Optimistically inline Math.sqrt as unboxed sqrtsd instruction.

runtime/vm/intermediate_language_ia32.cc

Index: runtime/vm/intermediate_language_ia32.cc
diff --git a/runtime/vm/intermediate_language_ia32.cc b/runtime/vm/intermediate_language_ia32.cc
index c28234b65b0964b06bd3bda6f62c0a6929a1c14d..3e3b0b97228758a86719e373625f1f5a1927781e 100644
--- a/runtime/vm/intermediate_language_ia32.cc
+++ b/runtime/vm/intermediate_language_ia32.cc
@@ -1979,6 +1979,22 @@ void UnboxedDoubleBinaryOpInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
 }
 
 
+LocationSummary* MathSqrtInstr::MakeLocationSummary() const {
+  const intptr_t kNumInputs = 1;
+  const intptr_t kNumTemps = 0;
+  LocationSummary* summary =
+      new LocationSummary(kNumInputs, kNumTemps, LocationSummary::kNoCall);
+  summary->set_in(0, Location::RequiresXmmRegister());
+  summary->set_out(Location::RequiresXmmRegister());
+  return summary;
+}
+
+
+void MathSqrtInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
+  __ sqrtsd(locs()->out().xmm_reg(), locs()->in(0).xmm_reg());
+}
+
+
 LocationSummary* UnarySmiOpInstr::MakeLocationSummary() const {
   const intptr_t kNumInputs = 1;
   const intptr_t kNumTemps = 0;