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

src/compiler/mips64/instruction-selector-mips64.cc

Index: src/compiler/mips64/instruction-selector-mips64.cc
diff --git a/src/compiler/mips64/instruction-selector-mips64.cc b/src/compiler/mips64/instruction-selector-mips64.cc
index 3e1f98e5e27abbf1f824b1e922360affa89a6c9a..dca98f745df5a898d0b766f6d86e252280f18fe2 100644
--- a/src/compiler/mips64/instruction-selector-mips64.cc
+++ b/src/compiler/mips64/instruction-selector-mips64.cc
@@ -109,7 +109,14 @@ static 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());
   }