->value > c1.Eval()->value);

TVM_TRY_REWRITE(x == c1 && x != c2, x == c1 && c1 != c2);
TVM_TRY_REWRITE(x != c2 && x == c1, x == c1 && c1 != c2);
return ret;
return RewriteBooleanOperators(ret);
}

PrimExpr RewriteSimplifier::Impl::VisitExpr_(const OrNode* op) {
PrimExpr ret = IRMutatorWithAnalyzer::VisitExpr_(op);
op = ret.as<OrNode>();
if (auto const_res = TryConstFold<Or>(op->a, op->b)) return const_res.value();
if (auto match = TryMatchLiteralConstraint(ret)) return match.value();

// Pattern var to match any expression
PVar<PrimExpr> x, y;
// Pattern var match IntImm
PVar<IntImm> c1, c2;
PVar<int> lanes;

if (op->dtype.lanes() != 1) {
TVM_TRY_REWRITE(broadcast(x, lanes) || broadcast(y, lanes), broadcast(x || y, lanes));
}

auto ctrue = PConst<PrimExpr>(make_const(op->dtype, true));

TVM_TRY_REWRITE(x == y || x != y, ctrue);
TVM_TRY_REWRITE(x != y || x == y, ctrue);
TVM_TRY_REWRITE(x || !x, ctrue);
TVM_TRY_REWRITE(x <= y || y < x, ctrue);
TVM_TRY_REWRITE(y < x || x <= y, ctrue);

TVM_TRY_REWRITE_IF(x < c1 || c2 < x, ctrue, c2.Eval()->value < c1.Eval()->value);
TVM_TRY_REWRITE_IF(c2 < x || x < c1, ctrue, c2.Eval()->value < c1.Eval()->value);

TVM_TRY_REWRITE_IF(x <= c1 || c2 < x, ctrue, c2.Eval()->value <= c1.Eval()->value);
TVM_TRY_REWRITE_IF(c2 < x || x <= c1, ctrue, c2.Eval()->value <= c1.Eval()->value);
TVM_TRY_REWRITE_IF(x < c1 || c2 <= x, ctrue, c2.Eval()->value <= c1.Eval()->value);
TVM_TRY_REWRITE_IF(c2 <= x || x < c1, ctrue, c2.Eval()->value <= c1.Eval()->value);

TVM_TRY_REWRITE_IF(x <= c1 || c2 <= x, ctrue, c2.Eval()->value <= c1.Eval()->value + 1);
TVM_TRY_REWRITE_IF(c2 <= x || x <= c1, ctrue, c2.Eval()->value <= c1.Eval()->value + 1);

TVM_TRY_REWRITE(x != c1 || x == c2, x != c1 || c1 == c2);
TVM_TRY_REWRITE(x == c2 || x != c1, x != c1 || c1 == c2);
return ret;
return RewriteBooleanOperators(ret);
}

PrimExpr RewriteSimplifier::Impl::VisitExpr_(const SelectNode* op) {
Expand Down Expand Up @@ -1746,5 +1668,164 @@ RewriteSimplifier::RewriteSimplifier(Analyzer* parent) : impl_(new Impl(parent))

RewriteSimplifier::~RewriteSimplifier() { delete impl_; }

namespace {
/* Utility for rewriting only boolean portions of an expression
*
* Intended for application on an expression that has previously been
* simplified, but has subsequent manipulations performed.
* (e.g. Finding the simplified negation of a conditional without
* performing a full simplification.)
*/
class BooleanRewriter : public ExprMutator {
private:
PrimExpr VisitExpr(const PrimExpr& expr) override {
if (expr.dtype().is_bool()) {
return ExprMutator::VisitExpr(expr);
} else {
return expr;
}
}

PrimExpr VisitExpr_(const NotNode* op) override {
PrimExpr ret = GetRef<PrimExpr>(op);

if (auto const_res = TryConstFold<Not>(op->a)) return const_res.value();

PVar<PrimExpr> x, y;
PVar<int> lanes;
if (op->dtype.lanes() != 1) {
TVM_TRY_REWRITE(!broadcast(x, lanes), broadcast(!x, lanes));
}

TVM_TRY_RECURSIVE_REWRITE(!(!x), x);
TVM_TRY_RECURSIVE_REWRITE(!(x || y), (!x) && (!y));
TVM_TRY_RECURSIVE_REWRITE(!(x && y), (!x) || (!y));
TVM_TRY_REWRITE(!(x <= y), y < x);
TVM_TRY_REWRITE(!(x >= y), x < y);
TVM_TRY_REWRITE(!(x < y), y <= x);
TVM_TRY_REWRITE(!(x > y), x <= y);
TVM_TRY_REWRITE(!(x == y), x != y);
TVM_TRY_REWRITE(!(x != y), x == y);

return ret;
}

PrimExpr VisitExpr_(const AndNode* op) override {
And ret = GetRef<And>(op);
if (allow_recursion_) {
allow_recursion_ = false;
PrimExpr a = VisitExpr(ret->a);
PrimExpr b = VisitExpr(ret->b);
bool is_same = a.same_as(ret->a) && b.same_as(b);
if (!is_same) {
ret = And(a, b);
}
allow_recursion_ = true;
}
op = ret.get();

if (auto const_res = TryConstFold<And>(op->a, op->b)) return const_res.value();

// Pattern var to match any expression
PVar<PrimExpr> x, y;
// Pattern var match IntImm
PVar<IntImm> c1, c2;
PVar<int> lanes;

if (op->dtype.lanes() != 1) {
TVM_TRY_REWRITE(broadcast(x, lanes) && broadcast(y, lanes), broadcast(x && y, lanes));
}

auto cfalse = PConst<PrimExpr>(make_const(op->dtype, false));

