Let NaN flow as double into HBranch

src/arm/lithium-codegen-arm.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 2180 matching lines @@
   if (r.IsInteger32() || r.IsSmi()) {
     ASSERT(!info()->IsStub());
     Register reg = ToRegister(instr->value());
     __ cmp(reg, Operand::Zero());
     EmitBranch(true_block, false_block, ne);
   } else if (r.IsDouble()) {
     ASSERT(!info()->IsStub());
     DwVfpRegister reg = ToDoubleRegister(instr->value());
     // Test the double value. Zero and NaN are false.
     __ VFPCompareAndSetFlags(reg, 0.0);
-    __ cmp(r0, r0, vs);  // If NaN, set the Z flag.
+    __ cmp(r0, r0, vs);  // If NaN, set the Z flag. (NaN -> false)
     EmitBranch(true_block, false_block, ne);
   } else {
     ASSERT(r.IsTagged());
     Register reg = ToRegister(instr->value());
     HType type = instr->hydrogen()->value()->type();
     if (type.IsBoolean()) {
       ASSERT(!info()->IsStub());
       __ CompareRoot(reg, Heap::kTrueValueRootIndex);
       EmitBranch(true_block, false_block, eq);
     } else if (type.IsSmi()) {
       ASSERT(!info()->IsStub());
       __ cmp(reg, Operand::Zero());
       EmitBranch(true_block, false_block, ne);
+    } else if (type.IsJSArray()) {
+      EmitBranch(true_block, false_block, al);
+    } else if (type.IsHeapNumber()) {
+      DwVfpRegister dbl_scratch = double_scratch0();
+      __ vldr(dbl_scratch, FieldMemOperand(reg, HeapNumber::kValueOffset));
+      // Test the double value. Zero and NaN are false.
+      __ VFPCompareAndSetFlags(dbl_scratch, 0.0);
+      __ cmp(r0, r0, vs);  // If NaN, set the Z flag. (NaN)
+      EmitBranch(true_block, false_block, ne);
+    } else if (type.IsString()) {
+      __ ldr(ip, FieldMemOperand(reg, String::kLengthOffset));
+      __ cmp(ip, Operand::Zero());
+      EmitBranch(true_block, false_block, ne);
     } else {
       Label* true_label = chunk_->GetAssemblyLabel(true_block);
       Label* false_label = chunk_->GetAssemblyLabel(false_block);
 
       ToBooleanStub::Types expected = instr->hydrogen()->expected_input_types();
       // Avoid deopts in the case where we've never executed this path before.
       if (expected.IsEmpty()) expected = ToBooleanStub::all_types();
 
       if (expected.Contains(ToBooleanStub::UNDEFINED)) {
         // undefined -> false.
@@ skipping 67 matching lines @@
         __ CompareRoot(map, Heap::kHeapNumberMapRootIndex);
         __ b(ne, &not_heap_number);
         __ vldr(dbl_scratch, FieldMemOperand(reg, HeapNumber::kValueOffset));
         __ VFPCompareAndSetFlags(dbl_scratch, 0.0);
         __ cmp(r0, r0, vs);  // NaN -> false.
         __ b(eq, false_label);  // +0, -0 -> false.
         __ b(true_label);
         __ bind(&not_heap_number);
       }
 
-      // We've seen something for the first time -> deopt.
-      DeoptimizeIf(al, instr->environment());
+      if (expected != ToBooleanStub::all_types()) {
+        // We've seen something for the first time -> deopt.
+        DeoptimizeIf(al, instr->environment());
+      }
     }
   }
 }
 
 
 void LCodeGen::EmitGoto(int block) {
   if (!IsNextEmittedBlock(block)) {
     __ jmp(chunk_->GetAssemblyLabel(chunk_->LookupDestination(block)));
   }
 }
@@ skipping 3566 matching lines @@
   __ sub(scratch, result, Operand::PointerOffsetFromSmiKey(index));
   __ ldr(result, FieldMemOperand(scratch,
                                  FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal