Like the already existing zip_shortest/zip_first iterators, zip_longest
iterates over multiple iterators at once, but has as many iterations as
the longest sequence.
This means some iterators may reach the end before others do.
zip_longest uses llvm::Optional's None value to mark a
past-the-end value.
zip_longest is not reverse-iteratable because the tuples iterated over
would be different for different length sequences (IMHO for the same
reason neither zip_shortest nor zip_first should be reverse-iteratable;
one can still reverse the ranges individually if that's the expected
behavior).
In contrast to zip_shortest/zip_first, zip_longest tuples contain
rvalues instead of references. This is because llvm::Optional cannot
contain reference types and the value-initialized default does not have
a memory location a reference could point to.
The motivation for these iterators is to use C++ foreach to compare two
lists of ordered attributes in D48100 (SemaOverload.cpp and
ASTReaderDecl.cpp).
Idea by @hfinkel.
This re-commits r348301 which was reverted by r348303.
The compilation error by gcc 5.4 was resolved using make_tuple in the in
the initializer_list.
The compileration error by msvc14 was resolved by splitting
ZipLongestValueType (which already was a workaround for msvc15) into
ZipLongestItemType and ZipLongestTupleType.
Differential Revision: https://reviews.llvm.org/D48348
llvm-svn: 348323
Like the already existing zip_shortest/zip_first iterators, zip_longest
iterates over multiple iterators at once, but has as many iterations as
the longest sequence.
This means some iterators may reach the end before others do.
zip_longest uses llvm::Optional's None value to mark a
past-the-end value.
zip_longest is not reverse-iteratable because the tuples iterated over
would be different for different length sequences (IMHO for the same
reason neither zip_shortest nor zip_first should be reverse-iteratable;
one can still reverse the ranges individually if that's the expected
behavior).
In contrast to zip_shortest/zip_first, zip_longest tuples contain
rvalues instead of references. This is because llvm::Optional cannot
contain reference types and the value-initialized default does not have
a memory location a reference could point to.
The motivation for these iterators is to use C++ foreach to compare two
lists of ordered attributes in D48100 (SemaOverload.cpp and
ASTReaderDecl.cpp).
Idea by @hfinkel.
Differential Revision: https://reviews.llvm.org/D48348
llvm-svn: 348301
The definition of `pointer_iterator` omits what should be a `iterator_traits::<>::iterator_category` parameter from `iterator_adaptor_base`. As a result, iterators based on `pointer_iterator` always have defaulted value types and the wrong iterator category.
The definition of `pointee_iterator` just a few lines above does this correctly.
This resolves [[ https://bugs.llvm.org/show_bug.cgi?id=39617 | bug 39617 ]].
Patch by Dylan MacKenzie!
Reviewers: dblaikie
Differential Revision: https://reviews.llvm.org/D54377
llvm-svn: 346833
Summary:
The instantiation of the drop_begin function template usually fails because the functions begin() and end() do not exist. Only when using on a container from the std namespace (or `llvm::iterator_range`s of something derived from `std::iterator`), they are matched to std::begin() and std::end() due to Koenig-lookup.
Explicitly use llvm::adl_begin and llvm::adl_end to make drop_begin applicable to anything iterable (including C-style arrays).
A solution for general `llvm::iterator_range`s was already tried in r244620, but got reverted in r244621 due to MSVC not liking it.
Reviewers: dblaikie, grosbach, aaron.ballman, ruiu
Reviewed By: dblaikie, aaron.ballman
Subscribers: aaron.ballman, llvm-commits
Differential Revision: https://reviews.llvm.org/D48598
llvm-svn: 335772
r332057 introduced distance() for ranges. Based on post-commit feedback,
this renames distance() to size(). The new size() is also only enabled
when the operation is O(1).
Differential Revision: https://reviews.llvm.org/D46976
llvm-svn: 332551
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
llvm-svn: 332057
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
llvm-svn: 330875
clang-format (https://reviews.llvm.org/D33932) to keep primary headers
at the top and handle new utility headers like 'gmock' consistently with
other utility headers.
No other change was made. I did no manual edits, all of this is
clang-format.
This should allow other changes to have more clear and focused diffs,
and is especially motivated by moving some headers into more focused
libraries.
llvm-svn: 304786
This commit provides `zip_{first,shortest}` with the standard member types and
methods expected of iterators (e.g., `difference_type`), in order for zip to be
used with other adaptors, such as `make_filter_range`.
Support for reverse iteration has also been added.
Differential Revision: https://reviews.llvm.org/D30246
llvm-svn: 296036
This augments the STLExtras toolset with a zip iterator and range
adapter. Zip comes in two varieties: `zip`, which will zip to the
shortest of the input ranges, and `zip_first`, which limits its
`begin() == end()` checks to just the first range.
Recommit r284035 after MSVC2013 support has been dropped.
Patch by: Bryant Wong <github.com/bryant>
Differential Revision: https://reviews.llvm.org/D23252
llvm-svn: 284623
This augments the STLExtras toolset with a zip iterator and range
adapter. Zip comes in two varieties: `zip`, which will zip to the
shortest of the input ranges, and `zip_first`, which limits its
`begin() == end()` checks to just the first krange.
Patch by: Bryant Wong <github.com/bryant>
Differential Revision: https://reviews.llvm.org/D23252
llvm-svn: 284035
Michael Kruse