Unlike SDag, we use a separate G_GEP instruction (much simplified, only taking
a single byte offset) to preserve the pointer type information through
selection.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@281205 91177308-0d34-0410-b5e6-96231b3b80d8
Remove createNode() and any API that depending on it, and add
HasCreateNode to the list of checks for HasObsoleteCustomizations. Now
an ilist *never* allocates (this was already true for iplist).
This factors out all the differences between iplist and ilist. I'll aim
to rename both to "owning_ilist" eventually, to call out the interesting
(not exactly intrusive) ownership semantics. In the meantime, I've left
both names around to reduce code churn.
One of the deleted APIs is the ilist copy constructor. I've lifted up
and tested iplist::cloneFrom (ala simple_ilist::cloneFrom) as a
replacement.
Users of ilist<> and iplist<> that want the list to allocate nodes have
a few options:
- use std::list;
- use AllocatorList or BumpPtrList (or build a similarly trivial list);
- use cloneFrom (which is explicit at the call site); or
- allocate at the call site.
See r280573, r281177, r281181, and r281182 for examples of what to do if
you're updating out-of-tree code.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@281184 91177308-0d34-0410-b5e6-96231b3b80d8
Now that MachineBasicBlock::reverse_instr_iterator knows when it's at
the end (since r281168 and r281170), implement
MachineBasicBlock::reverse_iterator directly on top of an
ilist::reverse_iterator by adding an IsReverse template parameter to
MachineInstrBundleIterator. This replaces another hard-to-reason-about
use of std::reverse_iterator on list iterators, matching the changes for
ilist::reverse_iterator from r280032 (see the "out of scope" section at
the end of that commit message). MachineBasicBlock::reverse_iterator
now has a handle to the current node and has obvious invalidation
semantics.
r280032 has a more detailed explanation of how list-style reverse
iterators (invalidated when the pointed-at node is deleted) are
different from vector-style reverse iterators like std::reverse_iterator
(invalidated on every operation). A great motivating example is this
commit's changes to lib/CodeGen/DeadMachineInstructionElim.cpp.
Note: If your out-of-tree backend deletes instructions while iterating
on a MachineBasicBlock::reverse_iterator or converts between
MachineBasicBlock::iterator and MachineBasicBlock::reverse_iterator,
you'll need to update your code in similar ways to r280032. The
following table might help:
[Old] ==> [New]
delete &*RI, RE = end() delete &*RI++
RI->erase(), RE = end() RI++->erase()
reverse_iterator(I) std::prev(I).getReverse()
reverse_iterator(I) ++I.getReverse()
--reverse_iterator(I) I.getReverse()
reverse_iterator(std::next(I)) I.getReverse()
RI.base() std::prev(RI).getReverse()
RI.base() ++RI.getReverse()
--RI.base() RI.getReverse()
std::next(RI).base() RI.getReverse()
(For more details, have a look at r280032.)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@281172 91177308-0d34-0410-b5e6-96231b3b80d8
Add an assertion to the MachineInstrBundleIterator from instr_iterator
that the underlying iterator is valid. This is possible know that we
can check ilist_node::isSentinel (since r281168), and is consistent with
the constructors from MachineInstr* and MachineInstr&.
Avoiding the new assertion in operator== and operator!= requires four
(!!!!) new overloads each.
(As an aside, I'm strongly in favour of:
- making the conversion from instr_iterator explicit;
- making the conversion from pointer explicit;
- making the conversion from reference explicit; and
- removing all the extra overloads of operator== and operator!= except
const_instr_iterator.
I'm not signing up for that at this point, but being clear about when
something is an MachineInstr-iterator (possibly instr_end()) vs
MachineInstr-bundle-iterator (possibly end()) vs MachineInstr* (possibly
nullptr) vs MachineInstr& (known valid) would surely make code
cleaner... and it would remove a ton of boilerplate from
MachineInstrBundleIterator operators.)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@281170 91177308-0d34-0410-b5e6-96231b3b80d8
This is a prep commit before fixing MachineBasicBlock::reverse_iterator
invalidation semantics, ala r281167 for ilist::reverse_iterator. This
changes MachineBasicBlock::Instructions to track which node is the
sentinel regardless of LLVM_ENABLE_ABI_BREAKING_CHECKS.
