Add scalar lowering for sqrt intrinsic.

src/IceInstX8632.h

Index: src/IceInstX8632.h
diff --git a/src/IceInstX8632.h b/src/IceInstX8632.h
index 0e4964fd4f31b2eb1e1e00034c871da178622fd8..f76d6df61655ac159d0ba3697b8ce0b94570b5bb 100644
--- a/src/IceInstX8632.h
+++ b/src/IceInstX8632.h
@@ -170,6 +170,7 @@ public:
     Shld,
     Shr,
     Shrd,
+    Sqrtss,
     Store,
     StoreQ,
     Sub,
@@ -827,6 +828,24 @@ private:
   virtual ~InstX8632Ret() {}
 };
 
+// Sqrtss - Scalar sqrt of a float or double.
+class InstX8632Sqrtss : public InstX8632 {
+public:
+  static InstX8632Sqrtss *create(Cfg *Func, Variable *Dest, Operand *Source) {
+    return new (Func->allocate<InstX8632Sqrtss>())
+        InstX8632Sqrtss(Func, Dest, Source);
+  }
+  virtual void emit(const Cfg *Func) const;
+  virtual void dump(const Cfg *Func) const;
+  static bool classof(const Inst *Inst) { return isClassof(Inst, Sqrtss); }
+
+private:
+  InstX8632Sqrtss(Cfg *Func, Variable *Dest, Operand *Source);
+  InstX8632Sqrtss(const InstX8632Sqrtss &) LLVM_DELETED_FUNCTION;
+  InstX8632Sqrtss &operator=(const InstX8632Sqrtss &) LLVM_DELETED_FUNCTION;
+  virtual ~InstX8632Sqrtss() {}
+};
+
 // Exchanging Add instruction.  Exchanges the first operand (destination
 // operand) with the second operand (source operand), then loads the sum
 // of the two values into the destination operand. The destination may be