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592 Commits

Author SHA1 Message Date
Sanjay Patel
ace9860241 propagate IR-level fast-math-flags to DAG nodes, disabled by default
This is an updated version of the patch that was checked in at:
http://reviews.llvm.org/rL237046

but subsequently reverted because it exposed a bug in the DAG Combiner:
http://reviews.llvm.org/D9893

This time, there's an enablement flag ("EnableFMFInDAG") around the code in
SelectionDAGBuilder where we copy the set of FP optimization flags from IR
instructions to DAG nodes. So, in theory, there should be no functional change
from this patch as-is, but it will allow testing with the added functionality
to proceed via "-enable-fmf-dag" passed to llc.

This patch adds the minimum plumbing necessary to use IR-level
fast-math-flags (FMF) in the backend without actually using
them for anything yet. This is a follow-on to:
http://reviews.llvm.org/rL235997

Differential Revision: http://reviews.llvm.org/D10403

llvm-svn: 239828
2015-06-16 16:25:43 +00:00
Nick Lewycky
fe62b3c55b Revert r237046. See the testcase on the thread where r237046 was committed.
llvm-svn: 237317
2015-05-13 23:41:47 +00:00
Sergey Dmitrouk
5e3a4d1a49 [DebugInfo] Debug locations for constant SD nodes
Several updates for [DebugInfo] Add debug locations to constant SD nodes (r235989).
Includes:

 *  re-enabling the change (disabled recently);
 *  missing change for FP constants;
 *  resetting debug location of constant node if it's used more than at one place
    to prevent emission of wrong locations in case of coalesced constants;
 *  a couple of additional tests.

Now all look ups in CSEMap are wrapped by additional method.

Comment in D9084 suggests that debug locations aren't useful for "target constants",
so there might be one more change related to this API (namely, dropping debug
locations for getTarget*Constant methods).

Differential Revision: http://reviews.llvm.org/D9604

llvm-svn: 237237
2015-05-13 08:58:03 +00:00
Sanjay Patel
29eae3af52 fix typos, grammar; NFC
llvm-svn: 237139
2015-05-12 14:52:42 +00:00
Sanjay Patel
87722498a9 propagate IR-level fast-math-flags to DAG nodes; 2nd try; NFC
This is a less ambitious version of:
http://reviews.llvm.org/rL236546

because that was reverted in:
http://reviews.llvm.org/rL236600

because it caused memory corruption that wasn't related to FMF
but was actually due to making nodes with 2 operands derive from a
plain SDNode rather than a BinarySDNode. 

This patch adds the minimum plumbing necessary to use IR-level
fast-math-flags (FMF) in the backend without actually using
them for anything yet. This is a follow-on to:
http://reviews.llvm.org/rL235997

...which split the existing nsw / nuw / exact flags and FMF
into their own struct.
 

llvm-svn: 237046
2015-05-11 21:07:09 +00:00
Sergey Dmitrouk
6e4ac5dd5c Disable r235989 "Reapply r235977 "[DebugInfo] Add debug locations to constant SD nodes""
Will be re-enabled with missing changes for ConstantFPSDNode and
fixes for wrong locations due to constant coalescing.

llvm-svn: 236758
2015-05-07 18:33:50 +00:00
NAKAMURA Takumi
3fdcf7a5c9 Reformat.
llvm-svn: 236601
2015-05-06 14:03:22 +00:00
NAKAMURA Takumi
2655f48b30 Revert r236546, "propagate IR-level fast-math-flags to DAG nodes (NFC)"
It caused undefined behavior.

llvm-svn: 236600
2015-05-06 14:03:12 +00:00
Sanjay Patel
b7125c62c7 propagate IR-level fast-math-flags to DAG nodes (NFC)
This patch adds the minimum plumbing necessary to use IR-level
fast-math-flags (FMF) in the backend without actually using
them for anything yet. This is a follow-on to:
http://reviews.llvm.org/rL235997

...which split the existing nsw / nuw / exact flags and FMF
into their own struct.

