Commit Graph

187 Commits

Author SHA1 Message Date
Teresa Johnson 43a65d9529 Revert commit r239480 as it causes https://code.google.com/p/chromium/issues/detail?id=499508#c3.
llvm-svn: 239589
2015-06-12 03:12:00 +00:00
Teresa Johnson 232fa9af3b Add new EliminateAvailableExternally module pass, which is performed in
O2 compiles just before GlobalDCE, unless we are preparing for LTO.

This pass eliminates available externally globals (turning them into
declarations), regardless of whether they are dead/unreferenced, since
we are guaranteed to have a copy available elsewhere at link time.
This enables additional opportunities for GlobalDCE.

If we are preparing for LTO (e.g. a -flto -c compile), the pass is not
included as we want to preserve available externally functions for possible
link time inlining. The FE indicates whether we are doing an -flto compile
via the new PrepareForLTO flag on the PassManagerBuilder.

llvm-svn: 239480
2015-06-10 17:49:28 +00:00
Akira Hatanaka d9699bc7bd Remove DisableTailCalls from TargetOptions and the code in resetTargetOptions
that was resetting it.

Remove the uses of DisableTailCalls in subclasses of TargetLowering and use
the value of function attribute "disable-tail-calls" instead. Also,
unconditionally add pass TailCallElim to the pipeline and check the function
attribute at the start of runOnFunction to disable the pass on a per-function
basis. 
 
This is part of the work to remove TargetMachine::resetTargetOptions, and since
DisableTailCalls was the last non-fast-math option that was being reset in that
function, we should be able to remove the function entirely after the work to
propagate IR-level fast-math flags to DAG nodes is completed.

Out-of-tree users should remove the uses of DisableTailCalls and make changes
to attach attribute "disable-tail-calls"="true" or "false" to the functions in
the IR.

rdar://problem/13752163

Differential Revision: http://reviews.llvm.org/D10099

llvm-svn: 239427
2015-06-09 19:07:19 +00:00
Wei Mi 6a671635e6 Remove the InstructionSimplifierPass immediately after InstructionCombiningPass.
InstructionCombiningPass was added after LoopUnrollPass in r237395. Because
InstructionCombiningPass is strictly more powerful than InstructionSimplifierPass,
remove the unnecessary InstructionSimplifierPass.

Differential Revision: http://reviews.llvm.org/D9838

llvm-svn: 237702
2015-05-19 16:09:11 +00:00
Jingyue Wu 25e2500ac8 [NFC] remove an extra new line
llvm-svn: 237462
2015-05-15 18:32:21 +00:00
Jingyue Wu 154eb5aa1d Add a speculative execution pass
Summary:
This is a pass for speculative execution of instructions for simple if-then (triangle) control flow. It's aimed at GPUs, but could perhaps be used in other contexts. Enabling this pass gives us a 1.0% geomean improvement on Google benchmark suites, with one benchmark improving 33%.

Credit goes to Jingyue Wu for writing an earlier version of this pass.

Patched by Bjarke Roune. 

Test Plan:
This patch adds a set of tests in test/Transforms/SpeculativeExecution/spec.ll
The pass is controlled by a flag which defaults to having the pass not run.

Reviewers: eliben, dberlin, meheff, jingyue, hfinkel

Reviewed By: jingyue, hfinkel

Subscribers: majnemer, jholewinski, llvm-commits

Differential Revision: http://reviews.llvm.org/D9360

llvm-svn: 237459
2015-05-15 17:54:48 +00:00
Wei Mi bf727ba371 Add another InstCombine pass after LoopUnroll.
This is to cleanup some redundency generated by LoopUnroll pass. Such redundency may not be cleaned up by existing passes after LoopUnroll.

Differential Revision: http://reviews.llvm.org/D9777

llvm-svn: 237395
2015-05-14 22:02:54 +00:00
Adam Nemet 938d3d63d6 New Loop Distribution pass
Summary:
This implements the initial version as was proposed earlier this year
(http://lists.cs.uiuc.edu/pipermail/llvmdev/2015-January/080462.html).
Since then Loop Access Analysis was split out from the Loop Vectorizer
and was made into a separate analysis pass.  Loop Distribution becomes
the second user of this analysis.

The pass is off by default and can be enabled
with -enable-loop-distribution.  There is currently no notion of
profitability; if there is a loop with dependence cycles, the pass will
try to split them off from other memory operations into a separate loop.

I decided to remove the control-dependence calculation from this first
version.  This and the issues with the PDT are actively discussed so it
probably makes sense to treat it separately.  Right now I just mark all
terminator instruction required which keeps identical CFGs for each
distributed loop.  This seems to be working pretty well for 456.hmmer
where even though there is an empty if-then block in the distributed
loop initially, it gets completely removed.

The pass keeps DominatorTree and LoopInfo updated.  I've tested this
with -loop-distribute-verify with the testsuite where we distribute ~90
loops.  SimplifyLoop is violated in some cases and I have a FIXME
covering this.

Reviewers: hfinkel, nadav, aschwaighofer

Reviewed By: aschwaighofer

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D8831

llvm-svn: 237358
2015-05-14 12:05:18 +00:00
Karthik Bhat 8210fdf26e Add support to interchange loops with reductions.
This patch enables interchanging of tightly nested loops with reductions.
Differential Revision: http://reviews.llvm.org/D8314

llvm-svn: 235571
2015-04-23 04:51:44 +00:00
James Molloy 0cbb2a8603 Reapply r233175 and r233183: float2int.
This re-adds float2int to the tree, after fixing PR23038. It turns
out the argument to APSInt() is true-if-unsigned, rather than
true-if-signed :(. Added testcase and explanatory comment.

llvm-svn: 233370
2015-03-27 10:36:57 +00:00
Nick Lewycky ffb0864b44 Revert r233175 and r233183 with it. This pulls float2int back out of the tree, due to PR23038.
llvm-svn: 233350
2015-03-27 02:00:11 +00:00
James Molloy cb75d92458 Reapply r233062: "float2int": Add a new pass to demote from float to int where possible.
Now with a fix for PR23008 and extra regression test.

llvm-svn: 233175
2015-03-25 10:03:42 +00:00
Hans Wennborg e42c64551a Revert r233062 ""float2int": Add a new pass to demote from float to int where possible."
This caused PR23008, compiles failing with: "Use still stuck around after Def is
destroyed: %.sroa.speculated"

Also reverting follow-up r233064.

llvm-svn: 233105
2015-03-24 20:07:08 +00:00
James Molloy 408df5160c "float2int": Add a new pass to demote from float to int where possible.
It is possible to have code that converts from integer to float, performs operations then converts back, and the result is provably the same as if integers were used.

This can come from different sources, but the most obvious is a helper function that uses floats but the arguments given at an inlined callsites are integers.

This pass considers all integers requiring a bitwidth less than or equal to the bitwidth of the mantissa of a floating point type (23 for floats, 52 for doubles) as exactly representable in floating point.

To reduce the risk of harming efficient code, the pass only attempts to perform complete removal of inttofp/fptoint operations, not just move them around.

llvm-svn: 233062
2015-03-24 11:15:23 +00:00
Duncan P. N. Exon Smith ab58a568ee Verifier: Remove the separate -verify-di pass
Remove `DebugInfoVerifierLegacyPass` and the `-verify-di` pass.
Instead, call into the `DebugInfoVerifier` from inside
`VerifierLegacyPass::finalizeModule()`.  This better matches the logic
in `verifyModule()` (used by the new PassManager), avoids requiring two
separate passes to verify the IR, and makes the API for "add a pass to
verify the IR" simple.

Note: the `-verify-debug-info` flag still works (for now, at least;
eventually it might make sense to just remove it).

llvm-svn: 232772
2015-03-19 22:24:17 +00:00
Peter Collingbourne 070843d60b libLTO, llvm-lto, gold: Introduce flag for controlling optimization level.
This change also introduces a link-time optimization level of 1. This
optimization level runs only the globaldce pass as well as cleanup passes for
passes that run at -O0, specifically simplifycfg which cleans up lowerbitsets.

http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20150316/266951.html

llvm-svn: 232769
2015-03-19 22:01:00 +00:00
Duncan P. N. Exon Smith 0a93e2db9c PassManagerBuilder: Remove effectively dead 'StripDebug' option
`StripDebug` was only used by tools/opt/opt.cpp in
`AddStandardLinkPasses()`, but opt.cpp adds the same pass based on its
command-line flag before it calls `AddStandardLinkPasses()`.  Stripping
debug info twice isn't very useful.

llvm-svn: 232765
2015-03-19 21:37:17 +00:00
Kevin Qin 49bc764310 Reapply 'Run LICM pass after loop unrolling pass.'
It's firstly committed at r231630, and reverted at r231635.

Function pass InstructionSimplifier is inserted as barrier to
make sure loop unroll pass won't affect on LICM pass.

llvm-svn: 232011
2015-03-12 05:36:01 +00:00
Michael Zolotukhin 267e12f714 Enable loop-rotate before loop-vectorize by default
llvm-svn: 231820
2015-03-10 19:07:41 +00:00
Kevin Qin 65b07b8e1b Revert r231630 - Run LICM pass after loop unrolling pass.
As it broke llvm bootstrap.

llvm-svn: 231635
2015-03-09 07:26:37 +00:00
Kevin Qin a998735def Run LICM pass after loop unrolling pass.
Runtime unrollng will introduce a runtime check in loop prologue.
If the unrolled loop is a inner loop, then the proglogue will be inside
the outer loop. LICM pass can help to promote the runtime check out if
the checked value is loop invariant.

llvm-svn: 231630
2015-03-09 06:14:07 +00:00
Karthik Bhat 88db86dd29 Add a new pass "Loop Interchange"
This pass interchanges loops to provide a more cache-friendly memory access.

For e.g. given a loop like -
  for(int i=0;i<N;i++)
    for(int j=0;j<N;j++)
      A[j][i] = A[j][i]+B[j][i];

is interchanged to -
  for(int j=0;j<N;j++)
    for(int i=0;i<N;i++)
      A[j][i] = A[j][i]+B[j][i];

This pass is currently disabled by default.

To give a brief introduction it consists of 3 stages-

LoopInterchangeLegality : Checks the legality of loop interchange based on Dependency matrix.
LoopInterchangeProfitability: A very basic heuristic has been added to check for profitibility. This will evolve over time.
LoopInterchangeTransform : Which does the actual transform.

LNT Performance tests shows improvement in Polybench/linear-algebra/kernels/mvt and Polybench/linear-algebra/kernels/gemver becnmarks.

TODO:
1) Add support for reductions and lcssa phi.
2) Improve profitability model.
3) Improve loop selection algorithm to select best loop for interchange. Currently the innermost loop is selected for interchange.
4) Improve compile time regression found in llvm lnt due to this pass.
5) Fix issues in Dependency Analysis module.

A special thanks to Hal for reviewing this code.
Review: http://reviews.llvm.org/D7499

llvm-svn: 231458
2015-03-06 10:11:25 +00:00
Peter Collingbourne e6909c8e8b Introduce bitset metadata format and bitset lowering pass.
This patch introduces a new mechanism that allows IR modules to co-operatively
build pointer sets corresponding to addresses within a given set of
globals. One particular use case for this is to allow a C++ program to
efficiently verify (at each call site) that a vtable pointer is in the set
of valid vtable pointers for the class or its derived classes. One way of
doing this is for a toolchain component to build, for each class, a bit set
that maps to the memory region allocated for the vtables, such that each 1
bit in the bit set maps to a valid vtable for that class, and lay out the
vtables next to each other, to minimize the total size of the bit sets.

The patch introduces a metadata format for representing pointer sets, an
'@llvm.bitset.test' intrinsic and an LTO lowering pass that lays out the globals
and builds the bitsets, and documents the new feature.

Differential Revision: http://reviews.llvm.org/D7288

llvm-svn: 230054
2015-02-20 20:30:47 +00:00
Hal Finkel 2bb61ba2fe [BDCE] Add a bit-tracking DCE pass
BDCE is a bit-tracking dead code elimination pass. It is based on ADCE (the
"aggressive DCE" pass), with the added capability to track dead bits of integer
valued instructions and remove those instructions when all of the bits are
dead.

Currently, it does not actually do this all-bits-dead removal, but rather
replaces the instruction's uses with a constant zero, and lets instcombine (and
the later run of ADCE) do the rest. Because we essentially get a run of ADCE
"for free" while tracking the dead bits, we also do what ADCE does and removes
actually-dead instructions as well (this includes instructions newly trivially
dead because all bits were dead, but not all such instructions can be removed).

The motivation for this is a case like:

int __attribute__((const)) foo(int i);
int bar(int x) {
  x |= (4 & foo(5));
  x |= (8 & foo(3));
  x |= (16 & foo(2));
  x |= (32 & foo(1));
  x |= (64 & foo(0));
  x |= (128& foo(4));
  return x >> 4;
}

As it turns out, if you order the bit-field insertions so that all of the dead
ones come last, then instcombine will remove them. However, if you pick some
other order (such as the one above), the fact that some of the calls to foo()
are useless is not locally obvious, and we don't remove them (without this
pass).

I did a quick compile-time overhead check using sqlite from the test suite
(Release+Asserts). BDCE took ~0.4% of the compilation time (making it about
twice as expensive as ADCE).

I've not looked at why yet, but we eliminate instructions due to having
all-dead bits in:
External/SPEC/CFP2006/447.dealII/447.dealII
External/SPEC/CINT2006/400.perlbench/400.perlbench
External/SPEC/CINT2006/403.gcc/403.gcc
MultiSource/Applications/ClamAV/clamscan
MultiSource/Benchmarks/7zip/7zip-benchmark

llvm-svn: 229462
2015-02-17 01:36:59 +00:00
James Molloy 83570247f1 Run LICM as part of the cleanup phase from the scalar optimizer.
Things like LoopUnrolling can produce loop invariant values - make sure
we pick them up.

llvm-svn: 229419
2015-02-16 18:59:54 +00:00
Chandler Carruth 30d69c2e36 [PM] Remove the old 'PassManager.h' header file at the top level of
LLVM's include tree and the use of using declarations to hide the
'legacy' namespace for the old pass manager.

This undoes the primary modules-hostile change I made to keep
out-of-tree targets building. I sent an email inquiring about whether
this would be reasonable to do at this phase and people seemed fine with
it, so making it a reality. This should allow us to start bootstrapping
with modules to a certain extent along with making it easier to mix and
match headers in general.

The updates to any code for users of LLVM are very mechanical. Switch
from including "llvm/PassManager.h" to "llvm/IR/LegacyPassManager.h".
Qualify the types which now produce compile errors with "legacy::". The
most common ones are "PassManager", "PassManagerBase", and
"FunctionPassManager".

llvm-svn: 229094
2015-02-13 10:01:29 +00:00
Chandler Carruth 1efa12d6d8 [PM] Sink the population of the pass manager with target-specific
analyses back into the LTO code generator.

The pass manager builder (and the transforms library in general)
shouldn't be referencing the target machine at all.

