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Commit Graph

540 Commits

Author SHA1 Message Date
Simon Pilgrim
26beaec6ae [DAGCombiner] Added SMAX/SMIN/UMAX/UMIN constant folding
We still need to add constant folding of vector comparisons to fold the tests for targets that don't support the respective min/max nodes

I needed to update 2011-12-06-AVXVectorExtractCombine to load a vector instead of using a constant vector to prevent it folding

Differential Revision: http://reviews.llvm.org/D12118

llvm-svn: 245503
2015-08-19 21:11:58 +00:00
James Molloy
cf490f8ffc Add new ISD nodes: ISD::FMINNAN and ISD::FMAXNAN
The intention of these is to be a corollary to ISD::FMINNUM/FMAXNUM,
differing only on how NaNs are treated. FMINNUM returns the non-NaN
input (when given one NaN and one non-NaN), FMINNAN returns the NaN
input instead.

This patch includes support for scalarizing, widening and splitting
vectors, but not expansion or softening. The reason is that these
should never be needed - FMINNAN nodes are only going to be created
in one place (SDAGBuilder::visitSelect) and there we'll check if the
node is legal or custom. I could preemptively add expand and soften
code, but I'm fairly opposed to adding code I can't test. It's bad
enough I can't create tests with this patch, but at least this code
will be exercised by the ARM and AArch64 backends fairly shortly.

llvm-svn: 244581
2015-08-11 09:13:05 +00:00
Pete Cooper
0736385f5e Add allnodes() iterator range to SelectionDAG. NFC.
SelectionDAG already had begin/end methods for iterating over all
the nodes, but didn't define an iterator_range for us in foreach
loops.

This adds such a method and uses it in some of the eligible places
throughout the backends.

llvm-svn: 242212
2015-07-14 22:10:54 +00:00
Mehdi Amini
22ecba9a15 Redirect DataLayout from TargetMachine to Module in SelectionDAG
Summary:
SelectionDAG itself is not invoking directly the DataLayout in the
TargetMachine, but the "TargetLowering" class is still using it. I'll
address it in a following commit.

This change is part of a series of commits dedicated to have a single
DataLayout during compilation by using always the one owned by the
module.

Reviewers: echristo

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D11000

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 241618
2015-07-07 19:07:19 +00:00
Rafael Espindola
49ad24ce06 Avoid a Symbol -> Name -> Symbol conversion.
Before this we were producing a TargetExternalSymbol from a MCSymbol.
That meant extracting the symbol name and fetching the symbol again
down the pipeline.

This patch adds a DAG.getMCSymbol that lets the MCSymbol pass unchanged on the
DAG.

Doing so removes the need for MO_NOPREFIX and fixes the root cause of pr23900,
allowing r240130 to be committed again.

llvm-svn: 240300
2015-06-22 17:46:53 +00:00
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
Chandler Carruth
6f372f0515 [sdag] Add the helper I most want to the DAG -- building a bitcast
around a value using its existing SDLoc.

Start using this in just one function to save omg lines of code.

llvm-svn: 238638
2015-05-30 04:14:10 +00:00
Duncan P. N. Exon Smith
d24ab51c79 SDAG: Give SDDbgValues their own allocator (and reset it)
Previously `SDDbgValue`s used the general allocator that lives for all
of `SelectionDAG`.  Instead, give them their own allocator, and reset it
whenever `SDDbgInfo::clear()` is called, plugging a spiritual leak.

This drops `SelectionDAGBuilder::visitIntrinsicCall()` off of my heap
profile (was at around 2% of `llc` for codegen of `-flto -g`).  Thanks
to Pete Cooper for spotting the problem and suggesting the fix.

llvm-svn: 237998
2015-05-22 05:45:19 +00:00
Matthias Braun
ed527f2f9e SelectionDAG: Cleanup and simplify FoldConstantArithmetic
This cleans up the FoldConstantArithmetic code by factoring out the case
of two ConstantSDNodes into an own function. This avoids unnecessary
complexity for many callers who already have ConstantSDNode arguments.

This also avoids an intermeidate SmallVector datastructure and a loop
over that datastructure.

llvm-svn: 237651
2015-05-19 01:40:21 +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
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
Sanjay Patel
0b97042089 group getNode() variants by purpose and add comments; NFC
llvm-svn: 237013
2015-05-11 19:34:10 +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
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
Krzysztof Parzyszek
3efcf81e03 Allow memory intrinsics to be tail calls
llvm-svn: 234764
2015-04-13 17:16:45 +00:00
Sanjay Patel
c92141d527 remove function/variable names from comments; NFC
llvm-svn: 234107
2015-04-04 21:06:39 +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
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
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
Frederic Riss
b2c059475b Totally forget deallocated SDNodes in SDDbgInfo.
What would happen before that commit is that the SDDbgValues associated with
a deallocated SDNode would be marked Invalidated, but SDDbgInfo would keep
a map entry keyed by the SDNode pointer pointing to this list of invalidated
SDDbgNodes. As the memory gets reused, the list might get wrongly associated
with another new SDNode. As the SDDbgValues are cloned when they are transfered,
this can lead to an exponential number of SDDbgValues being produced during
DAGCombine like in http://llvm.org/bugs/show_bug.cgi?id=20893

