Make UBSan happy.

src/hydrogen-instructions.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #include "src/double.h"
 #include "src/factory.h"
 #include "src/hydrogen-infer-representation.h"
 #include "src/property-details-inl.h"
@@ skipping 1904 matching lines @@
     if (!b->CanBeZero()) {
       ClearFlag(kCanBeDivByZero);
     }
     return result;
   } else {
     return HValue::InferRange(zone);
   }
 }
 
 
+// Returns the absolute value of its argument minus one, avoiding undefined
+// behavior at kMinInt.
+static int32_t AbsMinus1(int32_t a) { return a < 0 ? -(a + 1) : (a - 1); }
+
+
 Range* HMod::InferRange(Zone* zone) {
   if (representation().IsInteger32()) {
     Range* a = left()->range();
     Range* b = right()->range();
 
-    // The magnitude of the modulus is bounded by the right operand. Note that
-    // apart for the cases involving kMinInt, the calculation below is the same
-    // as Max(Abs(b->lower()), Abs(b->upper())) - 1.
-    int32_t positive_bound = -(Min(NegAbs(b->lower()), NegAbs(b->upper())) + 1);
+    // The magnitude of the modulus is bounded by the right operand.
+    int32_t positive_bound = Max(AbsMinus1(b->lower()), AbsMinus1(b->upper()));
 
     // The result of the modulo operation has the sign of its left operand.
     bool left_can_be_negative = a->CanBeMinusZero() || a->CanBeNegative();
     Range* result = new(zone) Range(left_can_be_negative ? -positive_bound : 0,
                                     a->CanBePositive() ? positive_bound : 0);
 
     result->set_can_be_minus_zero(!CheckFlag(kAllUsesTruncatingToInt32) &&
                                   left_can_be_negative);
 
     if (!a->CanBeNegative()) {
@@ skipping 2825 matching lines @@
       break;
     case HObjectAccess::kExternalMemory:
       os << "[external-memory]";
       break;
   }
 
   return os << "@" << access.offset();
 }
 
 } }  // namespace v8::internal