Commit Graph

405 Commits

Author SHA1 Message Date
Renato Golin
d30dbb6c8c [ARM] AArch32 v8 NEON is still not IEEE-754 compliant
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@266603 91177308-0d34-0410-b5e6-96231b3b80d8
2016-04-18 12:06:47 +00:00
Adrian Prantl
422c22e3d3 Convert this sample-based-profiling testcase to use a NoDebug CU.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@266481 91177308-0d34-0410-b5e6-96231b3b80d8
2016-04-15 22:05:38 +00:00
Adrian Prantl
4eeaa0da04 [PR27284] Reverse the ownership between DICompileUnit and DISubprogram.
Currently each Function points to a DISubprogram and DISubprogram has a
scope field. For member functions the scope is a DICompositeType. DIScopes
point to the DICompileUnit to facilitate type uniquing.

Distinct DISubprograms (with isDefinition: true) are not part of the type
hierarchy and cannot be uniqued. This change removes the subprograms
list from DICompileUnit and instead adds a pointer to the owning compile
unit to distinct DISubprograms. This would make it easy for ThinLTO to
strip unneeded DISubprograms and their transitively referenced debug info.

Motivation
----------

Materializing DISubprograms is currently the most expensive operation when
doing a ThinLTO build of clang.

We want the DISubprogram to be stored in a separate Bitcode block (or the
same block as the function body) so we can avoid having to expensively
deserialize all DISubprograms together with the global metadata. If a
function has been inlined into another subprogram we need to store a
reference the block containing the inlined subprogram.

Attached to https://llvm.org/bugs/show_bug.cgi?id=27284 is a python script
that updates LLVM IR testcases to the new format.

http://reviews.llvm.org/D19034
<rdar://problem/25256815>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@266446 91177308-0d34-0410-b5e6-96231b3b80d8
2016-04-15 15:57:41 +00:00
Vedant Kumar
891e9f4096 [test] Require 'asserts' for a test which uses -debug-only
Without this line, bots which run check-all on Release compilers will
break.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@266386 91177308-0d34-0410-b5e6-96231b3b80d8
2016-04-14 23:32:40 +00:00
Renato Golin
a447ca5c09 [ARM] Adding IEEE-754 SIMD detection to loop vectorizer
Some SIMD implementations are not IEEE-754 compliant, for example ARM's NEON.

This patch teaches the loop vectorizer to only allow transformations of loops
that either contain no floating-point operations or have enough allowance
flags supporting lack of precision (ex. -ffast-math, Darwin).

For that, the target description now has a method which tells us if the
vectorizer is allowed to handle FP math without falling into unsafe
representations, plus a check on every FP instruction in the candidate loop
to check for the safety flags.

This commit makes LLVM behave like GCC with respect to ARM NEON support, but
it stops short of fixing the underlying problem: sub-normals. Neither GCC
nor LLVM have a flag for allowing sub-normal operations. Before this patch,
GCC only allows it using unsafe-math flags and LLVM allows it by default with
no way to turn it off (short of not using NEON at all).

As a first step, we push this change to make it safe and in sync with GCC.
The second step is to discuss a new sub-normal's flag on both communitues
and come up with a common solution. The third step is to improve the FastMath
flags in LLVM to encode sub-normals and use those flags to restrict NEON FP.

Fixes PR16275.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@266363 91177308-0d34-0410-b5e6-96231b3b80d8
2016-04-14 20:42:18 +00:00
Adam Nemet
cf0a711bff Revert "Support arbitrary addrspace pointers in masked load/store intrinsics"
This reverts commit r266086.

It breaks the LTO build of gcc in SPEC2000.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@266282 91177308-0d34-0410-b5e6-96231b3b80d8
2016-04-14 08:47:17 +00:00
Artur Pilipenko
80ce67004b Support arbitrary addrspace pointers in masked load/store intrinsics
This is a resubmittion of 263158 change.

This patch fixes the problem which occurs when loop-vectorize tries to use @llvm.masked.load/store intrinsic for a non-default addrspace pointer. It fails with "Calling a function with a bad signature!" assertion in CallInst constructor because it tries to pass a non-default addrspace pointer to the pointer argument which has default addrspace.

The fix is to add pointer type as another overloaded type to @llvm.masked.load/store intrinsics.