Note that the previous behavior wasn't really buggy as the invalidation made
sure that the SDDbgValues won't be used. This commit can be considered a
memory optimization and as such is really hard to validate in a unit-test.

llvm-svn: 221709
2014-11-11 21:21:08 +00:00
Matt Arsenault
2257f6b589 Add minnum / maxnum codegen
llvm-svn: 220342
2014-10-21 23:01:01 +00:00
Eric Christopher
8acda9a737 Have the selection dag grab TargetLowering off of the subtarget
inside init rather than have it passed in as an argument.

llvm-svn: 219270
2014-10-08 01:57:58 +00:00
Adrian Prantl
2b1df58ebe Move the complex address expression out of DIVariable and into an extra
argument of the llvm.dbg.declare/llvm.dbg.value intrinsics.

Previously, DIVariable was a variable-length field that has an optional
reference to a Metadata array consisting of a variable number of
complex address expressions. In the case of OpPiece expressions this is
wasting a lot of storage in IR, because when an aggregate type is, e.g.,
SROA'd into all of its n individual members, the IR will contain n copies
of the DIVariable, all alike, only differing in the complex address
reference at the end.

By making the complex address into an extra argument of the
dbg.value/dbg.declare intrinsics, all of the pieces can reference the
same variable and the complex address expressions can be uniqued across
the CU, too.
Down the road, this will allow us to move other flags, such as
"indirection" out of the DIVariable, too.

The new intrinsics look like this:
declare void @llvm.dbg.declare(metadata %storage, metadata %var, metadata %expr)
declare void @llvm.dbg.value(metadata %storage, i64 %offset, metadata %var, metadata %expr)

This patch adds a new LLVM-local tag to DIExpressions, so we can detect
and pretty-print DIExpression metadata nodes.

What this patch doesn't do:

This patch does not touch the "Indirect" field in DIVariable; but moving
that into the expression would be a natural next step.

http://reviews.llvm.org/D4919
rdar://problem/17994491

Thanks to dblaikie and dexonsmith for reviewing this patch!

Note: I accidentally committed a bogus older version of this patch previously.
llvm-svn: 218787
2014-10-01 18:55:02 +00:00
Adrian Prantl
0959156fa3 Revert r218778 while investigating buldbot breakage.
"Move the complex address expression out of DIVariable and into an extra"

llvm-svn: 218782
2014-10-01 18:10:54 +00:00
Adrian Prantl
229943585f Move the complex address expression out of DIVariable and into an extra
argument of the llvm.dbg.declare/llvm.dbg.value intrinsics.

Previously, DIVariable was a variable-length field that has an optional
reference to a Metadata array consisting of a variable number of
complex address expressions. In the case of OpPiece expressions this is
wasting a lot of storage in IR, because when an aggregate type is, e.g.,
SROA'd into all of its n individual members, the IR will contain n copies
of the DIVariable, all alike, only differing in the complex address
reference at the end.

By making the complex address into an extra argument of the
dbg.value/dbg.declare intrinsics, all of the pieces can reference the
same variable and the complex address expressions can be uniqued across
the CU, too.
Down the road, this will allow us to move other flags, such as
"indirection" out of the DIVariable, too.

The new intrinsics look like this:
declare void @llvm.dbg.declare(metadata %storage, metadata %var, metadata %expr)
declare void @llvm.dbg.value(metadata %storage, i64 %offset, metadata %var, metadata %expr)

This patch adds a new LLVM-local tag to DIExpressions, so we can detect
and pretty-print DIExpression metadata nodes.

What this patch doesn't do:

This patch does not touch the "Indirect" field in DIVariable; but moving
that into the expression would be a natural next step.

http://reviews.llvm.org/D4919
rdar://problem/17994491

Thanks to dblaikie and dexonsmith for reviewing this patch!

llvm-svn: 218778
2014-10-01 17:55:39 +00:00
Robin Morisset
e583310c3b Fix typos in comments, NFC
Summary: Just fixing comments, no functional change.

Test Plan: N/A

Reviewers: jfb

Subscribers: mcrosier, llvm-commits

Differential Revision: http://reviews.llvm.org/D5130

llvm-svn: 216784
2014-08-29 21:53:01 +00:00
Alexey Samsonov
e029f253b7 Fix null reference creation in SelectionDAG constructor.
Store TargetSelectionDAGInfo as a pointer instead of a reference:
getSelectionDAGInfo() may not be implemented for certain backends
(e.g. it's not currently implemented for R600).

