[clang] [llvm] [clang] Reland Add tanf16 builtin and support for tan constrained intrinsic (PR #94559)

[Farzon Lotfi via cfe-commits]

================
@@ -151,6 +151,17 @@ entry:
   ret double %result
 }
 
+; Verify that tan(42.0) isn't simplified when the rounding mode is unknown.
+; CHECK-LABEL: ftan
+; CHECK: call double @llvm.experimental.constrained.tan
+define double @ftan() #0 {
+entry:
+  %result = call double @llvm.experimental.constrained.tan.f64(double 42.0,
+                                               metadata !"round.dynamic",
+                                               metadata !"fpexcept.strict") #0
+  ret double %result
+}
+
----------------
farzonl wrote:

add the @llvm.experimental.constrained.tan.f64 declare

https://github.com/llvm/llvm-project/pull/94559