Commit Graph

5498 Commits

Author SHA1 Message Date
Mehdi Amini
c94da20917 Make DataLayout Non-Optional in the Module
Summary:
DataLayout keeps the string used for its creation.

As a side effect it is no longer needed in the Module.
This is "almost" NFC, the string is no longer
canonicalized, you can't rely on two "equals" DataLayout
having the same string returned by getStringRepresentation().

Get rid of DataLayoutPass: the DataLayout is in the Module

The DataLayout is "per-module", let's enforce this by not
duplicating it more than necessary.
One more step toward non-optionality of the DataLayout in the
module.

Make DataLayout Non-Optional in the Module

Module->getDataLayout() will never returns nullptr anymore.

Reviewers: echristo

Subscribers: resistor, llvm-commits, jholewinski

Differential Revision: http://reviews.llvm.org/D7992

From: Mehdi Amini <mehdi.amini@apple.com>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231270 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-04 18:43:29 +00:00
Jan Wen Voung
87a61e97b7 Move TargetLibraryInfo data from two files into one common .def file.
Summary:
This makes it more obvious that the enum definition and the
"StandardName" array is in sync. Mechanically refactored w/ a
python script.

Test Plan: still compiles

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D7845

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231172 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-03 23:41:58 +00:00
Mehdi Amini
a716c07147 Remove getDataLayout() from Instruction/GlobalValue/BasicBlock/Function
Summary:
This does not conceptually belongs here. Instead provide a shortcut
getModule() that provides access to the DataLayout.

Reviewers: chandlerc, echristo

Reviewed By: echristo

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D8027

From: Mehdi Amini <mehdi.amini@apple.com>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231147 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-03 22:01:13 +00:00
Nadav Rotem
10faa1b211 Teach ComputeNumSignBits about signed divisions.
http://reviews.llvm.org/D8028
rdar://20023136



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231140 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-03 21:39:02 +00:00
David Blaikie
317ccafdbd Revert "Remove the explicit SDNodeIterator::operator= in favor of the implicit default"
Accidentally committed a few more of these cleanup changes than
intended. Still breaking these out & tidying them up.

This reverts commit r231135.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231136 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-03 21:18:16 +00:00
David Blaikie
b13215ec3b Remove the explicit SDNodeIterator::operator= in favor of the implicit default
There doesn't seem to be any need to assert that iterator assignment is
between iterators over the same node - if you want to reuse an iterator
variable to iterate another node, that's perfectly acceptable. Just
don't mix comparisons between iterators into disjoint sequences, as
usual.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231135 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-03 21:17:08 +00:00
David Blaikie
6e274fd1ab unique_ptrify FullDependenceAnalysis::DV
Making this type a little harder to abuse (see workaround relating to
use of the implicit copy ctor in the prior commit)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231104 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-03 19:20:18 +00:00
David Blaikie
9fefa526a2 FullDependenceAnalysis: Avoid using the (deprecated in C++11) copy ctor
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231103 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-03 19:20:16 +00:00
Duncan P. N. Exon Smith
b056aa798d DebugInfo: Move new hierarchy into place
Move the specialized metadata nodes for the new debug info hierarchy
into place, finishing off PR22464.  I've done bootstraps (and all that)
and I'm confident this commit is NFC as far as DWARF output is
concerned.  Let me know if I'm wrong :).

The code changes are fairly mechanical:

  - Bumped the "Debug Info Version".
  - `DIBuilder` now creates the appropriate subclass of `MDNode`.
  - Subclasses of DIDescriptor now expect to hold their "MD"
    counterparts (e.g., `DIBasicType` expects `MDBasicType`).
  - Deleted a ton of dead code in `AsmWriter.cpp` and `DebugInfo.cpp`
    for printing comments.
  - Big update to LangRef to describe the nodes in the new hierarchy.
    Feel free to make it better.

Testcase changes are enormous.  There's an accompanying clang commit on
its way.

If you have out-of-tree debug info testcases, I just broke your build.

  - `upgrade-specialized-nodes.sh` is attached to PR22564.  I used it to
    update all the IR testcases.
  - Unfortunately I failed to find way to script the updates to CHECK
    lines, so I updated all of these by hand.  This was fairly painful,
    since the old CHECKs are difficult to reason about.  That's one of
    the benefits of the new hierarchy.

This work isn't quite finished, BTW.  The `DIDescriptor` subclasses are
almost empty wrappers, but not quite: they still have loose casting
checks (see the `RETURN_FROM_RAW()` macro).  Once they're completely
gutted, I'll rename the "MD" classes to "DI" and kill the wrappers.  I
also expect to make a few schema changes now that it's easier to reason
about everything.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231082 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-03 17:24:31 +00:00
Michael Zolotukhin
a6f1fd6465 TLI: Factor out sanitizeFunctionName. NFC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231034 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-02 23:24:40 +00:00
Michael Zolotukhin
f027454edc TLI: Use lambda. NFC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231011 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-02 20:50:08 +00:00
Benjamin Kramer
d59c5f9a06 Add missing includes. make_unique proliferated everywhere.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230909 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-01 21:28:53 +00:00
Benjamin Kramer
9f9dcf8046 Reduce double set lookups.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230798 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-27 21:43:14 +00:00
Eric Christopher
930da21265 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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230780 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-27 19:03:38 +00:00
Sanjoy Das
e836f05d00 SCEVExpander incorrectly marks generated subtractions as nuw/nsw
It is not sound to mark the increment operation as `nuw` or `nsw`
based on a proof off of the add recurrence if the increment operation
we emit happens to be a `sub` instruction.

I could not come up with a test case for this -- the cases where
SCEVExpander decides to emit a `sub` instruction is quite small, and I
cannot think of a way I'd be able to get SCEV to prove that the
increment does not overflow in those cases.

Differential Revision: http://reviews.llvm.org/D7899



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230673 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-26 19:51:35 +00:00
Adam Nemet
e382bb9e35 [LV/LoopAccesses] Backward dependences are not safe just because the
accesses are via different types

Noticed this while generalizing the code for loop distribution.

I confirmed with Arnold that this was indeed a bug and managed to create
a testcase.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230647 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-26 17:58:48 +00:00
Adam Nemet
5a51d864b9 [LoopAccesses] Add command-line option for RuntimeMemoryCheckThreshold
Also remove the somewhat misleading initializers from
VectorizationFactor and VectorizationInterleave.  They will get
initialized with the default ctor since no cl::init is provided.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230608 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-26 04:39:09 +00:00
Ramkumar Ramachandra
e9a49d61ac MemDepPrinter: Fix some nits introduced in r228596
Differential Revision: http://reviews.llvm.org/D7644

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230582 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-25 23:55:00 +00:00
Sanjoy Das
a0a0b40aa3 Bugfix: SCEVExpander incorrectly marks increment operations as no-wrap
(The change was landed in r230280 and caused the regression PR22674.
This version contains a fix and a test-case for PR22674).
    
When emitting the increment operation, SCEVExpander marks the
operation as nuw or nsw based on the flags on the preincrement SCEV.
This is incorrect because, for instance, it is possible that {-6,+,1}
is <nuw> while {-6,+,1}+1 = {-5,+,1} is not.
    
This change teaches SCEV to mark the increment as nuw/nsw only if it
can explicitly prove that the increment operation won't overflow.
    
Apart from the attached test case, another (more realistic)
manifestation of the bug can be seen in
Transforms/IndVarSimplify/pr20680.ll.

Differential Revision: http://reviews.llvm.org/D7778



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230533 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-25 20:02:59 +00:00
Sanjay Patel
d2c64e2df9 Fix really obscure bug in CannotBeNegativeZero() (PR22688)
With a diabolically crafted test case, we could recurse
through this code and return true instead of false.

The larger engineering crime is the use of magic numbers. 
Added FIXME comments for those.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230515 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-25 18:00:15 +00:00
Hans Wennborg
b499b73e30 Revert r230280: "Bugfix: SCEVExpander incorrectly marks increment operations as no-wrap"
This caused PR22674, failing this assert:

Instructions.h:2281: llvm::Value* llvm::PHINode::getOperand(unsigned int) const: Assertion `i_nocapture < OperandTraits<PHINode>::operands(this) && "getOperand() out of range!"' failed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230341 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-24 16:19:29 +00:00
Sanjoy Das
edf1700d33 Fix bug 22641
The bug was a result of getPreStartForExtend interpreting nsw/nuw
flags on an add recurrence more strongly than is legal.  {S,+,X}<nsw>
implies S+X is nsw only if the backedge of the loop is taken at least
once.

NOTE: I had accidentally committed an unrelated change with the commit
message of this change in r230275 (r230275 was reverted in r230279).
This is the correct change for this commit message.

Differential Revision: http://reviews.llvm.org/D7808



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230291 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-24 01:02:42 +00:00
Adam Nemet
989a0200c2 [LoopAccesses] LAA::getInfo to use const reference for stride parameter
And other required const-correctness fixes to make this work.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230289 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-24 00:41:59 +00:00
Sanjoy Das
8d16a81c33 Bugfix: SCEVExpander incorrectly marks increment operations as no-wrap
When emitting the increment operation, SCEVExpander marks the
operation as nuw or nsw based on the flags on the preincrement SCEV.
This is incorrect because, for instance, it is possible that {-6,+,1}
is <nuw> while {-6,+,1}+1 = {-5,+,1} is not.

This change teaches SCEV to mark the increment as nuw/nsw only if it
can explicitly prove that the increment operation won't overflow.

Apart from the attached test case, another (more realistic) manifestation
of the bug can be seen in Transforms/IndVarSimplify/pr20680.ll.

NOTE: this change was landed with an incorrect commit message in
rL230275 and was reverted for that reason in rL230279.  This commit
message is the correct one.

Differential Revision: http://reviews.llvm.org/D7778



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230280 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-23 23:22:58 +00:00
Sanjoy Das
69048edf8a Revert 230275.
230275 got committed with an incorrect commit message due to a mixup
on my side.  Will re-land in a few moments with the correct commit
message.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230279 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-23 23:13:22 +00:00
Sanjoy Das
7ebbc8de2f Fix bug 22641
The bug was a result of getPreStartForExtend interpreting nsw/nuw
flags on an add recurrence more strongly than is legal.  {S,+,X}<nsw>
implies S+X is nsw only if the backedge of the loop is taken at least
once.

Differential Revision: http://reviews.llvm.org/D7808



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230275 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-23 22:55:13 +00:00
Chad Rosier
6229219f7e Prevent hoisting fmul from THEN/ELSE to IF if there is fmsub/fmadd opportunity.
This patch adds the isProfitableToHoist API.  For AArch64, we want to prevent a
fmul from being hoisted in cases where it is more profitable to form a
fmsub/fmadd.

Phabricator Review: http://reviews.llvm.org/D7299
Patch by Lawrence Hu <lawrence@codeaurora.org>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230241 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-23 19:15:16 +00:00
Mehdi Amini
2bd4b63e7a InstSimplify: simplify 0 / X if nnan and nsz
From: Fiona Glaser <fglaser@apple.com>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230238 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-23 18:30:25 +00:00
Adam Nemet
b7e0193c4d [LoopAccesses] Change LAA:getInfo to return a constant reference
As expected, this required a few more const-correctness fixes.

Based on Hal's feedback on D7684.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229899 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-19 19:15:21 +00:00
Adam Nemet
c182ce09e9 [LoopAccesses] Add -analyze support
The LoopInfo in combination with depth_first is used to enumerate the
loops.

Right now -analyze is not yet complete.  It only prints the result of
the analysis, the report and the run-time checks.  Printing the unsafe
depedences will require a bit more reshuffling which I'd like to do in a
follow-on to this patchset.  Unsafe dependences are currently checked
via -debug-only=loop-accesses in the new test.

This is part of the patchset that converts LoopAccessAnalysis into an
actual analysis pass.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229898 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-19 19:15:19 +00:00
Adam Nemet
4db669fb26 [LoopAccesses] Split out LoopAccessReport from VectorizerReport
The only difference between these two is that VectorizerReport adds a
vectorizer-specific prefix to its messages.  When LAA is used in the
vectorizer context the prefix is added when we promote the
LoopAccessReport into a VectorizerReport via one of the constructors.

This is part of the patchset that converts LoopAccessAnalysis into an
actual analysis pass.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229897 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-19 19:15:15 +00:00
Adam Nemet
7d39ae845d [LoopAccesses] Add missing const to APIs in VectorizationReport
When I split out LoopAccessReport from this, I need to create some temps
so constness becomes necessary.

This is part of the patchset that converts LoopAccessAnalysis into an
actual analysis pass.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229896 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-19 19:15:13 +00:00
Adam Nemet
5c4c262b3c [LoopAccesses] Add canAnalyzeLoop
This allows the analysis to be attempted with any loop.  This feature
will be used with -analysis.  (LV only requests the analysis on loops
that have already satisfied these tests.)

This is part of the patchset that converts LoopAccessAnalysis into an
actual analysis pass.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229895 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-19 19:15:10 +00:00
Adam Nemet
9fdb32eb84 [LoopAccesses] Change debug messages from LV to LAA
Also add pass name as an argument to VectorizationReport::emitAnalysis.

This is part of the patchset that converts LoopAccessAnalysis into an
actual analysis pass.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229894 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-19 19:15:07 +00:00
Adam Nemet
0ea25c2e64 [LoopAccesses] Create the analysis pass
This is a function pass that runs the analysis on demand.  The analysis
can be initiated by querying the loop access info via LAA::getInfo.  It
either returns the cached info or runs the analysis.

Symbolic stride information continues to reside outside of this analysis
pass. We may move it inside later but it's not a priority for me right
now.  The idea is that Loop Distribution won't support run-time stride
checking at least initially.

This means that when querying the analysis, symbolic stride information
can be provided optionally.  Whether stride information is used can
invalidate the cache entry and rerun the analysis.  Note that if the
loop does not have any symbolic stride, the entry should be preserved
across Loop Distribution and LV.

Since currently the only user of the pass is LV, I just check that the
symbolic stride information didn't change when using a cached result.

On the LV side, LoopVectorizationLegality requests the info object
corresponding to the loop from the analysis pass.  A large chunk of the
diff is due to LAI becoming a pointer from a reference.

A test will be added as part of the -analyze patch.

Also tested that with AVX, we generate identical assembly output for the
testsuite (including the external testsuite) before and after.

This is part of the patchset that converts LoopAccessAnalysis into an
actual analysis pass.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229893 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-19 19:15:04 +00:00
Adam Nemet
093a04b6d6 [LoopAccesses] Cache the result of canVectorizeMemory
LAA will be an on-demand analysis pass, so we need to cache the result
of the analysis.  canVectorizeMemory is renamed to analyzeLoop which
computes the result.  canVectorizeMemory becomes the query function for
the cached result.

This is part of the patchset that converts LoopAccessAnalysis into an
actual analysis pass.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229892 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-19 19:15:00 +00:00
Adam Nemet
7b507eb2a5 [LoopAccesses] Stash the report from the analysis rather than emitting it
The transformation passes will query this and then emit them as part of
their own report.  The currently only user LV is modified to do just
that.

This is part of the patchset that converts LoopAccessAnalysis into an
actual analysis pass.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229891 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-19 19:14:56 +00:00
Adam Nemet
4b86046b7c [LoopAccesses] Make VectorizerParams global + fix for cyclic dep
As LAA is becoming a pass, we can no longer pass the params to its
constructor.  This changes the command line flags to have external
storage.  These can now be accessed both from LV and LAA.

VectorizerParams is moved out of LoopAccessInfo in order to shorten the
code to access it.

This commits also has the fix (D7731) to the break dependence cycle
between the analysis and vector libraries.

This is part of the patchset that converts LoopAccessAnalysis into an
actual analysis pass.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229890 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-19 19:14:52 +00:00
Adam Nemet
c76d187944 Revert "Reformat."
This reverts commit r229651.

I'd like to ultimately revert r229650 but this reformat stands in the
way.  I'll reformat the affected files once the the loop-access pass is
fully committed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229889 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-19 19:14:34 +00:00
NAKAMURA Takumi
582e77af02 Reformat.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229651 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-18 08:36:14 +00:00
NAKAMURA Takumi
383d8c7fdd Revert r229622: "[LoopAccesses] Make VectorizerParams global" and others. r229622 brought cyclic dependencies between Analysis and Vector.
r229622: "[LoopAccesses] Make VectorizerParams global"
  r229623: "[LoopAccesses] Stash the report from the analysis rather than emitting it"
  r229624: "[LoopAccesses] Cache the result of canVectorizeMemory"
  r229626: "[LoopAccesses] Create the analysis pass"
  r229628: "[LoopAccesses] Change debug messages from LV to LAA"
  r229630: "[LoopAccesses] Add canAnalyzeLoop"
  r229631: "[LoopAccesses] Add missing const to APIs in VectorizationReport"
  r229632: "[LoopAccesses] Split out LoopAccessReport from VectorizerReport"
  r229633: "[LoopAccesses] Add -analyze support"
  r229634: "[LoopAccesses] Change LAA:getInfo to return a constant reference"
  r229638: "Analysis: fix buildbots"

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229650 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-18 08:34:47 +00:00
Sanjoy Das
b2c7cf6d16 Address post commit review on r229600.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229646 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-18 08:03:22 +00:00
Saleem Abdulrasool
74539a4a13 Analysis: fix buildbots
This should fix the compilation failure on the MSVC buildbots which find a
std::make_unique and llvm::make_unique via ADL, resulting in ambiguity.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229638 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-18 05:09:50 +00:00
Adam Nemet
5934863461 [LoopAccesses] Change LAA:getInfo to return a constant reference
As expected, this required a few more const-correctness fixes.

Based on Hal's feedback on D7684.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229634 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-18 03:44:33 +00:00
Adam Nemet
f367b60abe [LoopAccesses] Add -analyze support
The LoopInfo in combination with depth_first is used to enumerate the
loops.

Right now -analyze is not yet complete.  It only prints the result of
the analysis, the report and the run-time checks.  Printing the unsafe
depedences will require a bit more reshuffling which I'd like to do in a
follow-on to this patchset.  Unsafe dependences are currently checked
via -debug-only=loop-accesses in the new test.

This is part of the patchset that converts LoopAccessAnalysis into an
actual analysis pass.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229633 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-18 03:44:30 +00:00
Adam Nemet
c548c640bc [LoopAccesses] Split out LoopAccessReport from VectorizerReport
The only difference between these two is that VectorizerReport adds a
vectorizer-specific prefix to its messages.  When LAA is used in the
vectorizer context the prefix is added when we promote the
LoopAccessReport into a VectorizerReport via one of the constructors.

This is part of the patchset that converts LoopAccessAnalysis into an
actual analysis pass.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229632 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-18 03:44:25 +00:00
Adam Nemet
69c9697fa7 [LoopAccesses] Add missing const to APIs in VectorizationReport
When I split out LoopAccessReport from this, I need to create some temps
so constness becomes necessary.

This is part of the patchset that converts LoopAccessAnalysis into an
actual analysis pass.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229631 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-18 03:44:20 +00:00
Adam Nemet
4166c7ff59 [LoopAccesses] Add canAnalyzeLoop
This allows the analysis to be attempted with any loop.  This feature
will be used with -analysis.  (LV only requests the analysis on loops
that have already satisfied these tests.)

This is part of the patchset that converts LoopAccessAnalysis into an
actual analysis pass.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229630 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-18 03:44:08 +00:00
Adam Nemet
0cbfb71d7b [LoopAccesses] Factor out RuntimePointerCheck::needsChecking
Will be used by the new RuntimePointerCheck::print.

This is part of the patchset that converts LoopAccessAnalysis into an
actual analysis pass.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229629 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-18 03:43:58 +00:00
Adam Nemet
ce5c5c0301 [LoopAccesses] Change debug messages from LV to LAA
Also add pass name as an argument to VectorizationReport::emitAnalysis.

This is part of the patchset that converts LoopAccessAnalysis into an
actual analysis pass.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229628 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-18 03:43:37 +00:00
Adam Nemet
718b023033 [LoopAccesses] Create the analysis pass
This is a function pass that runs the analysis on demand.  The analysis
can be initiated by querying the loop access info via LAA::getInfo.  It
either returns the cached info or runs the analysis.

Symbolic stride information continues to reside outside of this analysis
pass. We may move it inside later but it's not a priority for me right
now.  The idea is that Loop Distribution won't support run-time stride
checking at least initially.

This means that when querying the analysis, symbolic stride information
can be provided optionally.  Whether stride information is used can
invalidate the cache entry and rerun the analysis.  Note that if the
loop does not have any symbolic stride, the entry should be preserved
across Loop Distribution and LV.

Since currently the only user of the pass is LV, I just check that the
symbolic stride information didn't change when using a cached result.

On the LV side, LoopVectorizationLegality requests the info object
corresponding to the loop from the analysis pass.  A large chunk of the
diff is due to LAI becoming a pointer from a reference.

A test will be added as part of the -analyze patch.

Also tested that with AVX, we generate identical assembly output for the
testsuite (including the external testsuite) before and after.

This is part of the patchset that converts LoopAccessAnalysis into an
actual analysis pass.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229626 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-18 03:43:24 +00:00
Adam Nemet
0d1e8dd84e [LoopAccesses] Make blockNeedsPredication static
blockNeedsPredication is in LoopAccess in order to share it with the
vectorizer.  It's a utility needed by LoopAccess not strictly provided
by it but it's a good place to share it.  This makes the function static
so that it no longer required to create an LoopAccessInfo instance in
order to access it from LV.

This was actually causing problems because it would have required
creating LAI much earlier that LV::canVectorizeMemory().

This is part of the patchset that converts LoopAccessAnalysis into an
actual analysis pass.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229625 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-18 03:43:19 +00:00
Adam Nemet
14cc2e25c5 [LoopAccesses] Cache the result of canVectorizeMemory
LAA will be an on-demand analysis pass, so we need to cache the result
of the analysis.  canVectorizeMemory is renamed to analyzeLoop which
computes the result.  canVectorizeMemory becomes the query function for
the cached result.

This is part of the patchset that converts LoopAccessAnalysis into an
actual analysis pass.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229624 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-18 03:42:57 +00:00
Adam Nemet
8b0647f26b [LoopAccesses] Stash the report from the analysis rather than emitting it
The transformation passes will query this and then emit them as part of
their own report.  The currently only user LV is modified to do just
that.

This is part of the patchset that converts LoopAccessAnalysis into an
actual analysis pass.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229623 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-18 03:42:50 +00:00
Adam Nemet
eefec589e8 [LoopAccesses] Make VectorizerParams global
As LAA is becoming a pass, we can no longer pass the params to its
constructor.  This changes the command line flags to have external
storage.  These can now be accessed both from LV and LAA.

VectorizerParams is moved out of LoopAccessInfo in order to shorten the
code to access it.

