[PATCH] These builtin functions set errno. Mark them accordingly.

[hfinkel at anl.gov]

================
Comment at: include/clang/Basic/Builtins.def:279
@@ -280,1 +278,3 @@
+BUILTIN(__builtin_sqrtf, "ff"  , "Fne")
+BUILTIN(__builtin_sqrtl, "LdLd", "Fne")
 BUILTIN(__builtin_tan , "dd"  , "Fnc")
----------------
Also, is this right? sqrt should become an ISD node, which at least on some platforms, gets directly lowered.

Generally, I'm a bit concerned here that we really need target feedback to make this decision properly. These are fine defaults, but we don't want to prevent the intended direct lowering (which is the whole point of the builtins anyway).

But, hey, Clang can use TTI too :-) [Unfortunately, I'm not kidding really].

http://reviews.llvm.org/D3806