There are 2 structural changes here:

1. The main diff is that we're preparing to extend the optimization
flags to affect more than just binary SDNodes. Eg, IR intrinsics 
( https://llvm.org/bugs/show_bug.cgi?id=21290 ) or non-binop nodes
that don't even exist in IR such as FMA, FNEG, etc.

2. The other change is that we're actually copying the FP fast-math-flags
from the IR instructions to SDNodes. 

Differential Revision: http://reviews.llvm.org/D8900

llvm-svn: 236546
2015-05-05 21:40:38 +00:00
Elena Demikhovsky
4068c4fa64 fixed comments, blanks, nullptr; NFC
llvm-svn: 236086
2015-04-29 06:49:50 +00:00
Sanjay Patel
877a22a3bc move IR-level optimization flags into their own struct
This is a preliminary step to using the IR-level floating-point fast-math-flags in the SDAG (D8900).

In this patch, we introduce the optimization flags as their own struct. As noted in the TODO comment, 
we should eventually share this data between the IR passes and the backend.

We also switch the existing nsw / nuw / exact bit functionality of the BinaryWithFlagsSDNode class to
use the new struct.

The tradeoff is that instead of using the free but limited space of SDNode's SubclassData, we add a
data member to the subclass. This means we don't have to repeat all of the get/set methods per flag,
but we're potentially adding size to all nodes of this subclassi type.

In practice on 64-bit systems (measured on Linux and MacOS X), there is no size difference between an
SDNode and BinaryWithFlagsSDNode after this change: they're both 80 bytes. This means that we had at
least one free byte to play with due to struct alignment.

Differential Revision: http://reviews.llvm.org/D9325

llvm-svn: 235997
2015-04-28 16:39:12 +00:00
Sergey Dmitrouk
7bfbc12128 Reapply r235977 "[DebugInfo] Add debug locations to constant SD nodes"
[DebugInfo] Add debug locations to constant SD nodes

This adds debug location to constant nodes of Selection DAG and updates
all places that create constants to pass debug locations
(see PR13269).

Can't guarantee that all locations are correct, but in a lot of cases choice
is obvious, so most of them should be. At least all tests pass.

Tests for these changes do not cover everything, instead just check it for
SDNodes, ARM and AArch64 where it's easy to get incorrect locations on
constants.

This is not complete fix as FastISel contains workaround for wrong debug
locations, which drops locations from instructions on processing constants,
but there isn't currently a way to use debug locations from constants there
as llvm::Constant doesn't cache it (yet). Although this is a bit different
issue, not directly related to these changes.

Differential Revision: http://reviews.llvm.org/D9084

llvm-svn: 235989
2015-04-28 14:05:47 +00:00
Daniel Jasper
39180626db Revert "[DebugInfo] Add debug locations to constant SD nodes"
This breaks a test:
http://bb.pgr.jp/builders/cmake-llvm-x86_64-linux/builds/23870

llvm-svn: 235987
2015-04-28 13:38:35 +00:00
Sergey Dmitrouk
01a4dcd3bb [DebugInfo] Add debug locations to constant SD nodes
This adds debug location to constant nodes of Selection DAG and updates
all places that create constants to pass debug locations
(see PR13269).

Can't guarantee that all locations are correct, but in a lot of cases choice
is obvious, so most of them should be. At least all tests pass.

Tests for these changes do not cover everything, instead just check it for
SDNodes, ARM and AArch64 where it's easy to get incorrect locations on
constants.

This is not complete fix as FastISel contains workaround for wrong debug
locations, which drops locations from instructions on processing constants,
but there isn't currently a way to use debug locations from constants there
as llvm::Constant doesn't cache it (yet). Although this is a bit different
issue, not directly related to these changes.

