877 Commits

Author SHA1 Message Date
Sanjay Patel
00e900afdb [IR] redefine 'UnsafeAlgebra' / 'reassoc' fast-math-flags and add 'trans' fast-math-flag
As discussed on llvm-dev:
http://lists.llvm.org/pipermail/llvm-dev/2016-November/107104.html
and again more recently:
http://lists.llvm.org/pipermail/llvm-dev/2017-October/118118.html

...this is a step in cleaning up our fast-math-flags implementation in IR to better match
the capabilities of both clang's user-visible flags and the backend's flags for SDNode.

As proposed in the above threads, we're replacing the 'UnsafeAlgebra' bit (which had the 
'umbrella' meaning that all flags are set) with a new bit that only applies to algebraic 
reassociation - 'AllowReassoc'.

We're also adding a bit to allow approximations for library functions called 'ApproxFunc' 
(this was initially proposed as 'libm' or similar).

...and we're out of bits. 7 bits ought to be enough for anyone, right? :) FWIW, I did 
look at getting this out of SubclassOptionalData via SubclassData (spacious 16-bits), 
but that's apparently already used for other purposes. Also, I don't think we can just 
add a field to FPMathOperator because Operator is not intended to be instantiated. 
We'll defer movement of FMF to another day.

We keep the 'fast' keyword. I thought about removing that, but seeing IR like this:
%f.fast = fadd reassoc nnan ninf nsz arcp contract afn float %op1, %op2
...made me think we want to keep the shortcut synonym.

Finally, this change is binary incompatible with existing IR as seen in the 
compatibility tests. This statement:
"Newer releases can ignore features from older releases, but they cannot miscompile 
them. For example, if nsw is ever replaced with something else, dropping it would be 
a valid way to upgrade the IR." 
( http://llvm.org/docs/DeveloperPolicy.html#ir-backwards-compatibility )
...provides the flexibility we want to make this change without requiring a new IR 
version. Ie, we're not loosening the FP strictness of existing IR. At worst, we will 
fail to optimize some previously 'fast' code because it's no longer recognized as 
'fast'. This should get fixed as we audit/squash all of the uses of 'isFast()'.

Note: an inter-dependent clang commit to use the new API name should closely follow 
commit.

Differential Revision: https://reviews.llvm.org/D39304



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@317488 91177308-0d34-0410-b5e6-96231b3b80d8
2017-11-06 16:27:15 +00:00
Benjamin Kramer
29c5a7e7b9 [LoopVectorize] Replace manual VPlan memory management with unique_ptr.
No functionality change intended.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@317003 91177308-0d34-0410-b5e6-96231b3b80d8
2017-10-31 14:58:22 +00:00
Dehao Chen
b1bfcf247f Do not add discriminator encoding for debug intrinsics.
Summary: There are certain requirements for debug location of debug intrinsics, e.g. the scope of the DILocalVariable should be the same as the scope of its debug location. As a result, we should not add discriminator encoding for debug intrinsics.

Reviewers: dblaikie, aprantl

Reviewed By: aprantl

Subscribers: JDevlieghere, aprantl, bjope, sanjoy, llvm-commits

Differential Revision: https://reviews.llvm.org/D39343

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@316703 91177308-0d34-0410-b5e6-96231b3b80d8
2017-10-26 21:20:52 +00:00
Eugene Zelenko
8187e7e301 [Transforms] Fix some Clang-tidy modernize and Include What You Use warnings; other minor fixes (NFC).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@315640 91177308-0d34-0410-b5e6-96231b3b80d8
2017-10-12 23:30:03 +00:00
Vivek Pandya
2540c741d5 [NFC] Convert OptimizationRemarkEmitter old emit() calls to new closure
parameterized emit() calls

Summary: This is not functional change to adopt new emit() API added in r313691.

Reviewed By: anemet

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D38285


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@315476 91177308-0d34-0410-b5e6-96231b3b80d8
2017-10-11 17:12:59 +00:00
Ayal Zaks
5eb1a9dfa9 [LV] Fix PR34743 - handle casts that sink after interleaved loads
When ignoring a load that participates in an interleaved group, make sure to
move a cast that needs to sink after it.

Testcase derived from reproducer of PR34743.