There's almost no functionality change (aside from ABI). However, in
the rare configuration:
#if !defined(NDEBUG) && !defined(LLVM_ENABLE_ABI_BREAKING_CHECKS)
the isKnownSentinel() assertions in ilist_iterator<>::operator* suddenly
have teeth for MachineInstr. If these assertions start firing for your
out-of-tree backend, have a look at the suggestions in the commit
message for r279314, and at some of the commits leading up to it that
avoid dereferencing the end() iterator.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@281168 91177308-0d34-0410-b5e6-96231b3b80d8
This adds two declarative configuration options for intrusive lists
(available for simple_ilist, iplist, and ilist). Both of these options
affect ilist_node interoperability and need to be passed both to the
node and the list. Instead of adding a new traits class, they're
specified as optional template parameters (in any order).
The two options:
1. Pass ilist_sentinel_tracking<true> or ilist_sentinel_tracking<false>
to control whether there's a bit on ilist_node "prev" pointer
indicating whether it's the sentinel. The default behaviour is to
use a bit if and only if LLVM_ENABLE_ABI_BREAKING_CHECKS.
2. Pass ilist_tag<TagA> and ilist_tag<TagB> to allow insertion of a
single node into two different lists (simultaneously).
I have an immediate use-case for (1) ilist_sentinel_tracking: fixing the
validation semantics of MachineBasicBlock::reverse_iterator to match
ilist::reverse_iterator (ala r280032: see the comments at the end of the
commit message there). I'm adding (2) ilist_tag in the same commit to
validate that the options framework supports expansion. Justin Bogner
mentioned this might enable a possible cleanup in SelectionDAG, but I'll
leave this to others to explore. In the meantime, the unit tests and
the comments for simple_ilist and ilist_node have usage examples.
Note that there's a layer of indirection to support optional,
out-of-order, template paramaters. Internal classes are templated on an
instantiation of the non-variadic ilist_detail::node_options.
User-facing classes use ilist_detail::compute_node_options to compute
the correct instantiation of ilist_detail::node_options.
The comments for ilist_detail::is_valid_option describe how to add new
options (e.g., ilist_packed_int<int NumBits>).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@281167 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
An IR load can be invariant, dereferenceable, neither, or both. But
currently, MI's notion of invariance is IR-invariant &&
IR-dereferenceable.
This patch splits up the notions of invariance and dereferenceability at
the MI level. It's NFC, so adds some probably-unnecessary
"is-dereferenceable" checks, which we can remove later if desired.
Reviewers: chandlerc, tstellarAMD
Subscribers: jholewinski, arsenm, nemanjai, llvm-commits
Differential Revision: https://reviews.llvm.org/D23371
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@281151 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
I want to separate out the notions of invariance and dereferenceability
at the MI level, so that they correspond to the equivalent concepts at
the IR level. (Currently an MI load is MI-invariant iff it's
IR-invariant and IR-dereferenceable.)
First step is renaming this function.
Reviewers: chandlerc
Subscribers: MatzeB, jfb, llvm-commits
Differential Revision: https://reviews.llvm.org/D23370
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@281125 91177308-0d34-0410-b5e6-96231b3b80d8
These were added in r281051, which, I am embarrassed to admit, has an
incomplete commit message that I forgot to update before pushing. You
can ignore element (2) in that list.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@281054 91177308-0d34-0410-b5e6-96231b3b80d8
1) On some platforms, sizeof(SDNodeBits) == 1, so we were only copying
one byte out of the bitfield when we wanted to copy two, and we were
leaving half of the return value of getRawSubclassData() undefined.
2) Something something bitfields, not sure exactly what the issue or fix
is, yet. (TODO)
Summary:
Previously we were assuming that SDNodeBits covered all of SDNode's
anonymous subclass data bitfield union. But that's not right; it might
have size 1, in which it clearly doesn't.
This patch adds a field that does cover the whole union and adds
static_asserts to ensure it stays correct.
Reviewers: ahatanak, chandlerc
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D24223
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@281051 91177308-0d34-0410-b5e6-96231b3b80d8
These instructions were only necessary when type information was stored in the
MachineInstr (because only generic MachineInstrs possessed a type). Now that
it's in MachineRegisterInfo, COPY and PHI work fine.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@281037 91177308-0d34-0410-b5e6-96231b3b80d8
We want each register to have a canonical type, which means the best place to
store this is in MachineRegisterInfo rather than on every MachineInstr that
happens to use or define that register.
