Commit Graph

1523 Commits

Author SHA1 Message Date
Nicola Zaghen 9588ad9611 [InstCombine] Fold icmp ugt/ult (add nuw X, C2), C --> icmp ugt/ult X, (C - C2)
Support for sgt/slt was added in rL294898, this adds the same cases also for unsigned compares.

This is the Alive proof: https://rise4fun.com/Alive/nyY

Differential Revision: https://reviews.llvm.org/D50972

llvm-svn: 341353
2018-09-04 10:29:48 +00:00
Nicolai Haehnle 65c026259e Move test/Analysis/DivergenceAnalysis/AMDGPU/loads.ll
Should fix failures of buildbots that don't build the AMDGPU backend.

Change-Id: I01cb84b4b47803b10c5b21ea0353546239860a51
llvm-svn: 341079
2018-08-30 15:24:00 +00:00
Nicolai Haehnle 35617ed4cb [NFC] Rename the DivergenceAnalysis to LegacyDivergenceAnalysis
Summary:
This is patch 1 of the new DivergenceAnalysis (https://reviews.llvm.org/D50433).

The purpose of this patch is to free up the name DivergenceAnalysis for the new generic
implementation. The generic implementation class will be shared by specialized
divergence analysis classes.

Patch by: Simon Moll

Reviewed By: nhaehnle

Subscribers: jvesely, jholewinski, arsenm, nhaehnle, mgorny, jfb, llvm-commits

Differential Revision: https://reviews.llvm.org/D50434

Change-Id: Ie8146b11be2c50d5312f30e11c7a3036a15b48cb
llvm-svn: 341071
2018-08-30 14:21:36 +00:00
Sanjay Patel 7a05641fa8 [InstCombine] remove unnecessary shuffle undef folding
Add a test for constant folding to show that 
(shuffle undef, undef, mask)
should already be handled via instsimplify.

llvm-svn: 340926
2018-08-29 13:24:34 +00:00
Kit Barton 7c80f98b69 [PPC] Remove Darwin support from POWER backend.
This patch issues an error message if Darwin ABI is attempted with the PPC
backend. It also cleans up existing test cases, either converting the test to
use an alternative triple or removing the test if the coverage is no longer
needed.

Updated Tests
-------------
The majority of test cases were updated to use a different triple that does not
include the Darwin ABI. Many tests were also updated to use FileCheck, in place
of grep.

Deleted Tests
-------------
llvm/test/tools/dsymutil/PowerPC/sibling.test was originally added to test
specific functionality of dsymutil using an object file created with an old
version of llvm-gcc for a Powerbook G4. After a discussion with @JDevlieghere he
suggested removing the test.

llvm/test/CodeGen/PowerPC/combine_loads_from_build_pair.ll was converted from a
PPC test to a SystemZ test, as the behavior is also reproducible there.

All other tests that were deleted were specific to the darwin/ppc ABI and no
longer necessary.

Phabricator Review: https://reviews.llvm.org/D50988

llvm-svn: 340795
2018-08-28 01:18:29 +00:00
Craig Topper a72012c206 [X86] Correct the cost of (v4i32 (fptoui (v4f64))) under AVX512F.
Summary: This was inheriting the cost from the AVX table, but should be legal under AVX512.

Reviewers: RKSimon

Reviewed By: RKSimon

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D51267

llvm-svn: 340708
2018-08-26 18:47:44 +00:00
John Brawn 980da83f84 [PhiValues] Use callback value handles to invalidate deleted values
The way that PhiValues is integrated with BasicAA it is possible for a pass
which uses BasicAA to pick up an instance of BasicAA that uses PhiValues without
intending to, and then delete values from a function in a way that causes
PhiValues to return dangling pointers to these deleted values. Fix this by
having a set of callback value handles to invalidate values when they're
deleted.

llvm-svn: 340613
2018-08-24 15:48:30 +00:00
Brian Homerding 3ecabd709f [FunctionAttrs] Infer WriteOnly Function Attribute
These changes expand the FunctionAttr logic in order to mark functions as
WriteOnly when appropriate. This is done through an additional bool variable
and extended logic.

