Made the detailed reason for deopts mandatory on ia32. Unified and improved things.

src/x64/code-stubs-x64.cc

Index: src/x64/code-stubs-x64.cc
diff --git a/src/x64/code-stubs-x64.cc b/src/x64/code-stubs-x64.cc
index a7d38cd03873453543c528f265c6071c64ce56c8..e3d5a13e9c8b0b63d8b9ab3ab98dcae8b728c887 100644
--- a/src/x64/code-stubs-x64.cc
+++ b/src/x64/code-stubs-x64.cc
@@ -318,7 +318,9 @@ void MathPowStub::Generate(MacroAssembler* masm) {
     Label fast_power, try_arithmetic_simplification;
     // Detect integer exponents stored as double.
     __ DoubleToI(exponent, double_exponent, double_scratch,
-                 TREAT_MINUS_ZERO_AS_ZERO, &try_arithmetic_simplification);
+                 TREAT_MINUS_ZERO_AS_ZERO, &try_arithmetic_simplification,
+                 &try_arithmetic_simplification,
+                 &try_arithmetic_simplification);
     __ jmp(&int_exponent);
 
     __ bind(&try_arithmetic_simplification);