Commit Graph

46 Commits

Author SHA1 Message Date
Jingyue Wu 5da831cc31 Divergence analysis for GPU programs
Summary:
Some optimizations such as jump threading and loop unswitching can negatively
affect performance when applied to divergent branches. The divergence analysis
added in this patch conservatively estimates which branches in a GPU program
can diverge. This information can then help LLVM to run certain optimizations
selectively.

Test Plan: test/Analysis/DivergenceAnalysis/NVPTX/diverge.ll

Reviewers: resistor, hfinkel, eliben, meheff, jholewinski

Subscribers: broune, bjarke.roune, madhur13490, tstellarAMD, dberlin, echristo, jholewinski, llvm-commits

Differential Revision: http://reviews.llvm.org/D8576

llvm-svn: 234567
2015-04-10 05:03:50 +00:00
Eric Christopher 3b94e33277 Remove the Forward Control Flow Integrity pass and its dependencies.
This work is currently being rethought along different lines and
if this work is needed it can be resurrected out of svn. Remove it
for now as no current work in ongoing on it and it's unused. Verified
with the authors before removal.

llvm-svn: 230780
2015-02-27 19:03:38 +00:00
Ramkumar Ramachandra 8378ac3684 Introduce print-memderefs to test isDereferenceablePointer
Since testing the function indirectly is tricky, introduce a direct
print-memderefs pass, in the same spirit as print-memdeps, which prints
dereferenceability information matched by FileCheck.

Differential Revision: http://reviews.llvm.org/D7075

llvm-svn: 228369
2015-02-06 01:46:42 +00:00
Chandler Carruth 705b185f90 [PM] Change the core design of the TTI analysis to use a polymorphic
type erased interface and a single analysis pass rather than an
extremely complex analysis group.

The end result is that the TTI analysis can contain a type erased
implementation that supports the polymorphic TTI interface. We can build
one from a target-specific implementation or from a dummy one in the IR.

I've also factored all of the code into "mix-in"-able base classes,
including CRTP base classes to facilitate calling back up to the most
specialized form when delegating horizontally across the surface. These
aren't as clean as I would like and I'm planning to work on cleaning
some of this up, but I wanted to start by putting into the right form.

There are a number of reasons for this change, and this particular
design. The first and foremost reason is that an analysis group is
complete overkill, and the chaining delegation strategy was so opaque,
confusing, and high overhead that TTI was suffering greatly for it.
Several of the TTI functions had failed to be implemented in all places
because of the chaining-based delegation making there be no checking of
this. A few other functions were implemented with incorrect delegation.
The message to me was very clear working on this -- the delegation and
analysis group structure was too confusing to be useful here.

The other reason of course is that this is *much* more natural fit for
the new pass manager. This will lay the ground work for a type-erased
per-function info object that can look up the correct subtarget and even
cache it.

Yet another benefit is that this will significantly simplify the
interaction of the pass managers and the TargetMachine. See the future
work below.

The downside of this change is that it is very, very verbose. I'm going
to work to improve that, but it is somewhat an implementation necessity
in C++ to do type erasure. =/ I discussed this design really extensively
with Eric and Hal prior to going down this path, and afterward showed
them the result. No one was really thrilled with it, but there doesn't
seem to be a substantially better alternative. Using a base class and
virtual method dispatch would make the code much shorter, but as
discussed in the update to the programmer's manual and elsewhere,
a polymorphic interface feels like the more principled approach even if
this is perhaps the least compelling example of it. ;]

Ultimately, there is still a lot more to be done here, but this was the
huge chunk that I couldn't really split things out of because this was
the interface change to TTI. I've tried to minimize all the other parts
of this. The follow up work should include at least:

1) Improving the TargetMachine interface by having it directly return
   a TTI object. Because we have a non-pass object with value semantics
   and an internal type erasure mechanism, we can narrow the interface
   of the TargetMachine to *just* do what we need: build and return
   a TTI object that we can then insert into the pass pipeline.
2) Make the TTI object be fully specialized for a particular function.
   This will include splitting off a minimal form of it which is
   sufficient for the inliner and the old pass manager.
3) Add a new pass manager analysis which produces TTI objects from the
   target machine for each function. This may actually be done as part
   of #2 in order to use the new analysis to implement #2.
4) Work on narrowing the API between TTI and the targets so that it is
   easier to understand and less verbose to type erase.
5) Work on narrowing the API between TTI and its clients so that it is
   easier to understand and less verbose to forward.
6) Try to improve the CRTP-based delegation. I feel like this code is
   just a bit messy and exacerbating the complexity of implementing
   the TTI in each target.

Many thanks to Eric and Hal for their help here. I ended up blocked on
this somewhat more abruptly than I expected, and so I appreciate getting
it sorted out very quickly.

Differential Revision: http://reviews.llvm.org/D7293

llvm-svn: 227669
2015-01-31 03:43:40 +00:00
Chandler Carruth 4f8f307c77 [PM] Split the LoopInfo object apart from the legacy pass, creating
a LoopInfoWrapperPass to wire the object up to the legacy pass manager.

This switches all the clients of LoopInfo over and paves the way to port
LoopInfo to the new pass manager. No functionality change is intended
with this iteration.

llvm-svn: 226373
2015-01-17 14:16:18 +00:00
Reid Kleckner 007239863e Revert "Don't make assumptions about the name of private global variables."
This reverts commit r222061.

It's causing linker errors.

llvm-svn: 222077
2014-11-15 02:03:53 +00:00
Rafael Espindola 2fc723099f Don't make assumptions about the name of private global variables.
Private variables are can be renamed, so it is not reliable to make
decisions on the name.

The name is also dropped by the assembler before getting to the
linker, so using the name causes a disconnect between how llvm makes a
decision (var name) and how the linker makes a decision (section it is
in).

This patch changes one case where we were looking at the variable name to use
the section instead.

Test tuning by Michael Gottesman.

llvm-svn: 222061
2014-11-14 23:17:47 +00:00
Hal Finkel 7529c55c02 Add a CFL Alias Analysis implementation
This provides an implementation of CFL alias analysis (including some
supporting data structures). Currently, we don't have any extremely fancy
features, sans some interprocedural analysis (i.e. no field sensitivity, etc.),
and we do best sitting behind BasicAA + TBAA. In such a configuration, we take
~0.6-0.8% of total compile time, and give ~7-8% NoAlias responses to queries
TBAA and BasicAA couldn't answer when bootstrapping LLVM. In testing this on
other projects, we've seen up to 10.5% of queries dropped by BasicAA+TBAA
answered with NoAlias by this algorithm.

Patch by George Burgess IV (with minor modifications by me -- mostly adapting
some BasicAA tests), thanks!

llvm-svn: 216970
2014-09-02 21:43:13 +00:00
Hal Finkel 9414665a3b Add scoped-noalias metadata
This commit adds scoped noalias metadata. The primary motivations for this
feature are:
  1. To preserve noalias function attribute information when inlining
  2. To provide the ability to model block-scope C99 restrict pointers

Neither of these two abilities are added here, only the necessary
infrastructure. In fact, there should be no change to existing functionality,
only the addition of new features. The logic that converts noalias function
parameters into this metadata during inlining will come in a follow-up commit.

What is added here is the ability to generally specify noalias memory-access
sets. Regarding the metadata, alias-analysis scopes are defined similar to TBAA
nodes:

!scope0 = metadata !{ metadata !"scope of foo()" }
!scope1 = metadata !{ metadata !"scope 1", metadata !scope0 }
!scope2 = metadata !{ metadata !"scope 2", metadata !scope0 }
!scope3 = metadata !{ metadata !"scope 2.1", metadata !scope2 }
!scope4 = metadata !{ metadata !"scope 2.2", metadata !scope2 }

Loads and stores can be tagged with an alias-analysis scope, and also, with a
noalias tag for a specific scope:

... = load %ptr1, !alias.scope !{ !scope1 }
... = load %ptr2, !alias.scope !{ !scope1, !scope2 }, !noalias !{ !scope1 }

When evaluating an aliasing query, if one of the instructions is associated
with an alias.scope id that is identical to the noalias scope associated with
the other instruction, or is a descendant (in the scope hierarchy) of the
noalias scope associated with the other instruction, then the two memory
accesses are assumed not to alias.

Note that is the first element of the scope metadata is a string, then it can
be combined accross functions and translation units. The string can be replaced
by a self-reference to create globally unqiue scope identifiers.

[Note: This overview is slightly stylized, since the metadata nodes really need
to just be numbers (!0 instead of !scope0), and the scope lists are also global
unnamed metadata.]