TVM_TRY_REWRITE(x == y && x != y, cfalse);
TVM_TRY_REWRITE(x != y && x == y, cfalse);
TVM_TRY_REWRITE(x && !x, cfalse);
TVM_TRY_REWRITE(x <= y && y < x, cfalse);
TVM_TRY_REWRITE(y < x && x <= y, cfalse);

TVM_TRY_REWRITE_IF(x < c1 && c2 < x, cfalse, c2.Eval()->value + 1 >= c1.Eval()->value);
TVM_TRY_REWRITE_IF(c2 < x && x < c1, cfalse, c2.Eval()->value + 1 >= c1.Eval()->value);

TVM_TRY_REWRITE_IF(x < c1 && c2 <= x, cfalse, c2.Eval()->value >= c1.Eval()->value);
TVM_TRY_REWRITE_IF(c2 <= x && x < c1, cfalse, c2.Eval()->value >= c1.Eval()->value);
TVM_TRY_REWRITE_IF(x <= c1 && c2 < x, cfalse, c2.Eval()->value >= c1.Eval()->value);
TVM_TRY_REWRITE_IF(c2 < x && x <= c1, cfalse, c2.Eval()->value >= c1.Eval()->value);

TVM_TRY_REWRITE_IF(x <= c1 && c2 <= x, cfalse, c2.Eval()->value > c1.Eval()->value);
TVM_TRY_REWRITE_IF(c2 <= x && x <= c1, cfalse, c2.Eval()->value > c1.Eval()->value);

TVM_TRY_REWRITE(x == c1 && x != c2, x == c1 && c1 != c2);
TVM_TRY_REWRITE(x != c2 && x == c1, x == c1 && c1 != c2);

return std::move(ret);
}

PrimExpr VisitExpr_(const OrNode* op) override {
Or ret = GetRef<Or>(op);
if (allow_recursion_) {
allow_recursion_ = false;
PrimExpr a = VisitExpr(ret->a);
PrimExpr b = VisitExpr(ret->b);
bool is_same = a.same_as(ret->a) && b.same_as(b);
if (!is_same) {
ret = Or(a, b);
}
allow_recursion_ = true;
}
op = ret.get();

if (auto const_res = TryConstFold<Or>(op->a, op->b)) return const_res.value();

// Pattern var to match any expression
PVar<PrimExpr> x, y;
// Pattern var match IntImm
PVar<IntImm> c1, c2;
PVar<int> lanes;

if (op->dtype.lanes() != 1) {
TVM_TRY_REWRITE(broadcast(x, lanes) || broadcast(y, lanes), broadcast(x || y, lanes));
}

auto ctrue = PConst<PrimExpr>(make_const(op->dtype, true));

TVM_TRY_REWRITE(x == y || x != y, ctrue);
TVM_TRY_REWRITE(x != y || x == y, ctrue);
TVM_TRY_REWRITE(x || !x, ctrue);
TVM_TRY_REWRITE(x <= y || y < x, ctrue);
TVM_TRY_REWRITE(y < x || x <= y, ctrue);

TVM_TRY_REWRITE_IF(x < c1 || c2 < x, ctrue, c2.Eval()->value < c1.Eval()->value);
TVM_TRY_REWRITE_IF(c2 < x || x < c1, ctrue, c2.Eval()->value < c1.Eval()->value);

TVM_TRY_REWRITE_IF(x <= c1 || c2 < x, ctrue, c2.Eval()->value <= c1.Eval()->value);
TVM_TRY_REWRITE_IF(c2 < x || x <= c1, ctrue, c2.Eval()->value <= c1.Eval()->value);
TVM_TRY_REWRITE_IF(x < c1 || c2 <= x, ctrue, c2.Eval()->value <= c1.Eval()->value);
TVM_TRY_REWRITE_IF(c2 <= x || x < c1, ctrue, c2.Eval()->value <= c1.Eval()->value);

TVM_TRY_REWRITE_IF(x <= c1 || c2 <= x, ctrue, c2.Eval()->value <= c1.Eval()->value + 1);
TVM_TRY_REWRITE_IF(c2 <= x || x <= c1, ctrue, c2.Eval()->value <= c1.Eval()->value + 1);

TVM_TRY_REWRITE(x != c1 || x == c2, x != c1 || c1 == c2);
TVM_TRY_REWRITE(x == c2 || x != c1, x != c1 || c1 == c2);

return std::move(ret);
}

PrimExpr RecursiveRewrite(const PrimExpr& expr) {
bool cache = true;
std::swap(cache, allow_recursion_);
auto output = VisitExpr(expr);
std::swap(cache, allow_recursion_);
return output;
}

private:
bool allow_recursion_{false};
};
} // namespace

PrimExpr RewriteBooleanOperators(const PrimExpr& expr) { return BooleanRewriter()(expr); }

} // namespace arith
} // namespace tvm
14 changes: 14 additions & 0 deletions src/arith/rewrite_simplify.h
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Original file line number Diff line number Diff line change
Expand Up @@ -149,6 +149,20 @@ class RewriteSimplifier::Impl : public IRMutatorWithAnalyzer {
}
};

/* Utility for rewriting only boolean portions of an expression
*
* Intended for application on an expression that has previously been
* simplified, but has subsequent manipulations performed.
* (e.g. Finding the simplified negation of a conditional without
* performing a full simplification.) Only a single simplication step
* is performed.
*
* \param expr The boolean expression to be simplified
*
* \returns The simplified boolean expression
*/
PrimExpr RewriteBooleanOperators(const PrimExpr& expr);

} // namespace arith
} // namespace tvm
#endif // TVM_ARITH_REWRITE_SIMPLIFY_H_