VM: Enable branch merging of isnan, isinf.

runtime/vm/simulator_dbc.cc

 // Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include <setjmp.h>  // NOLINT
 #include <stdlib.h>
 
 #include "vm/globals.h"
 #if defined(TARGET_ARCH_DBC)
 
@@ skipping 2211 matching lines @@
 
   {
     BYTECODE(FloatToDouble, A_D);
     const float valuef = *reinterpret_cast<float*>(&FP[rD]);
     const double value = static_cast<double>(valuef);
     FP[rA] = bit_cast<RawObject*, double>(value);
     DISPATCH();
   }
 
   {
-    BYTECODE(DoubleIsNaN, A_D);
-    const double v = bit_cast<double, RawObject*>(FP[rD]);
-    FP[rA] = isnan(v) ? true_value : false_value;
+    BYTECODE(DoubleIsNaN, A);
+    const double v = bit_cast<double, RawObject*>(FP[rA]);
+    if (!isnan(v)) {
+      pc++;
+    }
     DISPATCH();
   }
 
   {
-    BYTECODE(DoubleIsInfinite, A_D);
-    const double v = bit_cast<double, RawObject*>(FP[rD]);
-    FP[rA] = isinf(v) ? true_value : false_value;
+    BYTECODE(DoubleIsInfinite, A);
+    const double v = bit_cast<double, RawObject*>(FP[rA]);
+    if (!isinf(v)) {
+      pc++;
+    }
     DISPATCH();
   }
 
   {
     BYTECODE(LoadIndexedFloat32, A_B_C);
     uint8_t* data = SimulatorHelpers::GetTypedData(FP[rB], FP[rC]);
     const uint32_t value = *reinterpret_cast<uint32_t*>(data);
     const uint64_t value64 = value;
     FP[rA] = reinterpret_cast<RawObject*>(value64);
     DISPATCH();
@@ skipping 1486 matching lines @@
   pc_ = pc;
   special_[kExceptionSpecialIndex] = raw_exception;
   special_[kStacktraceSpecialIndex] = raw_stacktrace;
   buf->Longjmp();
   UNREACHABLE();
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_DBC