Commit Graph

7607 Commits

Author SHA1 Message Date
Craig Topper
8e8b6efdc8 [ValueTracking] Remove unnecessary temporary APInt from computeNumSignBitsVectorConstant.
We can just use getNumSignBits instead of inverting negative numbers.

llvm-svn: 316266
2017-10-21 16:35:41 +00:00
Craig Topper
b98ee58511 [ValueTracking] Simplify the known bits code for constant vectors a little.
Neither of these cases really require a temporary APInt outside the loop. For the ConstantDataSequential case the APInt will never be larger than 64-bits so its fine to just call getElementAsAPInt. For ConstantVector we can get the APInt by reference and only make a copy where the inversion is needed.

llvm-svn: 316265
2017-10-21 16:35:39 +00:00
Nikolai Bozhenov
fa8c5514c5 [ValueTracking] Enabling ValueTracking patch by default
(recommit #2 after checking for timeout issue). 

The original patch was an improvement to IR ValueTracking on
non-negative integers. It has been checked in to trunk (D18777,
r284022). But was disabled by default due to performance regressions.
Perf impact has improved. The patch would be enabled by default.

Reviewers: reames, hfinkel
 
Differential Revision: https://reviews.llvm.org/D34101
 
Patch by: Olga Chupina <olga.chupina@intel.com>

llvm-svn: 316208
2017-10-20 10:08:47 +00:00
Nikolai Bozhenov
8dcab54cb4 Revert r315992 because of a found miscompilation failure
llvm-svn: 316164
2017-10-19 15:36:18 +00:00
Sanjoy Das
2f27456c82 Revert "[ScalarEvolution] Handling for ICmp occuring in the evolution chain."
This reverts commit r316054.  There was some confusion over the review process:
http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20171016/495884.html

llvm-svn: 316129
2017-10-18 22:00:57 +00:00
Nikolai Bozhenov
9723f12491 Fixup patch for revision rL316070.
Added check that type of CmpConst and source type of trunc are equal
for correct matching of the case when we can set widened C constant
equal to CmpConstant.

  %cond = cmp iN %x, CmpConst
  %tr = trunc iN %x to iK
  %narrowsel = select i1 %cond, iK %t, iK C

Patch by: Gainullin, Artur <artur.gainullin@intel.com>

llvm-svn: 316082
2017-10-18 14:24:50 +00:00
Nikolai Bozhenov
74c047eabb Improve lookThroughCast function.
Summary:
When we have the following case:

  %cond = cmp iN %x, CmpConst
  %tr = trunc iN %x to iK
  %narrowsel = select i1 %cond, iK %t, iK C

We could possibly match only min/max pattern after looking through cast.
So it is more profitable if widened C constant will be equal CmpConst.
That is why just set widened C constant equal to CmpConst, because there
is a further check in this function that trunc CmpConst == C.

Also description for lookTroughCast function was added.

Reviewers: spatel

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D38536

Patch by: Artur Gainullin <artur.gainullin@intel.com>

llvm-svn: 316070
2017-10-18 09:28:09 +00:00
Jatin Bhateja
1fc49627e4 [ScalarEvolution] Handling for ICmp occuring in the evolution chain.
Summary:
 If a compare instruction is same or inverse of the compare in the
 branch of the loop latch, then return a constant evolution node.
 Currently scope of evaluation is limited to SCEV computation for
 PHI nodes.

 This shall facilitate computations of loop exit counts in cases
 where compare appears in the evolution chain of induction variables.

 Will fix PR 34538
Reviewers: sanjoy, hfinkel, junryoungju

Reviewed By: junryoungju

Subscribers: javed.absar, llvm-commits

Differential Revision: https://reviews.llvm.org/D38494

llvm-svn: 316054
2017-10-18 01:36:16 +00:00
Nikolai Bozhenov
346f4329c4 Improve clamp recognition in ValueTracking.
Summary:
ValueTracking was recognizing not all variations of clamp. Swapping of
true value and false value of select was added to fix this problem. This
change breaks the canonical form of cmp inside the matchMinMax function,
that is why additional checks for compare predicates is needed. Added
corresponding test cases.