Differential Revision: https://reviews.llvm.org/D38338


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@314986 91177308-0d34-0410-b5e6-96231b3b80d8
2017-10-05 15:45:14 +00:00
Ayal Zaks
0e8a63e67f [LV] Fix PR34711 - widen instruction ranges when sinking casts
Instead of trying to keep LastWidenRecipe updated after creating each recipe,
have tryToWiden() retrieve the last recipe of the current VPBasicBlock and check
if it's a VPWidenRecipe when attempting to extend its range. This ensures that
such extensions, optimized to maintain the original instruction order, do so
only when the instructions are to maintain their relative order. The latter does
not always hold, e.g., when a cast needs to sink to unravel first order
recurrence (r306884).

Testcase derived from reproducer of PR34711.

Differential Revision: https://reviews.llvm.org/D38339


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@314981 91177308-0d34-0410-b5e6-96231b3b80d8
2017-10-05 12:41:49 +00:00
Matthew Simpson
e0d97dea2f [LV] Use correct insertion point when type shrinking reductions
When type shrinking reductions, we should insert the truncations and extends at
the end of the loop latch block. Previously, these instructions were inserted
at the end of the loop header block. The difference is only a problem for loops
with predicated instructions (e.g., conditional stores and instructions that
may divide by zero). For these instructions, we create new basic blocks inside
the vectorized loop, which cause the loop header and latch to no longer be the
same block. This should fix PR34687.

Reference: https://bugs.llvm.org/show_bug.cgi?id=34687

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@314542 91177308-0d34-0410-b5e6-96231b3b80d8
2017-09-29 18:07:39 +00:00
Sanjoy Das
e87cf87e45 Use a BumpPtrAllocator for Loop objects
Summary:
And now that we no longer have to explicitly free() the Loop instances, we can
(with more ease) use the destructor of LoopBase to do what LoopBase::clear() was
doing.

Reviewers: chandlerc

Subscribers: mehdi_amini, mcrosier, llvm-commits

Differential Revision: https://reviews.llvm.org/D38201

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@314375 91177308-0d34-0410-b5e6-96231b3b80d8
2017-09-28 02:45:42 +00:00
Adam Nemet
093624c347 Allow ORE.emit to take a closure to delay building the remark object
In the lambda we are now returning the remark by value so we need to preserve
its type in the insertion operator.  This requires making the insertion
operator generic.

I've also converted a few cases to use the new API.  It seems to work pretty
well.  See the LoopUnroller for a slightly more interesting case.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@313691 91177308-0d34-0410-b5e6-96231b3b80d8
2017-09-19 23:00:55 +00:00
Vivek Pandya
18b4c37d1e This patch fixes https://bugs.llvm.org/show_bug.cgi?id=32352
It enables OptimizationRemarkEmitter::allowExtraAnalysis and MachineOptimizationRemarkEmitter::allowExtraAnalysis to return true not only for -fsave-optimization-record but when specific remarks are requested with
command line options.
The diagnostic handler used to be callback now this patch adds a class
DiagnosticHandler. It has virtual method to provide custom diagnostic handler
and methods to control which particular remarks are enabled. 
However LLVM-C API users can still provide callback function for diagnostic handler.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@313390 91177308-0d34-0410-b5e6-96231b3b80d8
2017-09-15 20:10:09 +00:00
Vivek Pandya
4abccff981 This reverts r313381
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@313387 91177308-0d34-0410-b5e6-96231b3b80d8
2017-09-15 19:53:54 +00:00
Vivek Pandya
bb8204f26f This patch fixes https://bugs.llvm.org/show_bug.cgi?id=32352
It enables OptimizationRemarkEmitter::allowExtraAnalysis and MachineOptimizationRemarkEmitter::allowExtraAnalysis to return true not only for -fsave-optimization-record but when specific remarks are requested with
command line options.
The diagnostic handler used to be callback now this patch adds a class
DiagnosticHandler. It has virtual method to provide custom diagnostic handler
and methods to control which particular remarks are enabled. 
However LLVM-C API users can still provide callback function for diagnostic handler.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@313382 91177308-0d34-0410-b5e6-96231b3b80d8
2017-09-15 19:30:59 +00:00
Alon Kom
dde48e1948 [LV] Fix maximum legal VF calculation
This patch fixes pr34283, which exposed that the computation of
maximum legal width for vectorization was wrong, because it relied
on MaxInterleaveFactor to obtain the maximum stride used in the loop,
however not all strided accesses in the loop have an interleave-group
associated with them.
Instead of recording the maximum stride in the loop, which can be over
conservative (e.g. if the access with the maximum stride is not involved
in the dependence limitation), this patch tracks the actual maximum legal
width imposed by accesses that are involved in dependencies.