Reviewed By: reames

Differential Revision: http://reviews.llvm.org/D17270


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@266086 91177308-0d34-0410-b5e6-96231b3b80d8
2016-04-12 15:58:04 +00:00
Davide Italiano
d63fceeb37 [DebugInfo/Test] Add CU as required.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@265999 91177308-0d34-0410-b5e6-96231b3b80d8
2016-04-11 21:16:48 +00:00
Matthew Simpson
09e9ded8a1 [LoopUtils, LV] Fix PR27246 (first-order recurrences)
This patch ensures that when we detect first-order recurrences, we reject a phi
node if its previous value is also a phi node. During vectorization the initial
and previous values of the recurrence are shuffled together to create the value
for the current iteration. However, phi nodes are not widened like other
instructions. This fixes PR27246.

Differential Revision: http://reviews.llvm.org/D18971

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@265983 91177308-0d34-0410-b5e6-96231b3b80d8
2016-04-11 19:48:18 +00:00
Elena Demikhovsky
9f62954aaa Loop vectorization with uniform load
Vectorization cost of uniform load wasn't correctly calculated.
As a result, a simple loop that loads a uniform value wasn't vectorized.

Differential Revision: http://reviews.llvm.org/D18940



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@265901 91177308-0d34-0410-b5e6-96231b3b80d8
2016-04-10 16:53:19 +00:00
David Majnemer
951ea8be17 [LoopVectorize] Register cloned assumptions
InstCombine cannot effectively remove redundant assumptions without them
registered in the assumption cache.  The vectorizer can create identical
assumptions but doesn't register them with the cache, resulting in
slower compile times because InstCombine tries to reason about a lot
more assumptions.

Fix this by registering the cloned assumptions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@265800 91177308-0d34-0410-b5e6-96231b3b80d8
2016-04-08 16:37:10 +00:00
Silviu Baranga
d8cc816f81 Re-commit [SCEV] Introduce a guarded backedge taken count and use it in LAA and LV
This re-commits r265535 which was reverted in r265541 because it
broke the windows bots. The problem was that we had a PointerIntPair
which took a pointer to a struct allocated with new. The problem
was that new doesn't provide sufficient alignment guarantees.
This pattern was already present before r265535 and it just happened
to work. To fix this, we now separate the PointerToIntPair from the
ExitNotTakenInfo struct into a pointer and a bool.

Original commit message:

Summary:
When the backedge taken codition is computed from an icmp, SCEV can
deduce the backedge taken count only if one of the sides of the icmp
is an AddRecExpr. However, due to sign/zero extensions, we sometimes
end up with something that is not an AddRecExpr.

However, we can use SCEV predicates to produce a 'guarded' expression.
This change adds a method to SCEV to get this expression, and the
SCEV predicate associated with it.

In HowManyGreaterThans and HowManyLessThans we will now add a SCEV
predicate associated with the guarded backedge taken count when the
analyzed SCEV expression is not an AddRecExpr. Note that we only do
this as an alternative to returning a 'CouldNotCompute'.

We use new feature in Loop Access Analysis and LoopVectorize to analyze
and transform more loops.

Reviewers: anemet, mzolotukhin, hfinkel, sanjoy

Subscribers: flyingforyou, mcrosier, atrick, mssimpso, sanjoy, mzolotukhin, llvm-commits

Differential Revision: http://reviews.llvm.org/D17201



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@265786 91177308-0d34-0410-b5e6-96231b3b80d8
2016-04-08 14:29:09 +00:00
Silviu Baranga
89e8236bfb Revert r265535 until we know how we can fix the bots
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@265541 91177308-0d34-0410-b5e6-96231b3b80d8
2016-04-06 14:06:32 +00:00
Silviu Baranga
39fbde60e1 [SCEV] Introduce a guarded backedge taken count and use it in LAA and LV
Summary:
When the backedge taken codition is computed from an icmp, SCEV can
deduce the backedge taken count only if one of the sides of the icmp
is an AddRecExpr. However, due to sign/zero extensions, we sometimes
end up with something that is not an AddRecExpr.

However, we can use SCEV predicates to produce a 'guarded' expression.
This change adds a method to SCEV to get this expression, and the
SCEV predicate associated with it.

In HowManyGreaterThans and HowManyLessThans we will now add a SCEV
predicate associated with the guarded backedge taken count when the
analyzed SCEV expression is not an AddRecExpr. Note that we only do
this as an alternative to returning a 'CouldNotCompute'.

We use new feature in Loop Access Analysis and LoopVectorize to analyze
and transform more loops.