Reviewers: spatel

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D38531

Patch by: Artur Gainullin <artur.gainullin@intel.com>

llvm-svn: 315992
2017-10-17 11:50:48 +00:00
Sanjoy Das
3a5e25278a Revert "[SCEV] Maintain and use a loop->loop invalidation dependency"
This reverts commit r315713.  It causes PR34968.

I think I know what the problem is, but I don't think I'll have time to fix it
this week.

llvm-svn: 315962
2017-10-17 01:03:56 +00:00
Anna Thomas
79503c035f [SCEV] Rename getMaxBECount and update comments. NFC
Post commit review comments at D38825.

llvm-svn: 315920
2017-10-16 17:47:17 +00:00
Sanjay Patel
b7d1238cfc [ValueTracking] fix typos, formatting; NFC
llvm-svn: 315909
2017-10-16 14:46:37 +00:00
Aaron Ballman
615eb47035 Reverting r315590; it did not include changes for llvm-tblgen, which is causing link errors for several people.
Error LNK2019 unresolved external symbol "public: void __cdecl `anonymous namespace'::MatchableInfo::dump(void)const " (?dump@MatchableInfo@?A0xf4f1c304@@QEBAXXZ) referenced in function "public: void __cdecl `anonymous namespace'::AsmMatcherEmitter::run(class llvm::raw_ostream &)" (?run@AsmMatcherEmitter@?A0xf4f1c304@@QEAAXAEAVraw_ostream@llvm@@@Z) llvm-tblgen D:\llvm\2017\utils\TableGen\AsmMatcherEmitter.obj 1

llvm-svn: 315854
2017-10-15 14:32:27 +00:00
Hongbin Zheng
73f650435b [LoopInfo][Refactor] Make SetLoopAlreadyUnrolled a member function of the Loop Pass, NFC.
This avoid code duplication and allow us to add the disable unroll metadata elsewhere.

Differential Revision: https://reviews.llvm.org/D38928

llvm-svn: 315850
2017-10-15 07:31:02 +00:00
Matthew Simpson
2284937bbc [IPSCCP] Move common functions to ValueLatticeUtils (NFC)
This patch moves some common utility functions out of IPSCCP and makes them
available globally. The functions determine if interprocedural data-flow
analyses can propagate information through function returns, arguments, and
global variables.

Differential Revision: https://reviews.llvm.org/D37638

llvm-svn: 315719
2017-10-13 17:53:44 +00:00
Sanjoy Das
c70a7a02ea [SCEV] Maintain and use a loop->loop invalidation dependency
Summary:
This change uses the loop use list added in the previous change to remember the
loops that appear in the trip count expressions of other loops; and uses it in
forgetLoop.  This lets us not scan every loop in the function on a forgetLoop
call.

With this change we no longer invalidate clear out backedge taken counts on
forgetValue.  I think this is fine -- the contract is that SCEV users must call
forgetLoop(L) if their change to the IR could have changed the trip count of L;
solely calling forgetValue on a value feeding into the backedge condition of L
is not enough.  Moreover, I don't think we can strengthen forgetValue to be
sufficient for invalidating trip counts without significantly re-architecting
SCEV.  For instance, if we have the loop:

  I = *Ptr;
  E = I + 10;
  do {
    // ...
  } while (++I != E);

then the backedge taken count of the loop is 9, and it has no reference to
either I or E, i.e. there is no way in SCEV today to re-discover the dependency
of the loop's trip count on E or I.  So a SCEV client cannot change E to (say)
"I + 20", call forgetValue(E) and expect the loop's trip count to be updated.

Reviewers: atrick, sunfish, mkazantsev

Subscribers: mcrosier, llvm-commits

Differential Revision: https://reviews.llvm.org/D38435

llvm-svn: 315713
2017-10-13 17:13:44 +00:00
Anna Thomas
a2ca902033 [SCEV] Teach SCEV to find maxBECount when loop endbound is variant
Summary:
This patch teaches SCEV to calculate the maxBECount when the end bound
of the loop can vary. Note that we cannot calculate the exactBECount.

This will only be done when both conditions are satisfied:
1. the loop termination condition is strictly LT.
2. the IV is proven to not overflow.

This provides more information to users of SCEV and can be used to
improve identification of finite loops.