Differential Revision: http://reviews.llvm.org/D9084

llvm-svn: 235977
2015-04-28 11:56:37 +00:00
Elena Demikhovsky
901c20e649 Masked gather and scatter: Added code for SelectionDAG.
All other patches, including tests will follow.

http://reviews.llvm.org/D7665

llvm-svn: 235970
2015-04-28 07:57:37 +00:00
Sanjay Patel
25d45a2b18 move helper function closer to use; NFC
llvm-svn: 234344
2015-04-07 19:13:06 +00:00
Simon Pilgrim
2751d2eb79 [DAGCombiner] Add support for TRUNCATE + FP_EXTEND vector constant folding
This patch adds supports for the vector constant folding of TRUNCATE and FP_EXTEND instructions and tidies up the SINT_TO_FP and UINT_TO_FP instructions to match.

It also moves the vector constant folding for the FNEG and FABS instructions to use the DAG.getNode() functionality like the other unary instructions.

Differential Revision: http://reviews.llvm.org/D8593

llvm-svn: 233224
2015-03-25 22:30:31 +00:00
Simon Pilgrim
60d1ada777 [DAGCombiner] Add a shuffle mask commutation helper function. NFCI.
We have an increasing number of cases where we are creating commuted shuffle masks - all implementing nearly the same code.

This patch adds a static helper function - ShuffleVectorSDNode::commuteMask() and replaces a number of cases to use it.

Differential Revision: http://reviews.llvm.org/D8139

llvm-svn: 231581
2015-03-07 22:33:11 +00:00
Sanjay Patel
f4078ff3ae don't repeat class / function / variable names in comments; NFC
llvm-svn: 231292
2015-03-04 21:49:03 +00:00
David Blaikie
384cb4ac84 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.

llvm-svn: 231138
2015-03-03 21:26:17 +00:00
David Blaikie
5fd9cda286 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.

llvm-svn: 231136
2015-03-03 21:18:16 +00:00
David Blaikie
f9b228449d 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.

llvm-svn: 231135
2015-03-03 21:17:08 +00:00
Aaron Ballman
0b45511a2e Removing LLVM_DELETED_FUNCTION, as MSVC 2012 was the last reason for requiring the macro. NFC; LLVM edition.
llvm-svn: 229340
2015-02-15 22:54:22 +00:00
Aaron Ballman
0e19b5d670 Removing LLVM_EXPLICIT, as MSVC 2012 was the last reason for requiring the macro. NFC; LLVM edition.
llvm-svn: 229335
2015-02-15 22:00:20 +00:00
Benjamin Kramer
a3a195bd27 Move DebugLocs around instead of copying.
llvm-svn: 228491
2015-02-07 12:28:15 +00:00
Elena Demikhovsky
4c1384e72f Fixed a bug in type legalizer for masked load/store intrinsics.
The problem occurs when after vectorization we have type
<2 x i32>. This type is promoted to <2 x i64> and then requires
additional efforts for expanding loads and truncating stores.
I added EXPAND / TRUNCATE attributes to the masked load/store
SDNodes. The code now contains additional shuffles.
I've prepared changes in the cost estimation for masked memory
operations, it will be submitted separately.

llvm-svn: 226808
2015-01-22 12:07:59 +00:00
Chandler Carruth
0b619fcc8e [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.

llvm-svn: 225974
2015-01-14 11:23:27 +00:00
Matt Arsenault
e5c13ba97b Add isNegative helper to ConstantFPSDNode
llvm-svn: 225309
2015-01-06 23:00:44 +00:00
Matt Arsenault
63f73f4f48 Add isInfinity helper to ConstantFPSDNode
llvm-svn: 225308
2015-01-06 23:00:43 +00:00
Michael Ilseman
dd56e9aa72 Silence more static analyzer warnings.
Add in definedness checks for shift operators, null checks when
pointers are assumed by the code to be non-null, and explicit
unreachables.

llvm-svn: 224255
2014-12-15 18:48:43 +00:00
Duncan P. N. Exon Smith
3d57886267 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.)

