Since forward references for uniqued node operands are expensive (and
those for distinct node operands are cheap due to
DistinctMDOperandPlaceholder), minimize forward references in uniqued
node operands.
Moreover, guarantee that when a cycle is broken by a distinct node, none
of the uniqued nodes have any forward references. In
ValueEnumerator::EnumerateMetadata, enumerate uniqued node subgraphs
first, delaying distinct nodes until all uniqued nodes have been
handled. This guarantees that uniqued nodes only have forward
references when there is a uniquing cycle (since r267276 changed
ValueEnumerator::organizeMetadata to partition distinct nodes in front
of uniqued nodes as a post-pass).
Note that a single uniqued subgraph can hit multiple distinct nodes at
its leaves. Ideally these would themselves be emitted in post-order,
but this commit doesn't attempt that; I think it requires an extra pass
through the edges, which I'm not convinced is worth it (since
DistinctMDOperandPlaceholder makes forward references quite cheap
between distinct nodes).
I've added two testcases:
- test/Bitcode/mdnodes-distinct-in-post-order.ll is just like
test/Bitcode/mdnodes-in-post-order.ll, except with distinct nodes
instead of uniqued ones. This confirms that, in the absence of
uniqued nodes, distinct nodes are still emitted in post-order.
- test/Bitcode/mdnodes-distinct-nodes-break-cycles.ll is the minimal
example where a naive post-order traversal would cause one uniqued
node to forward-reference another. IOW, it's the motivating test.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@267278 91177308-0d34-0410-b5e6-96231b3b80d8
When an operand of a distinct node hasn't been read yet, the reader can
use a DistinctMDOperandPlaceholder. This is much cheaper than forward
referencing from a uniqued node. Change
ValueEnumerator::organizeMetadata to partition distinct nodes and
uniqued nodes to reduce the overhead of cycles broken by distinct nodes.
Mehdi measured this for me; this removes most of the RAUW from the
importing step of -flto=thin, even after a WIP patch that removes
string-based DITypeRefs (introducing many more cycles to the metadata
graph).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@267276 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
As discussed in on the mailing list yesterday, I have refactored
BitcodeWriter.cpp to use classes to manage the bitcode writing process,
instead of passing around long lists of parameters between static
functions. See:
http://lists.llvm.org/pipermail/llvm-dev/2016-April/098610.html
I created a parent BitcodeWriter class to own the BitstreamWriter,
write the header, and contain the main entry point into the writing
process. There are two derived classes, one for writing a module and one
for writing a combined index file (for ThinLTO), which manage the
writing process specific to those bitcode file types.
I also changed the functions to conform to LLVM coding standards
(lowercase function name first letter). The only two routines that still
start with an uppercase letter are the two external interfaces, which
can be fixed as a follow-on (I wanted to keep this round just within
BitcodeWriter.cpp).
Reviewers: dexonsmith, joker.eph
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D19447
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@267273 91177308-0d34-0410-b5e6-96231b3b80d8
Mehdi's pattern recognition pulled this one out. This is cleaner with
std::find_if than with the strange helper function that took an iterator
by reference and updated it.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@267271 91177308-0d34-0410-b5e6-96231b3b80d8
Each reference to an unresolved MDNode is expensive, since the RAUW
support in MDNode uses a separate allocation and side map. Since
a distinct MDNode doesn't require its operands on creation (unlike
uniuqed nodes, there's no need to check for structural equivalence),
use nullptr for any of its unresolved operands. Besides reducing the
burden on MDNode maps, this can avoid allocating temporary MDNodes in
the first place.
We need some way to track operands. Invent DistinctMDOperandPlaceholder
for this purpose, which is a Metadata subclass that holds an ID and
points at its single user. DistinctMDOperandPlaceholder::replaceUseWith
is just like RAUW, but its name highlights that there is only ever
exactly one use.
There is no support for moving (or, obviously, copying) these. Move
support would be possible but expensive; leaving it unimplemented
prevents user error. In the BitcodeReader I originally considered
allocating on a BumpPtrAllocator and keeping a vector of pointers to
them, and then I realized that std::deque implements exactly this.
A couple of obvious follow-ups:
- Change ValueEnumerator to emit distinct nodes first to take more
advantage of this optimization. (How convenient... I think I might
have a couple of patches for this.)
- Change DIBuilder and its consumers (like CGDebugInfo in clang) to
use something like this when constructing debug info in the first
place.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@267270 91177308-0d34-0410-b5e6-96231b3b80d8
Consistently use the IsDistinct variable and start relying on it in
GET_OR_DISTINCT. This change has NFC, but prepares for using IsDistinct
to optimize the behaviour of the getMD() and getMDOrNull() helpers.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@267268 91177308-0d34-0410-b5e6-96231b3b80d8
The only functionality change was removing an error check from the
BitcodeReader (and an assertion from DILocation::getImpl) that is
already caught by Verifier::visitDILocation. The Verifier is a better
place for this anyway, and being inconsistent with other subclasses of
MDNode isn't serving anyone.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@267267 91177308-0d34-0410-b5e6-96231b3b80d8
Only one consumer (llvm-objdump) actually cared about the fact that there were
two triples. Others were actively working around the fact that the Triple
returned by getArch might have been invalid. As for llvm-objdump, it needs to
be acutely aware of both Triples anyway, so being generic in the exposed API is
no benefit.
Also rename the version of getArch returning a Triple. Users were having to
pass an unwanted nullptr to disambiguate the two, which was nasty.