Reviewers: sanjoy, mkazantsev, silviu.baranga, atrick

Reviewed by: mkazantsev

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D38825

llvm-svn: 315683
2017-10-13 14:30:43 +00:00
Daniel Jasper
3344a21236 Revert r314923: "Recommit : Use the basic cost if a GEP is not used as addressing mode"
Significantly reduces performancei (~30%) of gipfeli
(https://github.com/google/gipfeli)

I have not yet managed to reproduce this regression with the open-source
version of the benchmark on github, but will work with others to get a
reproducer to you later today.

llvm-svn: 315680
2017-10-13 14:04:21 +00:00
Sanjoy Das
e6b995f2b2 [SCEV] Maintain loop use lists, and use them in forgetLoop
Summary:
Currently we do not correctly invalidate memoized results for add recurrences
that were created directly (i.e. they were not created from a `Value`).  This
change fixes this by keeping loop use lists and using the loop use lists to
determine which SCEV expressions to invalidate.

Here are some statistics on the number of uses of in the use lists of all loops
on a clang bootstrap (config: release, no asserts):

     Count: 731310
       Min: 1
      Mean: 8.555150
50th %time: 4
95th %tile: 25
99th %tile: 53
       Max: 433

Reviewers: atrick, sunfish, mkazantsev

Subscribers: mcrosier, llvm-commits

Differential Revision: https://reviews.llvm.org/D38434

llvm-svn: 315672
2017-10-13 05:50:52 +00:00
Sanjay Patel
e272be7c9a [ValueTracking] return zero when there's conflict in known bits of a shift (PR34838)
Poison allows us to return a better result than undef.

llvm-svn: 315595
2017-10-12 17:31:46 +00:00
Don Hinton
3e0199f7eb [dump] Remove NDEBUG from test to enable dump methods [NFC]
Summary:
Add LLVM_FORCE_ENABLE_DUMP cmake option, and use it along with
LLVM_ENABLE_ASSERTIONS to set LLVM_ENABLE_DUMP.

Remove NDEBUG and only use LLVM_ENABLE_DUMP to enable dump methods.

Move definition of LLVM_ENABLE_DUMP from config.h to llvm-config.h so
it'll be picked up by public headers.

Differential Revision: https://reviews.llvm.org/D38406

llvm-svn: 315590
2017-10-12 16:16:06 +00:00
Hiroshi Inoue
b49b015bed [ScheduleDAGInstrs] fix behavior of getUnderlyingObjectsForCodeGen when no identifiable object found
This patch fixes the bug introduced in https://reviews.llvm.org/D35907; the bug is reported by http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20171002/491452.html.

Before D35907, when GetUnderlyingObjects fails to find an identifiable object, allMMOsOkay lambda in getUnderlyingObjectsForInstr returns false and Objects vector is cleared. This behavior is unintentionally changed by D35907.

This patch makes the behavior for such case same as the previous behavior.
Since D35907 introduced a wrapper function getUnderlyingObjectsForCodeGen around GetUnderlyingObjects, getUnderlyingObjectsForCodeGen is modified to return a boolean value to ask the caller to clear the Objects vector.

Differential Revision: https://reviews.llvm.org/D38735

llvm-svn: 315565
2017-10-12 06:26:04 +00:00
Daniel Neilson
5acfd1dd78 [SCEV] Properly handle the case of a non-constant start with a zero accum in ScalarEvolution::createAddRecFromPHIWithCastsImpl
Summary:
 This patch fixes an error in the patch to ScalarEvolution::createAddRecFromPHIWithCastsImpl
made in D37265. In that patch we handle the cases where the either the start or accum values can be
zero after truncation. But, we assume that the start value must be a constant if the accum is
zero. This is clearly an erroneous assumption. This change removes that assumption.

Reviewers: sanjoy, dorit, mkazantsev

Reviewed By: sanjoy

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D38814

llvm-svn: 315491
2017-10-11 19:05:14 +00:00
Vivek Pandya
9590658fb8 [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

llvm-svn: 315476
2017-10-11 17:12:59 +00:00
Adam Nemet
0965da2055 Rename OptimizationDiagnosticInfo.* to OptimizationRemarkEmitter.*
Sync it up with the name of the class actually defined here.  This has been
bothering me for a while...

llvm-svn: 315249
2017-10-09 23:19:02 +00:00
Matthew Simpson
49ee814996 [SparsePropagation] Move member definitions to header (NFC)
AbstractLatticeFunction and SparseSolver are class templates parameterized by a
lattice value, so we need to move these member functions over to the header.

