[llvm] r294349 - ADT: Add explicit conversions for reverse ilist iterators
Duncan P. N. Exon Smith via llvm-commits
llvm-commits at lists.llvm.org
Tue Feb 7 13:03:50 PST 2017
Author: dexonsmith
Date: Tue Feb 7 15:03:50 2017
New Revision: 294349
URL: http://llvm.org/viewvc/llvm-project?rev=294349&view=rev
Log:
ADT: Add explicit conversions for reverse ilist iterators
Add explicit conversions between forward and reverse ilist iterators.
These follow the conversion conventions of std::reverse_iterator, which
are off-by-one: the newly-constructed "reverse" iterator dereferences to
the previous node of the one sent in. This has the benefit of
converting reverse ranges in place:
- If [I, E) is a valid range,
- then [reverse(E), reverse(I)) gives the same range in reverse order.
ilist_iterator::getReverse() is unchanged: it returns a reverse iterator
to the *same* node.
Modified:
llvm/trunk/include/llvm/ADT/ilist_iterator.h
llvm/trunk/include/llvm/CodeGen/MachineInstrBundleIterator.h
llvm/trunk/unittests/ADT/IListIteratorTest.cpp
llvm/trunk/unittests/CodeGen/MachineInstrBundleIteratorTest.cpp
Modified: llvm/trunk/include/llvm/ADT/ilist_iterator.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/ADT/ilist_iterator.h?rev=294349&r1=294348&r2=294349&view=diff
==============================================================================
--- llvm/trunk/include/llvm/ADT/ilist_iterator.h (original)
+++ llvm/trunk/include/llvm/ADT/ilist_iterator.h Tue Feb 7 15:03:50 2017
@@ -102,10 +102,23 @@ public:
return *this;
}
- /// Convert from an iterator to its reverse.
+ /// Explicit conversion between forward/reverse iterators.
///
- /// TODO: Roll this into the implicit constructor once we're sure that no one
- /// is relying on the std::reverse_iterator off-by-one semantics.
+ /// Translate between forward and reverse iterators without changing range
+ /// boundaries. The resulting iterator will dereference (and have a handle)
+ /// to the previous node, which is somewhat unexpected; but converting the
+ /// two endpoints in a range will give the same range in reverse.
+ ///
+ /// This matches std::reverse_iterator conversions.
+ explicit ilist_iterator(
+ const ilist_iterator<OptionsT, !IsReverse, IsConst> &RHS)
+ : ilist_iterator(++RHS.getReverse()) {}
+
+ /// Get a reverse iterator to the same node.
+ ///
+ /// Gives a reverse iterator that will dereference (and have a handle) to the
+ /// same node. Converting the endpoint iterators in a range will give a
+ /// different range; for range operations, use the explicit conversions.
ilist_iterator<OptionsT, !IsReverse, IsConst> getReverse() const {
if (NodePtr)
return ilist_iterator<OptionsT, !IsReverse, IsConst>(*NodePtr);
Modified: llvm/trunk/include/llvm/CodeGen/MachineInstrBundleIterator.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/MachineInstrBundleIterator.h?rev=294349&r1=294348&r2=294349&view=diff
==============================================================================
--- llvm/trunk/include/llvm/CodeGen/MachineInstrBundleIterator.h (original)
+++ llvm/trunk/include/llvm/CodeGen/MachineInstrBundleIterator.h Tue Feb 7 15:03:50 2017
@@ -153,6 +153,18 @@ public:
: MII(I.getInstrIterator()) {}
MachineInstrBundleIterator() : MII(nullptr) {}
+ /// Explicit conversion between forward/reverse iterators.
+ ///
+ /// Translate between forward and reverse iterators without changing range
+ /// boundaries. The resulting iterator will dereference (and have a handle)
+ /// to the previous node, which is somewhat unexpected; but converting the
+ /// two endpoints in a range will give the same range in reverse.
