[cfe-commits] r73289 - in /cfe/trunk: docs/LanguageExtensions.html include/clang/Basic/DiagnosticLexKinds.td include/clang/Lex/Preprocessor.h lib/Lex/PPMacroExpansion.cpp test/Preprocessor/feature_tests.c

[Chris Lattner]

On Jun 13, 2009, at 2:21 AM, Eli Friedman wrote:

> On Sat, Jun 13, 2009 at 12:13 AM, Chris Lattner<sabre at nondot.org>  
> wrote:
>> Author: lattner
>> Date: Sat Jun 13 02:13:28 2009
>> New Revision: 73289
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=73289&view=rev
>> Log:
>> implement and document a new __has_feature and __has_builtin magic
>> builtin preprocessor macro.  This appears to work with two caveats:
>> 1) builtins are registered in -E mode,
>
> Why is this an issue?  Or is that backwards?

Yes, that was backwards.

>> 2) target-specific builtins
>> are unconditionally registered even if they aren't supported by the
>> target (e.g. SSE4 builtin when only SSE1 is enabled).
>
> Mmm, that's not good.  We don't actually keep track in the code at the
> moment, though.

Right.  Fortunately, in the case of SSE*, code should use the  
*mmintrin.h files, not the builtins directly.

-Chris