Introduce intrinsics for double values in Javascript.

src/ia32/lithium-codegen-ia32.cc

Index: src/ia32/lithium-codegen-ia32.cc
diff --git a/src/ia32/lithium-codegen-ia32.cc b/src/ia32/lithium-codegen-ia32.cc
index 1658d71f9112dde1da8b486b7f84a1c855531c15..d9418aaa36392bff5a38b8aa67240762ce511238 100644
--- a/src/ia32/lithium-codegen-ia32.cc
+++ b/src/ia32/lithium-codegen-ia32.cc
@@ -5747,6 +5747,46 @@ void LCodeGen::DoClampTToUint8NoSSE2(LClampTToUint8NoSSE2* instr) {
 }
 
 
+void LCodeGen::DoDoubleBits(LDoubleBits* instr) {
+  CpuFeatureScope scope(masm(), SSE2);
+  XMMRegister value_reg = ToDoubleRegister(instr->value());
+  Register result_reg = ToRegister(instr->result());
+  if (instr->hydrogen()->bits() == HDoubleBits::HIGH) {
+    if (CpuFeatures::IsSupported(SSE4_1)) {
+      CpuFeatureScope scope2(masm(), SSE4_1);
+      __ pextrd(result_reg, value_reg, 1);
+    } else {
+      XMMRegister xmm_scratch = double_scratch0();
+      __ pshufd(xmm_scratch, value_reg, 1);
+      __ movd(result_reg, xmm_scratch);
+    }
+  } else {
+    __ movd(result_reg, value_reg);
+  }
+}
+
+
+void LCodeGen::DoConstructDouble(LConstructDouble* instr) {
+  Register hi_reg = ToRegister(instr->hi());
+  Register lo_reg = ToRegister(instr->lo());
+  XMMRegister result_reg = ToDoubleRegister(instr->result());
+  CpuFeatureScope scope(masm(), SSE2);
+
+  if (CpuFeatures::IsSupported(SSE4_1)) {
+    CpuFeatureScope scope2(masm(), SSE4_1);
+    __ movd(result_reg, lo_reg);
+    __ pinsrd(result_reg, hi_reg, 1);
+  } else {
+    XMMRegister xmm_scratch = double_scratch0();
+    __ xorps(result_reg, result_reg);
+    __ movd(result_reg, hi_reg);
+    __ psllq(result_reg, 32);
+    __ movd(xmm_scratch, lo_reg);
+    __ orps(result_reg, xmm_scratch);
+  }
+}
+
+
 void LCodeGen::DoAllocate(LAllocate* instr) {
   class DeferredAllocate V8_FINAL : public LDeferredCode {
    public: