1) Turns out we're not great at recognizing redundant checks when one is a != and the other is an ==. This is a bug, but it's one that matters to frontend authors.
2) Frontends shouldn't use intrinsics unless strictly neccessary. This has been pretty widely proven by this point and is good to document.
llvm-svn: 235825
These came from my own experience and may not apply equally to all use cases. Any alternate perspective anyone has should be used to refine these.
As always, grammar and spelling adjustments are more than welcome. Please just directly commit a fix if you see something problematic.
llvm-svn: 231352
As mentioned on llvm-dev, this is a new documentation page intended to collect tips for frontend authors on how to generate IR that LLVM is able to optimize well. These types of things come up repeated in review threads and it would be good to have a place to save them.
I added a small handful to start us off, but I mostly want to get the framework in place. Once the docs are here, we can add to them incrementally. If you know of something appropriate for this page, please add it!
Differential Revision: http://reviews.llvm.org/D7890
llvm-svn: 230807
Philip Reames