[turbofan] Make sure binop results do not overwrite deoptimization inputs on arm.

Review-Url: https://codereview.chromium.org/2031593002
Cr-Commit-Position: refs/heads/master@{#36658}

src/compiler/arm/instruction-selector-arm.cc

@@ -252,7 +252,14 @@ void VisitBinop(InstructionSelector* selector, Node* node,
     inputs[input_count++] = g.Label(cont->false_block());
   }
 
-  outputs[output_count++] = g.DefineAsRegister(node);
+  if (cont->IsDeoptimize()) {
+    // If we can deoptimize as a result of the binop, we need to make sure that
+    // the deopt inputs are not overwritten by the binop result. One way
+    // to achieve that is to declare the output register as same-as-first.
+    outputs[output_count++] = g.DefineSameAsFirst(node);
+  } else {
+    outputs[output_count++] = g.DefineAsRegister(node);
+  }
   if (cont->IsSet()) {
     outputs[output_count++] = g.DefineAsRegister(cont->result());
   }