llvm-svn: 223802
2014-12-09 18:38:53 +00:00
Elena Demikhovsky
befed29343 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

llvm-svn: 223348
2014-12-04 09:40:44 +00:00
Duncan P. N. Exon Smith
73ce6dbb2b 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

llvm-svn: 222936
2014-11-28 21:29:14 +00:00
Elena Demikhovsky
36a2243ab7 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

llvm-svn: 222632
2014-11-23 08:07:43 +00:00
David Majnemer
f307a398f9 SelectionDAG: Assert if we truncate SDNode's NumOperands or NumValues
No functionality change intended, this just stops us early if we created
a bad SDNode.

llvm-svn: 221560
2014-11-07 22:39:11 +00:00
Craig Topper
65775cc03d Repace SmallPtrSet with SmallPtrSetImpl in function arguments to avoid needing to mention the size.
llvm-svn: 216158
2014-08-21 05:55:13 +00:00
Craig Topper
aa7422b5a6 Revert "Repace SmallPtrSet with SmallPtrSetImpl in function arguments to avoid needing to mention the size."
Getting a weird buildbot failure that I need to investigate.

llvm-svn: 215870
2014-08-18 00:24:38 +00:00
Craig Topper
227456e133 Repace SmallPtrSet with SmallPtrSetImpl in function arguments to avoid needing to mention the size.
llvm-svn: 215868
2014-08-17 23:47:00 +00:00
Hal Finkel
ac8c24afbf Fix classof for ISD::INTRINSIC_W_CHAIN and INTRINSIC_VOID
Unfortunately, our use of the SDNode class hierarchy for INTRINSIC_W_CHAIN and
INTRINSIC_VOID nodes is somewhat broken right now. These nodes sometimes are
used for memory intrinsics (those with MachineMemOperands), and sometimes not.
When not, the nodes are not created as instances of MemIntrinsicSDNode, but
rather created as some other subclass of SDNode using DAG::getNode. When they
are memory intrinsics, they are created using DAG::getMemIntrinsicNode as
instances of MemIntrinsicSDNode. MemIntrinsicSDNode is a subclass of
MemSDNode, but prior to r214452, we had a non-self-consistent setup whereby
MemIntrinsicSDNode::classof on INTRINSIC_W_CHAIN and INTRINSIC_VOID would
return true but MemSDNode::classof on INTRINSIC_W_CHAIN and INTRINSIC_VOID
would return false. In r214452, MemSDNode::classof was changed to return true
for INTRINSIC_W_CHAIN and INTRINSIC_VOID, which is now self-consistent. The
problem is that neither the pre-r214452 logic and the post-r214452 logic are
really right. The truth is that not all INTRINSIC_W_CHAIN and INTRINSIC_VOID
nodes are instances of MemIntrinsicSDNode (or MemSDNode for that matter), and
the return value from classof needs to reflect that. This was broken before
r214452 (because MemIntrinsicSDNode::classof always returned true), and was
broken afterward (because MemSDNode::classof also always returned true), and
will now be correct.

The minimal solution is to grab one of the SubclassData bits (there is one left
for MemIntrinsicSDNode nodes) and use it to store whether or not a particular
INTRINSIC_W_CHAIN or INTRINSIC_VOID is really an instance of
MemIntrinsicSDNode or not. Doing this allows both MemIntrinsicSDNode::classof
and MemSDNode::classof to return the correct answer for the underlying object
for both the memory-intrinsic and non-memory-intrinsic cases.

This fixes the problem that r214452 created in the SelectionDAGDumper (thanks
to Matt Arsenault for pointing it out).

Because PowerPC does not implement getTgtMemIntrinsic, this change breaks
test/CodeGen/PowerPC/unal-altivec-wint.ll. I've XFAILed it for now, and will
fix it in a follow-up commit.

llvm-svn: 215511
2014-08-13 01:15:37 +00:00
Hal Finkel
4ac8a41b35 Make classof in MemSDNode consistent with MemIntrinsicSDNode
If INTRINSIC_W_CHAIN and INTRINSIC_VOID are MemIntrinsicSDNodes, and a
MemIntrinsicSDNode is a MemSDNode, then INTRINSIC_W_CHAIN and INTRINSIC_VOID
must be MemSDNodes too.

