Use signaling NaN for holes in fixed double arrays.

build/toolchain.gypi

Index: build/toolchain.gypi
diff --git a/build/toolchain.gypi b/build/toolchain.gypi
index ee8efe13c4c0f8d960b8e39e354445bfd059c099..bac5e7875415578341f5d51e0f8cf3377dd03a50 100644
--- a/build/toolchain.gypi
+++ b/build/toolchain.gypi
@@ -223,6 +223,11 @@
               }, {
                 # 'v8_target_arch!=target_arch'
                 # Target not built with an Arm CXX compiler (simulator build).
+                'cflags': [
+                  '-msse2',
+                  '-mfpmath=sse',
+                  '-mmmx',  # Allows mmintrin.h for MMX intrinsics.
+                ],
                 'conditions': [
                   [ 'arm_float_abi=="hard"', {
                     'defines': [
@@ -811,6 +816,15 @@
       }],
       ['(OS=="linux" or OS=="freebsd" or OS=="openbsd" or OS=="solaris" \
          or OS=="netbsd" or OS=="mac" or OS=="android" or OS=="qnx") and \
+        (v8_target_arch=="ia32")', {
+        'cflags': [
+          '-msse2',
+          '-mfpmath=sse',
+          '-mmmx',  # Allows mmintrin.h for MMX intrinsics.
+        ],
+      }],
+      ['(OS=="linux" or OS=="freebsd" or OS=="openbsd" or OS=="solaris" \
+         or OS=="netbsd" or OS=="mac" or OS=="android" or OS=="qnx") and \
         (v8_target_arch=="arm" or v8_target_arch=="ia32" or \
          v8_target_arch=="x87" or v8_target_arch=="mips" or \
          v8_target_arch=="mipsel" or v8_target_arch=="ppc")', {