This is part of the patchset that converts LoopAccessAnalysis into an
actual analysis pass.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229622 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-18 03:42:43 +00:00
Adam Nemet
38a9ebb065 [LoopAccesses] Rename LoopAccessAnalysis to LoopAccessInfo
LoopAccessAnalysis will be used as the name of the pass.

This is part of the patchset that converts LoopAccessAnalysis into an
actual analysis pass.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229621 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-18 03:42:35 +00:00
Sanjoy Das
00af5b5d50 Generalize getExtendAddRecStart to work with both sign and zero
extensions.

This change also removes `DEBUG(dbgs() << "SCEV: untested prestart
overflow check\n");` because that case has a unit test now.

Differential Revision: http://reviews.llvm.org/D7645



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229600 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-18 01:47:07 +00:00
Sanjoy Das
0afc9b33fe Bugfix: SCEV incorrectly marks certain expressions as nsw
I could not come up with a test case for this one; but I don't think
`getPreStartForSignExtend` can assume `AR` is `nsw` -- there is one
place in scalar evolution that calls `getSignExtendAddRecStart(AR,
...)` without proving that `AR` is `nsw`

(line 1564)

   OperandExtendedAdd =
     getAddExpr(WideStart,
                getMulExpr(WideMaxBECount,
                           getZeroExtendExpr(Step, WideTy)));
   if (SAdd == OperandExtendedAdd) {
     // If AR wraps around then
     //
     //    abs(Step) * MaxBECount > unsigned-max(AR->getType())
     // => SAdd != OperandExtendedAdd
     //
     // Thus (AR is not NW => SAdd != OperandExtendedAdd) <=>
     // (SAdd == OperandExtendedAdd => AR is NW)

     const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNW);

     // Return the expression with the addrec on the outside.
     return getAddRecExpr(getSignExtendAddRecStart(AR, Ty, this),
                          getZeroExtendExpr(Step, Ty),
                          L, AR->getNoWrapFlags());
   }

Differential Revision: http://reviews.llvm.org/D7640



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229594 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-18 00:43:19 +00:00
Benjamin Kramer
1a50a12b43 Prefer SmallVector::append/insert over push_back loops.
Same functionality, but hoists the vector growth out of the loop.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229500 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-17 15:29:18 +00:00
Philip Reames
220a8ba114 Revert 229175
This change is a logical suspect in 22587 and 22590.  Given it's of minimal importanance and I can't get clang to build on my home machine, I'm reverting so that I can deal with this next week.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229322 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-15 19:07:31 +00:00
Reid Kleckner
f7f5309424 Unify the two EH personality classification routines I wrote
We only need one.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229193 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-14 00:21:02 +00:00
Duncan P. N. Exon Smith
efd49ea0d2 Analysis: Canonicalize access to function attributes, NFC
Canonicalize access to function attributes to use the simpler API.

getAttributes().getAttribute(AttributeSet::FunctionIndex, Kind)
  => getFnAttribute(Kind)

getAttributes().hasAttribute(AttributeSet::FunctionIndex, Kind)
  => hasFnAttribute(Kind)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229192 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-14 00:12:15 +00:00
Philip Reames
8c6097d490 Minor tweak to MDA
Two minor tweaks I noticed when reading through the code:
- No need to recompute begin() on every iteration.  We're not modifying the instructions in this loop.
- We can ignore PHINodes and Dbg intrinsics.  The current code does this anyways, but it will spend slightly more time doing so and will count towards the limit of instructions in the block.  It seems really silly to give up due the presence of PHIs...

Differential Revision: http://reviews.llvm.org/D7624



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229175 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-13 23:08:37 +00:00
Chandler Carruth
417c5c172c [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".

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229094 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-13 10:01:29 +00:00
Chandler Carruth
02d6288667 Re-sort #include lines using my handy dandy ./utils/sort_includes.py
script. This is in preparation for changes to lots of include lines.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229088 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-13 09:09:03 +00:00
Mehdi Amini
6ffd7173f2 InstCombine: cleanup redundant dyn_cast<> (NFC)
From: Mehdi Amini <mehdi.amini@apple.com>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229075 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-13 07:38:04 +00:00
Bjorn Steinbrink
53a7b568b2 Fix a crash in the assumption cache when inlining indirect function calls
Summary:
Instances of the AssumptionCache are per function, so we can't re-use
the same AssumptionCache instance when recursing in the CallAnalyzer to
analyze a different function. Instead we have to pass the
AssumptionCacheTracker to the CallAnalyzer so it can get the right
AssumptionCache on demand.

Reviewers: hfinkel

Subscribers: llvm-commits, hans

Differential Revision: http://reviews.llvm.org/D7533

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228957 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-12 21:04:22 +00:00
George Burgess IV
c571d114ba Fixed a bug where CFLAA would crash the compiler.
We would crash if we couldn't locate a Function that either Location's
Value belonged to. Now we just print out a debug message and return 
conservatively.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228901 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-12 03:07:07 +00:00
Zachary Turner
c371307e60 Use ADDITIONAL_HEADER_DIRS in all LLVM CMake projects.
This allows IDEs to recognize the entire set of header files for
each of the core LLVM projects.

Differential Revision: http://reviews.llvm.org/D7526
Reviewed By: Chris Bieneman

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228798 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-11 03:28:02 +00:00
Reid Kleckner
690248bf52 Don't promote asynch EH invokes of nounwind functions to calls
If the landingpad of the invoke is using a personality function that
catches asynch exceptions, then it can catch a trap.

Also add some landingpads to invalid LLVM IR test cases that lack them.

Over-the-shoulder reviewed by David Majnemer.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228782 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-11 01:23:16 +00:00
Andrew Kaylor
7741851819 Adding support for llvm.eh.begincatch and llvm.eh.endcatch intrinsics and beginning the documentation of native Windows exception handling.
Differential Revision: http://reviews.llvm.org/D7398



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228733 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-10 19:52:43 +00:00
Ramkumar Ramachandra
c904d5075f MemDerefPrinter: Require DataLayoutPass for higher accuracy
Without a valid data layout, deferenceable(N) doesn't get parsed or
propagated. Since this is the key item we are testing, add a dependency
on the pass.

Differential Revision: http://reviews.llvm.org/D7508

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228611 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-09 21:50:03 +00:00
Ramkumar Ramachandra
46b30b8252 MemDepPrinter: cleanup a few loops (NFC)
Make use of the newly introduced inst_range to clean up two loops. Clean
up a third one while at it.

Differential Revision: http://reviews.llvm.org/D7455

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228596 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-09 19:49:54 +00:00
Sanjoy Das
2ceba77dfa Bugfix: SCEV incorrectly marks certain add recurrences as nsw
When creating a scev for sext({X,+,Y}), scev checks if the expression
is equivalent to {sext X,+,zext Y}.  If it can prove that, it also
tags the original {X,+,Y} as <nsw>, which is not correct.

In the test case I run `-scalar-evolution` twice because the bug
manifests only once SCEV has run through and seen the `sext`
expressions (and then does a in-place mutation on {X,+,Y}).

Differential Revision: http://reviews.llvm.org/D7495



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228586 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-09 18:34:55 +00:00
Johannes Doerfert
f8c4fd6005 Allow ScalarEvolution to catch more min/max cases
For the attached test case different types are used in the ICmpInst
  and SelectInst that represent the min/max expressions. However, if the
  ICmpInst type is smaller a comparison with the sign/zero extended
  operands would have yielded the same result. This situation might
  arise after the instruction combination pass was applied.

  Differential Revision: http://reviews.llvm.org/D7338


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228572 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-09 12:34:23 +00:00
Sanjoy Das
1af442e572 Bugfix: ScalarEvolution incorrectly assumes that the start of certain
add recurrences don't overflow.

This change makes the optimization more restrictive.  It still assumes
that an overflowing `add nsw` is undefined behavior; and this change
will need revisiting once we have a consistent semantics for poison
values.

Differential Revision: http://reviews.llvm.org/D7331



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228552 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-08 22:52:17 +00:00
Bjorn Steinbrink
61a16d2a16 Correctly combine alias.scope metadata by a union instead of intersecting
Summary:
The alias.scope metadata represents sets of things an instruction might
alias with. When generically combining the metadata from two
instructions the result must be the union of the original sets, because
the new instruction might alias with anything any of the original
instructions aliased with.

Reviewers: hfinkel

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D7490

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228525 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-08 17:07:14 +00:00
Benjamin Kramer
a54b82a9fe ValueTracking: Make isBytewiseValue simpler and more powerful at the same time.
Turns out there is a simpler way of checking that all bytes in a word are equal
than binary decomposition.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228503 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-07 19:29:02 +00:00
Ahmed Bougacha
9c252165a7 [BasicAA] Try to disambiguate GEPs through arrays of structs into
different fields.

We can show that two GEPs off of the same (possibly multidimensional)
array of structs, into different fields, can't alias.  Quoting:

For two GEPOperators GEP1 and GEP2, if we find that:
- both GEPs begin indexing from the exact same pointer;
- the last indices in both GEPs are constants, indexing into a struct;
- said indices are different, hence,the pointed-to fields are different;
- and both GEPs only index through arrays prior to that;

this lets us determine that the struct that GEP1 indexes into and the
struct that GEP2 indexes into must either precisely overlap or be
completely disjoint.  Because they cannot partially overlap, indexing
into different non-overlapping fields of the struct will never alias.

The other BasicAA::aliasGEP rules worked in some cases, but not all
(for example, the i32x3 struct in the testcase).
We can add this simple ad-hoc rule to complement them.

rdar://19717375
Differential Revision: http://reviews.llvm.org/D7453


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228498 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-07 17:04:29 +00:00
Benjamin Kramer
0e0271af87 SCEV: Compress disposition pairs.
Composing DenseMaps and SmallVectors is still somewhat suboptimal,
but this at least halves the size of the vector elements. NFC.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228497 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-07 16:41:12 +00:00
Michael Zolotukhin
3da8e45675 [InstSimplify] Add SimplifyFPBinOp function.
It is a variation of SimplifyBinOp, but it takes into account
FastMathFlags.

It is needed in inliner and loop-unroller to accurately predict the
transformation's outcome (previously we dropped the flags and were too
conservative in some cases).

Example:
float foo(float *a, float b) {
 float r;
 if (a[1] * b)
   r = /* a lot of expensive computations */;
 else
   r = 1;
 return r;
}
float boo(float *a) {
 return foo(a, 0.0);
}

Without this patch, we don't inline 'foo' into 'boo'.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228432 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-06 20:02:51 +00:00
Adam Nemet
b3189eac3f [LV] Move addRuntimeCheck to LoopAccessAnalysis
This will allow it to be shared with the new Loop Distribution pass.

getFirstInst is currently duplicated across LoopVectorize.cpp and
LoopAccessAnalysis.cpp.  This is a short-term work-around until we figure out
a better solution.

NFC.  (The code moved is adjusted a bit for the name of the Loop member and
that PtrRtCheck is now a reference rather than a pointer.)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228418 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-06 18:31:04 +00:00
Chad Rosier
d553158799 Whitespace.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228397 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-06 14:14:41 +00:00
Ramkumar Ramachandra
ab28439f9a 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

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228369 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-06 01:46:42 +00:00
Cameron Esfahani
d02540a1d7 Value soft float calls as more expensive in the inliner.
Summary: When evaluating floating point instructions in the inliner, ask the TTI whether it is an expensive operation.  By default, it's not an expensive operation.  This keeps the default behavior the same as before.  The ARM TTI has been updated to return back TCC_Expensive for targets which don't have hardware floating point.

Reviewers: chandlerc, echristo

Reviewed By: echristo

Subscribers: t.p.northover, aemerson, llvm-commits

Differential Revision: http://reviews.llvm.org/D6936

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228263 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-05 02:09:33 +00:00
David Majnemer
9e8b7214ed ValueTracking: Make isSafeToSpeculativelyExecute a little cleaner
No functional change intended.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227760 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-01 19:10:19 +00:00
Adam Nemet
2000a7c9b2 [LoopVectorize] Move LoopAccessAnalysis to its own module
Other than moving code and adding the boilerplate for the new files, the code
being moved is unchanged.

There are a few global functions that are shared with the rest of the
LoopVectorizer.  I moved these to the new module as well (emitLoopAnalysis,
stripIntegerCast, replaceSymbolicStrideSCEV) along with the Report class used
by emitLoopAnalysis.  There is probably room for further improvement in this
area.

I kept DEBUG_TYPE "loop-vectorize" because it's used as the PassName with
emitOptimizationRemarkAnalysis.  This will obviously have to change.

NFC.  This is part of the patchset that splits out the memory dependence logic
from LoopVectorizationLegality into a new class LoopAccessAnalysis.
LoopAccessAnalysis will be used by the new Loop Distribution pass.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227756 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-01 16:56:15 +00:00
Chandler Carruth
38a2e36ad9 [multiversion] Kill FunctionTargetTransformInfo, TTI itself is now
per-function and supports the exact desired interface.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227743 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-01 14:37:03 +00:00
Chandler Carruth
26bc071088 [multiversion] Remove the function parameter from the unrolling
preferences interface on TTI now that all of TTI is per-function.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227741 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-01 14:31:23 +00:00
Chandler Carruth
276f405407 [multiversion] Implement the old pass manager's TTI wrapper pass in
terms of the new pass manager's TargetIRAnalysis.

Yep, this is one of the nicer bits of the new pass manager's design.
Passes can in many cases operate in a vacuum and so we can just nest
things when convenient. This is particularly convenient here as I can
now consolidate all of the TargetMachine logic on this analysis.

The most important change here is that this pushes the function we need
TTI for all the way into the TargetMachine, and re-creates the TTI
object for each function rather than re-using it for each function.
We're now prepared to teach the targets to produce function-specific TTI
objects with specific subtargets cached, etc.

One piece of feedback I'd love here is whether its worth renaming any of
this stuff. None of the names really seem that awesome to me at this
point, but TargetTransformInfoWrapperPass is particularly ... odd.
TargetIRAnalysisWrapper might make more sense. I would want to do that
rename separately anyways, but let me know what you think.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227731 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-01 12:26:09 +00:00
Chandler Carruth
baceda736e [multiversion] Thread a function argument through all the callers of the
getTTI method used to get an actual TTI object.

No functionality changed. This just threads the argument and ensures
code like the inliner can correctly look up the callee's TTI rather than
using a fixed one.

The next change will use this to implement per-function subtarget usage
by TTI. The changes after that should eliminate the need for FTTI as that
will have become the default.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227730 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-01 12:01:35 +00:00
Chandler Carruth
7724e8efa2 [PM] Port TTI to the new pass manager, introducing a TargetIRAnalysis to
produce it.

This adds a function to the TargetMachine that produces this analysis
via a callback for each function. This in turn faves the way to produce
a *different* TTI per-function with the correct subtarget cached.

I've also done the necessary wiring in the opt tool to thread the target
machine down and make it available to the pass registry so that we can
construct this analysis from a target machine when available.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227721 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-01 10:11:22 +00:00
Chandler Carruth
1937233a22 [PM] Switch the TargetMachine interface from accepting a pass manager
base which it adds a single analysis pass to, to instead return the type
erased TargetTransformInfo object constructed for that TargetMachine.

This removes all of the pass variants for TTI. There is now a single TTI
*pass* in the Analysis layer. All of the Analysis <-> Target
communication is through the TTI's type erased interface itself. While
the diff is large here, it is nothing more that code motion to make
types available in a header file for use in a different source file
within each target.

I've tried to keep all the doxygen comments and file boilerplate in line
with this move, but let me know if I missed anything.

With this in place, the next step to making TTI work with the new pass
manager is to introduce a really simple new-style analysis that produces
a TTI object via a callback into this routine on the target machine.
Once we have that, we'll have the building blocks necessary to accept
a function argument as well.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227685 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-31 11:17:59 +00:00
Chandler Carruth
a6a87b595d [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

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227669 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-31 03:43:40 +00:00
Elena Demikhovsky
b5c82c079a Fold fcmp in cases where value is provably non-negative. By Arch Robison.
This patch folds fcmp in some cases of interest in Julia. The patch adds a function CannotBeOrderedLessThanZero that returns true if a value is provably not less than zero. I.e. the function returns true if the value is provably -0, +0, positive, or a NaN. The patch extends InstructionSimplify.cpp to fold instances of fcmp where:
 - the predicate is olt or uge
 - the first operand is provably not less than zero
 - the second operand is zero
The motivation for handling these cases optimizing away domain checks for sqrt in Julia for common idioms such as sqrt(x*x+y*y)..

http://reviews.llvm.org/D6972



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227298 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-28 08:03:58 +00:00
Reid Kleckner
0935e7a79b Move EH personality type classification to Analysis/LibCallSemantics.h
Summary:
Also add enum types for __C_specific_handler and _CxxFrameHandler3 for
which we know a few things.

Reviewers: majnemer

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D7214

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227284 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-28 01:17:38 +00:00
Chad Rosier
13faabb6c5 Commoning of target specific load/store intrinsics in Early CSE.
Phabricator revision: http://reviews.llvm.org/D7121
Patch by Sanjin Sijaric <ssijaric@codeaurora.org>!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227149 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-26 22:51:15 +00:00
Philip Reames
cce3c83917 Refine memory dependence's notion of volatile semantics
According to my reading of the LangRef, volatiles are only ordered with respect to other volatiles. It is entirely legal and profitable to forward unrelated loads over the volatile load. This patch implements this for GVN by refining the transition rules MemoryDependenceAnalysis uses when encountering a volatile.

The added test cases show where the extra flexibility is profitable for local dependence optimizations. I have a related change (227110) which will extend this to non-local dependence (i.e. PRE), but that's essentially orthogonal to the semantic change in this patch. I have tested the two together and can confirm that PRE works over a volatile load with both changes.  I will be submitting a PRE w/volatiles test case seperately in the near future.

Differential Revision: http://reviews.llvm.org/D6901



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227112 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-26 18:54:27 +00:00
Philip Reames
8a5ad05c13 Pass QueryInst down through non-local dependency calculation
This change is mostly motivated by exposing information about the original query instruction to the actual scanning work in getPointerDependencyFrom when used by GVN PRE. In a follow up change, I will use this to be more precise with regards to the semantics of volatile instructions encountered in the scan of a basic block.

Worth noting, is that this change (despite appearing quite simple) is not semantically preserving. By providing more information to the helper routine, we allow some optimizations to kick in that weren't previously able to (when called from this code path.) In particular, we see that treatment of !invariant.load becomes more precise. In theory, we might see a difference with an ordered/atomic instruction as well, but I'm having a hard time actually finding a test case which shows that.

Test wise, I've included new tests for !invariant.load which illustrate this difference. I've also included some updated TBAA tests which highlight that this change isn't needed for that optimization to kick in - it's handled inside alias analysis itself. 

Eventually, it would be nice to factor the !invariant.load handling inside alias analysis as well.

Differential Revision: http://reviews.llvm.org/D6895



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227110 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-26 18:39:52 +00:00
Daniel Berlin
8e43882572 Fix incorrect partial aliasing
Update testcases

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227099 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-26 17:31:17 +00:00
Daniel Berlin
0d16cafbe3 Fix delegation
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227098 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-26 17:30:39 +00:00
Elena Demikhovsky
70bae89669 Implemented cost model for masked load/store operations.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227035 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-25 08:44:46 +00:00
Chandler Carruth
6f409cbc05 [PM] Rework how the TargetLibraryInfo pass integrates with the new pass
manager to support the actual uses of it. =]

When I ported instcombine to the new pass manager I discover that it
didn't work because TLI wasn't available in the right places. This is
a somewhat surprising and/or subtle aspect of the new pass manager
design that came up before but I think is useful to be reminded of:

While the new pass manager *allows* a function pass to query a module
analysis, it requires that the module analysis is already run and cached
prior to the function pass manager starting up, possibly with
a 'require<foo>' style utility in the pass pipeline. This is an
intentional hurdle because using a module analysis from a function pass
*requires* that the module analysis is run prior to entering the
function pass manager. Otherwise the other functions in the module could
be in who-knows-what state, etc.

A somewhat surprising consequence of this design decision (at least to
me) is that you have to design a function pass that leverages
a module analysis to do so as an optional feature. Even if that means
your function pass does no work in the absence of the module analysis,
you have to handle that possibility and remain conservatively correct.
This is a natural consequence of things being able to invalidate the
module analysis and us being unable to re-run it. And it's a generally
good thing because it lets us reorder passes arbitrarily without
breaking correctness, etc.

This ends up causing problems in one case. What if we have a module
analysis that is *definitionally* impossible to invalidate. In the
places this might come up, the analysis is usually also definitionally
trivial to run even while other transformation passes run on the module,
regardless of the state of anything. And so, it follows that it is
natural to have a hard requirement on such analyses from a function
pass.

It turns out, that TargetLibraryInfo is just such an analysis, and
InstCombine has a hard requirement on it.

The approach I've taken here is to produce an analysis that models this
flexibility by making it both a module and a function analysis. This
exposes the fact that it is in fact safe to compute at any point. We can
even make it a valid CGSCC analysis at some point if that is useful.
However, we don't want to have a copy of the actual target library info
state for each function! This state is specific to the triple. The
somewhat direct and blunt approach here is to turn TLI into a pimpl,
with the state and mutators in the implementation class and the query
routines primarily in the wrapper. Then the analysis can lazily
construct and cache the implementations, keyed on the triple, and
on-demand produce wrappers of them for each function.

One minor annoyance is that we will end up with a wrapper for each
function in the module. While this is a bit wasteful (one pointer per
function) it seems tolerable. And it has the advantage of ensuring that
we pay the absolute minimum synchronization cost to access this
information should we end up with a nice parallel function pass manager
in the future. We could look into trying to mark when analysis results
are especially cheap to recompute and more eagerly GC-ing the cached
results, or we could look at supporting a variant of analyses whose
results are specifically *not* cached and expected to just be used and
discarded by the consumer. Either way, these seem like incremental
enhancements that should happen when we start profiling the memory and
CPU usage of the new pass manager and not before.

The other minor annoyance is that if we end up using the TLI in both
a module pass and a function pass, those will be produced by two
separate analyses, and thus will point to separate copies of the
implementation state. While a minor issue, I dislike this and would like
to find a way to cleanly allow a single analysis instance to be used
across multiple IR unit managers. But I don't have a good solution to
this today, and I don't want to hold up all of the work waiting to come
up with one. This too seems like a reasonable thing to incrementally
improve later.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226981 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-24 02:06:09 +00:00
Chandler Carruth
9a78a64776 [PM] Actually add the new pass manager support for the assumption cache.
I had already factored this analysis specifically to enable doing this,
but hadn't actually committed the necessary wiring to get at this from
the new pass manager. This also nicely shows how the separate cache
object can be directly managed by the new pass manager.