Reviewers: hfinkel, jdoerfert

Differential Revision: https://reviews.llvm.org/D48387

llvm-svn: 340537
2018-08-23 15:05:22 +00:00
Philip Reames 6b6d2e0105 [AST] Add a test for attribute intersection
Already works, but I initially convinced myself it doesn't, so add a test which shows it does.  :)

llvm-svn: 340453
2018-08-22 21:10:56 +00:00
Scott Linder 72855e36c5 [AMDGPU] Consider loads from flat addrspace to be potentially divergent
In general we can't assume flat loads are uniform, and cases where we can prove
they are should be handled through infer-address-spaces.

Differential Revision: https://reviews.llvm.org/D50991

llvm-svn: 340343
2018-08-21 21:24:31 +00:00
Philip Reames c3c23e8cf2 [AST] Remove notion of volatile from alias sets [NFCI]
Volatility is not an aliasing property. We used to model volatile as if it had extremely conservative aliasing implications, but that hasn't been true for several years now. So, it doesn't make sense to be in AliasSet.

It also turns out the code is entirely a noop. Outside of the AST code to update it, there was only one user: load store promotion in LICM. L/S promotion doesn't need the check since it walks all the users of the address anyway. It already checks each load or store via !isUnordered which causes us to bail for volatile accesses. (Look at the lines immediately following the two remove asserts.)

There is the possibility of some small compile time impact here, but the only case which will get noticeably slower is a loop with a large number of loads and stores to the same address where only the last one we inspect is volatile. This is sufficiently rare it's not worth optimizing for..

llvm-svn: 340312
2018-08-21 17:59:11 +00:00
Sanjay Patel 3ce999fa41 [ConstantFolding] improve folding of binops with vector undef operand
A non-undef operand may still have undef constant elements, 
so we should always propagate the vector results per-lane.

llvm-svn: 340194
2018-08-20 18:19:02 +00:00
Sanjay Patel 7ff7bd9b3c [ConstantFolding] add tests for binops on vectors with undef elements; NFC
llvm-svn: 340190
2018-08-20 17:31:34 +00:00
Philip Reames 96bc076c3a [AST] Clarify printing of unknown size locations [NFC]
Printing "unknown" is much more clear than an arbitrary large integer

llvm-svn: 340108
2018-08-17 23:17:31 +00:00
Philip Reames 26f6176f38 [AST][Tests] Clarify what each test is doing
llvm-svn: 340100
2018-08-17 21:58:26 +00:00
Philip Reames 9e313167cf [AST[Tests] Shorten tests using noalias params
llvm-svn: 340099
2018-08-17 21:45:57 +00:00
Philip Reames 079c92e201 [AST] Add tests for argmemonly calls [NFC]
First step towards building a test set to rebase D50730 on top of.  Starting with clone of memtransfer tests, more to come.

llvm-svn: 340095
2018-08-17 21:42:18 +00:00
Sanjay Patel 411b86081e [ConstantFolding] add simplifications for funnel shift intrinsics
This is another step towards being able to canonicalize to the funnel shift 
intrinsics in IR (see D49242 for the initial patch). 
We should not have any loss of simplification power in IR between these and 
the equivalent IR constructs.

Differential Revision: https://reviews.llvm.org/D50848

llvm-svn: 340022
2018-08-17 13:23:44 +00:00
Max Kazantsev 7b78d3920c [MustExecute] Fix algorithmic bug in isGuaranteedToExecute. PR38514
The description of `isGuaranteedToExecute` does not correspond to its implementation.
According to description, it should return `true` if an instruction is executed under the
assumption that its loop is *entered*. However there is a sophisticated alrogithm inside
that tries to prove that the instruction is executed if the loop is *exited*, which is not the
same thing for infinite loops. There is an attempt to protect from dealing with infinite loops
by prohibiting loops without exit blocks, however an infinite loop can have exit blocks.

As result of that, MustExecute can falsely consider some blocks that are never entered as
mustexec, and LICM can hoist dangerous instructions out of them basing on this fact.
This may introduce UB to programs which did not contain it initially.

This patch removes the problematic algorithm and replaced it with a one which tries to
prove what is required in description.