Differential Revision: https://reviews.llvm.org/D37507

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@313237 91177308-0d34-0410-b5e6-96231b3b80d8
2017-09-14 07:40:02 +00:00
Anna Thomas
fb0da33fc1 [LV] Avoid computing the register usage for default VF. NFC
These are changes to reduce redundant computations when calculating a
feasible vectorization factor:
1. early return when target has no vector registers
2. don't compute register usage for the default VF.

Suggested during review for D37702.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@313176 91177308-0d34-0410-b5e6-96231b3b80d8
2017-09-13 19:35:45 +00:00
Ayal Zaks
3c0fd8c54b [LV] Fix PR34523 - avoid generating redundant selects
When converting a PHI into a series of 'select' instructions to combine the
incoming values together according their edge masks, initialize the first
value to the incoming value In0 of the first predecessor, instead of
generating a redundant assignment 'select(Cond[0], In0, In0)'. The latter
fails when the Cond[0] mask is null, representing a full mask, which can
happen only when there's a single incoming value.

No functional changes intended nor expected other than surviving null Cond[0]'s.

This fix follows D35725, which introduced using null to represent full masks.

Differential Revision: https://reviews.llvm.org/D37619


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@313119 91177308-0d34-0410-b5e6-96231b3b80d8
2017-09-13 06:28:37 +00:00
Anna Thomas
2691122302 [LV] Clamp the VF to the trip count
Summary:
When the MaxVectorSize > ConstantTripCount, we should just clamp the
vectorization factor to be the ConstantTripCount.
This vectorizes loops where the TinyTripCountThreshold >= TripCount < MaxVF.

Earlier we were finding the maximum vector width, which could be greater than
the trip count itself. The Loop vectorizer does all the work for generating a
vectorizable loop, but in the end we would always choose the scalar loop (since
the VF > trip count). This allows us to choose the VF keeping in mind the trip
count if available.

This is a fix on top of rL312472.

Reviewers: Ayal, zvi, hfinkel, dneilson

Reviewed by: Ayal

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D37702

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@313046 91177308-0d34-0410-b5e6-96231b3b80d8
2017-09-12 16:32:45 +00:00
Zvi Rackover
3438d07f09 LoopVectorize: MaxVF should not be larger than the loop trip count
Summary:
Improve how MaxVF is computed while taking into account that MaxVF should not be larger than the loop's trip count.

Other than saving on compile-time by pruning the possible MaxVF candidates, this patch fixes pr34438 which exposed the following flow:
1. Short trip count identified -> Don't bail out, set OptForSize:=True to avoid tail-loop and runtime checks.
2. Compute MaxVF returned 16 on a target supporting AVX512.
3. OptForSize -> choose VF:=MaxVF.
4. Bail out because TripCount = 8, VF = 16, TripCount % VF !=0 means we need a tail loop.

With this patch step 2. will choose MaxVF=8 based on TripCount.

Reviewers: Ayal, dorit, mkuper, hfinkel

Reviewed By: hfinkel

Subscribers: hfinkel, llvm-commits

Differential Revision: https://reviews.llvm.org/D37425

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@312472 91177308-0d34-0410-b5e6-96231b3b80d8
2017-09-04 08:35:13 +00:00
Benjamin Kramer
6bf02adee0 [LoopVectorize] Turn static DenseSet into switch.
LLVM transforms this into a bit test which is a lot faster and smaller.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@312417 91177308-0d34-0410-b5e6-96231b3b80d8
2017-09-02 16:41:55 +00:00
Manoj Gupta
5d292d77f5 [LoopVectorizer] Use two step casting for float to pointer types.
Summary:
LoopVectorizer is creating casts between vec<ptr> and vec<float> types
on ARM when compiling OpenCV. Since, tIs is illegal to directly cast a
floating point type to a pointer type even if the types have same size
causing a crash. Fix the crash using a two-step casting by bitcasting
to integer and integer to pointer/float.
Fixes PR33804.

Reviewers: mkuper, Ayal, dlj, rengolin, srhines

Reviewed By: rengolin

Subscribers: aemerson, kristof.beyls, mkazantsev, Meinersbur, rengolin, mzolotukhin, llvm-commits

Differential Revision: https://reviews.llvm.org/D35498

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@312331 91177308-0d34-0410-b5e6-96231b3b80d8
2017-09-01 15:36:00 +00:00
Ayal Zaks
a183d6cf2a [LV] Fix PR34248 - recommit D32871 after revert r311304
Original commit r311077 of D32871 was reverted in r311304 due to failures
reported in PR34248.

This recommit fixes PR34248 by restricting the packing of predicated scalars
into vectors only when vectorizing, avoiding doing so when unrolling w/o
vectorizing. Added a test derived from the reproducer of PR34248.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@311849 91177308-0d34-0410-b5e6-96231b3b80d8
2017-08-27 12:55:46 +00:00
Chandler Carruth
3f7e6da696 Revert r311077: [LV] Using VPlan ...
This causes LLVM to assert fail on PPC64 and crash / infloop in other
cases. Filed http://llvm.org/PR34248 with reproducer attached.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@311304 91177308-0d34-0410-b5e6-96231b3b80d8
2017-08-20 23:17:11 +00:00
Aditya Kumar
70fb4705b4 [Loop Vectorize] Added a separate metadata
Added a separate metadata to indicate when the loop
has already been vectorized instead of setting width and count to 1.

Patch written by Divya Shanmughan and Aditya Kumar

Differential Revision: https://reviews.llvm.org/D36220

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@311281 91177308-0d34-0410-b5e6-96231b3b80d8
2017-08-20 10:32:41 +00:00
Ayal Zaks
cd8f8f7fd4 [LV] Using VPlan to model the vectorized code and drive its transformation
VPlan is an ongoing effort to refactor and extend the Loop Vectorizer. This
patch introduces the VPlan model into LV and uses it to represent the vectorized
code and drive the generation of vectorized IR.

In this patch VPlan models the vectorized loop body: the vectorized control-flow
is represented using VPlan's Hierarchical CFG, with predication refactored from
being a post-vectorization-step into a vectorization planning step modeling
if-then VPRegionBlocks, and generating code inline with non-predicated code. The
vectorized code within each VPBasicBlock is represented as a sequence of
Recipes, each responsible for modelling and generating a sequence of IR
instructions. To keep the size of this commit manageable the Recipes in this
patch are coarse-grained and capture large chunks of LV's code-generation logic.
The constructed VPlans are dumped in dot format under -debug.

This commit retains current vectorizer output, except for minor instruction
reorderings; see associated modifications to lit tests.

For further details on the VPlan model see docs/Proposals/VectorizationPlan.rst
and its references.

Authors: Gil Rapaport and Ayal Zaks

Differential Revision: https://reviews.llvm.org/D32871


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@311077 91177308-0d34-0410-b5e6-96231b3b80d8
2017-08-17 09:29:59 +00:00
Ayal Zaks
745921f87f [LV] Minor savings to Sink casts to unravel first order recurrence
Two minor savings: avoid copying the SinkAfter map and avoid moving a cast if it
is not needed.

Differential Revision: https://reviews.llvm.org/D36408


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@310910 91177308-0d34-0410-b5e6-96231b3b80d8
2017-08-15 08:32:59 +00:00
Anna Thomas
0428548839 [LoopVectorize] Fix assertion failure in Fcmp vectorization
Summary:
When vectorizing fcmps we can trip on incorrect cast assertion when setting the
FastMathFlags after generating the vectorized FCmp.
This can happen if the FCmp can be folded to true or false directly. The fix
here is to set the FastMathFlag using the FastMathFlagBuilder *before* creating
the FCmp Instruction. This is what's done by other optimizations such as
InstCombine.
Added a test case which trips on cast assertion without this patch.

Reviewers: Ayal, mssimpso, mkuper, gilr

Reviewed by: Ayal, mssimpso

Subscribers: llvm-commits, mzolotukhin

Differential Revision: https://reviews.llvm.org/D36244

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@310389 91177308-0d34-0410-b5e6-96231b3b80d8
2017-08-08 18:07:44 +00:00
Matt Arsenault
c8df92092d LV: Don't insert runtime ptr checks on divergent targets
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@309890 91177308-0d34-0410-b5e6-96231b3b80d8
2017-08-02 21:43:08 +00:00
Ayal Zaks
343f60c4b2 [LV] Avoid redundant operations manipulating masks
The Loop Vectorizer generates redundant operations when manipulating masks:
AND with true, OR with false, compare equal to true. Instead of relying on
a subsequent pass to clean them up, this patch avoids generating them.

Use null (no-mask) to represent all-one full masks, instead of a constant
all-one vector, following the convention of masked gathers and scatters.

Preparing for a follow-up VPlan patch in which these mask manipulating
operations are modeled using recipes.

Differential Revision: https://reviews.llvm.org/D35725


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@309558 91177308-0d34-0410-b5e6-96231b3b80d8
2017-07-31 13:21:42 +00:00
Ayal Zaks
e1f7499ee7 [LV] Test once if vector trip count is zero, instead of twice
Generate a single test to decide if there are enough iterations to jump to the
vectorized loop, or else go to the scalar remainder loop. This test compares the
Scalar Trip Count: if STC < VF * UF go to the scalar loop. If
requiresScalarEpilogue() holds, at-least one iteration must remain scalar; the
rest can be used to form vector iterations. So in this case the test checks
instead if (STC - 1) < VF * UF by comparing STC <= VF * UF, and going to the
scalar loop if so. Otherwise the vector loop is entered for at-least one vector
iteration.

This test covers the case where incrementing the backedge-taken count will
overflow leading to an incorrect trip count of zero. In this (rare) case we will
also avoid the vector loop and jump to the scalar loop.

This patch simplifies the existing tests and effectively removes the basic-block
originally named "min.iters.checked", leaving the single test in block
"vector.ph".

Original observation and initial patch by Evgeny Stupachenko.

Differential Revision: https://reviews.llvm.org/D34150


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@308421 91177308-0d34-0410-b5e6-96231b3b80d8
2017-07-19 05:16:39 +00:00
Michael Kuperstein
73d05a2a19 [LV] Don't allow outside uses of IVs if the SCEV is predicated on loop conditions.
This fixes PR33706.
Differential Revision: https://reviews.llvm.org/D35227


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@307837 91177308-0d34-0410-b5e6-96231b3b80d8
2017-07-12 19:53:55 +00:00
Teresa Johnson
9d923b35aa Revert "r306473 - re-commit r306336: Enable vectorizer-maximize-bandwidth by default."
This still breaks PPC tests we have. I'll forward reproduction
instructions to dehao.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@306936 91177308-0d34-0410-b5e6-96231b3b80d8
2017-07-01 03:24:09 +00:00
Teresa Johnson
f7497bfb4a re-commit r306336: Enable vectorizer-maximize-bandwidth by default.
Differential Revision: https://reviews.llvm.org/D33341

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@306935 91177308-0d34-0410-b5e6-96231b3b80d8
2017-07-01 03:24:08 +00:00
Teresa Johnson
423d09931a revert r306336 for breaking ppc test.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@306934 91177308-0d34-0410-b5e6-96231b3b80d8
2017-07-01 03:24:07 +00:00
Teresa Johnson
005cfad2e8 Enable vectorizer-maximize-bandwidth by default.
Summary:
vectorizer-maximize-bandwidth is generally useful in terms of performance. I've tested the impact of changing this to default on speccpu benchmarks on sandybridge machines. The result shows non-negative impact:

spec/2006/fp/C++/444.namd                 26.84  -0.31%
spec/2006/fp/C++/447.dealII               46.19  +0.89%
spec/2006/fp/C++/450.soplex               42.92  -0.44%
spec/2006/fp/C++/453.povray               38.57  -2.25%
spec/2006/fp/C/433.milc                   24.54  -0.76%
spec/2006/fp/C/470.lbm                    41.08  +0.26%
spec/2006/fp/C/482.sphinx3                47.58  -0.99%
spec/2006/int/C++/471.omnetpp             22.06  +1.87%
spec/2006/int/C++/473.astar               22.65  -0.12%
spec/2006/int/C++/483.xalancbmk           33.69  +4.97%
spec/2006/int/C/400.perlbench             33.43  +1.70%
spec/2006/int/C/401.bzip2                 23.02  -0.19%
spec/2006/int/C/403.gcc                   32.57  -0.43%
spec/2006/int/C/429.mcf                   40.35  +0.27%
spec/2006/int/C/445.gobmk                 26.96  +0.06%
spec/2006/int/C/456.hmmer                  24.4  +0.19%
spec/2006/int/C/458.sjeng                 27.91  -0.08%
spec/2006/int/C/462.libquantum            57.47  -0.20%
spec/2006/int/C/464.h264ref               46.52  +1.35%

geometric mean                                   +0.29%

The regression on 453.povray seems real, but is due to secondary effects as all hot functions are bit-identical with and without the flag.

I started this patch to consult upstream opinions on this. It will be greatly appreciated if the community can help test the performance impact of this change on other architectures so that we can decided if this should be target-dependent.

Reviewers: hfinkel, mkuper, davidxl, chandlerc

Reviewed By: chandlerc

Subscribers: rengolin, sanjoy, javed.absar, bjope, dorit, magabari, RKSimon, llvm-commits, mzolotukhin

Differential Revision: https://reviews.llvm.org/D33341

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@306933 91177308-0d34-0410-b5e6-96231b3b80d8
2017-07-01 03:24:06 +00:00
Ayal Zaks
e050d57c74 [LV] Sink casts to unravel first order recurrence
Check if a single cast is preventing handling a first-order-recurrence Phi,
because the scheduling constraints it imposes on the first-order-recurrence
shuffle are infeasible; but they can be made feasible by moving the cast
downwards. Record such casts and move them when vectorizing the loop.

Differential Revision: https://reviews.llvm.org/D33058


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@306884 91177308-0d34-0410-b5e6-96231b3b80d8
2017-06-30 21:05:06 +00:00
Ayal Zaks
bfae62c2cb [LV] Optimize for size when vectorizing loops with tiny trip count
It may be detrimental to vectorize loops with very small trip count, as various
costs of the vectorized loop body as well as enclosing overheads including
runtime tests and scalar iterations may outweigh the gains of vectorizing. The
current cost model measures the cost of the vectorized loop body only, expecting
it will amortize other costs, and loops with known or expected very small trip
counts are not vectorized at all. This patch allows loops with very small trip
counts to be vectorized, but under OptForSize constraints, which ensure the cost
of the loop body is dominant, having no runtime guards nor scalar iterations.

Patch inspired by D32451.

Differential Revision: https://reviews.llvm.org/D34373


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@306803 91177308-0d34-0410-b5e6-96231b3b80d8
2017-06-30 08:02:35 +00:00
Daniel Jasper
ed1642feee Revert "r306473 - re-commit r306336: Enable vectorizer-maximize-bandwidth by default."
This still breaks PPC tests we have. I'll forward reproduction
instructions to dehao.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@306792 91177308-0d34-0410-b5e6-96231b3b80d8
2017-06-30 06:32:21 +00:00
Ayal Zaks
9a06b5298e [LV] Fix PR33613 - retain order of insertelement per part
r306381 caused PR33613, by reversing the order in which insertelements were
generated per unroll part. This patch fixes PR33613 by retraining this order,
placing each set of insertelements per part immediately after the last scalar
being packed for this part. Includes a test case derived from PR33613.

Reference: https://bugs.llvm.org/show_bug.cgi?id=33613
Differential Revision: https://reviews.llvm.org/D34760


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@306575 91177308-0d34-0410-b5e6-96231b3b80d8
2017-06-28 17:59:33 +00:00
Dehao Chen
c9d2291c96 re-commit r306336: Enable vectorizer-maximize-bandwidth by default.
Differential Revision: https://reviews.llvm.org/D33341


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@306473 91177308-0d34-0410-b5e6-96231b3b80d8
2017-06-27 22:05:58 +00:00
Ayal Zaks
84b5668c17 Recommitting 306331.
Undoing revert 306338 after fixed bug: add metadata to the load instead of the
reverse shuffle added to it, retaining the original ValueMap implementation.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@306381 91177308-0d34-0410-b5e6-96231b3b80d8
2017-06-27 08:41:19 +00:00
Dehao Chen
74c2abe3c6 revert r306336 for breaking ppc test.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@306344 91177308-0d34-0410-b5e6-96231b3b80d8
2017-06-26 23:05:35 +00:00
Ayal Zaks
bfc8711de9 reverting 306331.
Causes TBAA metadata to be generates on reverse shuffles, investigating.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@306338 91177308-0d34-0410-b5e6-96231b3b80d8
2017-06-26 22:26:54 +00:00
Dehao Chen
fd167cf907 Enable vectorizer-maximize-bandwidth by default.
Summary:
vectorizer-maximize-bandwidth is generally useful in terms of performance. I've tested the impact of changing this to default on speccpu benchmarks on sandybridge machines. The result shows non-negative impact:

