Commit Graph

821 Commits

Author SHA1 Message Date
Mehdi Amini
529919ff31 DataLayout is mandatory, update the API to reflect it with references.
Summary:
Now that the DataLayout is a mandatory part of the module, let's start
cleaning the codebase. This patch is a first attempt at doing that.

This patch is not exactly NFC as for instance some places were passing
a nullptr instead of the DataLayout, possibly just because there was a
default value on the DataLayout argument to many functions in the API.
Even though it is not purely NFC, there is no change in the
validation.

I turned as many pointer to DataLayout to references, this helped
figuring out all the places where a nullptr could come up.

I had initially a local version of this patch broken into over 30
independant, commits but some later commit were cleaning the API and
touching part of the code modified in the previous commits, so it
seemed cleaner without the intermediate state.

Test Plan:

Reviewers: echristo

Subscribers: llvm-commits

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

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231740 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-10 02:37:25 +00:00
Sanjoy Das
cd5029d001 [SCEV] Unify getUnsignedRange and getSignedRange
Summary:
This removes some duplicated code, and also helps optimization: e.g. in
the test case added, `%idx ULT 128` in `@x` is not currently optimized
to `true` by `-indvars` but will be, after this change.

The only functional change in ths commit is that for add recurrences,
ScalarEvolution::getRange will be more aggressive -- computing the
unsigned (resp. signed) range for a SCEVAddRecExpr will now look at the
NSW (resp. NUW) bits and check for signed (resp. unsigned) overflow.
This can be a strict improvement in some cases (such as the attached
test case), and should be no worse in other cases.

Reviewers: atrick, nlewycky

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D8142

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231709 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-09 21:43:43 +00:00
Sanjoy Das
afeb9bf44e [SCEV] Add a `scalar-evolution-print-constant-ranges' option
Summary:
Unused in this commit, but will be used in a subsequent change (D8142)
by a FileCheck test.

Reviewers: atrick

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D8143

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231708 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-09 21:43:39 +00:00
David Blaikie
da4471d726 Simplify expressions involving boolean constants with clang-tidy
Patch by Richard (legalize at xmission dot com).

Differential Revision: http://reviews.llvm.org/D8154

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231617 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-09 01:57:13 +00:00
NAKAMURA Takumi
d12ce78ca9 ScalarEvolution.cpp: Appease g++-4.7. He missed implicit "this" in lambda.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231331 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-05 01:02:45 +00:00
Sanjoy Das
12aa70b7e9 [SCEV] make SCEV smarter about proving no-wrap.
Summary:
Teach SCEV to prove no overflow for an add recurrence by proving
something about the range of another add recurrence a loop-invariant
distance away from it.

Reviewers: atrick, hfinkel

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D7980

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231305 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-04 22:24:17 +00:00
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
Sanjoy Das
de87c9165a Teach ScalarEvolution to sharpen range information.
If x is known to have the range [a, b), in a loop predicated by (icmp
ne x, a) its range can be sharpened to [a + 1, b).  Get
ScalarEvolution and hence IndVars to exploit this fact.

This change triggers an optimization to widen-loop-comp.ll, so it had
to be edited to get it to pass.

This change was originally landed in r219834 but had a bug and broke
ASan. It was reverted in r219878, and is now being re-landed after
fixing the original bug.

phabricator: http://reviews.llvm.org/D5639
reviewed by: atrick



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221839 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-13 00:00:58 +00:00
Duncan P. N. Exon Smith
5bf8ade9d0 Revert "IR: MDNode => Value"
Instead, we're going to separate metadata from the Value hierarchy.  See
PR21532.

This reverts commit r221375.
This reverts commit r221373.
This reverts commit r221359.
This reverts commit r221167.
This reverts commit r221027.
This reverts commit r221024.
This reverts commit r221023.
This reverts commit r220995.
This reverts commit r220994.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221711 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-11 21:30:22 +00:00
Duncan P. N. Exon Smith
3a84a6377c IR: MDNode => Value: Instruction::getMetadata()
Change `Instruction::getMetadata()` to return `Value` as part of
PR21433.

Update most callers to use `Instruction::getMDNode()`, which wraps the
result in a `cast_or_null<MDNode>`.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221024 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-01 00:10:31 +00:00
Bradley Smith
8cff277de2 [SCEV] Improve Scalar Evolution's use of no {un,}signed wrap flags
In a case where we have a no {un,}signed wrap flag on the increment, if
RHS - Start is constant then we can avoid inserting a max operation bewteen
the two, since we can statically determine which is greater.

This allows us to unroll loops such as:

 void testcase3(int v) {
   for (int i=v; i<=v+1; ++i)
     f(i);
 }


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220960 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-31 11:40:32 +00:00
Sanjoy Das
a0b0184b33 Revert "r219834 - Teach ScalarEvolution to sharpen range information"
This change breaks the asan buildbots:
http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux/builds/13468



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219878 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-15 23:46:04 +00:00
Sanjoy Das
40edbf130e Teach ScalarEvolution to sharpen range information.
If x is known to have the range [a, b) in a loop predicated by (icmp
ne x, a), its range can be sharpened to [a + 1, b).  Get
ScalarEvolution and hence IndVars to exploit this fact.
    
This change triggers an optimization to widen-loop-comp.ll, so it had
to be edited to get it to pass.

phabricator: http://reviews.llvm.org/D5639



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219834 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-15 19:25:28 +00:00
Chandler Carruth
c13c09106e [SCEV] Add some asserts to the recently improved trip count computation
routines and fix all of the bugs they expose.

I hit a test case that crashed even without these asserts due to passing
a non-exiting latch to the ExitingBlock parameter of the trip count
computation machinery. However, when I add the nice asserts, it turns
out we have plenty of coverage of these bugs, they just didn't manifest
in crashers.

The core problem seems to stem from an assumption that the latch *is*
the exiting block. While this is often true, and somewhat the "normal"
way to think about loops, it isn't necessarily true. The correct way to
call the trip count routines in a *generic* fashion (that is, without
a particular exit in mind) is to just use the loop's single exiting
block if it has one. The trip count can't be computed generically unless
it does. This works great for the loop vectorizer. The loop unroller
actually *wants* to select the latch when it has to chose between
multiple exits because for unrolling it is the latch trips that matter.
But if this is the desire, it needs to explicitly guard for non-exiting
latches and check for the generic trip count in that case.

I've added the asserts, and added convenience APIs for querying the trip
count generically that check for a single exit block. I've kept the APIs
consistent between computing trip count and trip multiples.

Thansk to Mark for the help debugging and tracking down the *right* fix
here!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219550 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-11 00:12:11 +00:00
Sanjoy Das
65f2077c62 This patch teaches ScalarEvolution to pick and use !range metadata.
It also makes it more aggressive in querying range information by
adding a call to isKnownPredicateWithRanges to
isLoopBackedgeGuardedByCond and isLoopEntryGuardedByCond.

phabricator: http://reviews.llvm.org/D5638

Reviewed by: atrick, hfinkel



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219532 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-10 21:22:34 +00:00
Mark Heffernan
ed05e3703e This patch de-pessimizes the calculation of loop trip counts in
ScalarEvolution in the presence of multiple exits. Previously all
loops exits had to have identical counts for a loop trip count to be
considered computable. This pessimization was implemented by calling
getBackedgeTakenCount(L) rather than getExitCount(L, ExitingBlock)
inside of ScalarEvolution::getSmallConstantTripCount() (see the FIXME
in the comments of that function). The pessimization was added to fix
a corner case involving undefined behavior (pr/16130). This patch more
precisely handles the undefined behavior case allowing the pessimization
to be removed.

ControlsExit replaces IsSubExpr to more precisely track the case where
undefined behavior is expected to occur. Because undefined behavior is
tracked more precisely we can remove MustExit from ExitLimit. MustExit
was used to track the case where the limit was computed potentially
assuming undefined behavior even if undefined behavior didn't necessarily
occur.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219517 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-10 17:39:11 +00:00
Hal Finkel
5f36b46bf0 Make use @llvm.assume for loop guards in ScalarEvolution
This adds a basic (but important) use of @llvm.assume calls in ScalarEvolution.
When SE is attempting to validate a condition guarding a loop (such as whether
or not the loop count can be zero), this check should also include dominating
assumptions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217348 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-07 21:37:59 +00:00
Hal Finkel
851b04c920 Make use of @llvm.assume in ValueTracking (computeKnownBits, etc.)
This change, which allows @llvm.assume to be used from within computeKnownBits
(and other associated functions in ValueTracking), adds some (optional)
parameters to computeKnownBits and friends. These functions now (optionally)
take a "context" instruction pointer, an AssumptionTracker pointer, and also a
DomTree pointer, and most of the changes are just to pass this new information
when it is easily available from InstSimplify, InstCombine, etc.

