MIPS/ARM: Fix benchmarks failures on simulator.

src/arm/simulator-arm.cc

Index: src/arm/simulator-arm.cc
diff --git a/src/arm/simulator-arm.cc b/src/arm/simulator-arm.cc
index def18186305f102da97890f23af79d7facc14bdf..f2d304ba1af95a115826599491bd5de548dd402f 100644
--- a/src/arm/simulator-arm.cc
+++ b/src/arm/simulator-arm.cc
@@ -26,6 +26,7 @@
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #include <stdlib.h>
+#include <fpu_control.h>
 #include <cmath>
 #include <cstdarg>
 #include "v8.h"
@@ -736,6 +737,8 @@ void Simulator::Initialize(Isolate* isolate) {
 
 
 Simulator::Simulator(Isolate* isolate) : isolate_(isolate) {
+  set_host_fp_precision();
+
   i_cache_ = isolate_->simulator_i_cache();
   if (i_cache_ == NULL) {
     i_cache_ = new v8::internal::HashMap(&ICacheMatch);
@@ -3854,6 +3857,21 @@ uintptr_t Simulator::PopAddress() {
   return address;
 }
 
+
+void Simulator::set_host_fp_precision() {
+#if !V8_HOST_ARCH_ARM
+  // Set Intel x87 FPU mode to 64-bit double.
+  // The default FPU mode is extended (80-bit),
+  // which can lead to unexpected precision failures.
+  fpu_control_t cw;
+  _FPU_GETCW(cw);
+  cw &= ~_FPU_EXTENDED;
+  cw |= _FPU_DOUBLE;
+  _FPU_SETCW(cw);
+#endif
+}
+
+
 } }  // namespace v8::internal
 
 #endif  // USE_SIMULATOR