This makes the LTO population work like the others -- the data layout
and target transform info need to be pre-populated.

llvm-svn: 227576
2015-01-30 13:33:42 +00:00
Eric Christopher b9f60c17dc Remove unused include.
llvm-svn: 227170
2015-01-27 05:58:44 +00:00
Chandler Carruth b98f63dbdb [PM] Separate the TargetLibraryInfo object from the immutable pass.
The pass is really just a means of accessing a cached instance of the
TargetLibraryInfo object, and this way we can re-use that object for the
new pass manager as its result.

Lots of delta, but nothing interesting happening here. This is the
common pattern that is developing to allow analyses to live in both the
old and new pass manager -- a wrapper pass in the old pass manager
emulates the separation intrinsic to the new pass manager between the
result and pass for analyses.

llvm-svn: 226157
2015-01-15 10:41:28 +00:00
Chandler Carruth 62d4215baa [PM] Move TargetLibraryInfo into the Analysis library.
While the term "Target" is in the name, it doesn't really have to do
with the LLVM Target library -- this isn't an abstraction which LLVM
targets generally need to implement or extend. It has much more to do
with modeling the various runtime libraries on different OSes and with
different runtime environments. The "target" in this sense is the more
general sense of a target of cross compilation.

This is in preparation for porting this analysis to the new pass
manager.

No functionality changed, and updates inbound for Clang and Polly.

llvm-svn: 226078
2015-01-15 02:16:27 +00:00
Roman Divacky d2b9a1b890 Disable header duplication at -Oz in loop-rotate pass.
llvm-svn: 222562
2014-11-21 19:53:24 +00:00
Arnold Schwaighofer eb1a38fa73 Add an option to the LTO code generator to disable vectorization during LTO
We used to always vectorize (slp and loop vectorize) in the LTO pass pipeline.

r220345 changed it so that we used the PassManager's fields 'LoopVectorize' and
'SLPVectorize' out of the desire to be able to disable vectorization using the
cl::opt flags 'vectorize-loops'/'slp-vectorize' which the before mentioned
fields default to.
Unfortunately, this turns off vectorization because those fields
default to false.
This commit adds flags to the LTO library to disable lto vectorization which
reconciles the desire to optionally disable vectorization during LTO and
the desired behavior of defaulting to enabled vectorization.

We really want tools to set PassManager flags directly to enable/disable
vectorization and not go the route via cl::opt flags *in*
PassManagerBuilder.cpp.

llvm-svn: 220652
2014-10-26 21:50:58 +00:00
Nick Lewycky 592d84974c If requested, apply function merging at -O0 too. It's useful there to reduce the time to compile.
llvm-svn: 220537
2014-10-23 23:49:31 +00:00
JF Bastien f42a6ea5ac LTO: respect command-line options that disable vectorization.
Summary: Patches 202051 and 208013 added calls to LTO's PassManager which unconditionally add LoopVectorizePass and SLPVectorizerPass instead of following the logic in PassManagerBuilder::populateModulePassManager and honoring the -vectorize-loops -run-slp-after-loop-vectorization flags.

Reviewers: nadav, aschwaighofer, yijiang

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D5884

llvm-svn: 220345
2014-10-21 23:18:21 +00:00
Chandler Carruth 7b8297a61e Add some optional passes around the vectorizer to both better prepare
the IR going into it and to clean up the IR produced by the vectorizers.

Note that these are *off by default* right now while folks collect data
on whether the performance tradeoff is reasonable.

In a build of the 'opt' binary, I see about 2% compile time regression
due to this change on average. This is in my mind essentially the worst
expected case: very little of the opt binary is going to *benefit* from
these extra passes.

I've seen several benchmarks improve in performance my small amounts due
to running these passes, and there are certain (rare) cases where these
passes make a huge difference by either enabling the vectorizer at all
or by hoisting runtime checks out of the outer loop. My primary
motivation is to prevent people from seeing runtime check overhead in
benchmarks where the existing passes and optimizers would be able to
eliminate that.

I've chosen the sequence of passes based on the kinds of things that
seem likely to be relevant for the code at each stage: rotaing loops for
the vectorizer, finding correlated values, loop invariants, and
unswitching opportunities from any runtime checks, and cleaning up
commonalities exposed by the SLP vectorizer.

I'll be pinging existing threads where some of these issues have come up
and will start new threads to get folks to benchmark and collect data on
whether this is the right tradeoff or we should do something else.

llvm-svn: 219644
2014-10-14 00:31:29 +00:00
Nick Lewycky 9e6d184803 Add control of function merging to the PMBuilder.
llvm-svn: 217731
2014-09-13 21:46:00 +00:00
Rafael Espindola c435adcde0 Add doInitialization/doFinalization to DataLayoutPass.
With this a DataLayoutPass can be reused for multiple modules.

Once we have doInitialization/doFinalization, it doesn't seem necessary to pass
a Module to the constructor.