spec/2006/fp/C++/444.namd                 26.84  -0.31%
spec/2006/fp/C++/447.dealII               46.19  +0.89%
spec/2006/fp/C++/450.soplex               42.92  -0.44%
spec/2006/fp/C++/453.povray               38.57  -2.25%
spec/2006/fp/C/433.milc                   24.54  -0.76%
spec/2006/fp/C/470.lbm                    41.08  +0.26%
spec/2006/fp/C/482.sphinx3                47.58  -0.99%
spec/2006/int/C++/471.omnetpp             22.06  +1.87%
spec/2006/int/C++/473.astar               22.65  -0.12%
spec/2006/int/C++/483.xalancbmk           33.69  +4.97%
spec/2006/int/C/400.perlbench             33.43  +1.70%
spec/2006/int/C/401.bzip2                 23.02  -0.19%
spec/2006/int/C/403.gcc                   32.57  -0.43%
spec/2006/int/C/429.mcf                   40.35  +0.27%
spec/2006/int/C/445.gobmk                 26.96  +0.06%
spec/2006/int/C/456.hmmer                  24.4  +0.19%
spec/2006/int/C/458.sjeng                 27.91  -0.08%
spec/2006/int/C/462.libquantum            57.47  -0.20%
spec/2006/int/C/464.h264ref               46.52  +1.35%

geometric mean                                   +0.29%

The regression on 453.povray seems real, but is due to secondary effects as all hot functions are bit-identical with and without the flag.

I started this patch to consult upstream opinions on this. It will be greatly appreciated if the community can help test the performance impact of this change on other architectures so that we can decided if this should be target-dependent.

Reviewers: hfinkel, mkuper, davidxl, chandlerc

Reviewed By: chandlerc

Subscribers: rengolin, sanjoy, javed.absar, bjope, dorit, magabari, RKSimon, llvm-commits, mzolotukhin

Differential Revision: https://reviews.llvm.org/D33341

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@306336 91177308-0d34-0410-b5e6-96231b3b80d8
2017-06-26 21:41:09 +00:00
Ayal Zaks
faf416b5ae [LV] Changing the interface of ValueMap, NFC.
Instead of providing access to the internal MapStorage holding all Values
associated with a given Key, used for setting or resetting them all together,
ValueMap keeps its MapStorage internal; its new interface allows getting,
setting or resetting a single Value, per part or per part-and-lane.
Follows the discussion in https://reviews.llvm.org/D32871.

Differential Revision: https://reviews.llvm.org/D34473


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@306331 91177308-0d34-0410-b5e6-96231b3b80d8
2017-06-26 21:03:51 +00:00
Diana Picus
e36adbda88 Revert "Enable vectorizer-maximize-bandwidth by default."
This reverts commit r305960 because it broke self-hosting on AArch64.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@305990 91177308-0d34-0410-b5e6-96231b3b80d8
2017-06-22 10:00:28 +00:00
Dehao Chen
998914d301 Enable vectorizer-maximize-bandwidth by default.
Summary:
vectorizer-maximize-bandwidth is generally useful in terms of performance. I've tested the impact of changing this to default on speccpu benchmarks on sandybridge machines. The result shows non-negative impact:

spec/2006/fp/C++/444.namd                 26.84  -0.31%
spec/2006/fp/C++/447.dealII               46.19  +0.89%
spec/2006/fp/C++/450.soplex               42.92  -0.44%
spec/2006/fp/C++/453.povray               38.57  -2.25%
spec/2006/fp/C/433.milc                   24.54  -0.76%
spec/2006/fp/C/470.lbm                    41.08  +0.26%
spec/2006/fp/C/482.sphinx3                47.58  -0.99%
spec/2006/int/C++/471.omnetpp             22.06  +1.87%
spec/2006/int/C++/473.astar               22.65  -0.12%
spec/2006/int/C++/483.xalancbmk           33.69  +4.97%
spec/2006/int/C/400.perlbench             33.43  +1.70%
spec/2006/int/C/401.bzip2                 23.02  -0.19%
spec/2006/int/C/403.gcc                   32.57  -0.43%
spec/2006/int/C/429.mcf                   40.35  +0.27%
spec/2006/int/C/445.gobmk                 26.96  +0.06%
spec/2006/int/C/456.hmmer                  24.4  +0.19%
spec/2006/int/C/458.sjeng                 27.91  -0.08%
spec/2006/int/C/462.libquantum            57.47  -0.20%
spec/2006/int/C/464.h264ref               46.52  +1.35%

