Access it through -passes=print-lcg-dot
Let me know any suggestions for changing the rendering; I'm not
particularly attached to what is implemented here.
llvm-svn: 273082
The way we elide max expressions when computing trip counts is incorrect
-- it breaks cases like this:
```
static int wrapping_add(int a, int b) {
return (int)((unsigned)a + (unsigned)b);
}
void test() {
volatile int end_buf = 2147483548; // INT_MIN - 100
int end = end_buf;
unsigned counter = 0;
for (int start = wrapping_add(end, 200); start < end; start++)
counter++;
print(counter);
}
```
Note: the `NoWrap` variable that was being tested has little to do with
the values flowing into the max expression; it is a property of the
induction variable.
test/Transforms/LoopUnroll/nsw-tripcount.ll was added to solely test
functionality I'm reverting in this change, so I've deleted the test
fully.
llvm-svn: 273079
This is a functional change for LLE and LDist. The other clients (LV,
LVerLICM) already had this explicitly enabled.
The temporary boolean parameter to LAA is removed that allowed turning
off speculation of symbolic strides. This makes LAA's caching interface
LAA::getInfo only take the loop as the parameter. This makes the
interface more friendly to the new Pass Manager.
The flag -enable-mem-access-versioning is moved from LV to a LAA which
now allows turning off speculation globally.
llvm-svn: 273064
pass manager passes' `run` methods.
This removes a bunch of SFINAE goop from the pass manager and just
requires pass authors to accept `AnalysisManager<IRUnitT> &` as a dead
argument. This is a small price to pay for the simplicity of the system
as a whole, despite the noise that changing it causes at this stage.
This will also helpfull allow us to make the signature of the run
methods much more flexible for different kinds af passes to support
things like intelligently updating the pass's progression over IR units.
While this touches many, many, files, the changes are really boring.
Mostly made with the help of my trusty perl one liners.
Thanks to Sean and Hal for bouncing ideas for this with me in IRC.
llvm-svn: 272978
This is still NFCI, so the list of clients that allow symbolic stride
speculation does not change (yes: LV and LoopVersioningLICM, no: LLE,
LDist). However since the symbolic strides are now managed by LAA
rather than passed by client a new bool parameter is used to enable
symbolic stride speculation.
The existing test Transforms/LoopVectorize/version-mem-access.ll checks
that stride speculation is performed for LV.
The previously added test Transforms/LoopLoadElim/symbolic-stride.ll
ensures that no speculation is performed for LLE.
The next patch will change the functionality and turn on symbolic stride
speculation in all of LAA's clients and remove the bool parameter.
llvm-svn: 272970
We should update results of the BranchProbabilityInfo after removing block in JumpThreading. Otherwise
we will get dangling pointer inside BranchProbabilityInfo cache.
Differential Revision: http://reviews.llvm.org/D20957
llvm-svn: 272891
This patch makes CFLAA ignore non-pointer values, since we can now
sanely do that with the escaping/unknown attributes. Additionally,
StratifiedAttrs make more sense to sit on nodes than edges (since
they're properties of values, and ultimately end up on the nodes of
StratifiedSets). So, this patch puts said attributes on nodes.
Patch by Jia Chen.
Differential Revision: http://reviews.llvm.org/D21387
llvm-svn: 272833
We would fail to validate the type of the tan function which would cause
downstream users of isValidProtoForLibFunc to assert.
This fixes PR28143.
llvm-svn: 272802
Use Optional<T> to denote the absence of a solution, not
SCEVCouldNotCompute. This makes the usage of SolveQuadraticEquation
somewhat simpler.
llvm-svn: 272752
If a local_unnamed_addr attribute is attached to a global, the address
is known to be insignificant within the module. It is distinct from the
existing unnamed_addr attribute in that it only describes a local property
of the module rather than a global property of the symbol.
This attribute is intended to be used by the code generator and LTO to allow
the linker to decide whether the global needs to be in the symbol table. It is
possible to exclude a global from the symbol table if three things are true:
- This attribute is present on every instance of the global (which means that
the normal rule that the global must have a unique address can be broken without
being observable by the program by performing comparisons against the global's
address)
- The global has linkonce_odr linkage (which means that each linkage unit must have
its own copy of the global if it requires one, and the copy in each linkage unit
must be the same)
- It is a constant or a function (which means that the program cannot observe that
the unique-address rule has been broken by writing to the global)
Although this attribute could in principle be computed from the module
contents, LTO clients (i.e. linkers) will normally need to be able to compute
this property as part of symbol resolution, and it would be inefficient to
materialize every module just to compute it.
See:
http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20160509/356401.htmlhttp://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20160516/356738.html
for earlier discussion.
Part of the fix for PR27553.
Differential Revision: http://reviews.llvm.org/D20348
llvm-svn: 272709
This change teaches llvm::isGuaranteedToTransferExecutionToSuccessor
that calls to @llvm.assume always terminate. Most other relevant
intrinsics should be covered by the "CS.onlyReadsMemory() ||
CS.onlyAccessesArgMemory()" bit but we were missing @llvm.assumes
because we state that it clobbers memory.
Added an LICM test case, but this change is not specific to LICM.
llvm-svn: 272703
This patch also includes some refactoring.
Prior to this patch, we tagged all CFLAA attributes as unknown. This is
suboptimal, since it meant that any Value used as an argument would be
considered to alias any other Value that existed.
Now that we have the machinery to tag sets below the set for an
arbitrary value with attributes, it's okay to be less conservative with
arguments. (Specifically, we still tag the set under an argument with
unknown).
Patch by Jia Chen.
Differential Revision: http://reviews.llvm.org/D21262
llvm-svn: 272690
This patch refactors CFLAA's graph building code. This makes keeping
track of common state (TargetLibraryInfo, ...) easier.