This bug is reported by UBSan.

llvm-svn: 216129
2014-08-20 21:40:15 +00:00
Hal Finkel
97fb1d4d91 [PowerPC] Implement PPCTargetLowering::getTgtMemIntrinsic
This implements PPCTargetLowering::getTgtMemIntrinsic for Altivec load/store
intrinsics. As with the construction of the MachineMemOperands for the
intrinsic calls used for unaligned load/store lowering, the only slight
complication is that we need to represent a larger memory range than the
loaded/stored value-type size (because the address is rounded down to an
aligned address, and we need to conservatively represent the entire possible
range of the actual access). This required adding an extra size field to
TargetLowering::IntrinsicInfo, and this was done in a way that required no
modifications to other targets (the size defaults to the store size of the
provided memory data type).

This fixes test/CodeGen/PowerPC/unal-altivec-wint.ll (so it can be un-XFAILed).

llvm-svn: 215512
2014-08-13 01:15:40 +00:00
Eric Christopher
67c04e77e5 Have MachineFunction cache a pointer to the subtarget to make lookups
shorter/easier and have the DAG use that to do the same lookup. This
can be used in the future for TargetMachine based caching lookups from
the MachineFunction easily.

Update the MIPS subtarget switching machinery to update this pointer
at the same time it runs.

llvm-svn: 214838
2014-08-05 02:39:49 +00:00
Louis Gerbarg
8048e52537 Make sure no loads resulting from load->switch DAGCombine are marked invariant
Currently when DAGCombine converts loads feeding a switch into a switch of
addresses feeding a load the new load inherits the isInvariant flag of the left
side. This is incorrect since invariant loads can be reordered in cases where it
is illegal to reoarder normal loads.

This patch adds an isInvariant parameter to getExtLoad() and updates all call
sites to pass in the data if they have it or false if they don't. It also
changes the DAGCombine to use that data to make the right decision when
creating the new load.

llvm-svn: 214449
2014-07-31 21:45:05 +00:00
Chandler Carruth
581bf74660 [SDAG] When performing post-legalize DAG combining, run the legalizer
over each node in the worklist prior to combining.

This allows the combiner to produce new nodes which need to go back
through legalization. This is particularly useful when generating
operands to target specific nodes in a post-legalize DAG combine where
the operands are significantly easier to express as pre-legalized
operations. My immediate use case will be PSHUFB formation where we need
to build a constant shuffle mask with a build_vector node.

This also refactors the relevant functionality in the legalizer to
support this, and updates relevant tests. I've spoken to the R600 folks
and these changes look like improvements to them. The avx512 change
needs to be investigated, I suspect there is a disagreement between the
legalizer and the DAG combiner there, but it seems a minor issue so
leaving it to be re-evaluated after this patch.

Differential Revision: http://reviews.llvm.org/D4564

llvm-svn: 214020
2014-07-26 05:49:40 +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
e861e0b7f6 [SDAG] Refactor the code for inserting a newly allocated SDNode into the
DAG into a helper function.

This adds a trip through the (very minimal) verification logic in
a bunch of places that were missing it, but shouldn't have any other
impact outside of refactoring. I'm hoping to use this to do more clever
things when DAG nodes are inserted into the graph.

llvm-svn: 213612
2014-07-22 04:07:55 +00:00
Andrea Di Biagio
9236ded3b5 [DAG] Refactor some logic. No functional change.
This patch removes function 'CommuteVectorShuffle' from X86ISelLowering.cpp
and moves its logic into SelectionDAG.cpp as method 'getCommutedVectorShuffles'.
This refactoring is in preperation of an upcoming change to the DAGCombiner.

llvm-svn: 213503
2014-07-21 07:28:51 +00:00
Chandler Carruth
b55565f54f [x86,SDAG] Introduce any- and sign-extend-vector-inreg nodes analogous
to the zero-extend-vector-inreg node introduced previously for the same
purpose: manage the type legalization of widened extend operations,
especially to support the experimental widening mode for x86.

I'm adding both because sign-extend is expanded in terms of any-extend
with shifts to propagate the sign bit. This removes the last
fundamental scalarization from vec_cast2.ll (a test case that hit many
really bad edge cases for widening legalization), although the trunc
tests in that file still appear scalarized because the the shuffle
legalization is scalarizing. Funny thing, I've been working on that.

Some initial experiments with this and SSE2 scenarios is showing
moderately good behavior already for sign extension. Still some work to
do on the shuffle combining on X86 before we're generating optimal
sequences, but avoiding scalarization is a huge step forward.

llvm-svn: 212714
2014-07-10 12:32:32 +00:00
Daniel Sanders
a59d10a761 Make it possible for ints/floats to return different values from getBooleanContents()
Summary:
On MIPS32r6/MIPS64r6, floating point comparisons return 0 or -1 but integer
comparisons return 0 or 1.