Existing noalias metadata in a callee is "cloned" for use by the inlined code.
This is necessary because the aliasing scopes are unique to each call site
(because of possible control dependencies on the aliasing properties). For
example, consider a function: foo(noalias a, noalias b) { *a = *b; } that gets
inlined into bar() { ... if (...) foo(a1, b1); ... if (...) foo(a2, b2); } --
now just because we know that a1 does not alias with b1 at the first call site,
and a2 does not alias with b2 at the second call site, we cannot let inlining
these functons have the metadata imply that a1 does not alias with b2.

llvm-svn: 213864
2014-07-24 14:25:39 +00:00
Matt Arsenault 1b8d83796d Templatify RegionInfo so it works on MachineBasicBlocks
llvm-svn: 213456
2014-07-19 18:29:29 +00:00
Alp Toker e69170a110 Revert "Introduce a string_ostream string builder facilty"
Temporarily back out commits r211749, r211752 and r211754.

llvm-svn: 211814
2014-06-26 22:52:05 +00:00
Alp Toker 2251672878 MSVC build fix following r211749
Avoid strndup()

llvm-svn: 211752
2014-06-26 00:25:41 +00:00
Alp Toker 614717388c Introduce a string_ostream string builder facilty
string_ostream is a safe and efficient string builder that combines opaque
stack storage with a built-in ostream interface.

small_string_ostream<bytes> additionally permits an explicit stack storage size
other than the default 128 bytes to be provided. Beyond that, storage is
transferred to the heap.

This convenient class can be used in most places an
std::string+raw_string_ostream pair or SmallString<>+raw_svector_ostream pair
would previously have been used, in order to guarantee consistent access
without byte truncation.

The patch also converts much of LLVM to use the new facility. These changes
include several probable bug fixes for truncated output, a programming error
that's no longer possible with the new interface.

llvm-svn: 211749
2014-06-26 00:00:48 +00:00
Tom Roeder 44cb65fff1 Add a new attribute called 'jumptable' that creates jump-instruction tables for functions marked with this attribute.
It includes a pass that rewrites all indirect calls to jumptable functions to pass through these tables.

This also adds backend support for generating the jump-instruction tables on ARM and X86.
Note that since the jumptable attribute creates a second function pointer for a
function, any function marked with jumptable must also be marked with unnamed_addr.

llvm-svn: 210280
2014-06-05 19:29:43 +00:00
Craig Topper 9f008867c0 [C++11] More 'nullptr' conversion. In some cases just using a boolean check instead of comparing to nullptr.
llvm-svn: 206243
2014-04-15 04:59:12 +00:00
Chandler Carruth 442f784814 [cleanup] Re-sort all the includes with utils/sort_includes.py.
llvm-svn: 202811
2014-03-04 10:07:28 +00:00
Chandler Carruth 043949d446 [PM] Make the verifier work independently of any pass manager.
This makes the 'verifyFunction' and 'verifyModule' functions totally
independent operations on the LLVM IR. It also cleans up their API a bit
by lifting the abort behavior into their clients and just using an
optional raw_ostream parameter to control printing.

The implementation of the verifier is now just an InstVisitor with no
multiple inheritance. It also is significantly more const-correct, and
hides the const violations internally. The two layers that force us to
break const correctness are building a DomTree and dispatching through
the InstVisitor.

A new VerifierPass is used to implement the legacy pass manager
interface in terms of the other pieces.

The error messages produced may be slightly different now, and we may
have slightly different short circuiting behavior with different usage
models of the verifier, but generally everything works equivalently and
this unblocks wiring the verifier up to the new pass manager.

llvm-svn: 199569
2014-01-19 02:22:18 +00:00
Chandler Carruth 5ad5f15cff [cleanup] Move the Dominators.h and Verifier.h headers into the IR
directory. These passes are already defined in the IR library, and it
doesn't make any sense to have the headers in Analysis.

Long term, I think there is going to be a much better way to divide
these matters. The dominators code should be fully separated into the
abstract graph algorithm and have that put in Support where it becomes
obvious that evn Clang's CFGBlock's can use it. Then the verifier can
manually construct dominance information from the Support-driven
interface while the Analysis library can provide a pass which both
caches, reconstructs, and supports a nice update API.

But those are very long term, and so I don't want to leave the really
confusing structure until that day arrives.

llvm-svn: 199082
2014-01-13 09:26:24 +00:00
Chandler Carruth 8a8cd2bab9 Re-sort all of the includes with ./utils/sort_includes.py so that
subsequent changes are easier to review. About to fix some layering
issues, and wanted to separate out the necessary churn.