Differential Revision: https://reviews.llvm.org/D50558
Reviewed By: reames

llvm-svn: 339984
2018-08-17 06:19:17 +00:00
Sanjay Patel 0ea8d8b951 [ConstantFolding] add tests for funnel shift intrinsics; NFC
No functionality for this yet.

llvm-svn: 339889
2018-08-16 16:10:42 +00:00
Easwaran Raman aca738b742 [BFI] Use rounding while computing profile counts.
Summary:
Profile count of a block is computed by multiplying its block frequency
by entry count and dividing the result by entry block frequency. Do
rounded division in the last step and update test cases appropriately.

Reviewers: davidxl

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D50822

llvm-svn: 339835
2018-08-16 00:26:59 +00:00
Max Kazantsev 5a10d127b9 [AliasSetTracker] Do not treat experimental_guard intrinsic as memory writing instruction
The `experimental_guard` intrinsic has memory write semantics to model the thread-exiting
logic, but does not do any actual writes to memory. Currently, `AliasSetTracker` treats it as a
normal memory write. As result, a loop-invariant load cannot be hoisted out of loop because
the guard may possibly alias with it.

This patch makes `AliasSetTracker` so that it doesn't treat guards as memory writes.

Differential Revision: https://reviews.llvm.org/D50497
Reviewed By: reames

llvm-svn: 339753
2018-08-15 06:21:02 +00:00
Max Kazantsev 837418f3f9 [NFC] Add comprehensive test of AliasSetTracker with guards
llvm-svn: 339643
2018-08-14 06:37:39 +00:00
Reid Kleckner 40e7663b1f [BasicAA] Don't assume tail calls with byval don't alias allocas
Summary:
Calls marked 'tail' cannot read or write allocas from the current frame
because the current frame might be destroyed by the time they run.
However, a tail call may use an alloca with byval. Calling with byval
copies the contents of the alloca into argument registers or stack
slots, so there is no lifetime issue. Tail calls never modify allocas,
so we can return just ModRefInfo::Ref.

Fixes PR38466, a longstanding bug.

Reviewers: hfinkel, nlewycky, gbiv, george.burgess.iv

Subscribers: hiraditya, llvm-commits

Differential Revision: https://reviews.llvm.org/D50679

llvm-svn: 339636
2018-08-14 01:24:35 +00:00
Max Kazantsev 4e9def57c7 [NFC] Add tests that demonstrate that MustExecute is fundamentally broken
llvm-svn: 339417
2018-08-10 09:20:46 +00:00
Krzysztof Parzyszek 90f3249ce2 [SCEV] Properly solve quadratic equations
Differential Revision: https://reviews.llvm.org/D48283

llvm-svn: 338758
2018-08-02 19:13:35 +00:00
John Brawn cd73fe8989 [BasicAA] Use PhiValuesAnalysis if available when handling phi alias
By using PhiValuesAnalysis we can get all the values reachable from a phi, so
we can be more precise instead of giving up when a phi has phi operands. We
can't make BaseicAA directly use PhiValuesAnalysis though, as the user of
BasicAA may modify the function in ways that PhiValuesAnalysis can't cope with.

For this optional usage to work correctly BasicAAWrapperPass now needs to be not
marked as CFG-only (i.e. it is now invalidated even when CFG is preserved) due
to how the legacy pass manager handles dependent passes being invalidated,
namely the depending pass still has a pointer to the now-dead dependent pass.

Differential Revision: https://reviews.llvm.org/D44564

llvm-svn: 338242
2018-07-30 11:52:08 +00:00
Keno Fischer 864fbd8e9a [SCEV] Don't expand Wrap predicate using inttoptr in ni addrspaces
Summary:
In non-integral address spaces, we're not allowed to introduce inttoptr/ptrtoint
intrinsics. Instead, we need to expand any pointer arithmetic as geps on the
base pointer. Luckily this is a common task for SCEV, so all we have to do here
is hook up the corresponding helper function and add test case.

Fixes PR38290

Reviewers: sanjoy
Differential Revision: https://reviews.llvm.org/D49832

llvm-svn: 338073
2018-07-26 21:55:06 +00:00
Stanislav Mekhanoshin b8269a9589 Fix llvm::ComputeNumSignBits with some operations and llvm.assume
Currently ComputeNumSignBits does early exit while processing some
of the operations (add, sub, mul, and select). This prevents the
function from using AssumptionCacheTracker if passed.

