Displaying 2 results from an estimated 2 matches for "__builtin_errno_address".
2013 Sep 17
1
[LLVMdev] [RFC] New function attributes for errno-setting functions
----- Original Message -----
> On 9/17/2013 2:43 PM, Hal Finkel wrote:
> >
> > That would depend on how this attribute was used; it could only be
> > used by a pass that did actually understand what those side
> > effects were (like the loop vectorizer understanding that, if
> > errno is ignored, then vectorizing cos() is legal). I don't object
> > to
2013 Sep 19
0
[LLVMdev] [RFC] New function attributes for errno-setting functions
...ow how feasible this is to roll out on linux or other platforms
> which may or may not have sympathetic libc maintainers. Assuming they aren't
> sympathetic, you only have one less-great option IMO. That is that you hack
> Clang to pattern match a well-known AST pattern into the
> __builtin_errno_address builtin. For targets without a well-known pattern,
> it would never add the "does not touch errno" attribute.
Would it be practical to determine the pattern by recognizing the definition
(or declaration, pre-'11) of errno? The language standards impose strict
conditions it must m...