This analysis didn't have any direct tests and so I've added a printer
pass and a boring test case. I chose to print the i1 value which is
being assumed rather than the call to llvm.assume as that seems much
more useful for testing... but suggestions on an even better printing
strategy welcome. My main goal was to make sure things actually work. =]

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226868 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-22 21:53:09 +00:00
Ramkumar Ramachandra
230796b278 Intrinsics: introduce llvm_any_ty aka ValueType Any
Specifically, gc.result benefits from this greatly. Instead of:

gc.result.int.*
gc.result.float.*
gc.result.ptr.*
...

We now have a gc.result.* that can specialize to literally any type.

Differential Revision: http://reviews.llvm.org/D7020

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226857 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-22 20:14:38 +00:00
Sanjoy Das
48fcc07856 Make ScalarEvolution less aggressive with respect to no-wrap flags.
ScalarEvolution currently lowers a subtraction recurrence to an add
recurrence with the same no-wrap flags as the subtraction.  This is
incorrect because `sub nsw X, Y` is not the same as `add nsw X, -Y`
and `sub nuw X, Y` is not the same as `add nuw X, -Y`.  This patch
fixes the issue, and adds two test cases demonstrating the bug.

Differential Revision: http://reviews.llvm.org/D7081



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226755 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-22 00:48:47 +00:00
George Burgess IV
bdcc4ec129 Fixed a bug with how we determine bitset indices.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226671 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-21 16:37:21 +00:00
Chandler Carruth
a37512049c [PM] Port LoopInfo to the new pass manager, adding both a LoopAnalysis
pass and a LoopPrinterPass with the expected associated wiring.

I've added a RUN line to the only test case (!!!) we have that actually
prints loops. Everything seems to be working.

This is somewhat exciting as this is the first analysis using another
analysis to go in for the new pass manager. =D I also believe it is the
last analysis necessary for porting instcombine, but of course I may yet
discover more.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226560 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-20 10:58:50 +00:00
Chandler Carruth
5a2d01e5b8 [PM] Now that LoopInfo isn't in the Pass type hierarchy, it is much
cleaner to derive from the generic base.

Thise removes a ton of boiler plate code and somewhat strange and
pointless indirections. It also remove a bunch of the previously needed
friend declarations. To fully remove these, I also lifted the verify
logic into the generic LoopInfoBase, which seems good anyways -- it is
generic and useful logic even for the machine side.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226385 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-18 01:25:51 +00:00
Chandler Carruth
e81cec19db [PM] Cleanup more warnings my refactoring exposed where now we have
unused variables in a no-asserts build.

I've fixed this by putting the entire loop behind an #ifndef as it
contains nothing other than asserts.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226377 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-17 14:49:23 +00:00
Chandler Carruth
de5df29556 [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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226373 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-17 14:16:18 +00:00
Chandler Carruth
e2ffd02ad3 [PM] Port TargetLibraryInfo to the new pass manager, provided by the
TargetLibraryAnalysis pass.

There are actually no direct tests of this already in the tree. I've
added the most basic test that the pass manager bits themselves work,
and the TLI object produced will be tested by an upcoming patches as
they port passes which rely on TLI.

This is starting to point out the awkwardness of the invalidate API --
it seems poorly fitting on the *result* object. I suspect I will change
it to live on the analysis instead, but that's not for this change, and
I'd rather have a few more passes ported in order to have more
experience with how this plays out.

I believe there is only one more analysis required in order to start
porting instcombine. =]

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226160 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-15 11:39:46 +00:00
Chandler Carruth
eeeec3ce0d [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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226157 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-15 10:41:28 +00:00
NAKAMURA Takumi
20b033eae5 Update libdeps since TLI was moved from Target to Analysis in r226078.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226126 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-15 05:21:00 +00:00
Chandler Carruth
bda134910a [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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226078 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-15 02:16:27 +00:00
Richard Smith
ef7d38d35a For PR21145: recognise a builtin call to a known deallocation function even if
it's defined in the current module. Clang generates this situation for the
C++14 sized deallocation functions, because it generates a weak definition in
case one isn't provided by the C++ runtime library.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226069 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-15 01:00:33 +00:00
Chandler Carruth
1b279144ec [cleanup] Re-sort all the #include lines in LLVM using
utils/sort_includes.py.

I clearly haven't done this in a while, so more changed than usual. This
even uncovered a missing include from the InstrProf library that I've
added. No functionality changed here, just mechanical cleanup of the
include order.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225974 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-14 11:23:27 +00:00
Chandler Carruth
c9109225e2 Revert r225854: [PM] Move the LazyCallGraph printing functionality to
a print method.

This was formulated on a bad idea, but sadly I didn't uncover how bad
this was until I got further down the path. I had hoped that we could
provide a low boilerplate way of printing analyses, but it just doesn't
seem like this really fits the needs of the analyses. Not all analyses
really want to do printing, and those that do don't all use the same
interface. Instead, with the new pass manager let's just take advantage
of the fact that creating an explicit printer pass like the LCG has is
pretty low boilerplate already and rely on that for testing.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225861 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-14 00:27:45 +00:00
Chandler Carruth
2a463a1060 [PM] Move the LazyCallGraph printing functionality to a print method.
I'm adding generic analysis printing utility pass support which will
require such a method (or a specialization) so this will let the
existing printing logic satisfy that.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225854 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-13 23:53:50 +00:00
Chandler Carruth
a28a251950 [PM] Remove the defunt CGSCC-specific debug flag.
Even before I sunk the debug flag into the opt tool this had been made
obsolete by factoring the pass and analysis managers into a single set
of templates that all used the core flag. No functionality changed here.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225842 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-13 22:45:13 +00:00
Chandler Carruth
92602ea18e [PM] Refactor the new pass manager to use a single template to implement
the generic functionality of the pass managers themselves.

In the new infrastructure, the pass "manager" isn't actually interesting
at all. It just pipelines a single chunk of IR through N passes. We
don't need to know anything about the IR or the passes to do this really
and we can replace the 3 implementations of the exact same functionality
with a single generic PassManager template, complementing the single
generic AnalysisManager template.

I've left typedefs in place to give convenient names to the various
obvious instantiations of the template.

With this, I think I've nuked almost all of the redundant logic in the
managers, and I think the overall design is actually simpler for having
single templates that clearly indicate there is no special logic here.
The logging is made somewhat more annoying by this change, but I don't
think the difference is worth having heavy-weight traits to help log
things.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225783 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-13 11:13:56 +00:00
Ramkumar Ramachandra
2bcc808cf9 Standardize {pred,succ,use,user}_empty()
The functions {pred,succ,use,user}_{begin,end} exist, but many users
have to check *_begin() with *_end() by hand to determine if the
BasicBlock or User is empty. Fix this with a standard *_empty(),
demonstrating a few usecases.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225760 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-13 03:46:47 +00:00
Chandler Carruth
6b1894aeae [PM] Fold all three analysis managers into a single AnalysisManager
template.

This consolidates three copies of nearly the same core logic. It adds
"complexity" to the ModuleAnalysisManager in that it makes it possible
to share a ModuleAnalysisManager across multiple modules... But it does
so by deleting *all of the code*, so I'm OK with that. This will
naturally make fixing bugs in this code much simpler, etc.

The only down side here is that we have to use 'typename' and 'this->'
in various places, and the implementation is lifted into the header.
I'll take that for the code size reduction.

The convenient names are still typedef-ed and used throughout so that
users can largely ignore this aspect of the implementation.

The follow-up change to this will do the exact same refactoring for the
PassManagers. =D

It turns out that the interesting different code is almost entirely in
the adaptors. At the end, that should be essentially all that is left.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225757 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-13 02:51:47 +00:00
Chandler Carruth
9136fdd9b7 [PM] Re-clang-format much of this code as the code has changed some and
so has clang-format. Notably, this fixes a bunch of formatting in the
CGSCC pass manager side of things that has been improved in clang-format
recently.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225743 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-13 00:36:47 +00:00
Sanjoy Das
7f0da20b97 Fix PR22179.
We were incorrectly inferring nsw for certain SCEVs. We can be more
aggressive here (see Richard Smith's comment on
http://llvm.org/bugs/show_bug.cgi?id=22179) but this change just
focuses on correctness.

Differential Revision: http://reviews.llvm.org/D6914



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225591 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-10 23:41:24 +00:00
Sanjay Patel
61478e3bf9 remove names from comments; NFC
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225526 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-09 16:47:20 +00:00
Sanjay Patel
a987742b0e fix typos; NFC
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225525 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-09 16:35:37 +00:00
Sanjay Patel
46b23a185f fix typo; NFC
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225524 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-09 16:29:50 +00:00
Sanjay Patel
b1d136dd4f more efficient use of a dyn_cast; no functional change intended
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225523 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-09 16:28:15 +00:00
Philip Reames
ce0e12f0b4 [REFACTOR] Push logic from MemDepPrinter into getNonLocalPointerDependency
Previously, MemDepPrinter handled volatile and unordered accesses without involving MemoryDependencyAnalysis.  By making a slight tweak to the documented interface - which is respected by both callers - we can move this responsibility to MDA for the benefit of any future callers.  This is basically just cleanup.

In the future, we may decide to extend MDA's non local dependency analysis to return useful results for ordered or volatile loads.  I believe (but have not really checked in detail) that local dependency analyis does get useful results for ordered, but not volatile, loads.




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225483 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-09 00:26:45 +00:00
Philip Reames
dba2d12578 [Refactor] Have getNonLocalPointerDependency take the query instruction
Previously, MemoryDependenceAnalysis::getNonLocalPointerDependency was taking a list of properties about the instruction being queried. Since I'm about to need one more property to be passed down through the infrastructure - I need to know a query instruction is non-volatile in an inner helper - fix the interface once and for all.

I also added some assertions and behaviour clarifications around volatile and ordered field accesses. At the moment, this is mostly to document expected behaviour. The only non-standard instructions which can currently reach this are atomic, but unordered, loads and stores. Neither ordered or volatile accesses can reach here.

The call in GVN is protected by an isSimple check when it first considers the load. The calls in MemDepPrinter are protected by isUnordered checks. Both utilities also check isVolatile for loads and stores.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225481 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-09 00:04:22 +00:00
Nick Lewycky
f411a8dd29 Remove empty statement. No functionality change.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225420 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-08 00:47:03 +00:00
Chandler Carruth
9fc5a53118 [PM] Fix a pretty nasty bug where the new pass manager would invalidate
passes too many time.

I think this is actually the issue that someone raised with me at the
developer's meeting and in an email, but that we never really got to the
bottom of. Having all the testing utilities made it much easier to dig
down and uncover the core issue.

When a pass manager is running many passes over a single function, we
need it to invalidate the analyses between each run so that they can be
re-computed as needed. We also need to track the intersection of
preserved higher-level analyses across all the passes that we run (for
example, if there is one module analysis which all the function analyses
preserve, we want to track that and propagate it). Unfortunately, this
interacted poorly with any enclosing pass adaptor between two IR units.
It would see the intersection of preserved analyses, and need to
invalidate any other analyses, but some of the un-preserved analyses
might have already been invalidated *and recomputed*! We would fail to
propagate the fact that the analysis had already been invalidated.

The solution to this struck me as really strange at first, but the more
I thought about it, the more natural it seemed. After a nice discussion
with Duncan about it on IRC, it seemed even nicer. The idea is that
invalidating an analysis *causes* it to be preserved! Preserving the
lack of result is trivial. If it is recomputed, great. Until something
*else* invalidates it again, we're good.

The consequence of this is that the invalidate methods on the analysis
manager which operate over many passes now consume their
PreservedAnalyses object, update it to "preserve" every analysis pass to
which it delivers an invalidation (regardless of whether the pass
chooses to be removed, or handles the invalidation itself by updating
itself). Then we return this augmented set from the invalidate routine,
letting the pass manager take the result and use the intersection of
*that* across each pass run to compute the final preserved set. This
accounts for all the places where the early invalidation of an analysis
has already "preserved" it for a future run.