Noticed by inspection.

llvm-svn: 214452
2014-07-31 22:31:33 +00:00
Chandler Carruth
ad37c4b412 [SDAG] Enable the new assert for out-of-range result numbers in
SDValues, fixing the two bugs left in the regression suite.

The key for both of these was the use a single value type rather than
a VTList which caused an unintentionally single-result merge-value node.
Fix this by getting the appropriate VTList in place.

Doing this exposed that the comments in x86's code abouth how MUL_LOHI
operands are handle is wrong. The bug with the use of out-of-range
result numbers was hiding the bug about the order of operands here (as
best i can tell). There are more places where the code appears to get
this backwards still...

llvm-svn: 213931
2014-07-25 09:19:23 +00:00
Chandler Carruth
033ee8b5b3 [SDAG] Start plumbing an assert into SDValues that we don't form one
with a result number outside the range of results for the node.

I don't know how we managed to not really check this very basic
invariant for so long, but the code is *very* broken at this point.
I have over 270 test failures with the assert enabled. I'm committing it
disabled so that others can join in the cleanup effort and reproduce the
issues. I've also included one of the obvious fixes that I already
found. More fixes to come.

llvm-svn: 213926
2014-07-25 07:23:23 +00:00
Hal Finkel
9be4aefa57 AA metadata refactoring (introduce AAMDNodes)
In order to enable the preservation of noalias function parameter information
after inlining, and the representation of block-level __restrict__ pointer
information (etc.), additional kinds of aliasing metadata will be introduced.
This metadata needs to be carried around in AliasAnalysis::Location objects
(and MMOs at the SDAG level), and so we need to generalize the current scheme
(which is hard-coded to just one TBAA MDNode*).

This commit introduces only the necessary refactoring to allow for the
introduction of other aliasing metadata types, but does not actually introduce
any (that will come in a follow-up commit). What it does introduce is a new
AAMDNodes structure to hold all of the aliasing metadata nodes associated with
a particular memory-accessing instruction, and uses that structure instead of
the raw MDNode* in AliasAnalysis::Location, etc.

No functionality change intended.

llvm-svn: 213859
2014-07-24 12:16:19 +00:00
Chandler Carruth
14de70ee01 [SDAG] At the suggestion of Hal, switch to an output parameter that
tracks which elements of the build vector are in fact undef.

This should make actually inpsecting them (likely in my next patch)
reasonably pretty. Also makes the output parameter optional as it is
clear now that *most* users are happy with undefs in their splats.

llvm-svn: 212581
2014-07-09 00:41:34 +00:00
Chandler Carruth
0764373bcc [SDAG] Build up a more rich set of APIs for querying build-vector SDAG
nodes about whether they are splats. This is factored out and improved
from r212324 which got reverted as it was far too aggressive. The new
API should help more conservatively handle buildvectors that are
a mixture of splatted and undef values.

No functionality change at this point. The hope is to slowly
re-introduce the undef-tolerant optimization of splats, but each time
being forced to make a concious decision about how to handle the undefs
in a way that doesn't lead to contradicting assumptions about the
collapsed value.

Hal has pointed out in discussions that this may not end up being the
desired API and instead it may be more convenient to get a mask of the
undef elements or something similar. I'm starting simple and will expand
the API as I adapt actual callers and see exactly what they need.

llvm-svn: 212514
2014-07-08 07:19:55 +00:00
Chandler Carruth
9fd1035842 [x86] Revert r212324 which was too aggressive w.r.t. allowing undef
lanes in vector splats.

The core problem here is that undef lanes can't *unilaterally* be
considered to contribute to splats. Their handling needs to be more
cautious. There is also a reported failure of the nightly testers
(thanks Tobias!) that may well stem from the same core issue. I'm going
to fix this theoretical issue, factor the APIs a bit better, and then
verify that I don't see anything bad with Tobias's reduction from the
test suite before recommitting.

