Commit Graph

1384 Commits

Author SHA1 Message Date
Matthias Braun a283cb3265 DAGCombiner: Fix crash in select(select) opt.
In case of different types used for the condition of the selects the
select(select) -> select(and) normalisation cannot be performed.

See also: http://reviews.llvm.org/D7622

llvm-svn: 234763
2015-04-13 17:16:33 +00:00
Benjamin Kramer 619c4e57ba Reduce dyn_cast<> to isa<> or cast<> where possible.
No functional change intended.

llvm-svn: 234586
2015-04-10 11:24:51 +00:00
Ahmed Bougacha df43737782 [CodeGen] Combine concat_vector of trunc'd scalar to scalar_to_vector.
We already do:
  concat_vectors(scalar, undef) -> scalar_to_vector(scalar)
When the scalar is legal.
When it's not, but is a truncated legal scalar, we can also do:
  concat_vectors(trunc(scalar), undef) -> scalar_to_vector(scalar)
Which is equivalent, since the upper lanes are undef anyway.
While there, teach the combine to look at more than 2 operands.

Differential Revision: http://reviews.llvm.org/D8883

llvm-svn: 234530
2015-04-09 20:04:47 +00:00
Rafael Espindola 1c84271694 Revert "Refactoring and enhancement to FMA combine."
This reverts commit r234513. It was failing on the bots.

llvm-svn: 234518
2015-04-09 18:29:32 +00:00
Olivier Sallenave 53703d0862 Refactoring and enhancement to FMA combine.
llvm-svn: 234513
2015-04-09 17:55:26 +00:00
Akira Hatanaka c6fab80536 [DAGCombine] Fix a bug in MergeConsecutiveStores.
The bug manifests when there are two loads and two stores chained as follows in
a DAG,

(ld v3f32) -> (st f32) -> (ld v3f32) -> (st f32)

and the stores' values are extracted from the preceding vector loads.

MergeConsecutiveStores would replace the first store in the chain with the
merged vector store, which would create a cycle between the merged store node
and the last load node that appears in the chain.

This commits fixes the bug by replacing the last store in the chain instead.

rdar://problem/20275084

Differential Revision: http://reviews.llvm.org/D8849

llvm-svn: 234430
2015-04-08 20:34:53 +00:00
Simon Pilgrim 07e063e44c [DAGCombiner] Add support for FCEIL, FFLOOR and FTRUNC vector constant folding
Differential Revision: http://reviews.llvm.org/D8715

llvm-svn: 234179
2015-04-06 17:15:41 +00:00
Simon Pilgrim bcf3bc2757 [DAGCombiner] Merge FMUL Scalar and Vector constant canonicalization to RHS. NFCI.
llvm-svn: 234118
2015-04-05 14:30:37 +00:00
Simon Pilgrim 20b7aba04a [DAGCombiner] Canonicalize vector constants for ADD/MUL/AND/OR/XOR re-association
Scalar integers are commuted to move constants to the RHS for re-association - this ensures vectors do the same.

llvm-svn: 234092
2015-04-04 10:20:31 +00:00
Simon Pilgrim ed2ba33ba0 [DAGCombiner] Combine shuffles of BUILD_VECTOR and SCALAR_TO_VECTOR
This patch attempts to fold the shuffling of 'scalar source' inputs - BUILD_VECTOR and SCALAR_TO_VECTOR nodes - if the shuffle node is the only user. This folds away a lot of unnecessary shuffle nodes, and allows quite a bit of constant folding that was being missed.

Differential Revision: http://reviews.llvm.org/D8516

llvm-svn: 234004
2015-04-03 10:02:21 +00:00
Jiangning Liu b0f076910b Fix PR23065. Avoid optimizing bitcast of build_vector with constant input to scalar_to_vector.
llvm-svn: 233778
2015-04-01 01:52:38 +00:00
Sanjay Patel d399d94837 typos; NFC
llvm-svn: 233701
2015-03-31 16:17:51 +00:00
Simon Pilgrim dcbe1213c8 Use SDValue bool check to tidyup some possible vector folding ops. NFC.
llvm-svn: 233498
2015-03-29 19:13:40 +00:00
Simon Pilgrim d15c2805ab Use SDValue bool check to tidyup some possible ReassociateOps. NFC.
llvm-svn: 233495
2015-03-29 16:49:51 +00:00
Simon Pilgrim 7fdcc30e93 [DAGCombiner] Fixed incorrect test for buildvector of constant integers.
DAGCombiner::ReassociateOps was correctly testing for an constant integer scalar but failed to correctly test for constant integer vectors (it was testing for any constant vector).

llvm-svn: 233482
2015-03-28 18:31:31 +00:00
Sanjay Patel 5b305d2d66 revert inadvertent change
llvm-svn: 233294
2015-03-26 17:19:24 +00:00
Sanjay Patel 4fa4a886d7 comment cleanup; NFC
llvm-svn: 233293
2015-03-26 17:18:17 +00:00
Sanjay Patel d95dd9e5fb fix indent; NFC
llvm-svn: 233288
2015-03-26 16:55:17 +00:00
Simon Pilgrim 09f3ff9a0a [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
Paul Robinson 284f0451cf 'optnone' should not disable DAG combiner.
Reverts the code change from r221168 and the relevant test.
It was a mistake to disable the combiner, and based on the ultimate
definition of 'optnone' we shouldn't have considered the test case
as failing in the first place.