Differential Revision: https://reviews.llvm.org/D49759

llvm-svn: 337936
2018-07-25 16:39:24 +00:00
Roman Tereshin 1ba1f9310c [SCEV] Add zext(C + x + ...) -> D + zext(C-D + x + ...)<nuw><nsw> transform
if the top level addition in (D + (C-D + x + ...)) could be proven to
not wrap, where the choice of D also maximizes the number of trailing
zeroes of (C-D + x + ...), ensuring homogeneous behaviour of the
transformation and better canonicalization of such expressions.

This enables better canonicalization of expressions like

  1 + zext(5 + 20 * %x + 24 * %y)  and
      zext(6 + 20 * %x + 24 * %y)

which get both transformed to

  2 + zext(4 + 20 * %x + 24 * %y)

This pattern is common in address arithmetics and the transformation
makes it easier for passes like LoadStoreVectorizer to prove that 2 or
more memory accesses are consecutive and optimize (vectorize) them.

Reviewed By: mzolotukhin

Differential Revision: https://reviews.llvm.org/D48853

llvm-svn: 337859
2018-07-24 21:48:56 +00:00
Max Kazantsev d41faecc49 [SCEV] Fix buggy behavior in getAddExpr with truncs
SCEV tries to constant-fold arguments of trunc operands in SCEVAddExpr, and when it does
that, it passes wrong flags into the recursion. It is only valid to pass flags that are proved for
narrow type into a computation in wider type if we can prove that trunc instruction doesn't
actually change the value. If it did lose some meaningful bits, we may end up proving wrong
no-wrap flags for sum of arguments of trunc.

In the provided test we end up with `nuw` where it shouldn't be because of this bug.

The solution is to conservatively pass `SCEV::FlagAnyWrap` which is always a valid thing to do.

Reviewed By: sanjoy
Differential Revision: https://reviews.llvm.org/D49471

llvm-svn: 337435
2018-07-19 01:46:21 +00:00
Max Kazantsev 6b12506200 [NFC] Make a test more neat
llvm-svn: 337379
2018-07-18 11:03:40 +00:00
Tim Shen a064622bd3 Re-apply "[SCEV] Strengthen StrengthenNoWrapFlags (reapply r334428)."
llvm-svn: 337075
2018-07-13 23:58:46 +00:00
Tim Renouf f3d8295105 DivergenceAnalysis: added debug output
Summary:
This commit does two things:

1. modified the existing DivergenceAnalysis::dump() so it dumps the
   whole function with added DIVERGENT: annotations;

2. added code to do that dump if the appropriate -debug-only option is
   on.

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D47700

Change-Id: Id97b605aab1fc6f5a11a20c58a99bbe8c565bf83
llvm-svn: 336998
2018-07-13 13:13:30 +00:00
Piotr Padlewski c63b492bcd Simplify recursive launder.invariant.group and strip
Summary:
This patch is crucial for proving equality laundered/stripped
pointers. eg:

  bool foo(A *a) {
    return a == std::launder(a);
  }

Clang with -fstrict-vtable-pointers will emit something like:

    define dso_local zeroext i1 @_Z3fooP1A(%struct.A* %a) {
    entry:
      %c = bitcast %struct.A* %a to i8*
      %call = tail call i8* @llvm.launder.invariant.group.p0i8(i8* %c)
      %0 = bitcast %struct.A* %a to i8*
      %1 = tail call i8* @llvm.strip.invariant.group.p0i8(i8* %0)
      %2 = tail call i8* @llvm.strip.invariant.group.p0i8(i8* %call)
      %cmp = icmp eq i8* %1, %2
      ret i1 %cmp
    }

and because %2 can be replaced with @llvm.strip.invariant.group(%0)
and that %2 and %1 will produce the same value (because strip is readnone)
we can replace compare with true.

Reviewers: rsmith, hfinkel, majnemer, amharc, kuhar

Subscribers: llvm-commits, hiraditya

Differential Revision: https://reviews.llvm.org/D47423

llvm-svn: 336963
2018-07-12 23:55:20 +00:00
Simon Pilgrim 667a5b541f [TargetTransformInfo] Add pow2 analysis for scalar constants
Add ConstantInt analysis to getOperandInfo so we get more realistic div/rem expansion costs comparable to the vector costs.

llvm-svn: 336827
2018-07-11 17:51:27 +00:00
Manoj Gupta 77eeac3d9e llvm: Add support for "-fno-delete-null-pointer-checks"
Summary:
Support for this option is needed for building Linux kernel.
This is a very frequently requested feature by kernel developers.