Overall this change seems in line with the idea of making DataLayout a required
part of Module. With it the only way of having a DataLayout used is to add it
to the Module.

llvm-svn: 217548
2014-09-10 21:27:43 +00:00
Gerolf Hoflehner 008e5cdcba [PassManager] Adding Hidden attribute to EnableMLSM option
llvm-svn: 217539
2014-09-10 20:24:03 +00:00
Gerolf Hoflehner 24815d9b8f [MergedLoadStoreMotion] Move pass enabling option to PassManagerBuilder
llvm-svn: 217538
2014-09-10 19:55:29 +00:00
Hal Finkel d67e463901 Add an AlignmentFromAssumptions Pass
This adds a ScalarEvolution-powered transformation that updates load, store and
memory intrinsic pointer alignments based on invariant((a+q) & b == 0)
expressions. Many of the simple cases we can get with ValueTracking, but we
still need something like this for the more complicated cases (such as those
with an offset) that require some algebra. Note that gcc's
__builtin_assume_aligned's optional third argument provides exactly for this
kind of 'misalignment' offset for which this kind of logic is necessary.

The primary motivation is to fixup alignments for vector loads/stores after
vectorization (and unrolling). This pass is added to the optimization pipeline
just after the SLP vectorizer runs (which, admittedly, does not preserve SE,
although I imagine it could).  Regardless, I actually don't think that the
preservation matters too much in this case: SE computes lazily, and this pass
won't issue any SE queries unless there are any assume intrinsics, so there
should be no real additional cost in the common case (SLP does preserve DT and
LoopInfo).

llvm-svn: 217344
2014-09-07 20:05:11 +00:00
James Molloy 6b95d8ed36 Enable noalias metadata by default and swap the order of the SLP and Loop vectorizers by default.
After some time maturing, hopefully the flags themselves will be removed.

llvm-svn: 217144
2014-09-04 13:23:08 +00:00
Hal Finkel 445dda5c4a Add pass-manager flags to use CFL AA
Add -use-cfl-aa (and -use-cfl-aa-in-codegen) to add CFL AA in the default pass
managers (for easy testing).

llvm-svn: 216978
2014-09-02 22:12:54 +00:00
Rafael Espindola 7cebf36a95 Move some logic to populateLTOPassManager.
This will avoid code duplication in the next commit which calls it directly
from the gold plugin.

llvm-svn: 216211
2014-08-21 20:03:44 +00:00
Rafael Espindola 216e0c0617 Respect LibraryInfo in populateLTOPassManager and use it. NFC.
llvm-svn: 216203
2014-08-21 18:49:52 +00:00
Rafael Espindola e07caad9e7 Handle inlining in populateLTOPassManager like in populateModulePassManager.
No functionality change.

llvm-svn: 216178
2014-08-21 13:35:30 +00:00
Rafael Espindola 208bc533cd Move DisableGVNLoadPRE from populateLTOPassManager to PassManagerBuilder.
llvm-svn: 216174
2014-08-21 13:13:17 +00:00
James Molloy 568da0990e Add a new option -run-slp-after-loop-vectorization.
This swaps the order of the loop vectorizer and the SLP/BB vectorizers. It is disabled by default so we can do performance testing - ideally we want to change to having the loop vectorizer running first, and the SLP vectorizer using its leftovers instead of the other way around.

llvm-svn: 214963
2014-08-06 12:56:19 +00:00
Rafael Espindola f9e52cf015 Don't internalize all but main by default.
This is mostly a cleanup, but it changes a fairly old behavior.

Every "real" LTO user was already disabling the silly internalize pass
and creating the internalize pass itself. The difference with this
patch is for "opt -std-link-opts" and the C api.

Now to get a usable behavior out of opt one doesn't need the funny
looking command line:

opt -internalize -disable-internalize -internalize-public-api-list=foo,bar -std-link-opts

llvm-svn: 214919
2014-08-05 20:10:38 +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
Gerolf Hoflehner f27ae6cdcf MergedLoadStoreMotion pass
Merges equivalent loads on both sides of a hammock/diamond
and hoists into into the header.
Merges equivalent stores on both sides of a hammock/diamond
and sinks it to the footer.
Can enable if conversion and tolerate better load misses
and store operand latencies.

llvm-svn: 213396
2014-07-18 19:13:09 +00:00
Gerolf Hoflehner 65b13324e1 Run interprocedural const prop before global optimizer
Exposes more constant globals that can be removed by
the global optimizer. A specific example is the removal
of the static global block address array in
clang/test/CodeGen/indirect-goto.c. This change impacts only
lower optimization levels. With LTO interprocedural
const prop runs already before global opt.

llvm-svn: 212284
2014-07-03 19:28:15 +00:00
Michael J. Spencer 289067cc3d Add LoadCombine pass.
This pass is disabled by default. Use -combine-loads to enable in -O[1-3]

Differential revision: http://reviews.llvm.org/D3580

llvm-svn: 209791
2014-05-29 01:55:07 +00:00
Peter Collingbourne 0a4376190f Add an extension point for peephole optimizers.
This extension point allows adding passes that perform peephole optimizations
similar to the instruction combiner. These passes will be inserted after
each instance of the instruction combiner pass.