Reviewers: anemet, mzolotukhin, hfinkel, sanjoy

Subscribers: flyingforyou, mcrosier, atrick, mssimpso, sanjoy, mzolotukhin, llvm-commits

Differential Revision: http://reviews.llvm.org/D17201

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@265535 91177308-0d34-0410-b5e6-96231b3b80d8
2016-04-06 13:18:26 +00:00
David Majnemer
8b680c27be [SLPVectorizer] Vectorizing the libm sqrt to llvm's sqrt intrinsic requires nnan
To quote the langref "Unlike sqrt in libm, however, llvm.sqrt has
undefined behavior for negative numbers other than -0.0 (which allows
for better optimization, because there is no need to worry about errno
being set). llvm.sqrt(-0.0) is defined to return -0.0 like IEEE sqrt."

This means that it's unsafe to replace sqrt with llvm.sqrt unless the
call is annotated with nnan.

Thanks to Hal Finkel for pointing this out!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@265521 91177308-0d34-0410-b5e6-96231b3b80d8
2016-04-06 07:04:53 +00:00
David Majnemer
731666ee90 [SLPVectorizer] Vectorize libcalls of sqrt
We didn't realize that we could transform the libcall into a vectorized
intrinsic.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@265493 91177308-0d34-0410-b5e6-96231b3b80d8
2016-04-06 00:14:59 +00:00
Davide Italiano
fe735e5923 [DebugInfo] Fix tests so that each subprogram belongs to a CU.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@265490 91177308-0d34-0410-b5e6-96231b3b80d8
2016-04-05 23:37:08 +00:00
Adrian Prantl
7876f64bc3 testcase gardening: update the emissionKind enum to the new syntax. (NFC)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@265081 91177308-0d34-0410-b5e6-96231b3b80d8
2016-04-01 00:16:49 +00:00
Adrian Prantl
39bb84a097 Move the DebugEmissionKind enum from DIBuilder into DICompileUnit.
This mostly cosmetic patch moves the DebugEmissionKind enum from DIBuilder
into DICompileUnit. DIBuilder is not the right place for this enum to live
in — a metadata consumer should not have to include DIBuilder.h.
I also added a Verifier check that checks that the emission kind of a
DICompileUnit is actually legal.

http://reviews.llvm.org/D18612
<rdar://problem/25427165>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@265077 91177308-0d34-0410-b5e6-96231b3b80d8
2016-03-31 23:56:58 +00:00
Hal Finkel
dfdada0adb [LoopVectorize] Don't vectorize loops when everything will be scalarized
This change prevents the loop vectorizer from vectorizing when all of the vector
types it generates will be scalarized. I've run into this problem on the PPC's QPX
vector ISA, which only holds floating-point vector types. The loop vectorizer
will, however, happily vectorize loops with purely integer computation. Here's
an example:

  LV: The Smallest and Widest types: 32 / 32 bits.
  LV: The Widest register is: 256 bits.
  LV: Found an estimated cost of 0 for VF 1 For instruction:   %indvars.iv25 = phi i64 [ 0, %entry ], [ %indvars.iv.next26, %for.body ]
  LV: Found an estimated cost of 0 for VF 1 For instruction:   %arrayidx = getelementptr inbounds [1600 x i32], [1600 x i32]* %a, i64 0, i64 %indvars.iv25
  LV: Found an estimated cost of 0 for VF 1 For instruction:   %2 = trunc i64 %indvars.iv25 to i32
  LV: Found an estimated cost of 1 for VF 1 For instruction:   store i32 %2, i32* %arrayidx, align 4
  LV: Found an estimated cost of 1 for VF 1 For instruction:   %indvars.iv.next26 = add nuw nsw i64 %indvars.iv25, 1
  LV: Found an estimated cost of 1 for VF 1 For instruction:   %exitcond27 = icmp eq i64 %indvars.iv.next26, 1600
  LV: Found an estimated cost of 0 for VF 1 For instruction:   br i1 %exitcond27, label %for.cond.cleanup, label %for.body
  LV: Scalar loop costs: 3.
  LV: Found an estimated cost of 0 for VF 2 For instruction:   %indvars.iv25 = phi i64 [ 0, %entry ], [ %indvars.iv.next26, %for.body ]
  LV: Found an estimated cost of 0 for VF 2 For instruction:   %arrayidx = getelementptr inbounds [1600 x i32], [1600 x i32]* %a, i64 0, i64 %indvars.iv25
  LV: Found an estimated cost of 0 for VF 2 For instruction:   %2 = trunc i64 %indvars.iv25 to i32
  LV: Found an estimated cost of 2 for VF 2 For instruction:   store i32 %2, i32* %arrayidx, align 4
  LV: Found an estimated cost of 1 for VF 2 For instruction:   %indvars.iv.next26 = add nuw nsw i64 %indvars.iv25, 1
  LV: Found an estimated cost of 1 for VF 2 For instruction:   %exitcond27 = icmp eq i64 %indvars.iv.next26, 1600
  LV: Found an estimated cost of 0 for VF 2 For instruction:   br i1 %exitcond27, label %for.cond.cleanup, label %for.body
  LV: Vector loop of width 2 costs: 2.
  LV: Found an estimated cost of 0 for VF 4 For instruction:   %indvars.iv25 = phi i64 [ 0, %entry ], [ %indvars.iv.next26, %for.body ]
  LV: Found an estimated cost of 0 for VF 4 For instruction:   %arrayidx = getelementptr inbounds [1600 x i32], [1600 x i32]* %a, i64 0, i64 %indvars.iv25
  LV: Found an estimated cost of 0 for VF 4 For instruction:   %2 = trunc i64 %indvars.iv25 to i32
  LV: Found an estimated cost of 4 for VF 4 For instruction:   store i32 %2, i32* %arrayidx, align 4
  LV: Found an estimated cost of 1 for VF 4 For instruction:   %indvars.iv.next26 = add nuw nsw i64 %indvars.iv25, 1
  LV: Found an estimated cost of 1 for VF 4 For instruction:   %exitcond27 = icmp eq i64 %indvars.iv.next26, 1600
  LV: Found an estimated cost of 0 for VF 4 For instruction:   br i1 %exitcond27, label %for.cond.cleanup, label %for.body
  LV: Vector loop of width 4 costs: 1.
  ...
  LV: Selecting VF: 8.
  LV: The target has 32 registers
  LV(REG): Calculating max register usage:
  LV(REG): At #0 Interval # 0
  LV(REG): At #1 Interval # 1
  LV(REG): At #2 Interval # 2
  LV(REG): At #4 Interval # 1
  LV(REG): At #5 Interval # 1
  LV(REG): VF = 8

The problem is that the cost model here is not wrong, exactly. Since all of
these operations are scalarized, their cost (aside from the uniform ones) are
indeed VF*(scalar cost), just as the model suggests. In fact, the larger the VF
picked, the lower the relative overhead from the loop itself (and the
induction-variable update and check), and so in a sense, picking the largest VF
here is the right thing to do.

The problem is that vectorizing like this, where all of the vectors will be
scalarized in the backend, isn't really vectorizing, but rather interleaving.
By itself, this would be okay, but then the vectorizer itself also interleaves,
and that's where the problem manifests itself. There's aren't actually enough
scalar registers to support the normal interleave factor multiplied by a factor
of VF (8 in this example). In other words, the problem with this is that our
register-pressure heuristic does not account for scalarization.

While we might want to improve our register-pressure heuristic, I don't think
this is the right motivating case for that work. Here we have a more-basic
problem: The job of the vectorizer is to vectorize things (interleaving aside),
and if the IR it generates won't generate any actual vector code, then
something is wrong. Thus, if every type looks like it will be scalarized (i.e.
will be split into VF or more parts), then don't consider that VF.

This is not a problem specific to PPC/QPX, however. The problem comes up under
SSE on x86 too, and as such, this change fixes PR26837 too. I've added Sanjay's
reduced test case from PR26837 to this commit.

Differential Revision: http://reviews.llvm.org/D18537

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@264904 91177308-0d34-0410-b5e6-96231b3b80d8
2016-03-30 19:37:08 +00:00
James Molloy
cd309008e2 [VectorUtils] Don't try and truncate PHIs to a smaller bitwidth
We already try not to truncate PHIs in computeMinimalBitwidths. LoopVectorize can't handle it and we really don't need to, because both induction and reduction PHIs are truncated by other means.

However, we weren't bailing out in all the places we should have, and we ended up by returning a PHI to be truncated, which has caused PR27018.

This fixes PR17018.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@264852 91177308-0d34-0410-b5e6-96231b3b80d8
2016-03-30 10:11:43 +00:00
Michael Kruse
6fde9c2db6 [Verifier] Reject PHIs using defs from own block.
Reject the following IR as malformed (assuming that %entry, %next are
not in a loop):

    next:
      %y = phi i32 [ 0, %entry ]
      %x = phi i32 [ %y, %entry ]

Such PHI nodes came up in PR26718. While there was no consensus on
whether or not this is valid IR, most opinions on that bug and in a
discussion on the llvm-dev mailing list tended towards a
"strict interpretation" (term by Joseph Tremoulet) of PHI node uses.
Also, the language reference explicitly states that "the use of each
incoming value is deemed to occur on the edge from the corresponding
predecessor block to the current block" and
`DominatorTree::dominates(Instruction*, Use&)` uses this definition as
well.

