Let NaN flow as double into HBranch

src/arm/lithium-arm.cc

Index: src/arm/lithium-arm.cc
diff --git a/src/arm/lithium-arm.cc b/src/arm/lithium-arm.cc
index b421f8a045204126c48babca9592b147b001f15f..642a0ab28f8f2932d1d13ecd5041daa60c5d3b09 100644
--- a/src/arm/lithium-arm.cc
+++ b/src/arm/lithium-arm.cc
@@ -999,10 +999,12 @@ LInstruction* LChunkBuilder::DoBranch(HBranch* instr) {
 
   LBranch* result = new(zone()) LBranch(UseRegister(value));
   // Tagged values that are not known smis or booleans require a
-  // deoptimization environment.
+  // deoptimization environment. Except in the Generic case.

[Toon Verwaest, 2013/06/20 12:45:59]

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()) {
+  ToBooleanStub::Types expected = instr->expected_input_types();
+  if (rep.IsTagged() && !type.IsSmi() && !type.IsBoolean() &&
+      !expected.IsGeneric()) {
     return AssignEnvironment(result);
   }
   return result;