llvm-svn: 233153
2015-03-25 00:10:24 +00:00
Benjamin Kramer 51f6096cf8 Move private classes into anonymous namespaces
NFC.

llvm-svn: 232944
2015-03-23 12:30:58 +00:00
Owen Anderson db4201235b Fix a nasty bug in DAGCombine of STORE nodes.
This is very related to the bug fixed in r174431.  The problem is that
SelectionDAG does not include alignment in the uniquing of loads and
stores.  When an otherwise no-op DAGCombine would increase the alignment
of a load or store, the original node would be returned (with the
alignment increased), which would cause the node not to be processed by
any further DAGCombines.

I don't have a direct testcase for this that manifests on an in-tree
target, but I did see some noise in the tests for other targets and have
updated them for it.

llvm-svn: 232780
2015-03-19 22:48:57 +00:00
David Majnemer e48237df95 DAGCombiner: fold (xor (shl 1, x), -1) -> (rotl ~1, x)
Targets which provide a rotate make it possible to replace a sequence of
(XOR (SHL 1, x), -1) with (ROTL ~1, x).  This saves an instruction on
architectures like X86 and POWER(64).

Differential Revision: http://reviews.llvm.org/D8350

llvm-svn: 232572
2015-03-18 00:03:36 +00:00
Simon Pilgrim 257849f11a XformToShuffleWithZero - Added clearer early outs and general tidy up. NFCI
llvm-svn: 232557
2015-03-17 22:19:08 +00:00
Simon Pilgrim 8c58c066b7 [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
Simon Pilgrim 2dcbe74dfd Use SDValue bool check to tidyup some possible combines. NFC.
llvm-svn: 231569
2015-03-07 16:34:55 +00:00
Andrea Di Biagio c9d79e8103 [DAGCombiner] Fix wrong folding of AND dag nodes.
This patch fixes the logic in the DAGCombiner that folds an AND node according
to rule: (and (X (load V)), C) -> (X (load V))

An AND between a vector load 'X' and a constant build_vector 'C' can be folded
into the load itself only if we can prove that the AND operation is redundant.
The algorithm implemented by 'visitAND' firstly computes the splat value 'S'
from C, and then checks if S has the lower 'B' bits set (where B is the size in
bits of the vector element type). The algorithm takes into account also the
'undef' bits in the splat mask.

Unfortunately, the algorithm only worked under the assumption that the size of S
is a multiple of the vector element type. With this patch, we conservatively
avoid folding the AND if the splat bits are not compatible with the vector
element type.

Added X86 test and-load-fold.ll

Differential Revision: http://reviews.llvm.org/D8085

llvm-svn: 231563
2015-03-07 12:24:55 +00:00
Simon Pilgrim bede80a440 [DAGCombiner] SCALAR_TO_VECTOR(EXTRACT_VECTOR_ELT(V,C)) -> VECTOR_SHUFFLE
This patch attempts to convert a SCALAR_TO_VECTOR using an operand from an EXTRACT_VECTOR_ELT into a VECTOR_SHUFFLE.

This prevents many cases of spilling scalar data between the gpr + simd registers. 

At present the optimization only accepts cases where there is no TRUNC of the scalar type (i.e. all types must match).

Differential Revision: http://reviews.llvm.org/D8132

llvm-svn: 231554
2015-03-07 05:52:42 +00:00
Matthias Braun 898d11e864 DAGCombiner: Canonicalize select(and/or,x,y) depending on target.
This is based on the following equivalences:
select(C0 & C1, X, Y) <=> select(C0, select(C1, X, Y), Y)
select(C0 | C1, X, Y) <=> select(C0, X, select(C1, X, Y))

Many target cannot perform and/or on the CPU flags and therefore the
right side should be choosen to avoid materializign the i1 flags in an
integer register. If the target can perform this operation efficiently
we normalize to the left form.

Differential Revision: http://reviews.llvm.org/D7622

llvm-svn: 231507
2015-03-06 19:49:10 +00:00
Matthias Braun 3ecb557739 DAGCombiner: Factor out some and/or combines.
This is in preparation for changing visitSELECT to normalize towards
select(Cond0, select(Cond1, X, Y), Y);
select(Cond0, X, select(Cond1, X, Y)) which perfom an implicit and/or of
the conditions.

The factored function contains all DAGCombine rules which reduce two values
combined by an And/Or operation to a single value. This does not include rules
involving constants as visitSELECT already handles that case.

Differential Revision: http://reviews.llvm.org/D8026

llvm-svn: 231506
2015-03-06 19:49:06 +00:00
Simon Pilgrim 7189084bef [DagCombiner] Allow shuffles to merge through bitcasts
Currently shuffles may only be combined if they are of the same type, despite the fact that bitcasts are often introduced in between shuffle nodes (e.g. x86 shuffle type widening).

This patch allows a single input shuffle to peek through bitcasts and if the input is another shuffle will merge them, shuffling using the smallest sized type, and re-applying the bitcasts at the inputs and output instead.

Dropped old ShuffleToZext test - this patch removes the use of the zext and vector-zext.ll covers these anyhow.