Differential Revision: http://reviews.llvm.org/D3905

llvm-svn: 209595
2014-05-25 10:27:02 +00:00
Yi Jiang 79eb0aa8cb Reapply: Add slp vectorization to LTO passes. The bug it exposed has been fixed by r207983. <radar://16641956>
llvm-svn: 208013
2014-05-05 23:14:46 +00:00
Yi Jiang e2d5f29c2f Revert r207571 - Add slp vectorization to LTO passes
llvm-svn: 207693
2014-04-30 19:27:24 +00:00
Yi Jiang 4e234aa790 Add slp vectorization to LTO passes
llvm-svn: 207571
2014-04-29 19:35:39 +00:00
Craig Topper f40110f4d8 [C++] Use 'nullptr'. Transforms edition.
llvm-svn: 207196
2014-04-25 05:29:35 +00:00
Duncan P. N. Exon Smith 49f3ec80c2 PMBuilder: Expose an option to disable tail calls
Adds API to allow frontends to disable tail calls in PassManagerBuilder.

<rdar://problem/16050591>

llvm-svn: 206542
2014-04-18 01:05:15 +00:00
Duncan P. N. Exon Smith 2b69189c9c LTO: Add more loop simplification passes to LTO
Similar to r202051, add missing loop simplification passes to the LTO
optimization pipeline.

Patch by Rafael Espindola.

llvm-svn: 206306
2014-04-15 17:48:15 +00:00
Hal Finkel 86b3064f2b Move partial/runtime unrolling late in the pipeline
The generic (concatenation) loop unroller is currently placed early in the
standard optimization pipeline. This is a good place to perform full unrolling,
but not the right place to perform partial/runtime unrolling. However, most
targets don't enable partial/runtime unrolling, so this never mattered.

However, even some x86 cores benefit from partial/runtime unrolling of very
small loops, and follow-up commits will enable this. First, we need to move
partial/runtime unrolling late in the optimization pipeline (importantly, this
is after SLP and loop vectorization, as vectorization can drastically change
the size of a loop), while keeping the full unrolling where it is now. This
change does just that.

llvm-svn: 205264
2014-03-31 23:23:51 +00:00
Arnold Schwaighofer 6ccda923e5 LTO: Add the loop vectorizer to the LTO pipeline.
During the LTO phase LICM will move loop invariant global variables out of loops
(informed by GlobalModRef). This makes more loops countable presenting
opportunity for the loop vectorizer.

Adding the loop vectorizer improves some TSVC benchmarks and twolf/ref dataset
(5%) on x86-64.

radar://15970632

llvm-svn: 202051
2014-02-24 18:19:31 +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
Renato Golin 729a3ae90a Add #pragma vectorize enable/disable to LLVM
The intended behaviour is to force vectorization on the presence
of the flag (either turn on or off), and to continue the behaviour
as expected in its absence. Tests were added to make sure the all
cases are covered in opt. No tests were added in other tools with
the assumption that they should use the PassManagerBuilder in the
same way.

This patch also removes the outdated -late-vectorize flag, which was
on by default and not helping much.

The pragma metadata is being attached to the same place as other loop
metadata, but nothing forbids one from attaching it to a function
(to enable #pragma optimize) or basic blocks (to hint the basic-block
vectorizers), etc. The logic should be the same all around.

Patches to Clang to produce the metadata will be produced after the
initial implementation is agreed upon and committed. Patches to other
vectorizers (such as SLP and BB) will be added once we're happy with
the pass manager changes.

llvm-svn: 196537
2013-12-05 21:20:02 +00:00
Hal Finkel 29aeb20518 Add a loop rerolling flag to the PassManagerBuilder
This adds a boolean member variable to the PassManagerBuilder to control loop
rerolling (just like we have for unrolling and the various vectorization
options). This is necessary for control by the frontend. Loop rerolling remains
disabled by default at all optimization levels.

llvm-svn: 194966
2013-11-17 16:02:50 +00:00
Hal Finkel bf45efde2d Add a loop rerolling pass
This adds a loop rerolling pass: the opposite of (partial) loop unrolling. The
transformation aims to take loops like this:

for (int i = 0; i < 3200; i += 5) {
  a[i]     += alpha * b[i];
  a[i + 1] += alpha * b[i + 1];
  a[i + 2] += alpha * b[i + 2];
  a[i + 3] += alpha * b[i + 3];
  a[i + 4] += alpha * b[i + 4];
}

and turn them into this:

for (int i = 0; i < 3200; ++i) {
  a[i] += alpha * b[i];
}

and loops like this:

for (int i = 0; i < 500; ++i) {
  x[3*i] = foo(0);
  x[3*i+1] = foo(0);
  x[3*i+2] = foo(0);
}

and turn them into this:

for (int i = 0; i < 1500; ++i) {
  x[i] = foo(0);
}

There are two motivations for this transformation:

  1. Code-size reduction (especially relevant, obviously, when compiling for
code size).

  2. Providing greater choice to the loop vectorizer (and generic unroller) to
choose the unrolling factor (and a better ability to vectorize). The loop
vectorizer can take vector lengths and register pressure into account when
choosing an unrolling factor, for example, and a pre-unrolled loop limits that
choice. This is especially problematic if the manual unrolling was optimized
for a machine different from the current target.

The current implementation is limited to single basic-block loops only. The
rerolling recognition should work regardless of how the loop iterations are
intermixed within the loop body (subject to dependency and side-effect
constraints), but the significant restriction is that the order of the
instructions in each iteration must be identical. This seems sufficient to
capture all current use cases.