Patch by Jia Chen.
Differential Revision: http://reviews.llvm.org/D21261
llvm-svn: 272688
Summary:
The SimplifyLibCalls part of InstCombine generates calls to those otherwise.
I wonder if at some point we shouldn't just call disableAllFunctions() and
then enable functions on a whitelist basis...
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=96495
Reviewers: arsenm, tstellarAMD
Subscribers: llvm-commits, kzhuravl
Differential Revision: http://reviews.llvm.org/D21282
llvm-svn: 272664
This is a bit gnarly since LVI is maintaining its own cache.
I think this port could be somewhat cleaner, but I'd rather not spend
too much time on it while we still have the old pass hanging around and
limiting how much we can clean things up.
Once the old pass is gone it will be easier (less time spent) to clean
it up anyway.
This is the last dependency needed for porting JumpThreading which I'll
do in a follow-up commit (there's no printer pass for LVI or anything to
test it, so porting a pass that depends on it seems best).
I've been mostly following:
r269370 / D18834 which ported Dependence Analysis
r268601 / D19839 which ported BPI
llvm-svn: 272593
Summary:
AAResults::callCapturesBefore would previously ignore operand
bundles. It was possible for a later instruction to miss its memory
dependency on a call site that would only access the pointer through a
bundle.
Patch by Oscar Blumberg!
Reviewers: sanjoy
Differential Revision: http://reviews.llvm.org/D21286
llvm-svn: 272580
Summary:
Make isGuaranteedToExecute use the
isGuaranteedToTransferExecutionToSuccessor helper, and make that helper
a bit more accurate.
There's a potential performance impact here from assuming that arbitrary
calls might not return. This probably has little impact on loads and
stores to a pointer because most things alias analysis can reason about
are dereferenceable anyway. The other impacts, like less aggressive
hoisting of sdiv by a variable and less aggressive hoisting around
volatile memory operations, are unlikely to matter for real code.
This also impacts SCEV, which uses the same helper. It's a minor
improvement there because we can tell that, for example, memcpy always
returns normally. Strictly speaking, it's also introducing
a bug, but it's not any worse than everywhere else we assume readonly
functions terminate.
Fixes http://llvm.org/PR27857.
Reviewers: hfinkel, reames, chandlerc, sanjoy
Subscribers: broune, llvm-commits
Differential Revision: http://reviews.llvm.org/D21167
llvm-svn: 272489
Add an option to enable the analysis of MachineFunction register
usage to extract the list of clobbered registers.
When enabled, the CodeGen order is changed to be bottom up on the Call
Graph.
The analysis is split in two parts, RegUsageInfoCollector is the
MachineFunction Pass that runs post-RA and collect the list of
clobbered registers to produce a register mask.
An immutable pass, RegisterUsageInfo, stores the RegMask produced by
RegUsageInfoCollector, and keep them available. A future tranformation
pass will use this information to update every call-sites after
instruction selection.
Patch by Vivek Pandya <vivekvpandya@gmail.com>
Differential Revision: http://reviews.llvm.org/D20769
llvm-svn: 272403
Prior to this patch, we used argument/global stratified attributes in
order to note that a value could have come from either dereferencing a
global/arg, or from the assignment from a global/arg.
Now, AttrUnknown is placed on sets when we see a dereference, instead of
the global/arg attributes. This allows us to be more aggressive in the
future when we see global/arg attributes without AttrUnknown.
Patch by Jia Chen.
Differential Revision: http://reviews.llvm.org/D21110
llvm-svn: 272335
Instead of directly using MaxFunctionCount and function entry count to determine callee hotness, use the isHotFunction/isColdFunction methods provided by ProfileSummaryInfo.
Differential revision: http://reviews.llvm.org/D21045
llvm-svn: 272321
We can safely rely on a NoWrap add recurrence causing UB down the road
only if we know the loop does not have a exit expressed in a way that is
opaque to ScalarEvolution (e.g. by a function call that conditionally
calls exit(0)).
I believe with this change PR28012 is fixed.
Note: I had to change some llvm-lit tests in LoopReroll, since it looks
like they were depending on this incorrect behavior.
llvm-svn: 272237
This is NFC as far as externally visible behavior is concerned, but will
keep us from spinning in the worklist traversal algorithm unnecessarily.
llvm-svn: 272182
Absence of may-unwind calls is not enough to guarantee that a
UB-generating use of an add-rec poison in the loop latch will actually
cause UB. We also need to guard against calls that terminate the thread
or infinite loop themselves.
This partially addresses PR28012.
llvm-svn: 272181
The worklist algorithm introduced in rL271151 didn't check to see if the
direct users of the post-inc add recurrence propagates poison. This
change fixes the problem and makes the code structure more obvious.
Note for release managers: correctness wise, this bug wasn't a
regression introduced by rL271151 -- the behavior of SCEV around
post-inc add recurrences was strictly improved (in terms of correctness)
in rL271151.
llvm-svn: 272179
As suggested by clang-tidy's performance-unnecessary-copy-initialization.
This can easily hit lifetime issues, so I audited every change and ran the
tests under asan, which came back clean.
llvm-svn: 272126
This patch does a few things:
- Unifies AttrAll and AttrUnknown (since they were used for more or less
the same purpose anyway).
- Introduces AttrEscaped, an attribute that notes that a value escapes
our analysis for a given set, but not that an unknown value flows into
said set.
- Removes functions that take bit indices, since we also had functions
that took bitsets, and the use of both (with similar names) was
unclear and bug-prone.
Patch by Jia Chen.
Differential Revision: http://reviews.llvm.org/D21000
llvm-svn: 272040
