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.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@235825 91177308-0d34-0410-b5e6-96231b3b80d8
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.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231352 91177308-0d34-0410-b5e6-96231b3b80d8
This could stand to be expanded - patches welcome! - but let's at least write them down so they don't get forgotten.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230995 91177308-0d34-0410-b5e6-96231b3b80d8
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
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230807 91177308-0d34-0410-b5e6-96231b3b80d8