+ ///
+ /// This matches std::reverse_iterator conversions.
+ explicit MachineInstrBundleIterator(
+ const MachineInstrBundleIterator<Ty, !IsReverse> &I)
+ : MachineInstrBundleIterator(++I.getReverse()) {}
+
/// Get the bundle iterator for the given instruction's bundle.
static MachineInstrBundleIterator getAtBundleBegin(instr_iterator MI) {
return MachineInstrBundleIteratorHelper<IsReverse>::getBundleBegin(MI);
@@ -258,6 +270,11 @@ public:
nonconst_iterator getNonConstIterator() const { return MII.getNonConst(); }
+ /// Get a reverse iterator to the same node.
+ ///
+ /// Gives a reverse iterator that will dereference (and have a handle) to the
+ /// same node. Converting the endpoint iterators in a range will give a
+ /// different range; for range operations, use the explicit conversions.
reverse_iterator getReverse() const { return MII.getReverse(); }
};
Modified: llvm/trunk/unittests/ADT/IListIteratorTest.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/ADT/IListIteratorTest.cpp?rev=294349&r1=294348&r2=294349&view=diff
==============================================================================
--- llvm/trunk/unittests/ADT/IListIteratorTest.cpp (original)
+++ llvm/trunk/unittests/ADT/IListIteratorTest.cpp Tue Feb 7 15:03:50 2017
@@ -131,4 +131,44 @@ TEST(IListIteratorTest, CheckEraseRevers
EXPECT_EQ(L.rend(), RI);
}
+TEST(IListIteratorTest, ReverseConstructor) {
+ simple_ilist<Node> L;
+ const simple_ilist<Node> &CL = L;
+ Node A, B;
+ L.insert(L.end(), A);
+ L.insert(L.end(), B);
+
+ // Save typing.
+ typedef simple_ilist<Node>::iterator iterator;
+ typedef simple_ilist<Node>::reverse_iterator reverse_iterator;
+ typedef simple_ilist<Node>::const_iterator const_iterator;
+ typedef simple_ilist<Node>::const_reverse_iterator const_reverse_iterator;
+
+ // Check conversion values.
+ EXPECT_EQ(L.begin(), iterator(L.rend()));
+ EXPECT_EQ(++L.begin(), iterator(++L.rbegin()));
+ EXPECT_EQ(L.end(), iterator(L.rbegin()));
+ EXPECT_EQ(L.rbegin(), reverse_iterator(L.end()));
+ EXPECT_EQ(++L.rbegin(), reverse_iterator(++L.begin()));
+ EXPECT_EQ(L.rend(), reverse_iterator(L.begin()));
+
+ // Check const iterator constructors.
+ EXPECT_EQ(CL.begin(), const_iterator(L.rend()));
+ EXPECT_EQ(CL.begin(), const_iterator(CL.rend()));
+ EXPECT_EQ(CL.rbegin(), const_reverse_iterator(L.end()));
+ EXPECT_EQ(CL.rbegin(), const_reverse_iterator(CL.end()));
+
+ // Confirm lack of implicit conversions.
