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

src/ia32/macro-assembler-ia32.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_IA32
 
 #include "src/base/bits.h"
 #include "src/base/division-by-constant.h"
@@ skipping 232 matching lines @@
   j(no_overflow, &done, Label::kNear);
 
   sub(esp, Immediate(kDoubleSize));
   movsd(MemOperand(esp, 0), input_reg);
   SlowTruncateToI(result_reg, esp, 0);
   add(esp, Immediate(kDoubleSize));
   bind(&done);
 }
 
 
-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) {
   DCHECK(!input_reg.is(scratch));
   cvttsd2si(result_reg, Operand(input_reg));
   Cvtsi2sd(scratch, Operand(result_reg));
   ucomisd(scratch, 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);
   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.
     test(result_reg, Operand(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.
     and_(result_reg, 1);
-    j(not_zero, conversion_failed, dst);
+    j(not_zero, minus_zero, dst);
     bind(&done);
   }
 }
 
 
 void MacroAssembler::TruncateHeapNumberToI(Register result_reg,
                                            Register input_reg) {
   Label done, slow_case;
 
   if (CpuFeatures::IsSupported(SSE3)) {
@@ skipping 3107 matching lines @@
   if (mag.shift > 0) sar(edx, mag.shift);
   mov(eax, dividend);
   shr(eax, 31);
   add(edx, eax);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32