Inline Math.sqrt in new compilers.

runtime/vm/assembler_x64_test.cc

Index: runtime/vm/assembler_x64_test.cc
===================================================================
--- runtime/vm/assembler_x64_test.cc	(revision 8696)
+++ runtime/vm/assembler_x64_test.cc	(working copy)
@@ -1277,9 +1277,10 @@
 
 
 ASSEMBLER_TEST_GENERATE(XorpdZeroing, assembler) {
-  __ movsd(XMM0, Address(RSP, kWordSize));
-  __ xorpd(XMM0, Address(RSP, kWordSize));
-  __ movq(RAX, Immediate(999));
+  __ pushq(RAX);
+  __ movsd(Address(RSP, 0), XMM0);
+  __ xorpd(XMM0, Address(RSP, 0));
+  __ popq(RAX);
   __ ret();
 }
 
@@ -1290,6 +1291,20 @@
   EXPECT_FLOAT_EQ(0.0, res, 0.0001);
 }
 
+
+ASSEMBLER_TEST_GENERATE(SquareRootDouble, assembler) {
+  __ sqrtsd(XMM0, XMM0);
+  __ ret();
+}
+
+
+ASSEMBLER_TEST_RUN(SquareRootDouble, entry) {
+  typedef double (*SquareRootDoubleCode)(double d);
+  const double kDoubleConst = .7;
+  double res = reinterpret_cast<SquareRootDoubleCode>(entry)(kDoubleConst);
+  EXPECT_FLOAT_EQ(sqrt(kDoubleConst), res, 0.0001);
+}
+
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64