Add scalar lowering for sqrt intrinsic.

src/IceTargetLoweringX8632.h

Index: src/IceTargetLoweringX8632.h
diff --git a/src/IceTargetLoweringX8632.h b/src/IceTargetLoweringX8632.h
index 4c2c527042dcffacf68e71f209c6eeea64acf7c3..f7097046569d706368302bdb168260cb867ea72a 100644
--- a/src/IceTargetLoweringX8632.h
+++ b/src/IceTargetLoweringX8632.h
@@ -252,6 +252,9 @@ protected:
   void _shrd(Variable *Dest, Variable *Src0, Variable *Src1) {
     Context.insert(InstX8632Shrd::create(Func, Dest, Src0, Src1));
   }
+  void _sqrtss(Variable *Dest, Operand *Src0) {
+    Context.insert(InstX8632Sqrtss::create(Func, Dest, Src0));
+  }
   void _store(Operand *Value, OperandX8632 *Mem) {
     Context.insert(InstX8632Store::create(Func, Value, Mem));
   }