For the code mentioned in PR15384, clang does not compile to such PHIs
(anymore?). The test case still hangs when replacing `%tmp6` with `%tmp`
in revisions before r176366 (where PR15384 has been fixed). The
occurrence of %tmp6 therefore was probably unintentional. Its value is
not used except in other PHIs.

Reviewers: majnemer, reames, JosephTremoulet, bkramer, grosser, jdoerfert, kparzysz, sanjoy

Differential Revision: http://reviews.llvm.org/D18443

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@264528 91177308-0d34-0410-b5e6-96231b3b80d8
2016-03-26 23:32:57 +00:00
Matthias Braun
a31e891389 Revert "Support arbitrary addrspace pointers in masked load/store intrinsics"
This commit broke LTO builds. Reverting it to unbreak the bots while the
issue is investigated. See also:

http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20160321/341002.html

This reverts r263158

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@264088 91177308-0d34-0410-b5e6-96231b3b80d8
2016-03-22 20:24:34 +00:00
Adam Nemet
367051414e [LoopVectorize] Annotate versioned loop with noalias metadata
Summary:
Use the new LoopVersioning facility (D16712) to add noalias metadata in
the vector loop if we versioned with memchecks.  This can enable some
optimization opportunities further down the pipeline (see the included
test or the benchmark improvement quoted in D16712).

The test also covers the bug I had in the initial version in D16712.

The vectorizer did not previously use LoopVersioning.  The reason is
that the vectorizer performs its transformations in single shot.  It
creates an empty single-block vector loop that it then populates with
the widened, if-converted instructions.  Thus creating an intermediate
versioned scalar loop seems wasteful.

So this patch (rather than bringing in LoopVersioning fully) adds a
special interface to LoopVersioning to allow the vectorizer to add
no-alias annotation while still performing its own versioning.

As the vectorizer propagates metadata from the instructions in the
original loop to the vector instructions we also check the pointer in
the original instruction and see if LoopVersioning can add no-alias
metadata based on the issued memchecks.

Reviewers: hfinkel, nadav, mzolotukhin

Subscribers: mzolotukhin, llvm-commits

Differential Revision: http://reviews.llvm.org/D17191

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@263744 91177308-0d34-0410-b5e6-96231b3b80d8
2016-03-17 20:32:37 +00:00
Adam Nemet
31bf7f9ec0 [LV] Preserve LoopInfo when store predication is used
This was a latent bug that got exposed by the change to add LoopSimplify
as a dependence to LoopLoadElimination.  Since LoopInfo was corrupted
after LV, LoopSimplify mis-compiled nbench in the test-suite (more
details in the PR).

The problem was that when we create the blocks for predicated stores we
didn't add those to any loops.

The original testcase for store predication provides coverage for this
assuming we verify LI on the way out of LV.

Fixes PR26952.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@263565 91177308-0d34-0410-b5e6-96231b3b80d8
2016-03-15 18:06:20 +00:00
Artur Pilipenko
980df33d17 Support arbitrary addrspace pointers in masked load/store intrinsics
This patch fixes the problem which occurs when loop-vectorize tries to use @llvm.masked.load/store intrinsic for a non-default addrspace pointer. It fails with "Calling a function with a bad signature!" assertion in CallInst constructor because it tries to pass a non-default addrspace pointer to the pointer argument which has default addrspace.

The fix is to add pointer type as another overloaded type to @llvm.masked.load/store intrinsics.

Reviewed By: reames

Differential Revision: http://reviews.llvm.org/D17270


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@263158 91177308-0d34-0410-b5e6-96231b3b80d8
2016-03-10 20:39:22 +00:00
Sanjay Patel
d05dce8ca6 [x86] fix cost model inaccuracy for vector memory ops
The irony of this patch is that one CPU that is affected is AMD Jaguar, and Jaguar
has a completely double-pumped AVX implementation. But getting the cost model to
reflect that is a much bigger problem. The small goal here is simply to improve on
the lie that !AVX2 == SandyBridge.

Differential Revision: http://reviews.llvm.org/D18000



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@263069 91177308-0d34-0410-b5e6-96231b3b80d8
2016-03-09 22:23:33 +00:00
Sanjay Patel
e8b70722e0 add a test RUN to show unexpected behavior
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@263037 91177308-0d34-0410-b5e6-96231b3b80d8
2016-03-09 17:53:28 +00:00
Matthew Simpson
72b5335cac [LoopUtils, LV] Fix PR26734
The vectorization of first-order recurrences (r261346) caused PR26734. When
detecting these recurrences, we need to ensure that the previous value is
actually defined inside the loop. This patch includes the fix and test case.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@262624 91177308-0d34-0410-b5e6-96231b3b80d8
2016-03-03 16:12:01 +00:00
Paul Robinson
45648a4496 Fix tests that used CHECK-NEXT-NOT and CHECK-DAG-NOT.
FileCheck actually doesn't support combo suffixes.

Differential Revision: http://reviews.llvm.org/D17588


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@262054 91177308-0d34-0410-b5e6-96231b3b80d8
2016-02-26 19:40:34 +00:00
Hans Wennborg
1836552368 Revert r255691 "[LoopVectorizer] Refine loop vectorizer's register usage calculator by ignoring specific instructions."
It caused PR26509.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@261368 91177308-0d34-0410-b5e6-96231b3b80d8
2016-02-19 21:40:12 +00:00
Matthew Simpson
3dd74513a8 [LV] Vectorize first-order recurrences
This patch enables the vectorization of first-order recurrences. A first-order
recurrence is a non-reduction recurrence relation in which the value of the
recurrence in the current loop iteration equals a value defined in the previous
iteration. The load PRE of the GVN pass often creates these recurrences by
hoisting loads from within loops.

In this patch, we add a new recurrence kind for first-order phi nodes and
attempt to vectorize them if possible. Vectorization is performed by shuffling
the values for the current and previous iterations. The vectorization cost
estimate is updated to account for the added shuffle instruction.

Contributed-by: Matthew Simpson and Chad Rosier <mcrosier@codeaurora.org>
Differential Revision: http://reviews.llvm.org/D16197

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@261346 91177308-0d34-0410-b5e6-96231b3b80d8
2016-02-19 17:56:08 +00:00
Silviu Baranga
865db3895b [LV] Fix PR26600: avoid out of bounds loads for interleaved access vectorization
Summary:
If we don't have the first and last access of an interleaved load group,
the first and last wide load in the loop can do an out of bounds
access. Even though we discard results from speculative loads,
this can cause problems, since it can technically generate page faults
(or worse).

We now discard interleaved load groups that don't have the first and
load in the group.

Reviewers: hfinkel, rengolin

Subscribers: rengolin, llvm-commits, mzolotukhin, anemet

Differential Revision: http://reviews.llvm.org/D17332

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@261331 91177308-0d34-0410-b5e6-96231b3b80d8
2016-02-19 15:46:10 +00:00
Elena Demikhovsky
2c7551bff2 Create masked gather and scatter intrinsics in Loop Vectorizer.
Loop vectorizer now knows to vectorize GEP and create masked gather and scatter intrinsics for random memory access.

The feature is enabled on AVX-512 target.
Differential Revision: http://reviews.llvm.org/D15690



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2016-02-17 19:23:04 +00:00
Silviu Baranga
23340531a1 [LV] Add support for insertelt/extractelt processing during type truncation
Summary:
While shrinking types according to the required bits, we can
encounter insert/extract element instructions. This will cause us to
reach an llvm_unreachable statement.

This change adds support for truncating insert/extract element
operations, and adds a regression test.

Reviewers: jmolloy

Subscribers: mzolotukhin, llvm-commits

Differential Revision: http://reviews.llvm.org/D17078

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@260893 91177308-0d34-0410-b5e6-96231b3b80d8
2016-02-15 15:38:17 +00:00
Silviu Baranga
e942cf87e8 [SCEV][LAA] Re-commit r260085 and r260086, this time with a fix for the memory
sanitizer issue. The PredicatedScalarEvolution's copy constructor
wasn't copying the Generation value, and was leaving it un-initialized.

Original commit message:

[SCEV][LAA] Add no wrap SCEV predicates and use use them to improve strided pointer detection

Summary:
This change adds no wrap SCEV predicates with:
  - support for runtime checking
  - support for expression rewriting:
      (sext ({x,+,y}) -> {sext(x),+,sext(y)}
      (zext ({x,+,y}) -> {zext(x),+,sext(y)}

Note that we are sign extending the increment of the SCEV, even for
the zext case. This is needed to cover the fairly common case where y would
be a (small) negative integer. In order to do this, this change adds two new
flags: nusw and nssw that are applicable to AddRecExprs and permit the
transformations above.