Differential Revision: http://reviews.llvm.org/D7939

llvm-svn: 231380
2015-03-05 17:14:04 +00:00
Michael Kuperstein fb95697c88 [DAGCombine] Fix a bug in a BUILD_VECTOR combine
When trying to convert a BUILD_VECTOR into a shuffle, we try to split a single source vector that is twice as wide as the destination vector. 
We can not do this when we also need the zero vector to create a blend.
This fixes PR22774.

Differential Revision: http://reviews.llvm.org/D8040

llvm-svn: 231219
2015-03-04 07:27:39 +00:00
David Blaikie 49cfb81665 DAGCombiner::LoadedSlice: Remove explicit copy ctor in favor of the Rule of Zero
This way, the copy assignment operator can be used without hitting the
deprecated case in C++11.

llvm-svn: 231144
2015-03-03 21:50:47 +00:00
David Blaikie 7f1e0565b3 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 bb8da4c08f 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
Sanjay Patel b8c907e2a7 avoid infinite looping when folding vector multiplies of constants (PR22698)
We were missing a check for the following fold in DAGCombiner:

// fold (fmul (fmul x, c1), c2) -> (fmul x, (fmul c1, c2))

If 'x' is also a constant, then we shouldn't do anything. Otherwise, we could end up swapping the operands back and forth forever.

This should fix:
http://llvm.org/bugs/show_bug.cgi?id=22698

Differential Revision: http://reviews.llvm.org/D7917

llvm-svn: 230884
2015-03-01 00:09:35 +00:00
Benjamin Kramer 5fbfe2ffdc Convert push_back loops into append calls.
No functionality change intended.

llvm-svn: 230849
2015-02-28 13:20:15 +00:00
Paul Robinson 093d6e1a70 When the source has a series of assignments, users reasonably want to
have the debugger step through each one individually. Turn off the
combine for adjacent stores at -O0 so we get this behavior.

Possibly, DAGCombine shouldn't run at all at -O0, but that's for
another day; see PR22346.

Differential Revision: http://reviews.llvm.org/D7181

llvm-svn: 230659
2015-02-26 18:47:57 +00:00
Simon Pilgrim d8820ae70c Reapplied D7816 & rL230177 & rL230278 - with an additional fix toensure that the smallest build vector input scalar type is always used. Additional (crash) test cases already committed.
llvm-svn: 230388
2015-02-24 22:08:56 +00:00
Eric Christopher af48495130 Revert:
Author: Simon Pilgrim <llvm-dev@redking.me.uk>
Date:   Mon Feb 23 23:04:28 2015 +0000

    Fix based on post-commit comment on D7816 & rL230177 - BUILD_VECTOR operand truncation was using the the BV's output scalar type instead of the input type.

and

Author: Simon Pilgrim <llvm-dev@redking.me.uk>
Date:   Sun Feb 22 18:17:28 2015 +0000

    [DagCombiner] Generalized BuildVector Vector Concatenation

    The CONCAT_VECTORS combiner pass can transform the concat of two BUILD_VECTOR nodes into a single BUILD_VECTOR node.

    This patch generalises this to support any number of BUILD_VECTOR nodes, and also permits UNDEF nodes to be included as well.

    This was noticed as AVX vec128 -> vec256 canonicalization sometimes creates a CONCAT_VECTOR with a real vec128 lower and an vec128 UNDEF upper.

    Differential Revision: http://reviews.llvm.org/D7816

as the root cause of PR22678 which is causing an assertion inside the DAG combiner.

I'll follow up to the main thread as well.

llvm-svn: 230358
2015-02-24 19:11:00 +00:00
Matthias Braun 00a4076e94 DAGCombiner: Move variable definitions closer to use; NFC
llvm-svn: 230354
2015-02-24 18:52:01 +00:00
Matthias Braun a8558ca2ed DAGCombiner: Move variable declaration closer to definiion; NFC
llvm-svn: 230353
2015-02-24 18:51:59 +00:00
Simon Pilgrim 662c1d2770 Fix based on post-commit comment on D7816 & rL230177 - BUILD_VECTOR operand truncation was using the the BV's output scalar type instead of the input type.
llvm-svn: 230278
2015-02-23 23:04:28 +00:00
Simon Pilgrim 4e30d9b6d8 [DagCombiner] Generalized BuildVector Vector Concatenation
The CONCAT_VECTORS combiner pass can transform the concat of two BUILD_VECTOR nodes into a single BUILD_VECTOR node.

This patch generalises this to support any number of BUILD_VECTOR nodes, and also permits UNDEF nodes to be included as well.

This was noticed as AVX vec128 -> vec256 canonicalization sometimes creates a CONCAT_VECTOR with a real vec128 lower and an vec128 UNDEF upper.

Differential Revision: http://reviews.llvm.org/D7816

llvm-svn: 230177
2015-02-22 18:17:28 +00:00
Hal Finkel e2dd84e42f [DAGCombine] Don't assume integer-type legailty in reduceBuildVecConvertToConvertBuildVec
DAGCombine will rewrite an BUILD_VECTOR where all non-undef inputs some from
[US]INT_TO_FP, as a BUILD_VECTOR of integers with the conversion applied as a
vector operation. We check operation legality of the conversion, but fail to
check legality of the integer vector type itself. Because targets don't
normally override operation legality defaults for illegal types, we need to
check this also.

