A64: Handle Smi representation in MathAbs and fix MathPowStub

src/a64/code-stubs-a64.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 2198 matching lines @@
 
     {
       AllowExternalCallThatCantCauseGC scope(masm);
       __ Mov(saved_lr, lr);
       __ CallCFunction(
           ExternalReference::power_double_double_function(masm->isolate()),
           0, 2);
       __ Mov(lr, saved_lr);
       __ B(&done);
     }
+
+    // Handle SMI exponents.
+    __ Bind(&exponent_is_smi);
+    //  x10   base_tagged       The tagged base (input).
+    //  x11   exponent_tagged   The tagged exponent (input).
+    //  d1    base_double       The base as a double.
+    __ SmiUntag(exponent_integer, exponent_tagged);
   }
 
-  // Handle integer (and SMI) exponents.
-  __ Bind(&exponent_is_smi);
-  //  x10   base_tagged       The tagged base (input).
-  //  x11   exponent_tagged   The tagged exponent (input).
-  //  d1    base_double       The base as a double.
-  __ SmiUntag(exponent_integer, exponent_tagged);
   __ Bind(&exponent_is_integer);
   //  x10   base_tagged       The tagged base (input).
   //  x11   exponent_tagged   The tagged exponent (input).
   //  x12   exponent_integer  The exponent as an integer.
   //  d1    base_double       The base as a double.
 
   // Find abs(exponent). For negative exponents, we can find the inverse later.
   Register exponent_abs = x13;
   __ Cmp(exponent_integer, 0);
   __ Cneg(exponent_abs, exponent_integer, mi);
@@ skipping 4843 matching lines @@
   __ Bind(&fast_elements_case);
   GenerateCase(masm, FAST_ELEMENTS);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_A64