I've beefed up the testing and adjusted the assertions to show that we
no longer repeatedly invalidate or compute the analyses across nested
pass managers.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225333 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-07 01:58:35 +00:00
David Majnemer
72a9513e92 Analysis: Reformulate WillNotOverflowUnsignedAdd for reusability
WillNotOverflowUnsignedAdd's smarts will live in ValueTracking as
computeOverflowForUnsignedAdd.  It now returns a tri-state result:
never overflows, always overflows and sometimes overflows.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225329 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-07 00:39:50 +00:00
Chandler Carruth
17395fa733 [PM] Add a utility pass template that synthesizes the invalidation of
a specific analysis result.

This is quite handy to test things, and will also likely be very useful
for debugging issues. You could narrow down pass validation failures by
walking these invalidate pass runs up and down the pass pipeline, etc.
I've added support to the pass pipeline parsing to be able to create one
of these for any analysis pass desired.

Just adding this class uncovered one latent bug where the
AnalysisManager CRTP base class had a hard-coded Module type rather than
using IRUnitT.

I've also added tests for invalidation and caching of analyses in
a basic way across all the pass managers. These in turn uncovered two
more bugs where we failed to correctly invalidate an analysis -- its
results were invalidated but the key for re-running the pass was never
cleared and so it was never re-run. Quite nasty. I'm very glad to debug
this here rather than with a full system.

Also, yes, the naming here is horrid. I'm going to update some of the
names to be slightly less awful shortly. But really, I've no "good"
ideas for naming. I'll be satisfied if I can get it to "not bad".

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225246 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-06 04:49:44 +00:00
Chandler Carruth
5b12a2f703 [PM] Add a collection of no-op analysis passes and switch the new pass
manager tests to use them and be significantly more comprehensive.

This, naturally, uncovered a bug where the CGSCC pass manager wasn't
printing analyses when they were run.

The only remaining core manipulator is I think an invalidate pass
similar to the require pass. That'll be next. =]

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225240 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-06 02:50:06 +00:00
Chandler Carruth
1ab487fdc7 [PM] Don't run the machinery of invalidating all the analysis passes
when all are being preserved.

We want to short-circuit this for a couple of reasons. One, I don't
really want passes to grow a dependency on actually receiving their
invalidate call when they've been preserved. I'm thinking about removing
this entirely. But more importantly, preserving everything is likely to
be the common case in a lot of scenarios, and it would be really good to
bypass all of the invalidation and preservation machinery there.
Avoiding calling N opaque functions to try to invalidate things that are
by definition still valid seems important. =]

This wasn't really inpsired by much other than seeing the spam in the
logging for analyses, but it seems better ot get it checked in rather
than forgetting about it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225163 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-05 12:32:11 +00:00
Chandler Carruth
040ca449b2 [PM] Add names and debug logging for analysis passes to the new pass
manager.

This starts to allow us to test analyses more easily, but it's really
only the beginning. Some of the code here is still untestable without
manual changes to create analysis passes, but I wanted to factor it into
a small of chunks as possible.

Next up in order to be able to test things are, in no particular order:
- No-op analyses passes so we don't have to use real ones to exercise
  the pass maneger itself.
- Automatic way of generating dummy passes that require an analysis be
  run, including a variant that calls a 'print' method on a pass to make
  it even easier to print out the results of an analysis.
- Dummy passes that invalidate all analyses for their IR unit so we can
  test invalidation and re-runs.
- Automatic way to print each analysis pass as it is re-run.
- Automatic but optional verification of analysis passes everywhere
  possible.

I'm not claiming I'll get to all of these immediately, but that's what
is in the pipeline at some stage. I'm fleshing out exactly what I need
and what to prioritize by working on converting analyses and then trying
to test the conversion. =]

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225162 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-05 12:21:44 +00:00
Chandler Carruth
b246acebf4 [PM] Switch the new pass manager to use a reference-based API for IR
units.

This was debated back and forth a bunch, but using references is now
clearly cleaner. Of all the code written using pointers thus far, in
only one place did it really make more sense to have a pointer. In most
cases, this just removes immediate dereferencing from the code. I think
it is much better to get errors on null IR units earlier, potentially
at compile time, than to delay it.

Most notably, the legacy pass manager uses references for its routines
and so as more and more code works with both, the use of pointers was
likely to become really annoying. I noticed this when I ported the
domtree analysis over and wrote the entire thing with references only to
have it fail to compile. =/ It seemed better to switch now than to
delay. We can, of course, revisit this is we learn that references are
really problematic in the API.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225145 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-05 02:47:05 +00:00
Chandler Carruth
186c5ccb07 [PM] Cleanup a const_cast and other machinery left over in this code
from before I removed thet non-const use of the function.

The unused variable that held the const_cast was already kindly removed
by Michael.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225143 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-04 23:13:57 +00:00
Michael Kuperstein
7362319120 Fix unused variable warning for non-asserts builds. NFC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225133 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-04 13:35:44 +00:00
Chandler Carruth
5a9cd4d44e [PM] Split the AssumptionTracker immutable pass into two separate APIs:
a cache of assumptions for a single function, and an immutable pass that
manages those caches.

The motivation for this change is two fold. Immutable analyses are
really hacks around the current pass manager design and don't exist in
the new design. This is usually OK, but it requires that the core logic
of an immutable pass be reasonably partitioned off from the pass logic.
This change does precisely that. As a consequence it also paves the way
for the *many* utility functions that deal in the assumptions to live in
both pass manager worlds by creating an separate non-pass object with
its own independent API that they all rely on. Now, the only bits of the
system that deal with the actual pass mechanics are those that actually
need to deal with the pass mechanics.

Once this separation is made, several simplifications become pretty
obvious in the assumption cache itself. Rather than using a set and
callback value handles, it can just be a vector of weak value handles.
The callers can easily skip the handles that are null, and eventually we
can wrap all of this up behind a filter iterator.

For now, this adds boiler plate to the various passes, but this kind of
boiler plate will end up making it possible to port these passes to the
new pass manager, and so it will end up factored away pretty reasonably.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225131 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-04 12:03:27 +00:00
David Majnemer
77e22b7836 ValueTracking: ComputeNumSignBits should tolerate misshapen phi nodes
PHI nodes can have zero operands in the middle of a transform.  It is
expected that utilities in Analysis don't freak out when this happens.

Note that it is considered invalid to allow these misshapen phi nodes to
make it to another pass.

This fixes PR22086.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225126 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-04 07:06:53 +00:00
David Majnemer
ef8f7e1a5a ValueTracking: Make computeKnownBits for Arguments a little more clear
We would sometimes leave the out-param APInts untouched while going
through computeKnownBits.  While I don't know of a way to trigger a bug
involving this in practice, it goes against the overall design of
computeKnownBits.

Found via code inspection.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225109 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-03 02:33:25 +00:00
David Majnemer
5e9c6212a8 InstCombine: Detect when llvm.umul.with.overflow always overflows
We know overflow always occurs if both ~LHSKnownZero * ~RHSKnownZero
and LHSKnownOne * RHSKnownOne overflow.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225077 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-02 07:29:47 +00:00
David Majnemer
25e8e79fab Analysis: Reformulate WillNotOverflowUnsignedMul for reusability
WillNotOverflowUnsignedMul's smarts will live in ValueTracking as
computeOverflowForUnsignedMul.  It now returns a tri-state result:
never overflows, always overflows and sometimes overflows.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225076 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-02 07:29:43 +00:00
David Majnemer
597e1ab1aa ValueTracking: Small cleanup in ComputeNumSignBits
Constant contains the isAllOnesValue and isNullValue predicates, not
ConstantInt.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224848 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-26 09:20:17 +00:00
Michael Kuperstein
a098c770e1 [ValueTracking] Move GlobalAlias handling to be after the max depth check in computeKnownBits()
GlobalAlias handling used to be after GlobalValue handling, which meant it was, in practice, dead code. r220165 moved GlobalAlias handling to be before GlobalValue handling, but also moved it to be before the max depth check, causing an assert due to a recursion depth limit violation. 

This moves GlobalAlias handling forward to where it's safe, and changes the GlobalValue handling to only look at GlobalObjects.

Differential Revision: http://reviews.llvm.org/D6758

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224765 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-23 11:33:41 +00:00
David Majnemer
821c6f765a InstSimplify: Don't bother if getScalarSizeInBits returns zero
getScalarSizeInBits returns zero when the comparison operands are not
integral.  No functionality change intended.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224675 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-20 04:45:33 +00:00
David Majnemer
f666c0549e Simplify the code
No functionality change intended.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224673 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-20 03:29:59 +00:00
David Majnemer
9cd99a0724 InstSimplify: Optimize away pointless comparisons
(X & INT_MIN) ? X & INT_MAX : X  into  X & INT_MAX
(X & INT_MIN) ? X : X & INT_MAX  into  X
(X & INT_MIN) ? X | INT_MIN : X  into  X
(X & INT_MIN) ? X : X | INT_MIN  into  X | INT_MIN

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224669 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-20 03:04:38 +00:00
Tilmann Scheller
6500a9867f Remove redundant assignment.
Found with the Clang static analyzer.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224570 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-19 11:29:34 +00:00
David Majnemer
891ec6d69f InstSimplify: shl nsw/nuw undef, %V -> undef
We can always choose an value for undef which might cause %V to shift
out an important bit except for one case, when %V is zero.

However, shl behaves like an identity function when the right hand side
is zero.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224405 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-17 01:54:33 +00:00
Sanjoy Das
574e01c32e Teach ScalarEvolution to exploit min and max expressions when proving
isKnownPredicate.

The motivation for this change is to optimize away checks in loops
like this:

    limit = min(t, len)
    for (i = 0 to limit)
      if (i >= len || i < 0) throw_array_of_of_bounds();
      a[i] = ...

Differential Revision: http://reviews.llvm.org/D6635



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224285 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-15 22:50:15 +00:00
Mark Heffernan
b10837d169 Clarify HowFarToZero computation when the step is a positive power of two. Functionally this should be identical to the existing code except for the case where Step is maximally negative (eg, INT_MIN). We now punt in that one corner case to make reasoning about the code easier.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224274 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-15 21:19:53 +00:00
Elena Demikhovsky
2f6d42351a Sink store based on alias analysis
- by Ella Bolshinsky
The alias analysis is used define whether the given instruction
is a barrier for store sinking. For 2 identical stores, following
instructions are checked in the both basic blocks, to determine
whether they are sinking barriers.

http://reviews.llvm.org/D6420



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224247 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-15 14:09:53 +00:00
Elena Demikhovsky
1c3a1516f8 Loop Vectorizer minor changes in the code -
some comments, function names, identation.

Reviewed here: http://reviews.llvm.org/D6527


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224218 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-14 09:43:50 +00:00
David Majnemer
fabf5cc5d9 ScalarEvolution: Remove SCEVUDivision, it's unused
This is just a code simplification, no functionality change is intended.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224216 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-14 09:12:33 +00:00
David Majnemer
3b7e6d27d2 ValueTracking: Don't recurse too deeply in computeKnownBitsFromAssume
Respect the MaxDepth recursion limit, doing otherwise will trigger an
assert in computeKnownBits.