This came up in the context of the QPX vector entensions for PowerPC (which can
have legal floating-point vector types without corresponding legal integer
vector types). No in-tree test case for this yes, but one can be added once
the QPX support has been committed.

llvm-svn: 230176
2015-02-22 16:10:22 +00:00
Matt Arsenault 0dc54c4dee Add generic fmad DAG node.
This allows sharing of FMA forming combines to work
with instructions that have the same semantics as a separate
multiply and add.

This is expand by default, and only formed post legalization
so it shouldn't have much impact on targets that do not want it.

llvm-svn: 230070
2015-02-20 22:10:33 +00:00
Ahmed Bougacha 4c2b0781a5 [CodeGen] Use ArrayRef instead of std::vector&. NFC.
The former lets us use SmallVectors.  Do so in ARM and AArch64.

llvm-svn: 229925
2015-02-19 23:13:10 +00:00
Chandler Carruth b89464a9b6 [x86,sdag] Two interrelated changes to the x86 and sdag code.
First, don't combine bit masking into vector shuffles (even ones the
target can handle) once operation legalization has taken place. Custom
legalization of vector shuffles may exist for these patterns (making the
predicate return true) but that custom legalization may in some cases
produce the exact bit math this matches. We only really want to handle
this prior to operation legalization.

However, the x86 backend, in a fit of awesome, relied on this. What it
would do is mark VSELECTs as expand, which would turn them into
arithmetic, which this would then match back into vector shuffles, which
we would then lower properly. Amazing.

Instead, the second change is to teach the x86 backend to directly form
vector shuffles from VSELECT nodes with constant conditions, and to mark
all of the vector types we support lowering blends as shuffles as custom
VSELECT lowering. We still mark the forms which actually support
variable blends as *legal* so that the custom lowering is bypassed, and
the legal lowering can even be used by the vector shuffle legalization
(yes, i know, this is confusing. but that's how the patterns are
written).

This makes the VSELECT lowering much more sensible, and in fact should
fix a bunch of bugs with it. However, as you'll see in the test cases,
right now what it does is point out the *hilarious* deficiency of the
new vector shuffle lowering when it comes to blends. Fortunately, my
very next patch fixes that. I can't submit it yet, because that patch,
somewhat obviously, forms the exact and/or pattern that the DAG combine
is matching here! Without this patch, teaching the vector shuffle
lowering to produce the right code infloops in the DAG combiner. With
this patch alone, we produce terrible code but at least lower through
the right paths. With both patches, all the regressions here should be
fixed, and a bunch of the improvements (like using 2 shufps with no
memory loads instead of 2 andps with memory loads and an orps) will
stay. Win!

There is one other change worth noting here. We had hilariously wrong
vectorization cost estimates for vselect because we fell through to the
code path that assumed all "expand" vector operations are scalarized.
However, the "expand" lowering of VSELECT is vector bit math, most
definitely not scalarized. So now we go back to the correct if horribly
naive cost of "1" for "not scalarized". If anyone wants to add actual
modeling of shuffle costs, that would be cool, but this seems an
improvement on its own. Note the removal of 16 and 32 "costs" for doing
a blend. Even in SSE2 we can blend in fewer than 16 instructions. ;] Of
course, we don't right now because of OMG bad code, but I'm going to fix
that. Next patch. I promise.

llvm-svn: 229835
2015-02-19 10:36:19 +00:00
Sanjay Patel ab7e86e5be Canonicalize splats as build_vectors (PR22283)
This is a follow-on patch to:
http://reviews.llvm.org/D7093

That patch canonicalized constant splats as build_vectors, 
and this patch removes the constant check so we can canonicalize
all splats as build_vectors.

This fixes the 2nd test case in PR22283:
http://llvm.org/bugs/show_bug.cgi?id=22283

The unfortunate code duplication between SelectionDAG and DAGCombiner
is discussed in the earlier patch review. At least this patch is just
removing code...

This improves an existing x86 AVX test and changes codegen in an ARM test.

Differential Revision: http://reviews.llvm.org/D7389

llvm-svn: 229511
2015-02-17 16:54:32 +00:00
Benjamin Kramer 6cd780ff21 Prefer SmallVector::append/insert over push_back loops.
Same functionality, but hoists the vector growth out of the loop.

llvm-svn: 229500
2015-02-17 15:29:18 +00:00
Mehdi Amini 3e0023b8f6 SelectionDAG: fold (fp_to_u/sint (s/uint_to_fp)) here too
Update SPARC tests to match.

From: Fiona Glaser <fglaser@apple.com>
llvm-svn: 229438
2015-02-16 21:47:58 +00:00
Chandler Carruth 499d7332c5 [x86] Fix PR22377, a regression with the new vector shuffle legality
test.

This was just a matter of the DAG combine for vector shuffles being too
aggressive. This is a bit of a grey area, but I think generally if we
can re-use intermediate shuffles, we should. Certainly, given the test
cases I have available, this seems like the right call.

llvm-svn: 229285
2015-02-15 07:01:10 +00:00
Duncan P. N. Exon Smith 70eb9c5ae5 CodeGen: Canonicalize access to function attributes, NFC
Canonicalize access to function attributes to use the simpler API.