Updated the various uses of getBooleanContents. Two simplifications had to be
disabled when float and int boolean contents differ:
- ScalarizeVecRes_VSELECT except when the kind of boolean contents is trivially
  discoverable (i.e. when the condition of the VSELECT is a SETCC node).
- visitVSELECT (select C, 0, 1) -> (xor C, 1).
  Come to think of it, this one could test for the common case of 'C'
  being a SETCC too.

Preserved existing behaviour for all other targets and updated the affected
MIPS32r6/MIPS64r6 tests. This also fixes the pi benchmark where the 'low'
variable was counting in the wrong direction because it thought it could simply
add the result of the comparison.

Reviewers: hfinkel

Reviewed By: hfinkel

Subscribers: hfinkel, jholewinski, mcrosier, llvm-commits

Differential Revision: http://reviews.llvm.org/D4389

llvm-svn: 212697
2014-07-10 10:18:12 +00:00
Chandler Carruth
eb00ef26a3 [x86] Add a ZERO_EXTEND_VECTOR_INREG DAG node and use it when widening
vector types to be legal and a ZERO_EXTEND node is encountered.

When we use widening to legalize vector types, extend nodes are a real
challenge. Either the input or output is likely to be legal, but in many
cases not both. As a consequence, we don't really have any way to
represent this situation and the prior code in the widening legalization
framework would just scalarize the extend operation completely.

This patch introduces a new DAG node to represent doing a zero extend of
a vector "in register". The core of the idea is to allow legal but
different vector types in the input and output. The output vector must
have fewer lanes but wider elements. The operation is defined to zero
extend the low elements of the input to the size of the output elements,
and drop all of the high elements which don't have a corresponding lane
in the output vector.

It also includes generic expansion of this node in terms of blending
a zero vector into the high elements of the vector and bitcasting
across. This in turn yields extremely nice code for x86 SSE2 when we use
the new widening legalization logic in conjunction with the new shuffle
lowering logic.

There is still more to do here. We need to support sign extension, any
extension, and potentially int-to-float conversions. My current plan is
to continue using similar synthetic nodes to model each of these
transitions with generic lowering code for each one.

However, with this patch LLVM already reaches performance parity with
GCC for the core C loops of the x264 code (assuming you disable the
hand-written assembly versions) when compiling for SSE2 and SSE3
architectures and enabling the new widening and lowering logic for
vectors.

Differential Revision: http://reviews.llvm.org/D4405

llvm-svn: 212610
2014-07-09 10:58:18 +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
Andrea Di Biagio
a2490b5eaa [DAG] Expose NoSignedWrap, NoUnsignedWrap and Exact flags to SelectionDAG.
This patch modifies SelectionDAGBuilder to construct SDNodes with associated
NoSignedWrap, NoUnsignedWrap and Exact flags coming from IR BinaryOperator
instructions.

Added a new SDNode type called 'BinaryWithFlagsSDNode' to allow accessing
nsw/nuw/exact flags during codegen.

Patch by Marcello Maggioni.

llvm-svn: 210467
2014-06-09 12:32:53 +00:00
Adam Nemet
807861a7b6 [SelectionDAG] Force cycle detection in AssignTopologicalOrder before aborting
DAG cycle detection is only enabled with ENABLE_EXPENSIVE_CHECKS.  However we
can run it just before we would crash in order to provide more informative
diagnostics.

Now in addition to the "Overran sorted position" message we also get the Node
printed if a cycle was detected.

Tested by building several configs: Debug+Assert, Debug+Assert+Check (this is
ENABLE_EXPENSIVE_CHECKS), Release+Assert and Release.  Also tried that the
AssignTopologicalOrder assert produces the expected results.

llvm-svn: 209977
2014-05-31 16:23:20 +00:00
Adam Nemet
267d4048ff [SelectionDAG] Pass DAG to checkForCycles
Pass the DAG down to checkForCycles from all callers where we have it.  This
allows target-specific nodes to be printed properly.

Also print some missing newlines.

llvm-svn: 209976
2014-05-31 16:23:17 +00:00
Adam Nemet
154449972f [SelectionDAG] Remove duplicate declaration
Prefer the decl in SelectionDAGNodes.h because it's used there and
SelectionDAG.h includes SelectionDAGNodes.h.

llvm-svn: 209975
2014-05-31 16:23:13 +00:00
Chandler Carruth
b94f570d99 Add a trivial ArrayRef helper overload to the SelectionDAG interface.
I'm using this pretty frequently in a patch I'm working on and it seems
generally useful.

llvm-svn: 209872
2014-05-30 03:50:06 +00:00