Differential Revision: https://reviews.llvm.org/D38561

llvm-svn: 314996
2017-10-05 18:03:30 +00:00
Sanjoy Das
005b88c0a6 Do not call Loop::getName on possibly dead loops
This fixes PR34832.

llvm-svn: 314938
2017-10-04 22:02:27 +00:00
Jun Bum Lim
d40e03c2d8 Recommit : Use the basic cost if a GEP is not used as addressing mode
Recommitting r314517 with the fix for handling ConstantExpr.

Original commit message:
  Currently, getGEPCost() returns TCC_FREE whenever a GEP is a legal addressing
  mode in the target. However, since it doesn't check its actual users, it will
  return FREE even in cases where the GEP cannot be folded away as a part of
  actual addressing mode. For example, if an user of the GEP is a call
  instruction taking the GEP as a parameter, then the GEP may not be folded in
  isel.

llvm-svn: 314923
2017-10-04 18:33:52 +00:00
Adam Nemet
6c381b7a2e [OptRemark] Move YAML writing to IR
Before the patch this was in Analysis.  Moving it to IR and making it implicit
part of LLVMContext::diagnose allows the full opt-remark facility to be used
outside passes e.g. the pass manager.  Jessica is planning to use this to
report function size after each pass.  The same could be used for time
reports.

Tested with BUILD_SHARED_LIBS=On.

llvm-svn: 314909
2017-10-04 15:18:11 +00:00
Adam Nemet
f31b1f310c Move verbosity check for remarks to the diag handler
Test needs some slight adjustment because we no longer check the existence of
BFI but rather that the actual hotness is set on the remark.  If entry_count
is not set getBlockProfileCount returns None.

llvm-svn: 314874
2017-10-04 04:26:23 +00:00
Hans Wennborg
9a9048e19f Revert r314806 "[SLP] Vectorize jumbled memory loads."
All the buildbots are red, e.g.
http://lab.llvm.org:8011/builders/clang-cmake-aarch64-lld/builds/2436/

> Summary:
> This patch tries to vectorize loads of consecutive memory accesses, accessed
> in non-consecutive or jumbled way. An earlier attempt was made with patch D26905
> which was reverted back due to some basic issue with representing the 'use mask' of
> jumbled accesses.
>
> This patch fixes the mask representation by recording the 'use mask' in the usertree entry.
>
> Change-Id: I9fe7f5045f065d84c126fa307ef6ebe0787296df
>
> Reviewers: mkuper, loladiro, Ayal, zvi, danielcdh
>
> Reviewed By: Ayal
>
> Subscribers: hans, mzolotukhin
>
> Differential Revision: https://reviews.llvm.org/D36130

llvm-svn: 314824
2017-10-03 18:32:29 +00:00
Mohammad Shahid
1d5422f27f [SLP] Vectorize jumbled memory loads.
Summary:
This patch tries to vectorize loads of consecutive memory accesses, accessed
in non-consecutive or jumbled way. An earlier attempt was made with patch D26905
which was reverted back due to some basic issue with representing the 'use mask' of
jumbled accesses.

This patch fixes the mask representation by recording the 'use mask' in the usertree entry.

Change-Id: I9fe7f5045f065d84c126fa307ef6ebe0787296df

Reviewers: mkuper, loladiro, Ayal, zvi, danielcdh

Reviewed By: Ayal

Subscribers: hans, mzolotukhin

Differential Revision: https://reviews.llvm.org/D36130

llvm-svn: 314806
2017-10-03 15:28:48 +00:00
Evgeny Astigeevich
d3558b5d5e [InlineCost, NFC] Extract code dealing with inbounds GEPs from visitGetElementPtr into a function
The code responsible for analysis of inbounds GEPs is extracted into a separate
function: CallAnalyzer::canFoldInboundsGEP. With the patch SROA
enabling/disabling code is localized at one place instead of spreading across
the code of CallAnalyzer::visitGetElementPtr.

