Address review comments

apache · Jul 10, 2019 · 974286a · 974286a
1 parent 885b182
commit 974286a
Show file tree

Hide file tree

Showing 2 changed files with 10 additions and 13 deletions.
diff --git a/src/arithmetic/int_set.cc b/src/arithmetic/int_set.cc
@@ -202,16 +202,13 @@ inline IntervalSet Combine<ir::Div>(Analyzer* analyzer,
     }
     if (is_one(b->min_value)) return a;
     // no relaxation is needed in here due to set is inclusive
-    if (is_zero(b->min_value)) {
-      // if b is in [0, k] and we assume that be won't be zero
-      // then we can directly return a.
-      CHECK(!is_zero(b->max_value)) << "Divide by zero";
-      return a;
-    } else if (analyzer->CanProveGreaterEqual(b->min_value, 1)) {
+    // NOTE: given b is a single point, we can allow division to error out.
+    // So it is not harmful to include zero point.
+    if (analyzer->CanProveGreaterEqual(b->min_value, 0)) {
       Expr min_value = a->HasLowerBound() ? a->min_value / b->min_value : neg_inf();
       Expr max_value = a->HasUpperBound() ? a->max_value / b->min_value : pos_inf();
       return IntervalSet(min_value, max_value);
-    } else if (analyzer->CanProveGreaterEqual(-b->min_value, 1)) {
+    } else if (analyzer->CanProveGreaterEqual(-b->min_value, 0)) {
       Expr min_value = a->HasUpperBound() ? a->max_value / b->min_value : neg_inf();
       Expr max_value = a->HasLowerBound() ? a->min_value / b->min_value : pos_inf();
       return IntervalSet(min_value, max_value);

diff --git a/src/arithmetic/rewrite_simplify.cc b/src/arithmetic/rewrite_simplify.cc
@@ -1024,8 +1024,8 @@ Mutate_(const Min* op, const Expr& self) {
     }
 
     // DivMod rules
-    // Divide up rounding: truc div
-    // NOTE: trucdiv(x, y) >= floordiv(x, y)
+    // Divide up rounding: trunc div
+    // NOTE: truncdiv(x, y) >= floordiv(x, y)
     TVM_TRY_REWRITE_IF(min(((x + c1) / c2) * c2, x), x,
                        c2.Eval()->value > 0 &&
                        c1.Eval()->value + 1 == c2.Eval()->value);
@@ -1209,8 +1209,8 @@ Mutate_(const Max* op, const Expr& self) {
     }
 
     // DivMod rules
-    // Divide up rounding: truc div
-    // NOTE: trucdiv(x, y) >= floordiv(x, y)
+    // Divide up rounding: trunc div
+    // NOTE: truncdiv(x, y) >= floordiv(x, y)
     TVM_TRY_REWRITE_IF(max(((x + c1) / c2) * c2, x), ((x + c1) / c2) * c2,
                        c2.Eval()->value > 0 &&
                        c1.Eval()->value + 1 == c2.Eval()->value);
@@ -1425,7 +1425,7 @@ Mutate_(const LT* op, const Expr& self) {
                        c1.Eval()->value < 0);
 
     // constant cancelation: only need to make use of one mod
-    // truc div
+    // trunc div
     TVM_TRY_REWRITE_IF(x * c2 < c1, x < (c1 - 1) / c2 + 1,
                        c1.Eval()->value > 0 &&
                        c2.Eval()->value > 0);
@@ -1457,7 +1457,7 @@ Mutate_(const LT* op, const Expr& self) {
                        c1.Eval()->value >= 0 &&
                        c2.Eval()->value < 0);
     // DivMod rules
-    // trucdiv
+    // truncdiv
     TVM_TRY_REWRITE_IF(x / c1 < c2, x < c1 * c2,
                        c1.Eval()->value > 0 &&
                        c2.Eval()->value > 0);