We also change isStridedPtr in LAA to be able to make use of
these predicates. With this feature we should now always be able to
work around overflow issues in the dependence analysis.

Reviewers: mzolotukhin, sanjoy, anemet

Subscribers: mzolotukhin, sanjoy, llvm-commits, rengolin, jmolloy, hfinkel

Differential Revision: http://reviews.llvm.org/D15412



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@260112 91177308-0d34-0410-b5e6-96231b3b80d8
2016-02-08 17:02:45 +00:00
Silviu Baranga
bbaff75d11 Revert r260086 and r260085. They have broken the memory
sanitizer bots.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@260087 91177308-0d34-0410-b5e6-96231b3b80d8
2016-02-08 11:56:15 +00:00
Silviu Baranga
41fcf12691 [SCEV][LAA] Add no wrap SCEV predicates and use use them to improve strided pointer detection
Summary:
This change adds no wrap SCEV predicates with:
  - support for runtime checking
  - support for expression rewriting:
      (sext ({x,+,y}) -> {sext(x),+,sext(y)}
      (zext ({x,+,y}) -> {zext(x),+,sext(y)}

Note that we are sign extending the increment of the SCEV, even for
the zext case. This is needed to cover the fairly common case where y would
be a (small) negative integer. In order to do this, this change adds two new
flags: nusw and nssw that are applicable to AddRecExprs and permit the
transformations above.

We also change isStridedPtr in LAA to be able to make use of
these predicates. With this feature we should now always be able to
work around overflow issues in the dependence analysis.

Reviewers: mzolotukhin, sanjoy, anemet

Subscribers: mzolotukhin, sanjoy, llvm-commits, rengolin, jmolloy, hfinkel

Differential Revision: http://reviews.llvm.org/D15412

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@260085 91177308-0d34-0410-b5e6-96231b3b80d8
2016-02-08 10:45:50 +00:00
James Molloy
c48890e194 [DemandedBits] Revert r249687 due to PR26071
This regresses a test in LoopVectorize, so I'll need to go away and think about how to solve this in a way that isn't broken.

From the writeup in PR26071:

What's happening is that ComputeKnownZeroes is telling us that all bits except the LSB are zero. We're then deciding that only the LSB needs to be demanded from the icmp's inputs.

This is where we're wrong - we're assuming that after simplification the bits that were known zero will continue to be known zero. But they're not - during trivialization the upper bits get changed (because an XOR isn't shrunk), so the icmp fails.

The fault is in demandedbits - its contract does clearly state that a non-demanded bit may either be zero or one.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@259649 91177308-0d34-0410-b5e6-96231b3b80d8
2016-02-03 15:05:06 +00:00
Igor Breger
3c3041375c AVX1 : Enable vector masked_load/store to AVX1.
Use AVX1 FP instructions (vmaskmovps/pd) in place of the AVX2 int instructions (vpmaskmovd/q).

Differential Revision: http://reviews.llvm.org/D16528

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@258675 91177308-0d34-0410-b5e6-96231b3b80d8
2016-01-25 10:17:11 +00:00
Cong Hou
e956465289 [LoopVectorizer] Refine loop vectorizer's register usage calculator by ignoring specific instructions.
(This is the third attempt to check in this patch, and the first two are r255454
and r255460. The once failed test file reg-usage.ll is now moved to
test/Transform/LoopVectorize/X86 directory with target datalayout and target
triple indicated.)

LoopVectorizationCostModel::calculateRegisterUsage() is used to estimate the
register usage for specific VFs. However, it takes into account many
instructions that won't be vectorized, such as induction variables,
GetElementPtr instruction, etc.. This makes the loop vectorizer too conservative
when choosing VF. In this patch, the induction variables that won't be
vectorized plus GetElementPtr instruction will be added to ValuesToIgnore set
so that their register usage won't be considered any more.


Differential revision: http://reviews.llvm.org/D15177




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@255691 91177308-0d34-0410-b5e6-96231b3b80d8
2015-12-15 22:45:09 +00:00
Cong Hou
dbef3b079d Revert r255460, which still causes test failures on some platforms.
Further investigation on the failures is ongoing.




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@255463 91177308-0d34-0410-b5e6-96231b3b80d8
2015-12-13 17:15:38 +00:00
Cong Hou
f26946fa52 [LoopVectorizer] Refine loop vectorizer's register usage calculator by ignoring specific instructions.
(This is the second attempt to check in this patch: REQUIRES: asserts is added
to reg-usage.ll now.)