This fixes PR21891.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224168 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-12 23:59:29 +00:00
Mark Heffernan
1e9d355499 Fix PR21694. r219517 added a use of SCEV divide in HowFarToZero computation. This divide can produce incorrect results as we are using an unsigned divide for what should be a modular divide. This change reverts back to a more conservative computation using trailing zeros.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223974 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-10 22:53:52 +00:00
David Majnemer
72c6bdbf70 ConstantFold, InstSimplify: undef >>a x can be either -1 or 0, choose 0
Zero is usually a nicer constant to have than -1.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223969 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-10 21:58:15 +00:00
David Majnemer
6578f1beb1 InstSimplify: [al]shr exact undef, %X -> undef
Exact shifts always keep the non-zero bits of their input.  This means
it keeps it's undef bits.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223923 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-10 09:14:52 +00:00
David Majnemer
1297775557 InstSimplify: div %X, 0 -> undef
We already optimized rem %X, 0 to undef, we should do the same for div.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223919 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-10 07:52:18 +00:00
Duncan P. N. Exon Smith
dad20b2ae2 IR: Split Metadata from Value
Split `Metadata` away from the `Value` class hierarchy, as part of
PR21532.  Assembly and bitcode changes are in the wings, but this is the
bulk of the change for the IR C++ API.

I have a follow-up patch prepared for `clang`.  If this breaks other
sub-projects, I apologize in advance :(.  Help me compile it on Darwin
I'll try to fix it.  FWIW, the errors should be easy to fix, so it may
be simpler to just fix it yourself.

This breaks the build for all metadata-related code that's out-of-tree.
Rest assured the transition is mechanical and the compiler should catch
almost all of the problems.

Here's a quick guide for updating your code:

  - `Metadata` is the root of a class hierarchy with three main classes:
    `MDNode`, `MDString`, and `ValueAsMetadata`.  It is distinct from
    the `Value` class hierarchy.  It is typeless -- i.e., instances do
    *not* have a `Type`.

  - `MDNode`'s operands are all `Metadata *` (instead of `Value *`).

  - `TrackingVH<MDNode>` and `WeakVH` referring to metadata can be
    replaced with `TrackingMDNodeRef` and `TrackingMDRef`, respectively.

    If you're referring solely to resolved `MDNode`s -- post graph
    construction -- just use `MDNode*`.

  - `MDNode` (and the rest of `Metadata`) have only limited support for
    `replaceAllUsesWith()`.

    As long as an `MDNode` is pointing at a forward declaration -- the
    result of `MDNode::getTemporary()` -- it maintains a side map of its
    uses and can RAUW itself.  Once the forward declarations are fully
    resolved RAUW support is dropped on the ground.  This means that
    uniquing collisions on changing operands cause nodes to become
    "distinct".  (This already happened fairly commonly, whenever an
    operand went to null.)

    If you're constructing complex (non self-reference) `MDNode` cycles,
    you need to call `MDNode::resolveCycles()` on each node (or on a
    top-level node that somehow references all of the nodes).  Also,
    don't do that.  Metadata cycles (and the RAUW machinery needed to
    construct them) are expensive.

  - An `MDNode` can only refer to a `Constant` through a bridge called
    `ConstantAsMetadata` (one of the subclasses of `ValueAsMetadata`).

    As a side effect, accessing an operand of an `MDNode` that is known
    to be, e.g., `ConstantInt`, takes three steps: first, cast from
    `Metadata` to `ConstantAsMetadata`; second, extract the `Constant`;
    third, cast down to `ConstantInt`.

    The eventual goal is to introduce `MDInt`/`MDFloat`/etc. and have
    metadata schema owners transition away from using `Constant`s when
    the type isn't important (and they don't care about referring to
    `GlobalValue`s).

    In the meantime, I've added transitional API to the `mdconst`
    namespace that matches semantics with the old code, in order to
    avoid adding the error-prone three-step equivalent to every call
    site.  If your old code was:

        MDNode *N = foo();
        bar(isa             <ConstantInt>(N->getOperand(0)));
        baz(cast            <ConstantInt>(N->getOperand(1)));
        bak(cast_or_null    <ConstantInt>(N->getOperand(2)));
        bat(dyn_cast        <ConstantInt>(N->getOperand(3)));
        bay(dyn_cast_or_null<ConstantInt>(N->getOperand(4)));

    you can trivially match its semantics with:

        MDNode *N = foo();
        bar(mdconst::hasa               <ConstantInt>(N->getOperand(0)));
        baz(mdconst::extract            <ConstantInt>(N->getOperand(1)));
        bak(mdconst::extract_or_null    <ConstantInt>(N->getOperand(2)));
        bat(mdconst::dyn_extract        <ConstantInt>(N->getOperand(3)));
        bay(mdconst::dyn_extract_or_null<ConstantInt>(N->getOperand(4)));

    and when you transition your metadata schema to `MDInt`:

        MDNode *N = foo();
        bar(isa             <MDInt>(N->getOperand(0)));
        baz(cast            <MDInt>(N->getOperand(1)));
        bak(cast_or_null    <MDInt>(N->getOperand(2)));
        bat(dyn_cast        <MDInt>(N->getOperand(3)));
        bay(dyn_cast_or_null<MDInt>(N->getOperand(4)));

  - A `CallInst` -- specifically, intrinsic instructions -- can refer to
    metadata through a bridge called `MetadataAsValue`.  This is a
    subclass of `Value` where `getType()->isMetadataTy()`.

    `MetadataAsValue` is the *only* class that can legally refer to a
    `LocalAsMetadata`, which is a bridged form of non-`Constant` values
    like `Argument` and `Instruction`.  It can also refer to any other
    `Metadata` subclass.

(I'll break all your testcases in a follow-up commit, when I propagate
this change to assembly.)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223802 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-09 18:38:53 +00:00
David Majnemer
fca9c7b21c InstSimplify: Try to bring back the rest of r223583
This reverts r223624 with a small tweak, hopefully this will make stage3
equivalent.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223679 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-08 18:30:43 +00:00
NAKAMURA Takumi
e4a5390406 Revert a part of r223583, for now. It seems causing different emission between stage2(gcc-clang) and stage3 clang. Investigating.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223624 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-08 02:07:22 +00:00
David Majnemer
620e8763ec InstSimplify: Optimize away useless unsigned comparisons
Code like X < Y && Y == 0 should always be folded away to false.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223583 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-06 10:51:40 +00:00
Nick Lewycky
8a51f8e8ce Canonicalize multiplies by looking at whether the operands have any constants themselves. Patch by Tim Murray!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223554 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-06 00:45:50 +00:00
Duncan P. N. Exon Smith
1a283409bc BFI: Saturate when combining edges to a successor
When a loop gets bundled up, its outgoing edges are quite large, and can
just barely overflow 64-bits.  If one successor has multiple incoming
edges -- and that successor is getting all the incoming mass --
combining just its edges can overflow.  Handle that by saturating rather
than asserting.

This fixes PR21622.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223500 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-05 19:13:42 +00:00
Hal Finkel
efbb95a1be Revert "r223364 - Revert r223347 which has caused crashes on bootstrap bots."
Reapply r223347, with a fix to not crash on uninserted instructions (or more
precisely, instructions in uninserted blocks). bugpoint was able to reduce the
test case somewhat, but it is still somewhat large (and relies on setting
things up to be simplified during inlining), so I've not included it here.
Nevertheless, it is clear what is going on and why.

Original commit message:

Restrict somewhat the memory-allocation pointer cmp opt from r223093

Based on review comments from Richard Smith, restrict this optimization from
applying to globals that might resolve lazily to other dynamically-loaded
modules, and also from dynamic allocas (which might be transformed into malloc
calls). In short, take extra care that the compared-to pointer is really
simultaneously live with the memory allocation.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223371 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-04 17:45:19 +00:00
Alexander Potapenko
182d9aaccb Revert r223347 which has caused crashes on bootstrap bots.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223364 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-04 14:22:27 +00:00
Elena Demikhovsky
73ae1df82c Masked Load / Store Intrinsics - the CodeGen part.
I'm recommiting the codegen part of the patch.
The vectorizer part will be send to review again.

Masked Vector Load and Store Intrinsics.
Introduced new target-independent intrinsics in order to support masked vector loads and stores. The loop vectorizer optimizes loops containing conditional memory accesses by generating these intrinsics for existing targets AVX2 and AVX-512. The vectorizer asks the target about availability of masked vector loads and stores.
Added SDNodes for masked operations and lowering patterns for X86 code generator.
Examples:
<16 x i32> @llvm.masked.load.v16i32(i8* %addr, <16 x i32> %passthru, i32 4 /* align */, <16 x i1> %mask)
declare void @llvm.masked.store.v8f64(i8* %addr, <8 x double> %value, i32 4, <8 x i1> %mask)

Scalarizer for other targets (not AVX2/AVX-512) will be done in a separate patch.

http://reviews.llvm.org/D6191



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223348 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-04 09:40:44 +00:00
Hal Finkel
d70d5148a6 Restrict somewhat the memory-allocation pointer cmp opt from r223093
Based on review comments from Richard Smith, restrict this optimization from
applying to globals that might resolve lazily to other dynamically-loaded
modules, and also from dynamic allocas (which might be transformed into malloc
calls). In short, take extra care that the compared-to pointer is really
simultaneously live with the memory allocation.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223347 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-04 09:22:28 +00:00
Hal Finkel
7e32aa1015 Simplify pointer comparisons involving memory allocation functions
System memory allocation functions, which are identified at the IR level by the
noalias attribute on the return value, must return a pointer into a memory region
disjoint from any other memory accessible to the caller. We can use this
property to simplify pointer comparisons between allocated memory and local
stack addresses and the addresses of global variables. Neither the stack nor
global variables can overlap with the region used by the memory allocator.

Fixes PR21556.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223093 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-01 23:38:06 +00:00
Philip Reames
204e21b51a [Statepoints 1/4] Statepoint infrastructure for garbage collection: IR Intrinsics
The statepoint intrinsics are intended to enable precise root tracking through the compiler as to support garbage collectors of all types. The addition of the statepoint intrinsics to LLVM should have no impact on the compilation of any program which does not contain them. There are no side tables created, no extra metadata, and no inhibited optimizations.

A statepoint works by transforming a call site (or safepoint poll site) into an explicit relocation operation. It is the frontend's responsibility (or eventually the safepoint insertion pass we've developed, but that's not part of this patch series) to ensure that any live pointer to a GC object is correctly added to the statepoint and explicitly relocated. The relocated value is just a normal SSA value (as seen by the optimizer), so merges of relocated and unrelocated values are just normal phis. The explicit relocation operation, the fact the statepoint is assumed to clobber all memory, and the optimizers standard semantics ensure that the relocations flow through IR optimizations correctly.

This is the first patch in a small series.  This patch contains only the IR parts; the documentation and backend support will be following separately.  The entire series can be seen as one combined whole in http://reviews.llvm.org/D5683.

Reviewed by: atrick, ributzka





git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223078 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-01 21:18:12 +00:00
Rafael Espindola
6c8ce66b03 Relax an assert a bit to avoid a crash on unreachable code.
Patch by Duncan Exon Smith with a small tweak by me.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222984 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-01 02:55:24 +00:00
Duncan P. N. Exon Smith
54786a0936 Revert "Masked Vector Load and Store Intrinsics."
This reverts commit r222632 (and follow-up r222636), which caused a host
of LNT failures on an internal bot.  I'll respond to the commit on the
list with a reproduction of one of the failures.