This pass is not currently enabled by default at any optimization level.

llvm-svn: 194939
2013-11-16 23:59:05 +00:00
Rafael Espindola 282a47037b Use LTO_SYMBOL_SCOPE_DEFAULT_CAN_BE_HIDDEN instead of the "dso list".
There are two ways one could implement hiding of linkonce_odr symbols in LTO:
* LLVM tells the linker which symbols can be hidden if not used from native
  files.
* The linker tells LLVM which symbols are not used from other object files,
  but will be put in the dso symbol table if present.

GOLD's API is the second option. It was implemented almost 1:1 in llvm by
passing the list down to internalize.

LLVM already had partial support for the first option. It is also very similar
to how ld64 handles hiding these symbols when *not* doing LTO.

This patch then
* removes the APIs for the DSO list.
* marks LTO_SYMBOL_SCOPE_DEFAULT_CAN_BE_HIDDEN all linkonce_odr unnamed_addr
  global values and other linkonce_odr whose address is not used.
* makes the gold plugin responsible for handling the API mismatch.

llvm-svn: 193800
2013-10-31 20:51:58 +00:00
Nadav Rotem 7f27e0b0ce Mark some command line flags as hidden
llvm-svn: 193013
2013-10-18 23:38:13 +00:00
Rafael Espindola cda2911caa Optimize linkonce_odr unnamed_addr functions during LTO.
Generalize the API so we can distinguish symbols that are needed just for a DSO
symbol table from those that are used from some native .o.

The symbols that are only wanted for the dso symbol table can be dropped if
llvm can prove every other dso has a copy (linkonce_odr) and the address is not
important (unnamed_addr).

llvm-svn: 191922
2013-10-03 18:29:09 +00:00
Nadav Rotem 5d78dba6d9 Enable late-vectorization by default.
This patch changes the default setting for the LateVectorization flag that controls where the loop-vectorizer is ran.

Perf gains:
SingleSource/Benchmarks/Shootout/matrix -37.33%
MultiSource/Benchmarks/PAQ8p/paq8p  -22.83%
SingleSource/Benchmarks/Linpack/linpack-pc  -16.22%
SingleSource/Benchmarks/Shootout-C++/ary3 -15.16%
MultiSource/Benchmarks/TSVC/NodeSplitting-flt/NodeSplitting-flt -10.34%
MultiSource/Benchmarks/TSVC/NodeSplitting-dbl/NodeSplitting-dbl -7.12%

Regressions:
SingleSource/Benchmarks/Misc/lowercase  15.10%
MultiSource/Benchmarks/TSVC/Equivalencing-flt/Equivalencing-flt 13.18%
SingleSource/Benchmarks/Shootout-C++/matrix 8.27%
SingleSource/Benchmarks/CoyoteBench/lpbench 7.30%

llvm-svn: 189858
2013-09-03 21:33:17 +00:00
Bill Wendling 4c0d9adecb Random cleanup: No need to use a std::vector here, since createInternalizePass uses an ArrayRef.
llvm-svn: 189632
2013-08-30 00:48:37 +00:00
Nadav Rotem 4c459bcd47 Vectorizer/PassManager: I am working on moving the vectorizer out of the SCC passes. This patch moves the SLP-vectorizer and BB-vectorizer back into SCC passes for two reasons:
1. They are a kind of cannonicalization.
2. The performance measurements show that it is better to keep them in.

There should be no functional change if you are not enabling the LateVectorization mode.

llvm-svn: 189539
2013-08-28 23:40:29 +00:00
Hal Finkel 6d09904cc9 Disable unrolling in the loop vectorizer when disabled in the pass manager
When unrolling is disabled in the pass manager, the loop vectorizer should also
not unroll loops. This will allow the -fno-unroll-loops option in Clang to
behave as expected (even for vectorizable loops). The loop vectorizer's
-force-vector-unroll option will (continue to) override the pass-manager
setting (including -force-vector-unroll=0 to force use of the internal
auto-selection logic).

In order to test this, I added a flag to opt (-disable-loop-unrolling) to force
disable unrolling through opt (the analog of -fno-unroll-loops in Clang). Also,
this fixes a small bug in opt where the loop vectorizer was enabled only after
the pass manager populated the queue of passes (the global_alias.ll test needed
a slight update to the RUN line as a result of this fix).

llvm-svn: 189499
2013-08-28 18:33:10 +00:00
Arnold Schwaighofer 124ccf3ad1 Also remove logic in LateVectorize
llvm-svn: 188285
2013-08-13 16:12:04 +00:00
Arnold Schwaighofer c14b59d1a1 Remove logic that decides whether to vectorize or not depending on O-levels
I have moved this logic into clang and opt.

llvm-svn: 188281
2013-08-13 15:51:25 +00:00
Tom Stellard aa664d9b92 Factor FlattenCFG out from SimplifyCFG
Patch by: Mei Ye

llvm-svn: 187764
2013-08-06 02:43:45 +00:00
Nadav Rotem e4e6e9ed47 Move the optlevel check to the frontend.
llvm-svn: 187628
2013-08-01 22:41:58 +00:00
Nadav Rotem 9153b3871d Only enable SLP-vectorization on O3 builds.
llvm-svn: 187595
2013-08-01 18:28:15 +00:00
Tom Stellard 8b1e021e85 SimplifyCFG: Use parallel-and and parallel-or mode to consolidate branch conditions
Merge consecutive if-regions if they contain identical statements.
Both transformations reduce number of branches.  The transformation
is guarded by a target-hook, and is currently enabled only for +R600,
but the correctness has been tested on X86 target using a variety of
CPU benchmarks.

