This commit adds a wrapper for std::distance() which works with ranges.
As it would be a common case to write `distance(predecessors(BB))`, this
also introduces `pred_size()` and `succ_size()` helpers to make that
easier to write.
Differential Revision: https://reviews.llvm.org/D46668
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@332057 91177308-0d34-0410-b5e6-96231b3b80d8
This makes it possible to reverse a filtered range. For example, here's
a way to visit memory accesses in a BasicBlock in reverse order:
auto MemInsts = reverse(make_filter_range(BB, [](Instruction &I) {
return isa<StoreInst>(&I) || isa<LoadInst>(&I);
}));
for (auto &MI : MemInsts)
...
To implement this functionality, I factored out forward iteration
functionality into filter_iterator_base, and added a specialization of
filter_iterator_impl which supports bidirectional iteration. Thanks to
Tim Shen, Zachary Turner, and others for suggesting this design and
providing feedback! This version of the patch supersedes the original
(https://reviews.llvm.org/D45792).
This was motivated by a problem we encountered in D45657: we'd like to
visit the non-debug-info instructions in a BasicBlock in reverse order.
Testing: check-llvm, check-clang
Differential Revision: https://reviews.llvm.org/D45853
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@330875 91177308-0d34-0410-b5e6-96231b3b80d8
block.
This allows writing much more natural and readable range based for loops
directly over the PHI nodes. It also takes advantage of the same tricks
for terminating the sequence as the hand coded versions.
I've replaced one example of this mostly to showcase the difference and
I've added a unit test to make sure the facilities really work the way
they're intended. I want to use this inside of SimpleLoopUnswitch but it
seems generally nice.
Differential Revision: https://reviews.llvm.org/D33533
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@303964 91177308-0d34-0410-b5e6-96231b3b80d8
