Orthogonalize Lithium binary op instructions.

src/arm/lithium-codegen-arm.cc

Index: src/arm/lithium-codegen-arm.cc
diff --git a/src/arm/lithium-codegen-arm.cc b/src/arm/lithium-codegen-arm.cc
index b01f840c63140aff23c46f227798c2592a52db22..059aa13322adb4dde769c9be9cf594fac8133cb4 100644
--- a/src/arm/lithium-codegen-arm.cc
+++ b/src/arm/lithium-codegen-arm.cc
@@ -5007,15 +5007,19 @@ void LCodeGen::DoTaggedToI(LTaggedToI* instr) {
 
   Register input_reg = ToRegister(input);
 
-  DeferredTaggedToI* deferred = new(zone()) DeferredTaggedToI(this, instr);
-
-  // Optimistically untag the input.
-  // If the input is a HeapObject, SmiUntag will set the carry flag.
-  __ SmiUntag(input_reg, SetCC);
-  // Branch to deferred code if the input was tagged.
-  // The deferred code will take care of restoring the tag.
-  __ b(cs, deferred->entry());
-  __ bind(deferred->exit());
+  if (instr->hydrogen()->value()->representation().IsSmi()) {
+    __ SmiUntag(input_reg);
+  } else {
+    DeferredTaggedToI* deferred = new(zone()) DeferredTaggedToI(this, instr);
+
+    // Optimistically untag the input.
+    // If the input is a HeapObject, SmiUntag will set the carry flag.
+    __ SmiUntag(input_reg, SetCC);
+    // Branch to deferred code if the input was tagged.
+    // The deferred code will take care of restoring the tag.
+    __ b(cs, deferred->entry());
+    __ bind(deferred->exit());
+  }
 }