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

src/x64/macro-assembler-x64.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/base/bits.h"
 #include "src/base/division-by-constant.h"
@@ skipping 3499 matching lines @@
   movsd(MemOperand(rsp, 0), input_reg);
   SlowTruncateToI(result_reg, rsp, 0);
   addp(rsp, Immediate(kDoubleSize));
 
   bind(&done);
   // Keep our invariant that the upper 32 bits are zero.
   movl(result_reg, result_reg);
 }
 
 
-void MacroAssembler::DoubleToI(Register result_reg,
-                               XMMRegister input_reg,
+void MacroAssembler::DoubleToI(Register result_reg, XMMRegister input_reg,
                                XMMRegister scratch,
                                MinusZeroMode minus_zero_mode,
-                               Label* conversion_failed,
-                               Label::Distance dst) {
+                               Label* lost_precision, Label* is_nan,
+                               Label* minus_zero, Label::Distance dst) {
   cvttsd2si(result_reg, input_reg);
   Cvtlsi2sd(xmm0, result_reg);
   ucomisd(xmm0, input_reg);
-  j(not_equal, conversion_failed, dst);
-  j(parity_even, conversion_failed, dst);  // NaN.
+  j(not_equal, lost_precision, dst);
+  j(parity_even, is_nan, dst);  // NaN.
   if (minus_zero_mode == FAIL_ON_MINUS_ZERO) {
     Label done;
     // The integer converted back is equal to the original. We
     // only have to test if we got -0 as an input.
     testl(result_reg, result_reg);
     j(not_zero, &done, Label::kNear);
     movmskpd(result_reg, input_reg);
     // Bit 0 contains the sign of the double in input_reg.
     // If input was positive, we are ok and return 0, otherwise
-    // jump to conversion_failed.
+    // jump to minus_zero.
     andl(result_reg, Immediate(1));
-    j(not_zero, conversion_failed, dst);
+    j(not_zero, minus_zero, dst);
     bind(&done);
   }
 }
 
 
 void MacroAssembler::LoadInstanceDescriptors(Register map,
                                              Register descriptors) {
   movp(descriptors, FieldOperand(map, Map::kDescriptorsOffset));
 }
 
@@ skipping 1783 matching lines @@
   if (mag.shift > 0) sarl(rdx, Immediate(mag.shift));
   movl(rax, dividend);
   shrl(rax, Immediate(31));
   addl(rdx, rax);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64