More details : https://lkml.org/lkml/2018/4/4/601

GCC option description for -fdelete-null-pointer-checks:
This Assume that programs cannot safely dereference null pointers,
and that no code or data element resides at address zero.

-fno-delete-null-pointer-checks is the inverse of this implying that
null pointer dereferencing is not undefined.

This feature is implemented in LLVM IR in this CL as the function attribute
"null-pointer-is-valid"="true" in IR (Under review at D47894).
The CL updates several passes that assumed null pointer dereferencing is
undefined to not optimize when the "null-pointer-is-valid"="true"
attribute is present.

Reviewers: t.p.northover, efriedma, jyknight, chandlerc, rnk, srhines, void, george.burgess.iv

Reviewed By: efriedma, george.burgess.iv

Subscribers: eraman, haicheng, george.burgess.iv, drinkcat, theraven, reames, sanjoy, xbolva00, llvm-commits

Differential Revision: https://reviews.llvm.org/D47895

llvm-svn: 336613
2018-07-09 22:27:23 +00:00
Simon Pilgrim dc113dc7ed [CostModel][X86] Add SREM/UREM general and constant costs (PR38056)
We penalize general SDIV/UDIV costs but don't do the same for SREM/UREM.

This patch makes general vector SREM/UREM x20 as costly as scalar, the same approach as we do for SDIV/UDIV. The patch also extends the existing SDIV/UDIV constant costs for SREM/UREM - at the moment this means the additional cost of a MUL+SUB (see D48975).

Differential Revision: https://reviews.llvm.org/D48980

llvm-svn: 336486
2018-07-07 16:53:30 +00:00
Tim Shen 2ed501d656 Revert "[SCEV] Strengthen StrengthenNoWrapFlags (reapply r334428)."
This reverts commit r336140. Our tests shows that LSR assert fails with it.

llvm-svn: 336473
2018-07-06 23:20:35 +00:00
Max Kazantsev 20da7e467a Revert "[InstCombine] Delay foldICmpUsingKnownBits until simple transforms are done"
llvm-svn: 336410
2018-07-06 04:04:13 +00:00
Simon Pilgrim 8c3765dc6b [CostModel][X86] Add UDIV/UREM by pow2 costs
Normally InstCombine would have simplified these to SRL/AND instructions but we may still see these during SLP vectorization etc.

llvm-svn: 336371
2018-07-05 16:56:28 +00:00
Max Kazantsev 3097b76e8c [InstCombine] Delay foldICmpUsingKnownBits until simple transforms are done
This patch changes order of transform in InstCombineCompares to avoid
performing transforms based on ranges which produce complex bit arithmetics
before more simple things (like folding with constants) are done. See PR37636
for the motivating example.

Differential Revision: https://reviews.llvm.org/D48584
Reviewed By: spatel, lebedev.ri

llvm-svn: 336172
2018-07-03 06:23:57 +00:00
Tim Shen c7cef4bcc4 [SCEV] Strengthen StrengthenNoWrapFlags (reapply r334428).
Summary:
Comment on Transforms/LoopVersioning/incorrect-phi.ll: With the change
SCEV is able to prove that the loop doesn't wrap-self (due to zext i16
to i64), disabling the entire loop versioning pass. Removed the zext and
just use i64.

Reviewers: sanjoy

Subscribers: jlebar, hiraditya, javed.absar, bixia, llvm-commits

Differential Revision: https://reviews.llvm.org/D48409

llvm-svn: 336140
2018-07-02 20:01:54 +00:00
Simon Pilgrim ac193d4b5c [CostModel][X86] Add cost tests for fp rounding intrinsics
Add cost tests for fp ceil, floor, nearbyint, rint and trunc.

llvm-svn: 336122
2018-07-02 17:07:01 +00:00
Piotr Padlewski 5b3db45e8f Implement strip.invariant.group
Summary:
This patch introduce new intrinsic -
strip.invariant.group that was described in the
RFC: Devirtualization v2

Reviewers: rsmith, hfinkel, nlopes, sanjoy, amharc, kuhar

Subscribers: arsenm, nhaehnle, JDevlieghere, hiraditya, xbolva00, llvm-commits

Differential Revision: https://reviews.llvm.org/D47103

Co-authored-by: Krzysztof Pszeniczny <krzysztof.pszeniczny@gmail.com>
llvm-svn: 336073
2018-07-02 04:49:30 +00:00
Roman Shirokiy 272eac85c7 Fix overconfident assert in ScalarEvolution::isImpliedViaMerge
We can have AddRec with loops having many predecessors.
This changes an assert to an early return.