Also comment and sink the include of "Windows.h" in three .inc files to
match the usage in Memory.inc.

llvm-svn: 198685
2014-01-07 11:48:04 +00:00
Sebastian Pop c62c679c1b delinearization of arrays
llvm-svn: 194527
2013-11-12 22:47:20 +00:00
Chandler Carruth ea56494625 Remove the very substantial, largely unmaintained legacy PGO
infrastructure.

This was essentially work toward PGO based on a design that had several
flaws, partially dating from a time when LLVM had a different
architecture, and with an effort to modernize it abandoned without being
completed. Since then, it has bitrotted for several years further. The
result is nearly unusable, and isn't helping any of the modern PGO
efforts. Instead, it is getting in the way, adding confusion about PGO
in LLVM and distracting everyone with maintenance on essentially dead
code. Removing it paves the way for modern efforts around PGO.

Among other effects, this removes the last of the runtime libraries from
LLVM. Those are being developed in the separate 'compiler-rt' project
now, with somewhat different licensing specifically more approriate for
runtimes.

llvm-svn: 191835
2013-10-02 15:42:23 +00:00
Filip Pizlo dec20e43c0 This patch breaks up Wrap.h so that it does not have to include all of
the things, and renames it to CBindingWrapping.h.  I also moved 
CBindingWrapping.h into Support/.

This new file just contains the macros for defining different wrap/unwrap 
methods.

The calls to those macros, as well as any custom wrap/unwrap definitions 
(like for array of Values for example), are put into corresponding C++ 
headers.

Doing this required some #include surgery, since some .cpp files relied 
on the fact that including Wrap.h implicitly caused the inclusion of a 
bunch of other things.

This also now means that the C++ headers will include their corresponding 
C API headers; for example Value.h must include llvm-c/Core.h.  I think 
this is harmless, since the C API headers contain just external function 
declarations and some C types, so I don't believe there should be any 
nasty dependency issues here.

llvm-svn: 180881
2013-05-01 20:59:00 +00:00
Eric Christopher 04d4e9312c Move C++ code out of the C headers and into either C++ headers
or the C++ files themselves. This enables people to use
just a C compiler to interoperate with LLVM.

llvm-svn: 180063
2013-04-22 22:47:22 +00:00
David Blaikie 1f7ff93cda Remove -print-dbginfo as it is unused & bitrotten.
This pass hasn't been touched in two years & would fail with assertions against
the current debug info metadata format (the only test case for it still uses a
many-versions old debug info metadata format)

llvm-svn: 176707
2013-03-08 18:17:46 +00:00
Chandler Carruth f1f5452778 Move the initialization to the Analysis library as well as the pass.
This was (somewhat distressingly) only caught be the ocaml bindings
tests...

llvm-svn: 171690
2013-01-07 03:33:08 +00:00
Chandler Carruth ed0881b2a6 Use the new script to sort the includes of every file under lib.
Sooooo many of these had incorrect or strange main module includes.
I have manually inspected all of these, and fixed the main module
include to be the nearest plausible thing I could find. If you own or
care about any of these source files, I encourage you to take some time
and check that these edits were sensible. I can't have broken anything
(I strictly added headers, and reordered them, never removed), but they
may not be the headers you'd really like to identify as containing the
API being implemented.

Many forward declarations and missing includes were added to a header
files to allow them to parse cleanly when included first. The main
module rule does in fact have its merits. =]

llvm-svn: 169131
2012-12-03 16:50:05 +00:00
Nadav Rotem a6b91ac307 Add a cost model analysis that allows us to estimate the cost of IR-level instructions.
llvm-svn: 167324
2012-11-02 21:48:17 +00:00
Benjamin Kramer 6dc1e2f287 Remove LoopDependenceAnalysis.
It was unmaintained and not much more than a stub. The new DependenceAnalysis
pass is both more general and complete.

llvm-svn: 166810
2012-10-26 20:25:01 +00:00
Sebastian Pop 59b61b9e2c dependence analysis
Patch from Preston Briggs <preston.briggs@gmail.com>.

This is an updated version of the dependence-analysis patch, including an MIV
test based on Banerjee's inequalities.

It's a fairly complete implementation of the paper

    Practical Dependence Testing
    Gina Goff, Ken Kennedy, and Chau-Wen Tseng
    PLDI 1991

It cannot yet propagate constraints between coupled RDIV subscripts (discussed
in Section 5.3.2 of the paper).