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

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

Also, add `Function::getFnStackAlignment()`, and canonicalize:

getAttributes().getStackAlignment(AttributeSet::FunctionIndex)
  => getFnStackAlignment()

llvm-svn: 229208
2015-02-14 01:44:41 +00:00
Benjamin Kramer 5f6a907288 MathExtras: Bring Count(Trailing|Leading)Ones and CountPopulation in line with countTrailingZeros
Update all callers.

llvm-svn: 228930
2015-02-12 15:35:40 +00:00
Ahmed Bougacha 24433a7005 [CodeGen] Don't blindly combine (fp_round (fp_round x)) to (fp_round x).
We used to do this DAG combine, but it's not always correct:
If the first fp_round isn't a value preserving truncation, it might
introduce a tie in the second fp_round, that wouldn't occur in the
single-step fp_round we want to fold to.
In other words, double rounding isn't the same as rounding.

Differential Revision: http://reviews.llvm.org/D7571

llvm-svn: 228911
2015-02-12 06:15:29 +00:00
Jonas Paulsson bf8d0cc699 Fix SelectionDAG compile time issue with alias analysis.
Add new token factor node and its users to worklist if alias analysis is
turned on, in DAGCombiner::visitTokenFactor(). Alias analysis may cause
a lot of new token factors to be inserted into the DAG, and they need to
be optimized to avoid significant slow-downs.

Reviewed by Hal Finkel.

llvm-svn: 228841
2015-02-11 16:10:31 +00:00
Jonas Paulsson a25a3f4fea Two comment typo fixes in lib/CodeGen/SelectionDAG/DAGCombiner.cpp.
llvm-svn: 228700
2015-02-10 15:34:29 +00:00
Chandler Carruth b65d61a2e8 [x86] Fix PR22524: the DAG combiner was incorrectly handling illegal
nodes when folding bitcasts of constants.

We can't fold things and then check after-the-fact whether it was legal.
Once we have formed the DAG node, arbitrary other nodes may have been
collapsed to it. There is no easy way to go back. Instead, we need to
test for the specific folding cases we're interested in and ensure those
are legal first.

This could in theory make this less powerful for bitcasting from an
integer to some vector type, but AFAICT, that can't actually happen in
the SDAG so its fine. Now, we *only* whitelist specific int->fp and
fp->int bitcasts for post-legalization folding. I've added the test case
from the PR.

(Also as a note, this does not appear to be in 3.6, no backport needed)

llvm-svn: 228656
2015-02-10 02:25:56 +00:00
Ahmed Bougacha e892d13d90 [CodeGen] Add hook/combine to form vector extloads, enabled on X86.
The combine that forms extloads used to be disabled on vector types,
because "None of the supported targets knows how to perform load and
sign extend on vectors in one instruction."

That's not entirely true, since at least SSE4.1 X86 knows how to do
those sextloads/zextloads (with PMOVS/ZX).
But there are several aspects to getting this right.
First, vector extloads are controlled by a profitability callback.
For instance, on ARM, several instructions have folded extload forms,
so it's not always beneficial to create an extload node (and trying to
match extloads is a whole 'nother can of worms).

The interesting optimization enables folding of s/zextloads to illegal
(splittable) vector types, expanding them into smaller legal extloads.

It's not ideal (it introduces some legalization-like behavior in the
combine) but it's better than the obvious alternative: form illegal
extloads, and later try to split them up.  If you do that, you might
generate extloads that can't be split up, but have a valid ext+load
expansion.  At vector-op legalization time, it's too late to generate
this kind of code, so you end up forced to scalarize. It's better to
just avoid creating egregiously illegal nodes.

This optimization is enabled unconditionally on X86.

Note that the splitting combine is happy with "custom" extloads. As
is, this bypasses the actual custom lowering, and just unrolls the
extload. But from what I've seen, this is still much better than the
current custom lowering, which does some kind of unrolling at the end
anyway (see for instance load_sext_4i8_to_4i64 on SSE2, and the added
FIXME).

Also note that the existing combine that forms extloads is now also
enabled on legal vectors.  This doesn't have a big effect on X86
(because sext+load is usually combined to sext_inreg+aextload).
On ARM it fires on some rare occasions; that's for a separate commit.

Differential Revision: http://reviews.llvm.org/D6904

llvm-svn: 228325
2015-02-05 18:31:02 +00:00
Quentin Colombet 308b171318 Revert r227242 - Merge vector stores into wider vector stores (PR21711).
This commit creates infinite loop in DAG combine for in the LLVM test-suite
for aarch64 with mcpu=cylcone (just having neon may be enough to expose this).

llvm-svn: 227272
2015-01-27 23:58:01 +00:00
Sanjay Patel bcf62f2fa2 Merge vector stores into wider vector stores (PR21711)
This patch resolves part of PR21711 ( http://llvm.org/bugs/show_bug.cgi?id=21711 ).

The 'f3' test case in that report presents a situation where we have two 128-bit
stores extracted from a 256-bit source vector. 