LoopVectorizationCostModel::calculateRegisterUsage() is used to estimate the
register usage for specific VFs. However, it takes into account many
instructions that won't be vectorized, such as induction variables,
GetElementPtr instruction, etc.. This makes the loop vectorizer too conservative
when choosing VF. In this patch, the induction variables that won't be
vectorized plus GetElementPtr instruction will be added to ValuesToIgnore set
so that their register usage won't be considered any more.


Differential revision: http://reviews.llvm.org/D15177




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@255460 91177308-0d34-0410-b5e6-96231b3b80d8
2015-12-13 16:55:46 +00:00
Cong Hou
6f344e5da6 Revert r255454 as it leads to several test failers on buildbots.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@255456 91177308-0d34-0410-b5e6-96231b3b80d8
2015-12-13 09:28:57 +00:00
Cong Hou
c731de4630 [LoopVectorizer] Refine loop vectorizer's register usage calculator by ignoring specific instructions.
LoopVectorizationCostModel::calculateRegisterUsage() is used to estimate the
register usage for specific VFs. However, it takes into account many
instructions that won't be vectorized, such as induction variables,
GetElementPtr instruction, etc.. This makes the loop vectorizer too conservative
when choosing VF. In this patch, the induction variables that won't be
vectorized plus GetElementPtr instruction will be added to ValuesToIgnore set
so that their register usage won't be considered any more.


Differential revision: http://reviews.llvm.org/D15177




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@255454 91177308-0d34-0410-b5e6-96231b3b80d8
2015-12-13 08:44:08 +00:00
Charlie Turner
c8dc70b584 [LoopVectorize] Use MapVector rather than DenseMap for MinBWs.
The order in which instructions are truncated in truncateToMinimalBitwidths
effects code generation. Switch to a map with a determinisic order, since the
iteration order over a DenseMap is not defined.

This code is not hot, so the difference in container performance isn't
interesting.

Many thanks to David Blaikie for making me aware of MapVector!

Fixes PR25490.

Differential Revision: http://reviews.llvm.org/D14981



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@254179 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-26 20:39:51 +00:00
Elena Demikhovsky
43be5f580c Pointers in Masked Load, Store, Gather, Scatter intrinsics
The masked intrinsics support all integer and floating point data types. I added the pointer type to this list.
Added tests for CodeGen and for Loop Vectorizer.
Updated the Language Reference.

Differential Revision: http://reviews.llvm.org/D14150



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253544 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-19 07:17:16 +00:00
James Molloy
ae263d48b0 [LoopVectorize] Address post-commit feedback on r250032
Implemented as many of Michael's suggestions as were possible:
  * clang-format the added code while it is still fresh.
  * tried to change Value* to Instruction* in many places in computeMinimumValueSizes - unfortunately there are several places where Constants need to be handled so this wasn't possible.
  * Reduce the pass list on loop-vectorization-factors.ll.
  * Fix a bug where we were querying MinBWs for I->getOperand(0) but using MinBWs[I].

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@252469 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-09 14:32:05 +00:00
Peter Collingbourne
5f220beefc DI: Reverse direction of subprogram -> function edge.
Previously, subprograms contained a metadata reference to the function they
described. Because most clients need to get or set a subprogram for a given
function rather than the other way around, this created unneeded inefficiency.

For example, many passes needed to call the function llvm::makeSubprogramMap()
to build a mapping from functions to subprograms, and the IR linker needed to
fix up function references in a way that caused quadratic complexity in the IR
linking phase of LTO.

This change reverses the direction of the edge by storing the subprogram as
function-level metadata and removing DISubprogram's function field.

Since this is an IR change, a bitcode upgrade has been provided.

Fixes PR23367. An upgrade script for textual IR for out-of-tree clients is
attached to the PR.

Differential Revision: http://reviews.llvm.org/D14265

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@252219 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-05 22:03:56 +00:00
Elena Demikhovsky
2c4a333422 LoopVectorizer - skip 'bitcast' between GEP and load.
Skipping 'bitcast' in this case allows to vectorize load:

  %arrayidx = getelementptr inbounds double*, double** %in, i64 %indvars.iv
  %tmp53 = bitcast double** %arrayidx to i64*
  %tmp54 = load i64, i64* %tmp53, align 8

Differential Revision http://reviews.llvm.org/D14112



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@251907 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-03 10:29:34 +00:00