[Crankshaft] ia32/x64: Fix environment handling for LMulI

src/crankshaft/x64/lithium-x64.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/crankshaft/x64/lithium-x64.h"
 
 #include <sstream>
 
 #if V8_TARGET_ARCH_X64
 
@@ skipping 1493 matching lines @@
     return DoArithmeticT(Token::MOD, instr);
   }
 }
 
 
 LInstruction* LChunkBuilder::DoMul(HMul* instr) {
   if (instr->representation().IsSmiOrInteger32()) {
     DCHECK(instr->left()->representation().Equals(instr->representation()));
     DCHECK(instr->right()->representation().Equals(instr->representation()));
     LOperand* left = UseRegisterAtStart(instr->BetterLeftOperand());
-    LOperand* right = UseOrConstant(instr->BetterRightOperand());
+    HValue* h_right = instr->BetterRightOperand();
+    LOperand* right = UseOrConstant(h_right);
     LMulI* mul = new(zone()) LMulI(left, right);
-    if (instr->CheckFlag(HValue::kCanOverflow) ||
-        instr->CheckFlag(HValue::kBailoutOnMinusZero)) {
+    int constant_value =
+        h_right->IsConstant() ? HConstant::cast(h_right)->Integer32Value() : 0;
+    // |needs_environment| must mirror the cases where LCodeGen::DoMulI calls
+    // |DeoptimizeIf|.
+    bool needs_environment =
+        instr->CheckFlag(HValue::kCanOverflow) ||
+        (instr->CheckFlag(HValue::kBailoutOnMinusZero) &&
+         (!right->IsConstantOperand() || constant_value <= 0));
+    if (needs_environment) {
       AssignEnvironment(mul);
     }
     return DefineSameAsFirst(mul);
   } else if (instr->representation().IsDouble()) {
     return DoArithmeticD(Token::MUL, instr);
   } else {
     return DoArithmeticT(Token::MUL, instr);
   }
 }
 
@@ skipping 1148 matching lines @@
   LAllocateBlockContext* result =
       new(zone()) LAllocateBlockContext(context, function);
   return MarkAsCall(DefineFixed(result, rsi), instr);
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64