Instead of producing this:

vmovaps %xmm0, (%rdi)
vextractf128    $1, %ymm0, 16(%rdi)

This patch merges the 128-bit stores into a single 256-bit store:

vmovups %ymm0, (%rdi)

Differential Revision: http://reviews.llvm.org/D7208

llvm-svn: 227242
2015-01-27 20:50:27 +00:00
Sanjay Patel 37c41c1d2c merge consecutive stores of extracted vector elements (PR21711)
This is a 2nd try at the same optimization as http://reviews.llvm.org/D6698. 
That patch was checked in at r224611, but reverted at r225031 because it
caused a failure outside of the regression tests.

The cause of the crash was not recognizing consecutive stores that have mixed
source values (loads and vector element extracts), so this patch adds a check
to bail out if any store value is not coming from a vector element extract.

This patch also refactors the shared logic of the constant source and vector
extracted elements source cases into a helper function.

Differential Revision: http://reviews.llvm.org/D6850
 

llvm-svn: 226845
2015-01-22 18:21:26 +00:00
Michael Kuperstein 25e34d11f3 [DAGCombine] Produce better code for constant splats
This solves PR22276.
Splats of constants would sometimes produce redundant shuffles, sometimes ridiculously so (see the PR for details). Fold these shuffles into BUILD_VECTORs early on instead.

Differential Revision: http://reviews.llvm.org/D7093

Fixed recommit of r226811.

llvm-svn: 226816
2015-01-22 13:07:28 +00:00
Michael Kuperstein ff74032018 Revert r226811, MSVC accepts code sane compilers don't.
llvm-svn: 226814
2015-01-22 12:48:07 +00:00
Michael Kuperstein 84fad3e5c9 [DAGCombine] Produce better code for constant splats
This solves PR22276.
Splats of constants would sometimes produce redundant shuffles, sometimes ridiculously so (see the PR for details). Fold these shuffles into BUILD_VECTORs early on instead.

Differential Revision: http://reviews.llvm.org/D7093

llvm-svn: 226811
2015-01-22 12:37:23 +00:00
Elena Demikhovsky 150d9f3187 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 94cfbbab33 Fixed a comment
llvm-svn: 226806
2015-01-22 10:01:36 +00:00
Elena Demikhovsky 9c26462a27 Fixed a bug in narrowing store operation.
Type MVT::i1 became legal in KNL, but store operation can't be narrowed to this type,
since the size of VT (1 bit) is not equal to its actual store size(8 bits).

Added a test provided by David (dag@cray.com)

llvm-svn: 226805
2015-01-22 09:39:08 +00:00
Tim Northover 3007ba0ab3 DAGCombine: fold (or (and X, M), (and X, N)) -> (and X, (or M, N))
It can help with argument juggling on some targets, and is generally a good
idea.

llvm-svn: 226740
2015-01-21 23:17:19 +00:00
Tim Northover cf3d80fedb Revert "DAGCombine: fold (or (and X, M), (and X, N)) -> (and X, (or M, N))"
It hadn't gone through review yet, but was still on my local copy.

This reverts commit r226663

llvm-svn: 226665
2015-01-21 15:48:52 +00:00
Tim Northover 85cd2791c9 DAGCombine: fold (or (and X, M), (and X, N)) -> (and X, (or M, N))
llvm-svn: 226663
2015-01-21 15:43:28 +00:00
Mehdi Amini 37f316afaf Improve DAG combine pass on certain IR vector patterns
Loading 2 2x32-bit float vectors into the bottom half of a 256-bit vector
produced suboptimal code in AVX2 mode with certain IR combinations.

In particular, the IR optimizer folded 2f32 + 2f32 -> 4f32, 4f32 + 4f32
(undef) -> 8f32 into a 2f32 + 2f32 -> 8f32, which seems more canonical,
but then mysteriously generated rather bad code; the movq/movhpd combination
didn't match.

The problem lay in the BUILD_VECTOR optimization path. The 2f32 inputs
would get promoted to 4f32 by the type legalizer, eventually resulting
in a BUILD_VECTOR on two 4f32 into an 8f32. The BUILD_VECTOR then, recognizing
these were both half the output size, concatted them and then produced
a shuffle. However, the resulting concat + shuffle was more complex than
it should be; in the case where the upper half of the output is undef, we
probably want to generate shuffle + concat instead.

This enhancement causes the vector_shuffle combine step to recognize this
suboptimal pattern and correct it. I included it there instead of in BUILD_VECTOR
in case the same suboptimal pattern occurs for other reasons.

This results in the optimizer correctly producing the optimal movq + movhpd
sequence for all three variations on this IR, even with AVX2.

I've included a test case.

Radar link: rdar://problem/19287012
Fix for PR 21943.

From: Fiona Glaser <fglaser@apple.com>
llvm-svn: 226360
2015-01-17 01:35:56 +00:00
Chandler Carruth d9903888d9 [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
Mehdi Amini 648eff1695 DAG Combiner: Fold SelectCC When Cond is UNDEF
In case folding a node end up with a NaN as operand for the select, 
the folding of the condition of the selectcc node returns "UNDEF".