geometric mean                                   +0.29%

The regression on 453.povray seems real, but is due to secondary effects as all hot functions are bit-identical with and without the flag.

I started this patch to consult upstream opinions on this. It will be greatly appreciated if the community can help test the performance impact of this change on other architectures so that we can decided if this should be target-dependent.

Reviewers: hfinkel, mkuper, davidxl, chandlerc

Reviewed By: chandlerc

Subscribers: rengolin, sanjoy, javed.absar, bjope, dorit, magabari, RKSimon, llvm-commits, mzolotukhin

Differential Revision: https://reviews.llvm.org/D33341

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@305960 91177308-0d34-0410-b5e6-96231b3b80d8
2017-06-21 22:01:32 +00:00
Taewook Oh
9f93c9df69 Improve profile-guided heuristics to use estimated trip count.
Summary:
Existing heuristic uses the ratio between the function entry
frequency and the loop invocation frequency to find cold loops. However,
even if the loop executes frequently, if it has a small trip count per
each invocation, vectorization is not beneficial. On the other hand,
even if the loop invocation frequency is much smaller than the function
invocation frequency, if the trip count is high it is still beneficial
to vectorize the loop.

This patch uses estimated trip count computed from the profile metadata
as a primary metric to determine coldness of the loop. If the estimated
trip count cannot be computed, it falls back to the original heuristics.

Reviewers: Ayal, mssimpso, mkuper, danielcdh, wmi, tejohnson

Reviewed By: tejohnson

Subscribers: tejohnson, mzolotukhin, llvm-commits

Differential Revision: https://reviews.llvm.org/D32451

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@305729 91177308-0d34-0410-b5e6-96231b3b80d8
2017-06-19 18:48:58 +00:00
George Burgess IV
9276050d30 [LoopVectorize] Don't preserve nsw/nuw flags on shrunken ops.
If we're shrinking a binary operation, it may be the case that the new
operations wraps where the old didn't. If this happens, the behavior
should be well-defined. So, we can't always carry wrapping flags with us
when we shrink operations.

If we do, we get incorrect optimizations in cases like:

void foo(const unsigned char *from, unsigned char *to, int n) {
  for (int i = 0; i < n; i++)
    to[i] = from[i] - 128;
}

which gets optimized to:

void foo(const unsigned char *from, unsigned char *to, int n) {
  for (int i = 0; i < n; i++)
    to[i] = from[i] | 128;
}

Because:
- InstCombine turned `sub i32 %from.i, 128` into
  `add nuw nsw i32 %from.i, 128`.
- LoopVectorize vectorized the add to be `add nuw nsw <16 x i8>` with a
  vector full of `i8 128`s
- InstCombine took advantage of the fact that the newly-shrunken add
  "couldn't wrap", and changed the `add` to an `or`.

InstCombine seems happy to figure out whether we can add nuw/nsw on its
own, so I just decided to drop the flags. There are already a number of
places in LoopVectorize where we rely on InstCombine to clean up.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@305053 91177308-0d34-0410-b5e6-96231b3b80d8
2017-06-09 03:56:15 +00:00
Ayal Zaks
2cfe765f46 [LV] Make scalarizeInstruction() non-virtual. NFC.
Following the request made in https://reviews.llvm.org/D32871,
scalarizeInstruction() which is no longer overridden by InnerLoopUnroller is
hereby made non-virtual in InnerLoopVectorizer.

Should have been part of r297580 originally.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@304685 91177308-0d34-0410-b5e6-96231b3b80d8
2017-06-04 13:29:51 +00:00
Galina Kistanova
143302b9f0 Added LLVM_FALLTHROUGH to address warning: this statement may fall through. NFC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@304636 91177308-0d34-0410-b5e6-96231b3b80d8
2017-06-03 05:18:46 +00:00