Original commit message for r212324:
  [x86] Generalize BuildVectorSDNode::getConstantSplatValue to work for
  any constant, constant FP, or undef splat and to tolerate any undef
  lanes in a splat, then replace all uses of isSplatVector in X86's
  lowering with it.

  This fixes issues where undef lanes in an otherwise splat vector would
  prevent the splat logic from firing. It is a touch more awkward to use
  this interface, but it is much more accurate. Suggestions for better
  interface structuring welcome.

  With this fix, the code generated with the widening legalization
  strategy for widen_cast-4.ll is *dramatically* improved as the special
  lowering strategies for a v16i8 SRA kick in even though the high lanes
  are undef.

  We also get a slightly different choice for broadcasting an aligned
  memory location, and use vpshufd instead of vbroadcastss. This looks
  like a minor win for pipelining and domain crossing, but a minor loss
  for the number of micro-ops. I suspect its a wash, but folks can
  easily tweak the lowering if they want.

llvm-svn: 212475
2014-07-07 19:03:32 +00:00
Chandler Carruth
ab7167839a [x86] Generalize BuildVectorSDNode::getConstantSplatValue to work for
any constant, constant FP, or undef splat and to tolerate any undef
lanes in a splat, then replace all uses of isSplatVector in X86's
lowering with it.

This fixes issues where undef lanes in an otherwise splat vector would
prevent the splat logic from firing. It is a touch more awkward to use
this interface, but it is much more accurate. Suggestions for better
interface structuring welcome.

With this fix, the code generated with the widening legalization
strategy for widen_cast-4.ll is *dramatically* improved as the special
lowering strategies for a v16i8 SRA kick in even though the high lanes
are undef.

We also get a slightly different choice for broadcasting an aligned
memory location, and use vpshufd instead of vbroadcastss. This looks
like a minor win for pipelining and domain crossing, but a minor loss
for the number of micro-ops. I suspect its a wash, but folks can easily
tweak the lowering if they want.

llvm-svn: 212324
2014-07-04 08:11:49 +00:00
Chandler Carruth
8b1d54a22e Add an explicit bool operator to SDValue to make it easier to test for
a non-null node. In particular, this makes it easier to use condition
variables with SDValues, etc.

llvm-svn: 212323
2014-07-04 08:11:38 +00:00
Craig Topper
4c15d35f50 Add ops() method to SDNode that returns an ArrayRef<SDUse>. Use it to simplify some code.
llvm-svn: 211993
2014-06-29 00:40:57 +00:00
Tim Northover
b9ec29d7c5 IR: add "cmpxchg weak" variant to support permitted failure.
This commit adds a weak variant of the cmpxchg operation, as described
in C++11. A cmpxchg instruction with this modifier is permitted to
fail to store, even if the comparison indicated it should.

As a result, cmpxchg instructions must return a flag indicating
success in addition to their original iN value loaded. Thus, for
uniformity *all* cmpxchg instructions now return "{ iN, i1 }". The
second flag is 1 when the store succeeded.

At the DAG level, a new ATOMIC_CMP_SWAP_WITH_SUCCESS node has been
added as the natural representation for the new cmpxchg instructions.
It is a strong cmpxchg.

By default this gets Expanded to the existing ATOMIC_CMP_SWAP during
Legalization, so existing backends should see no change in behaviour.
If they wish to deal with the enhanced node instead, they can call
setOperationAction on it. Beware: as a node with 2 results, it cannot
be selected from TableGen.

Currently, no use is made of the extra information provided in this
patch. Test updates are almost entirely adapting the input IR to the
new scheme.

Summary for out of tree users:
------------------------------

+ Legacy Bitcode files are upgraded during read.
+ Legacy assembly IR files will be invalid.
+ Front-ends must adapt to different type for "cmpxchg".
+ Backends should be unaffected by default.

llvm-svn: 210903
2014-06-13 14:24:07 +00:00