From 3555769efd52c08d004962757d4cf15e3e5b4294 Mon Sep 17 00:00:00 2001
From: Ziheng Jiang <jzhtomas@gmail.com>
Date: Tue, 21 Feb 2017 12:42:46 -0800
Subject: [PATCH] [ARITH] Add CombineInterval<Div> in IntSet (#48)
* [FIX] add CombineInterval<Div>
* fix error message and add comment about rounding
* fix comment
---
src/arithmetic/int_set.cc | 28 +++++++++++++++++++++++++++-
1 file changed, 27 insertions(+), 1 deletion(-)
diff --git a/src/arithmetic/int_set.cc b/src/arithmetic/int_set.cc
index 8c89d93e6..709da26a6 100644
--- a/src/arithmetic/int_set.cc
+++ b/src/arithmetic/int_set.cc
@@ -244,7 +244,7 @@ inline IntSet CombineInterval<Mul>(Interval a, Interval b) {
if (is_one(b.min)) return IntervalSet::make(a);
Expr e1 = a.has_lower_bound() ? ComputeExpr<Mul>(a.min, b.min) : a.min;
Expr e2 = a.has_upper_bound() ? ComputeExpr<Mul>(a.max, b.min) : a.max;
- // This is relaxiation
+ // no relaxation is needed in here due to set is inclusive
// TODO(tqchen): consider convert to StrideSet.
if (is_positive_const(b.min)) {
return IntervalSet::make(e1, e2);
@@ -259,6 +259,32 @@ inline IntSet CombineInterval<Mul>(Interval a, Interval b) {
return IntSet::everything();
}
+template<>
+inline IntSet CombineInterval<Div>(Interval a, Interval b) {
+ if (a.is_single_point() && b.is_single_point()) {
+ return IntSet::single_point(ComputeExpr<Div>(a.min, b.min));
+ }
+ if (b.is_single_point()) {
+ if (is_zero(b.min)) {
+ LOG(FATAL) << "Divide by zero in CombineInterval Div";
+ }
+ if (is_one(b.min)) return IntervalSet::make(a);
+ Expr e1 = a.has_lower_bound() ? ComputeExpr<Div>(a.min, b.min) : a.min;
+ Expr e2 = a.has_upper_bound() ? ComputeExpr<Div>(a.max, b.min) : a.max;
+ // no relaxation is needed in here due to set is inclusive
+ if (is_positive_const(b.min)) {
+ return IntervalSet::make(e1, e2);
+ } else if (is_negative_const(b.min)) {
+ return IntervalSet::make(e2, e1);
+ } else if (a.is_bounded()) {
+ Expr cmp = b.min >= make_zero(b.min.type().element_of());
+ return IntervalSet::make(select(cmp, e1, e2), select(cmp, e2, e1));
+ }
+ }
+ LOG(WARNING) << "Return Everything in CombineInterval Div";
+ return IntSet::everything();
+}
+
template<>
inline IntSet CombineInterval<Max>(Interval a, Interval b) {
if (a.is_single_point() && b.is_single_point()) {
--
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