ARM64: do not optimize away shift if its result is used as both left and right

src/arm64/lithium-arm64.cc

Index: src/arm64/lithium-arm64.cc
diff --git a/src/arm64/lithium-arm64.cc b/src/arm64/lithium-arm64.cc
index 91b4430566060e90a1241a0ba25c366dbe510cb9..a9d661d35d2f5a3eb7162c38fd12231136a90ef1 100644
--- a/src/arm64/lithium-arm64.cc
+++ b/src/arm64/lithium-arm64.cc
@@ -2126,6 +2126,11 @@ HBitwiseBinaryOperation* LChunkBuilder::CanTransformToShiftedOp(HValue* val,
   DCHECK(hleft->representation().Equals(hinstr->representation()));
   DCHECK(hright->representation().Equals(hinstr->representation()));
 
+  if (hleft == hright) {
+    // Cannot replace two operands at once.
+    return NULL;
+  }
+
   if ((hright->IsConstant() &&
        LikelyFitsImmField(hinstr, HConstant::cast(hright)->Integer32Value())) ||
       (hinstr->IsCommutative() && hleft->IsConstant() &&