Conflicts:
	lib/Target/X86/X86TargetTransformInfo.cpp

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222936 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-28 21:29:14 +00:00
David Majnemer
f45536e75e InstSimplify: Restore optimizations lost in r210006
This restores our ability to optimize:
(X & C) ? X & ~C : X  into  X & ~C
(X & C) ? X : X & ~C  into  X
(X & C) ? X | C : X  into  X
(X & C) ? X : X | C  into  X | C

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222868 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-27 06:32:46 +00:00
Hans Wennborg
4d48c3f1aa LazyValueInfo: Actually re-visit partially solved block-values in solveBlockValue()
If solveBlockValue() needs results from predecessors that are not already
computed, it returns false with the intention of resuming when the dependencies
have been resolved. However, the computation would never be resumed since an
'overdefined' result had been placed in the cache, preventing any further
computation.

The point of placing the 'overdefined' result in the cache seems to have been
to break cycles, but we can check for that when inserting work items in the
BlockValue stack instead. This makes the "stop and resume" mechanism of
solveBlockValue() work as intended, unlocking more analysis.

Using this patch shaves 120 KB off a 64-bit Chromium build on Linux.

I benchmarked compiling bzip2.c at -O2 but couldn't measure any difference in
compile time.

Tests by Jiangning Liu from r215343 / PR21238, Pete Cooper, and me.

Differential Revision: http://reviews.llvm.org/D6397

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222768 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-25 17:23:05 +00:00
Chandler Carruth
a87c35420b Revert r220349 to re-instate r220277 with a fix for PR21330 -- quite
clearly only exactly equal width ptrtoint and inttoptr casts are no-op
casts, it says so right there in the langref. Make the code agree.

Original log from r220277:
Teach the load analysis to allow finding available values which require
inttoptr or ptrtoint cast provided there is datalayout available.
Eventually, the datalayout can just be required but in practice it will
always be there today.

To go with the ability to expose available values requiring a ptrtoint
or inttoptr cast, helpers are added to perform one of these three casts.

These smarts are necessary to finish canonicalizing loads and stores to
the operational type requirements without regressing fundamental
combines.

I've added some test cases. These should actually improve as the load
combining and store combining improves, but they may fundamentally be
highlighting some missing combines for select in addition to exercising
the specific added logic to load analysis.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222739 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-25 08:20:27 +00:00
David Majnemer
044b644f54 InstSimplify: Handle some simple tautological comparisons
This handles cases where we are comparing a masked value against itself.
The analysis could be further improved by making it recursive but such
expense is not currently justified.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222716 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-25 02:55:48 +00:00
Philip Reames
521c9dc7d8 Factor check for the assume intrinsic out of checks in computeKnownBitsFromAssume
We were matching against the assume intrinsic in every check.  Since we know that it must be an assume, this is just wasted work.  Somewhat surprisingly, matching an intrinsic id is actually relatively expensive.  It devolves to a string construction and comparison in Function::isIntrinsic.

I originally spotted this because it showed up in a performance profile of my compiler.  I've since discovered a separate issue which seems to be the actual root cause, but this is minor perf goodness regardless.  

I'm likely to follow up with another change to factor out the comparison matching.  There's no need to match the compare instruction in every single one of the tests.

Differential Revision: http://reviews.llvm.org/D6312



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222709 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-24 23:44:28 +00:00
Rafael Espindola
7fe9d46f39 Remove the unused FindUsedTypes pass.
It was dead since r134829.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222684 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-24 20:53:26 +00:00
Rafael Espindola
468d2fc5ca Add and use Type::subtypes. NFC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222682 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-24 20:44:36 +00:00
Elena Demikhovsky
ae1ae2c3a1 Masked Vector Load and Store Intrinsics.
Introduced new target-independent intrinsics in order to support masked vector loads and stores. The loop vectorizer optimizes loops containing conditional memory accesses by generating these intrinsics for existing targets AVX2 and AVX-512. The vectorizer asks the target about availability of masked vector loads and stores.
Added SDNodes for masked operations and lowering patterns for X86 code generator.
Examples:
<16 x i32> @llvm.masked.load.v16i32(i8* %addr, <16 x i32> %passthru, i32 4 /* align */, <16 x i1> %mask)
declare void @llvm.masked.store.v8f64(i8* %addr, <8 x double> %value, i32 4, <8 x i1> %mask)

Scalarizer for other targets (not AVX2/AVX-512) will be done in a separate patch.

http://reviews.llvm.org/D6191



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222632 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-23 08:07:43 +00:00
David Majnemer
7eca618dfc InstSimplify: Simplify (sub 0, X) -> X if it's NUW
This is a generalization of the X - (0 - Y) -> X transform.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222611 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-22 07:15:16 +00:00
Hans Wennborg
b4401e33d5 LazyValueInfo: range'ify some for-loops. No functional change.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222557 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-21 19:07:46 +00:00
Hans Wennborg
36c3fc5ddc LazyValueInfo: fix some typos and indentation, etc. NFC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222554 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-21 18:58:23 +00:00
David Majnemer
a44c501561 AliasSet: Simplify mergeSetIn
No functional change intended.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222376 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-19 19:36:18 +00:00
David Majnemer
f47d325eec AliasSetTracker: UnknownInsts should contribute to the refcount
AliasSetTracker::addUnknown may create an AliasSet devoid of pointers
just to contain an instruction if no suitable AliasSet already exists.
It will then AliasSet::addUnknownInst and we will be done.

However, it's possible for addUnknown to choose an existing AliasSet to
addUnknownInst.
If this were to occur, we are in a bit of a pickle: removing pointers
from the AliasSet can cause the entire AliasSet to become destroyed,
taking our unknown instructions out with them.

Instead, keep track whether or not our AliasSet has any unknown
instructions.

This fixes PR21582.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222338 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-19 09:41:05 +00:00
David Blaikie
5401ba7099 Update SetVector to rely on the underlying set's insert to return a pair<iterator, bool>
This is to be consistent with StringSet and ultimately with the standard
library's associative container insert function.

This lead to updating SmallSet::insert to return pair<iterator, bool>,
and then to update SmallPtrSet::insert to return pair<iterator, bool>,
and then to update all the existing users of those functions...

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222334 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-19 07:49:26 +00:00
David Majnemer
2014c91510 ScalarEvolution: Construct SCEVDivision's Derived type instead of itself
SCEVDivision::divide constructed an object of SCEVDivision<Derived>
instead of Derived.  divide would call visit which would cast the
SCEVDivision<Derived> to type Derived.  As it happens,
SCEVDivision<Derived> and Derived currently have the same layout but
this is fragile and grounds for UB.

Instead, just construct Derived.  No functional change intended.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222126 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-17 11:27:45 +00:00
David Majnemer
2aad1e3567 ScalarEvolution: Introduce SCEVSDivision and SCEVUDivision
It turns out that not all users of SCEVDivision want the same
signedness.  Let the users determine which operation they'd like by
explicitly choosing SCEVUDivision or SCEVSDivision.

findArrayDimensions and computeAccessFunctions will use SCEVSDivision
while HowFarToZero will use SCEVUDivision.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222104 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-16 20:35:19 +00:00
Jingyue Wu
ec3cfb00dc [DependenceAnalysis] Allow subscripts of different types
Summary:
Several places in DependenceAnalysis assumes both SCEVs in a subscript pair
share the same integer type. For instance, isKnownPredicate calls
SE->getMinusSCEV(X, Y) which asserts X and Y share the same type. However,
DependenceAnalysis fails to ensure this assumption when producing a subscript
pair, causing tests such as NonCanonicalizedSubscript to crash. With this
patch, DependenceAnalysis runs unifySubscriptType before producing any
subscript pair, ensuring the assumption.

Test Plan:
Added NonCanonicalizedSubscript.ll on which DependenceAnalysis before the fix
crashed because subscripts have different types.

Reviewers: spop, sebpop, jingyue

Reviewed By: jingyue

Subscribers: eliben, meheff, llvm-commits

Differential Revision: http://reviews.llvm.org/D6289

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222100 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-16 16:52:44 +00:00
David Majnemer
62baa594d7 ScalarEvolution: HowFarToZero was wrongly using signed division
HowFarToZero was supposed to use unsigned division in order to calculate
the backedge taken count.  However, SCEVDivision::divide performs signed
division.  Unless I am mistaken, no users of SCEVDivision actually want
signed arithmetic: switch to udiv and urem.

This fixes PR21578.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222093 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-16 07:30:35 +00:00
David Majnemer
f5dc5ae36b InstSimplify: Optimize ICmpInst xform that uses computeKnownBits
A few things:
- computeKnownBits is relatively expensive, let's delay its use as long
  as we can.
- Don't create two APInt values just to run computeKnownBits on a
  ConstantInt, we already know the exact value!
- Avoid creating a temporary APInt value in order to calculate unary
  negation.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222092 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-16 02:20:08 +00:00
Reid Kleckner
bfabc8f8c5 Revert "Don't make assumptions about the name of private global variables."
This reverts commit r222061.

It's causing linker errors.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222077 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-15 02:03:53 +00:00
Rafael Espindola
e2eb8b632d 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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222061 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-14 23:17:47 +00:00
David Blaikie
7ffaebf9da Remove redundant virtual on overriden functions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222023 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-14 19:06:36 +00:00
Hal Finkel
db1e51359d Revert r219432 - "Revert "[BasicAA] Revert "Revert r218714 - Make better use of zext and sign information."""
Let's try this again...

This reverts r219432, plus a bug fix.

Description of the bug in r219432 (by Nick):

The bug was using AllPositive to break out of the loop; if the loop break
condition i != e is changed to i != e && AllPositive then the
test_modulo_analysis_with_global test I've added will fail as the Modulo will
be calculated incorrectly (as the last loop iteration is skipped, so Modulo
isn't updated with its Scale).

Nick also adds this comment:

ComputeSignBit is safe to use in loops as it takes into account phi nodes, and
the  == EK_ZeroEx check is safe in loops as, no matter how the variable changes
between iterations, zero-extensions will always guarantee a zero sign bit. The
isValueEqualInPotentialCycles check is therefore definitely not needed as all
the variable analysis holds no matter how the variables change between loop
iterations.

And this patch also adds another enhancement to GetLinearExpression - basically
to convert ConstantInts to Offsets (see test_const_eval and
test_const_eval_scaled for the situations this improves).

Original commit message:

This reverts r218944, which reverted r218714, plus a bug fix.

Description of the bug in r218714 (by Nick):

The original patch forgot to check if the Scale in VariableGEPIndex flipped the
sign of the variable. The BasicAA pass iterates over the instructions in the
order they appear in the function, and so BasicAliasAnalysis::aliasGEP is
called with the variable it first comes across as parameter GEP1. Adding a
%reorder label puts the definition of %a after %b so aliasGEP is called with %b
as the first parameter and %a as the second. aliasGEP later calculates that %a
== %b + 1 - %idxprom where %idxprom >= 0 (if %a was passed as the first
parameter it would calculate %b == %a - 1 + %idxprom where %idxprom >= 0) -
ignoring that %idxprom is scaled by -1 here lead the patch to incorrectly
conclude that %a > %b.

Revised patch by Nick White, thanks! Thanks to Lang to isolating the bug.
Slightly modified by me to add an early exit from the loop and avoid
unnecessary, but expensive, function calls.

Original commit message:

Two related things:

 1. Fixes a bug when calculating the offset in GetLinearExpression. The code
    previously used zext to extend the offset, so negative offsets were converted
    to large positive ones.

 2. Enhance aliasGEP to deduce that, if the difference between two GEP
    allocations is positive and all the variables that govern the offset are also
    positive (i.e. the offset is strictly after the higher base pointer), then
    locations that fit in the gap between the two base pointers are NoAlias.

Patch by Nick White!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221876 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-13 09:16:54 +00:00