Differential Revision: http://reviews.llvm.org/D6889

llvm-svn: 225952
2015-01-14 05:45:24 +00:00
Matthias Braun f50ab43214 DAGCombiner: simplify by using condition variables; NFC
llvm-svn: 225836
2015-01-13 22:17:46 +00:00
Matt Arsenault bf0db918b2 R600: Implement getRecipEstimate
This requires a new hook to prevent expanding sqrt in terms
of rsqrt and reciprocal. v_rcp_f32, v_rsq_f32, and v_sqrt_f32 are
all the same rate, so this expansion would just double the number
of instructions and cycles.

llvm-svn: 225828
2015-01-13 20:53:23 +00:00
Olivier Sallenave 325096980b Added TLI hook for isFPExtFree. Some of the FMA combine heuristics are now guarded with that hook.
llvm-svn: 225795
2015-01-13 15:06:36 +00:00
Matt Arsenault a982e4f82b Combine fcmp + select to fminnum / fmaxnum if no nans and legal
Also require unsafe FP math for no since there isn't a way to
test for signed zeros.

llvm-svn: 225744
2015-01-13 00:43:00 +00:00
Hal Finkel 0ce7f372e5 [DAGCombine] Remainder of fix to r225380 (More FMA folding opportunities)
As pointed out by Aditya (and Owen), when we elide an FP extend to form an FMA,
we need to extend the incoming operands so that the resulting node will really
be legal. This is currently enabled only for PowerPC, and it happens to work
there regardless, but this should fix the functionality for everyone else
should anyone else wish to use it.

llvm-svn: 225492
2015-01-09 01:29:29 +00:00
Hal Finkel 33ead6f901 Partial fix to r225380 (More FMA folding opportunities)
As pointed out by Aditya (and Owen), there are two things wrong with this code.
First, it adds patterns which elide FP extends when forming FMAs, and that might
not be profitable on all targets (it belongs behind the pre-existing
aggressive-FMA-formation flag). This is fixed by this change.

Second, the resulting nodes might have operands of different types (the
extensions need to be re-added). That will be fixed in the follow-up commit.

llvm-svn: 225485
2015-01-09 00:45:54 +00:00
Ahmed Bougacha 2b6917b020 [SelectionDAG] Allow targets to specify legality of extloads' result
type (in addition to the memory type).

The *LoadExt* legalization handling used to only have one type, the
memory type.  This forced users to assume that as long as the extload
for the memory type was declared legal, and the result type was legal,
the whole extload was legal.

However, this isn't always the case.  For instance, on X86, with AVX,
this is legal:
    v4i32 load, zext from v4i8
but this isn't:
    v4i64 load, zext from v4i8
Whereas v4i64 is (arguably) legal, even without AVX2.

Note that the same thing was done a while ago for truncstores (r46140),
but I assume no one needed it yet for extloads, so here we go.

Calls to getLoadExtAction were changed to add the value type, found
manually in the surrounding code.

Calls to setLoadExtAction were mechanically changed, by wrapping the
call in a loop, to match previous behavior.  The loop iterates over
the MVT subrange corresponding to the memory type (FP vectors, etc...).
I also pulled neighboring setTruncStoreActions into some of the loops;
those shouldn't make a difference, as the additional types are illegal.
(e.g., i128->i1 truncstores on PPC.)

No functional change intended.

Differential Revision: http://reviews.llvm.org/D6532

llvm-svn: 225421
2015-01-08 00:51:32 +00:00
Olivier Sallenave 0451532996 More FMA folding opportunities.
llvm-svn: 225380
2015-01-07 20:54:17 +00:00
Olivier Sallenave e64ad7cedd Test commit
llvm-svn: 225368
2015-01-07 19:45:17 +00:00
Craig Topper d3c02f177a Replace several 'assert(false' with 'llvm_unreachable' or fold a condition into the assert.
llvm-svn: 225160
2015-01-05 10:15:49 +00:00
Alexey Samsonov 553185ee4b Revert "merge consecutive stores of extracted vector elements"
This reverts commit r224611. This change causes crashes
in X86 DAG->DAG Instruction Selection.

llvm-svn: 225031
2014-12-31 00:40:28 +00:00
Mehdi Amini d38920891e Always assert in DAGCombine and not only when -debug is enabled
Right now in DAG Combine check the validity of the returned type 
only when -debug is given on the command line. However usually 
the test cases in the validation does not use -debug. 
An Assert build should always check this.

llvm-svn: 224779
2014-12-23 18:59:02 +00:00
Michael Kuperstein f4536ea6e8 [DagCombine] Improve DAGCombiner BUILD_VECTOR when it has two sources of elements
This partially fixes PR21943.

For AVX, we go from:

vmovq   (%rsi), %xmm0
vmovq   (%rdi), %xmm1
vpermilps       $-27, %xmm1, %xmm2 ## xmm2 = xmm1[1,1,2,3]
vinsertps       $16, %xmm2, %xmm1, %xmm1 ## xmm1 = xmm1[0],xmm2[0],xmm1[2,3]
vinsertps       $32, %xmm0, %xmm1, %xmm1 ## xmm1 = xmm1[0,1],xmm0[0],xmm1[3]
vpermilps       $-27, %xmm0, %xmm0 ## xmm0 = xmm0[1,1,2,3]
vinsertps       $48, %xmm0, %xmm1, %xmm0 ## xmm0 = xmm1[0,1,2],xmm0[0]

To the expected:

vmovq   (%rdi), %xmm0
vmovhpd (%rsi), %xmm0, %xmm0
retq

Fixing this for AVX2 is still open.