It's organized as a FunctionPass with a single entry point that supports testing
for dependence between two instructions in a function. If there's no dependence,
it returns null. If there's a dependence, it returns a pointer to a Dependence
which can be queried about details (what kind of dependence, is it loop
independent, direction and distance vector entries, etc). I haven't included
every imaginable feature, but there's a good selection that should be adequate
for supporting many loop transformations. Of course, it can be extended as
necessary.

Included in the patch file are many test cases, commented with C code showing
the loops and array references.

llvm-svn: 165708
2012-10-11 07:32:34 +00:00
Manman Ren abbb01abea Profile: set branch weight metadata with data generated from profiling.
This patch implements ProfileDataLoader which loads profile data generated by
-insert-edge-profiling and updates branch weight metadata accordingly.

Patch by Alastair Murray.

llvm-svn: 162799
2012-08-28 22:21:25 +00:00
Benjamin Kramer 5a656883b1 C API functions must be able to see their extern "C" definitions, or it will be impossible to call them from C.
llvm-svn: 138022
2011-08-19 01:36:54 +00:00
Jakub Staszak 875ebd5f5d Rename BlockFrequency to BlockFrequencyInfo and MachineBlockFrequency to
MachineBlockFrequencyInfo.

llvm-svn: 135937
2011-07-25 19:25:40 +00:00
Jakub Staszak be52acc98a Introduce BlockFrequency analysis for BasicBlocks.
llvm-svn: 133766
2011-06-23 21:45:20 +00:00
Andrew Trick 49371f3f33 New BranchProbabilityInfo analysis. Patch by Jakub Staszak!
BranchProbabilityInfo provides an interface for IR passes to query the
likelihood that control follows a CFG edge. This patch provides an
initial implementation of static branch predication that will populate
BranchProbabilityInfo for branches with no external profile
information using very simple heuristics. It currently isn't hooked up
to any external profile data, so static prediction does all the work.

llvm-svn: 132613
2011-06-04 01:16:30 +00:00
Chris Lattner 57ee5a5db7 remove postdom frontiers, because it is dead. Forward dom frontiers are
still used by RegionInfo :(

llvm-svn: 128943
2011-04-05 21:57:17 +00:00
Dan Gohman 161058838c Delete the LiveValues pass. I won't get get back to the project it
was started for in the foreseeable future.

llvm-svn: 126668
2011-02-28 19:37:59 +00:00
Andrew Trick 24f5ff0f23 Implementation of path profiling.
Modified patch by Adam Preuss.

This builds on the existing framework for block tracing, edge profiling and optimal edge profiling.
See -help-hidden for new flags.
For documentation, see the technical report "Implementation of Path Profiling..." in llvm.org/pubs.

llvm-svn: 124515
2011-01-29 01:09:53 +00:00
Cameron Zwarich 6b0c4c9b6c Move DominanceFrontier from VMCore to Analysis.
llvm-svn: 123747
2011-01-18 06:06:27 +00:00
Owen Anderson 6875c2ea26 Add initialization routines for Analysis and IPA.
llvm-svn: 115946
2010-10-07 18:31:00 +00:00
Chris Lattner 25963c6113 "In order to ease automatic bindings generation, it would be helpful if boolean values were distinguishable from integers. The attached patch introduces "typedef int LLVMBool;", and uses LLVMBool instead of int throughout the C API, wherever a boolean value is called for."
Patch by James Y Knight!

llvm-svn: 93079
2010-01-09 22:27:07 +00:00
Dan Gohman 7c50c9bd63 Tidy #includes.
llvm-svn: 78677
2009-08-11 16:02:12 +00:00
Erick Tryzelaar 4a0da98825 Expose Function::viewCFG and Function::viewCFGOnly to bindings.
llvm-svn: 48982
2008-03-31 16:22:09 +00:00
Anton Korobeynikov 579f07135a Unbreak build with gcc 4.3: provide missed includes and silence most annoying warnings.
llvm-svn: 47367
2008-02-20 11:08:44 +00:00
Chris Lattner f3ebc3f3d2 Remove attribution from file headers, per discussion on llvmdev.
llvm-svn: 45418
2007-12-29 20:36:04 +00:00
Gordon Henriksen 34eb6d877e Adding bindings for memory buffers and module providers. Switching
to exceptions rather than variants for error handling in Ocaml.

llvm-svn: 45226
2007-12-19 22:30:40 +00:00
Gordon Henriksen c3d661a0ee Bindings for the verifier.
llvm-svn: 42707
2007-10-06 21:00:36 +00:00