Most changes following from this are pretty simple (you need an MRI anyway if
you're going to be doing any transformations, so just check the type there).
But legalization doesn't really want to check redundant operands (when, for
example, a G_ADD only ever has one type) so I've made use of MCInstrDesc's
operand type field to encode these constraints and limit legalization's work.
As an added bonus, more validation is possible, both in MachineVerifier and
MachineIRBuilder (coming soon).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@281035 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
While woring on mapping attributes in the C API, it clearly appeared that the recent changes in the API on the C++ side left Function and Call/Invoke with an attribute API that grew in an ad hoc manner. This makes it difficult to work with it, because one doesn't know which overloads exists and which do not.
Make sure that getter/setter function exists for both enum and string version. Remove inconsistent getter/setter, unless they have many callsites.
This should make it easier to work with attributes in the future.
This doesn't change how attribute works.
Reviewers: bkramer, whitequark, mehdi_amini, void
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D21514
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@281019 91177308-0d34-0410-b5e6-96231b3b80d8
And associated commits, as they broke the Thumb bots.
This reverts commit r280935.
This reverts commit r280891.
This reverts commit r280888.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@280967 91177308-0d34-0410-b5e6-96231b3b80d8
CGP tail-duplicates rets into blocks that end with a call that feed the ret.
This puts the call in tail position, potentially allowing the DAG builder to
lower it as a tail call. To avoid tail duplication in cases where we won't
form the tail call, CGP tried to predict whether this is going to be possible,
and avoids doing it when lowering as a tail call will definitely fail.
However, it was being too conservative by always throwing away calls to
functions with a signext/zeroext attribute on the return type.
Instead, we can use the same logic the builder uses to determine whether the
attributes work out.
Differential Revision: https://reviews.llvm.org/D24315
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@280894 91177308-0d34-0410-b5e6-96231b3b80d8
Inheriting from std::iterator uses more boiler-plate than manual
typedefs. Avoid that in both ilist_iterator and
MachineInstrBundleIterator.
This has the side effect of removing ilist_iterator from certain ADL
lookups in namespace std; calls to std::next need to be qualified by
"std::" that didn't have to before. The one case of this in-tree was
operating on a temporary, so I used the more compact operator++.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@280570 91177308-0d34-0410-b5e6-96231b3b80d8
They're another source of generic vregs, which are going to need a type on the
definition when we remove the register width from MachineRegisterInfo.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@280412 91177308-0d34-0410-b5e6-96231b3b80d8
LLVM has an @llvm.eh.dwarf.cfa intrinsic, used to lower the GCC-compatible
__builtin_dwarf_cfa() builtin. As pointed out in PR26761, this is currently
broken on PowerPC (and likely on ARM as well). Currently, @llvm.eh.dwarf.cfa is
lowered using:
ADD(FRAMEADDR, FRAME_TO_ARGS_OFFSET)
where FRAME_TO_ARGS_OFFSET defaults to the constant zero. On x86,
FRAME_TO_ARGS_OFFSET is lowered to 2*SlotSize. This setup, however, does not
work for PowerPC. Because of the way that the stack layout works, the canonical
frame address is not exactly (FRAMEADDR + FRAME_TO_ARGS_OFFSET) on PowerPC
(there is a lower save-area offset as well), so it is not just a matter of
implementing FRAME_TO_ARGS_OFFSET for PowerPC (unless we redefine its
semantics -- We can do that, since it is currently used only for
@llvm.eh.dwarf.cfa lowering, but the better to directly lower the CFA construct
itself (since it can be easily represented as a fixed-offset FrameIndex)). Mips
currently does this, but by using a custom lowering for ADD that specifically
recognizes the (FRAMEADDR, FRAME_TO_ARGS_OFFSET) pattern.
This change introduces a ISD::EH_DWARF_CFA node, which by default expands using
the existing logic, but can be directly lowered by the target. Mips is updated
to use this method (which simplifies its implementation, and I suspect makes it
more robust), and updates PowerPC to do the same.
Fixes PR26761.