Differential Revision: http://reviews.llvm.org/D6749

llvm-svn: 224759
2014-12-23 08:59:45 +00:00
Sanjay Patel 0428a5786e merge consecutive stores of extracted vector elements
Add a path to DAGCombiner::MergeConsecutiveStores() 
to combine multiple scalar stores when the store operands
are extracted vector elements. This is a partial fix for
PR21711 ( http://llvm.org/bugs/show_bug.cgi?id=21711 ).

For the new test case, codegen improves from:

   vmovss  %xmm0, (%rdi)
   vextractps      $1, %xmm0, 4(%rdi)
   vextractps      $2, %xmm0, 8(%rdi)
   vextractps      $3, %xmm0, 12(%rdi)
   vextractf128    $1, %ymm0, %xmm0
   vmovss  %xmm0, 16(%rdi)
   vextractps      $1, %xmm0, 20(%rdi)
   vextractps      $2, %xmm0, 24(%rdi)
   vextractps      $3, %xmm0, 28(%rdi)
   vzeroupper
   retq

To:

   vmovups	%ymm0, (%rdi)
   vzeroupper
   retq

Patch reviewed by Nadav Rotem.

Differential Revision: http://reviews.llvm.org/D6698

llvm-svn: 224611
2014-12-19 20:23:41 +00:00
Michael Kuperstein 047b1a0400 [DAGCombine] Slightly improve lowering of BUILD_VECTOR into a shuffle.
This handles the case of a BUILD_VECTOR being constructed out of elements extracted from a vector twice the size of the result vector. Previously this was always scalarized. Now, we try to construct a shuffle node that feeds on extract_subvectors.

This fixes PR15872 and provides a partial fix for PR21711.

Differential Revision: http://reviews.llvm.org/D6678

llvm-svn: 224429
2014-12-17 12:32:17 +00:00
Matt Arsenault 810cb62962 Add target hook for whether it is profitable to reduce load widths
Add an option to disable optimization to shrink truncated larger type
loads to smaller type loads. On SI this prevents using scalar load
instructions in some cases, since there are no scalar extloads.

llvm-svn: 224084
2014-12-12 00:00:24 +00:00
Owen Anderson 558012a3fc Fix a few instances found in SelectionDAG where we were not handling F16 at parity with F32 and F64.
llvm-svn: 223760
2014-12-09 06:50:39 +00:00
Simon Pilgrim be24ab367b [InstCombine] Minor optimization for bswap with binary ops
Added instcombine optimizations for BSWAP with AND/OR/XOR ops:

OP( BSWAP(x), BSWAP(y) ) -> BSWAP( OP(x, y) )
OP( BSWAP(x), CONSTANT ) -> BSWAP( OP(x, BSWAP(CONSTANT) ) )

Since its just a one liner, I've also added BSWAP to the DAGCombiner equivalent as well:

fold (OP (bswap x), (bswap y)) -> (bswap (OP x, y))

Refactored bswap-fold tests to use FileCheck instead of just checking that the bswaps had gone.

Differential Revision: http://reviews.llvm.org/D6407

llvm-svn: 223349
2014-12-04 09:44:01 +00:00
Elena Demikhovsky f1de34b84d 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 9bc81fbe92 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 9e5089a938 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
Andrea Di Biagio 0225b5bf6f [DAG] Teach how to turn a build_vector into a shuffle if some of the operands are zero.
Before this patch, the DAGCombiner only tried to convert build_vector dag nodes
into shuffles if all operands were either extract_vector_elt or undef.

This patch improves that logic and teaches the DAGCombiner how to deal with
build_vector dag nodes where one or more operands are zero. A build_vector
dag node with some zero operands is turned into a shuffle only if the resulting
shuffle mask is legal for the target.

llvm-svn: 222536
2014-11-21 14:32:06 +00:00
Andrea Di Biagio 26e8f4d166 [DAG] Refactor the shuffle combining logic in DAGCombiner. NFC.
This patch simplifies the logic that combines a pair of shuffle nodes into
a single shuffle if there is a legal mask. Also added comments to better
describe the algorithm. No functional change intended.

llvm-svn: 222522
2014-11-21 11:33:07 +00:00
Hao Liu 44e5d7a131 DAGCombiner: Allow the DAGCombiner to combine multiple FDIVs with the same divisor info FMULs by the reciprocal.
E.g., ( a / D; b / D ) -> ( recip = 1.0 / D; a * recip; b * recip)

A hook is added to allow the target to control whether it needs to do such combine.

Reviewed in http://reviews.llvm.org/D6334

llvm-svn: 222510
2014-11-21 06:39:58 +00:00
David Blaikie 70573dcd9f 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...

llvm-svn: 222334
2014-11-19 07:49:26 +00:00
Oliver Stannard d29db9b949 Fix optimisations of SELECT_CC which assumed result is boolean
Some optimisations in DAGCombiner cause miscompilations for targets that use
TargetLowering::UndefinedBooleanContent, because they assume that the results
of a SELECT_CC node are boolean values, and can be safely ANDed, ORed and
XORed. These optimisations are only valid for targets that use
ZeroOrOneBooleanContent or ZeroOrNegativeOneBooleanContent.

This is a follow-up to D6210/r221693.

llvm-svn: 222123
2014-11-17 10:49:31 +00:00