Patch by: Mei Ye

llvm-svn: 187278
2013-07-27 00:01:07 +00:00
Chandler Carruth 08e1b8742b Add a flag to defer vectorization into a phase after the inliner and its
CGSCC pass manager. This should insulate the inlining decisions from the
vectorization decisions, however it may have both compile time and code
size problems so it is just an experimental option right now.

Adding this based on a discussion with Arnold and it seems at least
worth having this flag for us to both run some experiments to see if
this strategy is workable. It may solve some of the regressions seen
with the loop vectorizer.

llvm-svn: 184698
2013-06-24 07:21:47 +00:00
Meador Inge dfb08a2cb8 Remove the simplify-libcalls pass (finally)
This commit completely removes what is left of the simplify-libcalls
pass.  All of the functionality has now been migrated to the instcombine
and functionattrs passes.  The following C API functions are now NOPs:

  1. LLVMAddSimplifyLibCallsPass
  2. LLVMPassManagerBuilderSetDisableSimplifyLibCalls

llvm-svn: 184459
2013-06-20 19:48:07 +00:00
Nadav Rotem cde24ef389 Disable vectorization for -Oz.
llvm-svn: 184089
2013-06-17 17:22:40 +00:00
Nadav Rotem 7dd8210b71 Enable the loop vectorizer by default for -Os and -O2.
llvm-svn: 184084
2013-06-17 16:23:34 +00:00
Nadav Rotem 99e529ea3c Jeffrey Yasskin volunteered to benchmark the vectorizer on -O2 or -Os when compiling chrome. This patch adds a new flag to enable vectorization on all levels and not only on -O3. It should go away once we make a decision.
llvm-svn: 183456
2013-06-06 22:35:47 +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
Nadav Rotem b9116e6966 SLPVectorizer: Make it a function pass and add code for hoisting the vector-gather sequence out of loops.
llvm-svn: 179562
2013-04-15 22:00:26 +00:00
Nadav Rotem d4dcc003df Add an option -vectorize-slp-aggressive for running the BB vectorizer. Make -fslp-vectorize run the slp-vectorizer.
llvm-svn: 179508
2013-04-15 05:39:58 +00:00
Nadav Rotem a1e5e44eb3 Rename the slp-vectorizer clang/llvm flags. No functionality change.
llvm-svn: 179505
2013-04-15 04:54:42 +00:00
Nick Lewycky 5f50854186 Use LLVMBool instead of 'bool' in the C API. Based on a patch by Peter Zotov!
llvm-svn: 176793
2013-03-10 21:58:22 +00:00
Andrew Trick fcb37243f9 Generalize my previous fix for -print-options.
Always print options that differ from their implicit default. At least
for simple option types.

llvm-svn: 176572
2013-03-06 19:04:56 +00:00
Andrew Trick 946c2b32e6 Give -loop-vectorize an explicit default.
This way, clang -mllvm -print-options shows that the driver is overriding it.

llvm-svn: 176569
2013-03-06 18:22:22 +00:00
Hal Finkel bf4db4fe11 Unroll again after running BBVectorize
Because BBVectorize may significantly shorten a loop body, unroll
again after vectorization. This is especially important when using
runtime or partial unrolling.

llvm-svn: 173730
2013-01-29 00:22:49 +00:00
Chandler Carruth 683ff2d7f9 Remove the long defunct 'DefaultPasses' header. We have a pass manager
builder these days, and this thing hasn't seen updates for a very long
time.

llvm-svn: 171741
2013-01-07 15:16:50 +00:00
Nadav Rotem be6570d429 Move the loop vectorizer from O2 to O3. It looks like the increase in code size actually hurts the performance on many programs.
llvm-svn: 171471
2013-01-04 17:57:44 +00:00
Roman Divacky a229186a82 Remove duplicate includes.
llvm-svn: 170902
2012-12-21 17:06:44 +00:00
Nadav Rotem 9aee065e3c Enable the loop vectorizer in clang and not in the pass manager, so that we can disable it in clang.
llvm-svn: 170470
2012-12-18 23:09:44 +00:00
Nadav Rotem c0699854dd Enable the loop vectorizer.
llvm-svn: 170416
2012-12-18 06:37:12 +00:00
NAKAMURA Takumi 8f45b6c709 Revert r170246, "Enable the loop vectorizer by default."
llvm-svn: 170267
2012-12-15 06:11:13 +00:00
Nadav Rotem acde77481d Enable the loop vectorizer by default.
llvm-svn: 170246
2012-12-14 21:30:23 +00:00
Nadav Rotem d3a3c9fdd5 revert r170166 - disable the loop vectorizer.
llvm-svn: 170172
2012-12-14 01:57:00 +00:00