Differential Revision: https://reviews.llvm.org/D24038
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@280350 91177308-0d34-0410-b5e6-96231b3b80d8
As discussed in https://reviews.llvm.org/D22666, our current mechanism to
support -pg profiling, where we insert calls to mcount(), or some similar
function, is fundamentally broken. We insert these calls in the frontend, which
means they get duplicated when inlining, and so the accumulated execution
counts for the inlined-into functions are wrong.
Because we don't want the presence of these functions to affect optimizaton,
they should be inserted in the backend. Here's a pass which would do just that.
The knowledge of the name of the counting function lives in the frontend, so
we're passing it here as a function attribute. Clang will be updated to use
this mechanism.
Differential Revision: https://reviews.llvm.org/D22825
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@280347 91177308-0d34-0410-b5e6-96231b3b80d8
This reverts commit r280268, it causes all MSVC 2013 to ICE. This
appears to have been fixed in a later MSVC 2013 update, because I cannot
reproduce it locally. That said, all upstream LLVM bots are broken right
now, so I am reverting.
Also reverts dependent change r280275, "[Hexagon] Deal with undefs when
extending live intervals".
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@280301 91177308-0d34-0410-b5e6-96231b3b80d8
More preparation for dropping source types from MachineInstrs: regsters coming
out of already-selected code (i.e. non-generic instructions) don't have a type,
but that information is needed so we must add it manually.
This is done via a new G_TYPE instruction.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@280292 91177308-0d34-0410-b5e6-96231b3b80d8
Legalization ends up creating many G_SEQUENCE/G_EXTRACT pairs which leads to
inefficient codegen (even for -O0), so add a quick pass over the function to
remove them again.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@280155 91177308-0d34-0410-b5e6-96231b3b80d8
Many lists want to override only allocation semantics, or callbacks for
iplist. Split these up to prevent code duplication.
- Specialize ilist_alloc_traits to change the implementations of
deleteNode() and createNode().
- One common desire is to do nothing deleteNode() and disable
createNode(). Specialize ilist_alloc_traits to inherit from
ilist_noalloc_traits for that behaviour.
- Specialize ilist_callback_traits to use the addNodeToList(),
removeNodeFromList(), and transferNodesFromList() callbacks.
As a drive-by, add some coverage to the callback-related unit tests.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@280128 91177308-0d34-0410-b5e6-96231b3b80d8
The existing code hard-coded a limit of 20 instructions for duplication
when a block ended with an indirect branch. Extract this as an option.
No functional change intended.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@280125 91177308-0d34-0410-b5e6-96231b3b80d8
Reverse iterators to doubly-linked lists can be simpler (and cheaper)
than std::reverse_iterator. Make it so.
In particular, change ilist<T>::reverse_iterator so that it is *never*
invalidated unless the node it references is deleted. This matches the
guarantees of ilist<T>::iterator.
(Note: MachineBasicBlock::iterator is *not* an ilist iterator, but a
MachineInstrBundleIterator<MachineInstr>. This commit does not change
MachineBasicBlock::reverse_iterator, but it does update
MachineBasicBlock::reverse_instr_iterator. See note at end of commit
message for details on bundle iterators.)
Given the list (with the Sentinel showing twice for simplicity):
[Sentinel] <-> A <-> B <-> [Sentinel]
the following is now true:
1. begin() represents A.
2. begin() holds the pointer for A.
3. end() represents [Sentinel].
4. end() holds the poitner for [Sentinel].
5. rbegin() represents B.
6. rbegin() holds the pointer for B.
7. rend() represents [Sentinel].
8. rend() holds the pointer for [Sentinel].
The changes are #6 and #8. Here are some properties from the old
scheme (which used std::reverse_iterator):
- rbegin() held the pointer for [Sentinel] and rend() held the pointer
for A;
- operator*() cost two dereferences instead of one;
- converting from a valid iterator to its valid reverse_iterator
involved a confusing increment; and
- "RI++->erase()" left RI invalid. The unintuitive replacement was
"RI->erase(), RE = end()".
With vector-like data structures these properties are hard to avoid
(since past-the-beginning is not a valid pointer), and don't impose a
real cost (since there's still only one dereference, and all iterators
are invalidated on erase). But with lists, this was a poor design.