Differential Revision: https://reviews.llvm.org/D38233

llvm-svn: 314787
2017-10-03 12:00:40 +00:00
Mikael Holmen
6efe507e42 [Lint] Avoid failed assertion by fetching the proper pointer type
Summary:
When checking if a constant expression is a noop cast we fetched the
IntPtrType by doing DL->getIntPtrType(V->getType())). However, there can
be cases where V doesn't return a pointer, and then getIntPtrType()
triggers an assertion.

Now we pass DataLayout to isNoopCast so the method itself can determine
what the IntPtrType is.

Reviewers: arsenm

Reviewed By: arsenm

Subscribers: wdng, llvm-commits

Differential Revision: https://reviews.llvm.org/D37894

llvm-svn: 314763
2017-10-03 06:03:49 +00:00
Daniel Berlin
67fbb351e3 SparseSolver: Rename getOrInitValueState to getValueState, matching what SCCP calls it
llvm-svn: 314744
2017-10-03 00:26:21 +00:00
Haicheng Wu
25f6c196d7 [InstSimplify] teach SimplifySelectInst() to fold more vector selects
Call ConstantFoldSelectInstruction() to fold cases like below

select <2 x i1><i1 true, i1 false>, <2 x i8> <i8 0, i8 1>, <2 x i8> <i8 2, i8 3>

All operands are constants and the condition has mixed true and false conditions.

Differential Revision: https://reviews.llvm.org/D38369

llvm-svn: 314741
2017-10-02 23:43:52 +00:00
Daniel Berlin
4d825bcf09 Template the sparse propagation solver instead of using void pointers
Summary:
This avoids using void * as the type of the lattice value and ugly casts needed to make that happen.
(If folks want to use references, etc, they can use a reference_wrapper).

Reviewers: davide, mssimpso

Subscribers: sanjoy, llvm-commits

Differential Revision: https://reviews.llvm.org/D38476

llvm-svn: 314734
2017-10-02 22:49:49 +00:00
Xin Tong
c063c3f09d Revert "Fix typo [NFC]"
This reverts commit e60b5028619be1c81bd039d63a0627dac32d38f9.

Incorrectly include changes that are not typo fix.

llvm-svn: 314614
2017-10-01 00:09:53 +00:00
Xin Tong
efec219e1b Fix typo [NFC]
llvm-svn: 314613
2017-10-01 00:07:24 +00:00
Alex Shlyapnikov
e76aa3b0b2 Revert "Use the basic cost if a GEP is not used as addressing mode"
This reverts commit r314517.

This commit crashes sanitizer bots, for example:
http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux/builds/4167

Stack snippet:
...
/mnt/b/sanitizer-buildbot1/sanitizer-x86_64-linux/build/llvm/include/llvm/Support/Casting.h:255:0
llvm::TargetTransformInfoImplCRTPBase<llvm::X86TTIImpl>::getGEPCost(llvm::GEPOperator const*, llvm::ArrayRef<llvm::Value const*>)
/mnt/b/sanitizer-buildbot1/sanitizer-x86_64-linux/build/llvm/include/llvm/Analysis/TargetTransformInfoImpl.h:742:0
llvm::TargetTransformInfoImplCRTPBase<llvm::X86TTIImpl>::getUserCost(llvm::User const*, llvm::ArrayRef<llvm::Value const*>)
/mnt/b/sanitizer-buildbot1/sanitizer-x86_64-linux/build/llvm/include/llvm/Analysis/TargetTransformInfoImpl.h:782:0
/mnt/b/sanitizer-buildbot1/sanitizer-x86_64-linux/build/llvm/lib/Analysis/TargetTransformInfo.cpp:116:0
/mnt/b/sanitizer-buildbot1/sanitizer-x86_64-linux/build/llvm/include/llvm/ADT/SmallVector.h:116:0
/mnt/b/sanitizer-buildbot1/sanitizer-x86_64-linux/build/llvm/include/llvm/ADT/SmallVector.h:343:0
/mnt/b/sanitizer-buildbot1/sanitizer-x86_64-linux/build/llvm/include/llvm/ADT/SmallVector.h:864:0
/mnt/b/sanitizer-buildbot1/sanitizer-x86_64-linux/build/llvm/include/llvm/Analysis/TargetTransformInfo.h:285:0
...

llvm-svn: 314560
2017-09-29 22:04:45 +00:00
Jun Bum Lim
0e16a59e83 Use the basic cost if a GEP is not used as addressing mode
Summary:
Currently, getGEPCost() returns TCC_FREE whenever a GEP is a legal addressing mode in the target.
However, since it doesn't check its actual users, it will return FREE even in cases
where the GEP cannot be folded away as a part of actual addressing mode.
For example, if an user of the GEP is a call instruction taking the GEP as a parameter,
then the GEP may not be folded in isel.