+ static_assert(std::is_convertible<iterator, reverse_iterator>::value,
+ "unexpected implicit conversion");
+ static_assert(std::is_convertible<reverse_iterator, iterator>::value,
+ "unexpected implicit conversion");
+ static_assert(
+ std::is_convertible<const_iterator, const_reverse_iterator>::value,
+ "unexpected implicit conversion");
+ static_assert(
+ std::is_convertible<const_reverse_iterator, const_iterator>::value,
+ "unexpected implicit conversion");
+}
+
} // end namespace
Modified: llvm/trunk/unittests/CodeGen/MachineInstrBundleIteratorTest.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/CodeGen/MachineInstrBundleIteratorTest.cpp?rev=294349&r1=294348&r2=294349&view=diff
==============================================================================
--- llvm/trunk/unittests/CodeGen/MachineInstrBundleIteratorTest.cpp (original)
+++ llvm/trunk/unittests/CodeGen/MachineInstrBundleIteratorTest.cpp Tue Feb 7 15:03:50 2017
@@ -130,4 +130,68 @@ TEST(MachineInstrBundleIteratorTest, Com
ASSERT_TRUE(CI != CMBI.getIterator());
}
+struct MyUnbundledInstr
+ : ilist_node<MyUnbundledInstr, ilist_sentinel_tracking<true>> {
+ bool isBundledWithPred() const { return false; }
+ bool isBundledWithSucc() const { return false; }
+};
+typedef MachineInstrBundleIterator<MyUnbundledInstr> unbundled_iterator;
+typedef MachineInstrBundleIterator<const MyUnbundledInstr>
+ const_unbundled_iterator;
+typedef MachineInstrBundleIterator<MyUnbundledInstr, true>
+ reverse_unbundled_iterator;
+typedef MachineInstrBundleIterator<const MyUnbundledInstr, true>
+ const_reverse_unbundled_iterator;
+
+TEST(MachineInstrBundleIteratorTest, ReverseConstructor) {
+ simple_ilist<MyUnbundledInstr, ilist_sentinel_tracking<true>> L;
+ const auto &CL = L;
+ MyUnbundledInstr A, B;
+ L.insert(L.end(), A);
+ L.insert(L.end(), B);
+
+ // Save typing.
+ typedef MachineInstrBundleIterator<MyUnbundledInstr> iterator;
+ typedef MachineInstrBundleIterator<MyUnbundledInstr, true> reverse_iterator;
+ typedef MachineInstrBundleIterator<const MyUnbundledInstr> const_iterator;
+ typedef MachineInstrBundleIterator<const MyUnbundledInstr, true>
+ const_reverse_iterator;
+
+ // Convert to bundle iterators.
+ auto begin = [&]() -> iterator { return L.begin(); };
+ auto end = [&]() -> iterator { return L.end(); };
+ auto rbegin = [&]() -> reverse_iterator { return L.rbegin(); };
+ auto rend = [&]() -> reverse_iterator { return L.rend(); };
+ auto cbegin = [&]() -> const_iterator { return CL.begin(); };
+ auto cend = [&]() -> const_iterator { return CL.end(); };
+ auto crbegin = [&]() -> const_reverse_iterator { return CL.rbegin(); };
+ auto crend = [&]() -> const_reverse_iterator { return CL.rend(); };
+
+ // Check conversion values.
+ EXPECT_EQ(begin(), iterator(rend()));
+ EXPECT_EQ(++begin(), iterator(++rbegin()));
+ EXPECT_EQ(end(), iterator(rbegin()));
+ EXPECT_EQ(rbegin(), reverse_iterator(end()));
+ EXPECT_EQ(++rbegin(), reverse_iterator(++begin()));
+ EXPECT_EQ(rend(), reverse_iterator(begin()));
+
+ // Check const iterator constructors.
+ EXPECT_EQ(cbegin(), const_iterator(rend()));
+ EXPECT_EQ(cbegin(), const_iterator(crend()));
+ EXPECT_EQ(crbegin(), const_reverse_iterator(end()));
+ EXPECT_EQ(crbegin(), const_reverse_iterator(cend()));
+
+ // Confirm lack of implicit conversions.
+ static_assert(!std::is_convertible<iterator, reverse_iterator>::value,
+ "unexpected implicit conversion");
+ static_assert(!std::is_convertible<reverse_iterator, iterator>::value,
+ "unexpected implicit conversion");
+ static_assert(
+ !std::is_convertible<const_iterator, const_reverse_iterator>::value,
+ "unexpected implicit conversion");
+ static_assert(
+ !std::is_convertible<const_reverse_iterator, const_iterator>::value,
+ "unexpected implicit conversion");
+}
+
} // end namespace
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