Specifically, the following code (which obviously works with normal
iterators) now works with ilist::reverse_iterator as well:
for (auto RI = L.rbegin(), RE = L.rend(); RI != RE;)
fooThatMightRemoveArgFromList(*RI++);
Converting between iterator and reverse_iterator for the same node uses
the getReverse() function.
reverse_iterator iterator::getReverse();
iterator reverse_iterator::getReverse();
Why doesn't iterator <=> reverse_iterator conversion use constructors?
In order to catch and update old code, reverse_iterator does not even
have an explicit conversion from iterator. It wouldn't be safe because
there would be no reasonable way to catch all the bugs from the changed
semantic (see the changes at call sites that are part of this patch).
Old code used this API:
std::reverse_iterator::reverse_iterator(iterator);
iterator std::reverse_iterator::base();
Here's how to update from old code to new (that incorporates the
semantic change), assuming I is an ilist<>::iterator and RI is an
ilist<>::reverse_iterator:
[Old] ==> [New]
reverse_iterator(I) (--I).getReverse()
reverse_iterator(I) ++I.getReverse()
--reverse_iterator(I) I.getReverse()
reverse_iterator(++I) I.getReverse()
RI.base() (--RI).getReverse()
RI.base() ++RI.getReverse()
--RI.base() RI.getReverse()
(++RI).base() RI.getReverse()
delete &*RI, RE = end() delete &*RI++
RI->erase(), RE = end() RI++->erase()
=======================================
Note: bundle iterators are out of scope
=======================================
MachineBasicBlock::iterator, also known as
MachineInstrBundleIterator<MachineInstr>, is a wrapper to represent
MachineInstr bundles. The idea is that each operator++ takes you to the
beginning of the next bundle. Implementing a sane reverse iterator for
this is harder than ilist. Here are the options:
- Use std::reverse_iterator<MBB::i>. Store a handle to the beginning of
the next bundle. A call to operator*() runs a loop (usually
operator--() will be called 1 time, for unbundled instructions).
Increment/decrement just works. This is the status quo.
- Store a handle to the final node in the bundle. A call to operator*()
still runs a loop, but it iterates one time fewer (usually
operator--() will be called 0 times, for unbundled instructions).
Increment/decrement just works.
- Make the ilist_sentinel<MachineInstr> *always* store that it's the
sentinel (instead of just in asserts mode). Then the bundle iterator
can sniff the sentinel bit in operator++().
I initially tried implementing the end() option as part of this commit,
but updating iterator/reverse_iterator conversion call sites was
error-prone. I have a WIP series of patches that implements the final
option.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@280032 91177308-0d34-0410-b5e6-96231b3b80d8
Instead of putting all possible requests into a single table, we can perform
the extremely dense lookup based on opcode and type-index in constant time
using multi-dimensional array-like things.
This roughly halves the time spent doing legalization, which was dominated by
queries against the Actions table.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@280011 91177308-0d34-0410-b5e6-96231b3b80d8
There should be no functional change here, I'm just making the implementation
of "frem" (to libcall) legalization easier for a followup.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@279987 91177308-0d34-0410-b5e6-96231b3b80d8
When global-isel fails on a MachineFunction MF, MF will be cleaned up
and given to SDISel.
Thanks to this fallback, we can already perform correctness test even if
we support only a small portion of the functions in a test.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@279891 91177308-0d34-0410-b5e6-96231b3b80d8
This is used to communicate that the instruction selection pipeline
failed at some point.
Another way to achieve that would be to have some kind of conditional
scheduling in the PassManager, such that we only schedule a pass based
on the success/failure of another one. The property approach has the
advantage of being lightweight and solve the problem at stake.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@279885 91177308-0d34-0410-b5e6-96231b3b80d8
By default, this hook tells GlobalISel to abort (report a fatal error)
when it encounters an error. The alternative will be to fall back on
SDISel.
This fall back will be removed when the bring-up of GlobalISel is over.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@279879 91177308-0d34-0410-b5e6-96231b3b80d8
This method allows to reset the state of a MachineFunction as if it was
just created. This will be used during the bring-up of GlobalISel to
provide a way to fallback on SelectionDAG. That way, we can start doing
correctness testing even if we are not able to select all functions via
the global instruction selector.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@279876 91177308-0d34-0410-b5e6-96231b3b80d8