Reviewers: hfinkel, efriedma, mcrosier, jingyue, haicheng

Reviewed By: hfinkel

Subscribers: javed.absar, llvm-commits

Differential Revision: https://reviews.llvm.org/D38085

llvm-svn: 314517
2017-09-29 14:50:16 +00:00
Florian Hahn
8af01573a3 [LVI] Move LVILatticeVal class to separate header file (NFC).
Summary:
This allows sharing the lattice value code between LVI and SCCP (D36656). 

It also adds a `satisfiesPredicate` function, used by D36656.

Reviewers: davide, sanjoy, efriedma

Reviewed By: sanjoy

Subscribers: mgorny, llvm-commits

Differential Revision: https://reviews.llvm.org/D37591

llvm-svn: 314411
2017-09-28 11:09:22 +00:00
Sanjoy Das
def1729dc4 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

llvm-svn: 314375
2017-09-28 02:45:42 +00:00
Haicheng Wu
3ec848bc50 [InlineCost] add visitSelectInst()
InlineCost can understand Select IR now.  This patch finds free Select IRs and
continue the propagation of SimplifiedValues, ConstantOffsetPtrs, and
SROAArgValues.

Differential Revision: https://reviews.llvm.org/D37198

llvm-svn: 314307
2017-09-27 14:44:56 +00:00
Daniel Berlin
97f34e887f MemorySSAUpdater: Only add phis to insertedphis if we actually inserted them, not if we just found existing ones
llvm-svn: 314273
2017-09-27 05:35:19 +00:00
Matthias Braun
cc603ee3d5 TargetLibraryInfo: Stop guessing wchar_t size
Usually the frontend communicates the size of wchar_t via metadata and
we can optimize wcslen (and possibly other calls in the future). In
cases without the wchar_size metadata we would previously try to guess
the correct size based on the target triple; however this is fragile to
keep up to date and may miss users manually changing the size via flags.
Better be safe and stop guessing and optimizing if the frontend didn't
communicate the size.

Differential Revision: https://reviews.llvm.org/D38106

llvm-svn: 314185
2017-09-26 02:36:57 +00:00
Michael Liao
b30286d81c Remove trailing whitespaces.
llvm-svn: 314115
2017-09-25 16:21:21 +00:00
Clement Courbet
2807c0a442 [CodeGenPrepare][NFC] Rename TargetTransformInfo::expandMemCmp -> TargetTransformInfo::enableMemCmpExpansion.
Summary:
Right now there are two functions with the same name, one does the work
and the other one returns true if expansion is needed. Rename
TargetTransformInfo::expandMemCmp to make it more consistent with other
members of TargetTransformInfo.

Remove the unused Instruction* parameter.

Differential Revision: https://reviews.llvm.org/D38165

llvm-svn: 314096
2017-09-25 06:35:16 +00:00
Daniel Neilson
1341ac2ced [SCEV] Generalize folding of trunc(x)+n*trunc(y) into folding m*trunc(x)+n*trunc(y)
Summary:
A SCEV such as:
 {%v2,+,((-1 * (trunc i64 (-1 * %v1) to i32)) + (-1 * (trunc i64 %v1 to i32)))}<%loop>

can be folded into, simply, {%v2,+,0}. However, the current code in ::getAddExpr()
will not try to apply the simplification m*trunc(x)+n*trunc(y) -> trunc(trunc(m)*x+trunc(n)*y)
because it only keys off having a non-multiplied trunc as the first term in the simplification.

This patch generalizes this code to try to do a more generic fold of these trunc
expressions.

Reviewers: sanjoy

Reviewed By: sanjoy

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D37888

llvm-svn: 313988
2017-09-22 15:47:57 +00:00
Sanjoy Das
388b012f4e Rename markAsErased to erase, as pointed out in a previous review; NFC
llvm-svn: 313951
2017-09-22 01:47:41 +00:00