Differential Revision: https://reviews.llvm.org/D48766

llvm-svn: 335965
2018-06-29 11:46:30 +00:00
John Brawn bdbbd8381f Add a PhiValuesAnalysis pass to calculate the underlying values of phis
This pass is being added in order to make the information available to BasicAA,
which can't do caching of this information itself, but possibly this information
may be useful for other passes.

Incorporates code based on Daniel Berlin's implementation of Tarjan's algorithm.

Differential Revision: https://reviews.llvm.org/D47893

llvm-svn: 335857
2018-06-28 14:13:06 +00:00
Adhemerval Zanella cadcfed7aa [AArch64] Add custom lowering for v4i8 trunc store
This patch adds a custom trunc store lowering for v4i8 vector types.
Since there is not v.4b register, the v4i8 is promoted to v4i16 (v.4h)
and default action for v4i8 is to extract each element and issue 4
byte stores.

A better strategy would be to extended the promoted v4i16 to v8i16
(with undef elements) and extract and store the word lane which
represents the v4i8 subvectores. The construction:

  define void @foo(<4 x i16> %x, i8* nocapture %p) {
    %0 = trunc <4 x i16> %x to <4 x i8>
    %1 = bitcast i8* %p to <4 x i8>*
    store <4 x i8> %0, <4 x i8>* %1, align 4, !tbaa !2
    ret void
  }

Can be optimized from:

  umov    w8, v0.h[3]
  umov    w9, v0.h[2]
  umov    w10, v0.h[1]
  umov    w11, v0.h[0]
  strb    w8, [x0, #3]
  strb    w9, [x0, #2]
  strb    w10, [x0, #1]
  strb    w11, [x0]
  ret

To:

  xtn     v0.8b, v0.8h
  str     s0, [x0]
  ret

The patch also adjust the memory cost for autovectorization, so the C
code:

  void foo (const int *src, int width, unsigned char *dst)
  {
    for (int i = 0; i < width; i++)
       *dst++ = *src++;
  }

can be vectorized to:

  .LBB0_4:                                // %vector.body
                                          // =>This Inner Loop Header: Depth=1
        ldr     q0, [x0], #16
        subs    x12, x12, #4            // =4
        xtn     v0.4h, v0.4s
        xtn     v0.8b, v0.8h
        st1     { v0.s }[0], [x2], #4
        b.ne    .LBB0_4

Instead of byte operations.

llvm-svn: 335735
2018-06-27 13:58:46 +00:00
David Green 8699492304 [DA] Delinearise AddRecs if we can prove they don't wrap
We can prove that some delinearized subscripts do not wrap around to become
negative by the fact that they are from inbound geps of load/store locations.
This helps improve the delinearisation in cases where we can't prove that they
are non-negative from SCEV alone.

Differential Revision: https://reviews.llvm.org/D48481

llvm-svn: 335481
2018-06-25 15:13:26 +00:00
Simon Pilgrim 9c8f9374b5 [CostModel][AArch64] Add some initial costs for SK_Select and SK_PermuteSingleSrc
AArch64 was only setting costs for SK_Transpose, which meant that many of the simpler shuffles (e.g. SK_Select and SK_PermuteSingleSrc for larger vector elements) was being severely overestimated by the default shuffle expansion.

This patch adds costs to help improve SLP performance and avoid a regression in reductions introduced by D48174.

I'm not very knowledgeable about AArch64 shuffle lowering so I've kept the extra costs to a minimum - someone who knows this code can add extra costs which should improve vectorization a lot more.

Differential Revision: https://reviews.llvm.org/D48172

llvm-svn: 335329
2018-06-22 09:45:31 +00:00