As explained below, the significant conceptual change is that known properties
of a value might depend on the control-flow location of the use (because we
care that the @llvm.assume dominates the use because assumptions have
control-flow dependencies). This means that, when we ask if bits are known in a
value, we might get different answers for different uses.

The significant changes are all in ValueTracking. Two main changes: First, as
with the rest of the code, new parameters need to be passed around. To make
this easier, I grouped them into a structure, and I made internal static
versions of the relevant functions that take this structure as a parameter. The
new code does as you might expect, it looks for @llvm.assume calls that make
use of the value we're trying to learn something about (often indirectly),
attempts to pattern match that expression, and uses the result if successful.
By making use of the AssumptionTracker, the process of finding @llvm.assume
calls is not expensive.

Part of the structure being passed around inside ValueTracking is a set of
already-considered @llvm.assume calls. This is to prevent a query using, for
example, the assume(a == b), to recurse on itself. The context and DT params
are used to find applicable assumptions. An assumption needs to dominate the
context instruction, or come after it deterministically. In this latter case we
only handle the specific case where both the assumption and the context
instruction are in the same block, and we need to exclude assumptions from
being used to simplify their own ephemeral values (those which contribute only
to the assumption) because otherwise the assumption would prove its feeding
comparison trivial and would be removed.

This commit adds the plumbing and the logic for a simple masked-bit propagation
(just enough to write a regression test). Future commits add more patterns
(and, correspondingly, more regression tests).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217342 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-07 18:57:58 +00:00
Nick Lewycky
7ba4e0705e Remove an errant outer loop that contains nothing but an inner loop over exactly the same elements. While no functionality is change intended (and hence there are no changes to tests), you don't want to skip this revision if bisecting for errors.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216864 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-01 05:17:15 +00:00
Duncan P. N. Exon Smith
facdfc6781 Revert "[C++11] Add predecessors(BasicBlock *) / successors(BasicBlock *) iterator ranges."
This reverts commit r213474 (and r213475), which causes a miscompile on
a stage2 LTO build.  I'll reply on the list in a moment.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213562 91177308-0d34-0410-b5e6-96231b3b80d8
2014-07-21 17:06:51 +00:00
Manuel Jacob
a4697dad19 [C++11] Add predecessors(BasicBlock *) / successors(BasicBlock *) iterator ranges.
Summary: This patch introduces two new iterator ranges and updates existing code to use it.  No functional change intended.

Test Plan: All tests (make check-all) still pass.

Reviewers: dblaikie

Reviewed By: dblaikie

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D4481

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213474 91177308-0d34-0410-b5e6-96231b3b80d8
2014-07-20 09:10:11 +00:00
Tobias Grosser
5e66eea5ba ScalarEvolution: Derive element size from the type of the loaded element
Before, we where looking at the size of the pointer type that specifies the
location from which to load the element. This did not make any sense at all.

This change fixes a bug in the delinearization where we failed to delinerize
certain load instructions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210435 91177308-0d34-0410-b5e6-96231b3b80d8
2014-06-08 19:21:20 +00:00
Sebastian Pop
20b6ed3c9c implement missing SCEVDivision case
without this case we would end on an infinite recursion: the remainder is zero,
so Numerator - Remainder is equal to Numerator and so we would recursively ask
for the division of Numerator by Denominator.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209838 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-29 19:44:09 +00:00
Sebastian Pop
e741924230 fail to find dimensions when ElementSize is nullptr
when ScalarEvolution::getElementSize returns nullptr it is safe to early return
in ScalarEvolution::findArrayDimensions such that we avoid later problems when
we try to divide the terms by ElementSize.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209837 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-29 19:44:05 +00:00
Sebastian Pop
5013d1d5e4 avoid type mismatch when building SCEVs
This is a corner case I have stumbled upon when dealing with ARM64 type
conversions. I was not able to extract a testcase for the community codebase to
fail on. The patch conservatively discards a division that would have ended up
in an ICE due to a type mismatch when building a multiply expression. I have
also added code to a place that builds add expressions and in which we should be
careful not to pass in operands of different types.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209694 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-27 22:42:00 +00:00