The only functional change here is that armv7m and armv7em object files no
longer crash llvm-objdump.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@267249 91177308-0d34-0410-b5e6-96231b3b80d8
The dwo_name was added to dwo files to improve diagnostics in dwp, but
it confuses tools that attempt to load any dwo named by a dwo_name, even
ones inside dwos. Avoid this by keeping track of whether a unit is
already a dwo unit, and if so, not loading further dwos.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@267241 91177308-0d34-0410-b5e6-96231b3b80d8
Rather than relying on the gmlt-like data emitted into the .o/executable
which only contains the simple name of any inlined functions, use the
.dwo file if present.
Test symbolication with/without a .dwo, and the old test that was
testing behavior when no gmlt-like data was present. (I haven't included
a test of non-gmlt-like data + no .dwo (that would be akin to
symbolication with no debug info) but we could add one for completeness)
The test was simplified a bit to be a little clearer (unoptimized, force
inline, using a function call as the inlined entity) and regenerated
with ToT clang. For the no-gmlt-like-data case, I modified Clang back to
its old behavior temporarily & the .dwo file is identical so it is
shared between the two executables.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@267227 91177308-0d34-0410-b5e6-96231b3b80d8
Summary: The clang assembler assumes that the discriminator remains the same when there is source line change. The correct behavior is that when there is line change, discriminator will automatically reset to 0.
Reviewers: dnovillo, davidxl, echristo
Subscribers: echristo, llvm-commits
Differential Revision: http://reviews.llvm.org/D19436
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@267226 91177308-0d34-0410-b5e6-96231b3b80d8
This intrinsic takes two arguments, ``%ptr`` and ``%offset``. It loads
a 32-bit value from the address ``%ptr + %offset``, adds ``%ptr`` to that
value and returns it. The constant folder specifically recognizes the form of
this intrinsic and the constant initializers it may load from; if a loaded
constant initializer is known to have the form ``i32 trunc(x - %ptr)``,
the intrinsic call is folded to ``x``.
LLVM provides that the calculation of such a constant initializer will
not overflow at link time under the medium code model if ``x`` is an
``unnamed_addr`` function. However, it does not provide this guarantee for
a constant initializer folded into a function body. This intrinsic can be
used to avoid the possibility of overflows when loading from such a constant.
Differential Revision: http://reviews.llvm.org/D18367
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@267223 91177308-0d34-0410-b5e6-96231b3b80d8
The existing code turned out to be completely correct when auditted. Thus, only minor code changes and adding a couple of tests.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@267215 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
We can fold compares to false when two distinct allocations within a
function are compared for equality.
Patch by Anna Thomas!
Reviewers: majnemer, reames, sanjoy
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D19390
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@267214 91177308-0d34-0410-b5e6-96231b3b80d8
The relative vtable ABI (PR26723) needs PLT relocations to refer to virtual
functions defined in other DSOs. The unnamed_addr attribute means that the
function's address is not significant, so we're allowed to substitute it
with the address of a PLT entry.
Also includes a bonus feature: addends for COFF image-relative references.
Differential Revision: http://reviews.llvm.org/D17938
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@267211 91177308-0d34-0410-b5e6-96231b3b80d8
Extend the type canonicalization logic to work for unordered atomic loads and stores. Note that while this change itself is fairly simple and low risk, there's a reasonable chance this will expose problems in the backends by suddenly generating IR they wouldn't have seen before. Anything of this nature will be an existing bug in the backend (you could write an atomic float load), but this will definitely change the frequency with which such cases are encountered. If you see problems, feel free to revert this change, but please make sure you collect a test case.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@267210 91177308-0d34-0410-b5e6-96231b3b80d8
The opcode for the optimized branch does not depend on the size
of the activate bits in the AND masks, but the AND opcode itself.
Indeed, we need to use a X or W variant based on the AND variant
not based on whether the mask fits into the related variant.
Otherwise, we may end up using the W variant of the optimized branch
for 64-bit register inputs!
This fixes the last make check verifier issues for AArch64: PR27479.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@267206 91177308-0d34-0410-b5e6-96231b3b80d8
Summary: This change will shorten memset if the beginning of memset is overwritten by later stores.
Reviewers: hfinkel, eeckstein, dberlin, mcrosier
Subscribers: mgrang, mcrosier, llvm-commits
Differential Revision: http://reviews.llvm.org/D18906
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@267197 91177308-0d34-0410-b5e6-96231b3b80d8
Also add a very basic test, since apparently there aren't any tests
for DCE whatsoever to add the new pass version to.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@267196 91177308-0d34-0410-b5e6-96231b3b80d8
E.g. for:
!1 = {"llvm.distribute", i32 1}
it now returns the MDOperand for 1.
I will use this in LoopDistribution to check the value of the metadata.
Note that the change is backward-compatible with its current use in
LoopVersioningLICM. An Optional implicitly converts to a bool depending
whether it contains a value or not.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@267190 91177308-0d34-0410-b5e6-96231b3b80d8
We used to simply set the kill flags to true when transforming a scalar
instruction to a vector one.
SrcScalar1 = copy SrcVector1
... = opScalar SrcScalar1
=>
SrcScalar1 = copy SrcVector1
... = opVector SrcVector1<kill>
This is obviously wrong. The proper update consists in:
1. Propagate the kill status from the copy to the new opVector
2. Reset the kill status on the copy, since the live-range of
SrcVector1 got extended.
This fixes some of the machine verifier errors for AArch64 with make check.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@267180 91177308-0d34-0410-b5e6-96231b3b80d8
