[clang] [CIR][X86] Implement lowering for sqrt builtins (PR #169310)

[Andy Kaylor via cfe-commits]

================
@@ -44,6 +46,96 @@
 
 using namespace cir;
 using namespace llvm;
+using namespace mlir;
----------------
andykaylor wrote:

We prefer to have the `mlir` namespace explicit when used.

https://github.com/llvm/llvm-project/pull/169310