Let NaN flow as double into HBranch

src/ia32/lithium-ia32.cc

 // Copyright 2012 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 1042 matching lines @@
   HValue* value = instr->value();
   if (value->EmitAtUses()) {
     ASSERT(value->IsConstant());
     ASSERT(!value->representation().IsDouble());
     HBasicBlock* successor = HConstant::cast(value)->BooleanValue()
         ? instr->FirstSuccessor()
         : instr->SecondSuccessor();
     return new(zone()) LGoto(successor->block_id());
   }
 
-  // Untagged integers or doubles, smis and booleans don't require a
-  // deoptimization environment nor a temp register.
+  ToBooleanStub::Types expected = instr->expected_input_types();
+
+  // Tagged values that are not known smis or booleans require a
+  // deoptimization environment. If the instruction is generic no
+  // environment is needed since all cases are handled.
   Representation rep = value->representation();
   HType type = value->type();
   if (!rep.IsTagged() || type.IsSmi() || type.IsBoolean()) {
     return new(zone()) LBranch(UseRegister(value), NULL);
   }
 
-  ToBooleanStub::Types expected = instr->expected_input_types();
+  bool needs_temp = expected.NeedsMap() || expected.IsEmpty();
+  LOperand* temp = needs_temp ? TempRegister() : NULL;
+
+  // The Generic stub does not have a deopt, so we need no environment.
+  if (expected.IsGeneric()) {
+    return new(zone()) LBranch(UseRegister(value), temp);
+  }
+
   // We need a temporary register when we have to access the map *or* we have
   // no type info yet, in which case we handle all cases (including the ones
   // involving maps).
-  bool needs_temp = expected.NeedsMap() || expected.IsEmpty();
-  LOperand* temp = needs_temp ? TempRegister() : NULL;
   return AssignEnvironment(new(zone()) LBranch(UseRegister(value), temp));
 }
 
 
 LInstruction* LChunkBuilder::DoDebugBreak(HDebugBreak* instr) {
   return new(zone()) LDebugBreak();
 }
 
 
 LInstruction* LChunkBuilder::DoCompareMap(HCompareMap* instr) {
@@ skipping 1719 matching lines @@
 LInstruction* LChunkBuilder::DoLoadFieldByIndex(HLoadFieldByIndex* instr) {
   LOperand* object = UseRegister(instr->object());
   LOperand* index = UseTempRegister(instr->index());
   return DefineSameAsFirst(new(zone()) LLoadFieldByIndex(object, index));
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32