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Commit Graph

172427 Commits

Author SHA1 Message Date
Craig Topper
456baa52f2 [CostModel][X86] Fix overcounting arithmetic cost in illegal types in getArithmeticReductionCost/getMinMaxReductionCost
We were overcounting the number of arithmetic operations needed at each level before we reach a legal type. We were using the full vector type for that level, but we are going to split the input vector at that level in half. So the effective arithmetic operation cost at that level is half the width.

So for example on 8i32 on an sse target. Were were calculating the cost of an 8i32 op which is likely 2 for basic integer. Then after the loop we count 2 more v4i32 ops. For a total arith cost of 4. But if you look at the assembly there would only be 3 arithmetic ops.

There are still more bugs in this code that I'm going to work on next. The non pairwise code shouldn't count extract subvectors in the loop. There are no extracts, the types are split in registers. For pairwise we need to use 2 two src permute shuffles.

Differential Revision: https://reviews.llvm.org/D55397

llvm-svn: 348621
2018-12-07 18:20:56 +00:00
Craig Topper
bccb7f13ae [X86] Initialize and Register X86CondBrFoldingPass
To make X86CondBrFoldingPass can be run with --run-pass option, this can test one wrong assertion on analyzeCompare function for SUB32ri when its operand is not imm

Patch by Jianping Chen

Differential Revision: https://reviews.llvm.org/D55412

llvm-svn: 348620
2018-12-07 18:10:34 +00:00
Matt Arsenault
e910613f08 AMDGPU: Remove llvm.SI.tbuffer.store
llvm-svn: 348619
2018-12-07 18:03:47 +00:00
Simon Pilgrim
80dd2fdab9 [X86] Improve pfm counter coverage for llvm-exegesis
This patch attempts to improve pfm perf counter coverage for all the x86 CPUs that libpfm4 supports.

Intel/AMD CPU families tend to share names for cycle/uops counters so even if they don't have a scheduler model yet they can at least use the default values (checked against the libpfm4 source code).

The remaining CPUs (where their port/pipe resource counters are known) I've tried to add to the existing model mappings.

These are untested but don't represent a regression to current llvm-exegesis behaviour for these CPUs.

Differential Revision: https://reviews.llvm.org/D55432

llvm-svn: 348617
2018-12-07 17:48:40 +00:00
Matt Arsenault
a3f67ed4ba AMDGPU: Remove llvm.SI.buffer.load.dword
llvm-svn: 348616
2018-12-07 17:46:20 +00:00
Matt Arsenault
f4454532b0 AMDGPU: Remove llvm.AMDGPU.kill
This is the last of the old AMDGPU intrinsics.

llvm-svn: 348615
2018-12-07 17:46:16 +00:00
Sanjay Patel
d4c88a8dd2 [DAGCombiner] disable truncation of binops by default
As discussed in the post-commit thread of r347917, this
transform is fighting with an existing transform causing
an infinite loop or out-of-memory, so this is effectively 
reverting r347917 and its follow-up r348195 while we
investigate the bug.

llvm-svn: 348604
2018-12-07 15:47:52 +00:00
Nikita Popov
04e5b3198b Reapply "[DemandedBits][BDCE] Support vectors of integers"
DemandedBits and BDCE currently only support scalar integers. This
patch extends them to also handle vector integer operations. In this
case bits are not tracked for individual vector elements, instead a
bit is demanded if it is demanded for any of the elements. This matches
the behavior of computeKnownBits in ValueTracking and
SimplifyDemandedBits in InstCombine.

Unlike the previous iteration of this patch, getDemandedBits() can now
again be called on arbirary (sized) instructions, even if they don't
have integer or vector of integer type. (For vector types the size of the
returned mask will now be the scalar size in bits though.)

The added LoopVectorize test case shows a case which triggered an
assertion failure with the previous attempt, because getDemandedBits()
was called on a pointer-typed instruction.

Differential Revision: https://reviews.llvm.org/D55297

llvm-svn: 348602
2018-12-07 15:38:13 +00:00
Graham Sellers
141144803d [AMDGPU] Shrink scalar AND, OR, XOR instructions
This change attempts to shrink scalar AND, OR and XOR instructions which take an immediate that isn't inlineable.

It performs:
AND s0, s0, ~(1 << n) -> BITSET0 s0, n
OR s0, s0, (1 << n) -> BITSET1 s0, n
AND s0, s1, x -> ANDN2 s0, s1, ~x
OR s0, s1, x -> ORN2 s0, s1, ~x
XOR s0, s1, x -> XNOR s0, s1, ~x

In particular, this catches setting and clearing the sign bit for fabs (and x, 0x7ffffffff -> bitset0 x, 31 and or x, 0x80000000 -> bitset1 x, 31).

llvm-svn: 348601
2018-12-07 15:33:21 +00:00
Sanjay Patel
bf412c9070 [DAGCombiner] remove explicit calls to AddToWorkList; NFCI
As noted in the post-commit thread for rL347917:
http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20181203/608936.html
...we don't need to repeat these calls because the combiner does it automatically.

llvm-svn: 348597
2018-12-07 15:00:56 +00:00
Max Kazantsev
be11b6ca1a Introduce llvm.experimental.widenable_condition intrinsic
This patch introduces a new instinsic `@llvm.experimental.widenable_condition`
that allows explicit representation for guards. It is an alternative to using
`@llvm.experimental.guard` intrinsic that does not contain implicit control flow.

We keep finding places where `@llvm.experimental.guard` is not supported or
treated too conservatively, and there are 2 reasons to that:

- `@llvm.experimental.guard` has memory write side effect to model implicit control flow,
  and this sometimes confuses passes and analyzes that work with memory;
- Not all passes and analysis are aware of the semantics of guards. These passes treat them
  as regular throwing call and have no idea that the condition of guard may be used to prove
  something. One well-known place which had caused us troubles in the past is explicit loop
  iteration count calculation in SCEV. Another example is new loop unswitching which is not
  aware of guards. Whenever a new pass appears, we potentially have this problem there.

Rather than go and fix all these places (and commit to keep track of them and add support
in future), it seems more reasonable to leverage the existing optimizer's logic as much as possible.
The only significant difference between guards and regular explicit branches is that guard's condition
can be widened. It means that a guard contains (explicitly or implicitly) a `deopt` block successor,
and it is always legal to go there no matter what the guard condition is. The other successor is
a guarded block, and it is only legal to go there if the condition is true.

This patch introduces a new explicit form of guards alternative to `@llvm.experimental.guard`
intrinsic. Now a widenable guard can be represented in the CFG explicitly like this:


    %widenable_condition = call i1 @llvm.experimental.widenable.condition()
    %new_condition = and i1 %cond, %widenable_condition
    br i1 %new_condition, label %guarded, label %deopt

  guarded:
    ; Guarded instructions

  deopt:
    call type @llvm.experimental.deoptimize(<args...>) [ "deopt"(<deopt_args...>) ]

The new intrinsic `@llvm.experimental.widenable.condition` has semantics of an
`undef`, but the intrinsic prevents the optimizer from folding it early. This form
should exploit all optimization boons provided to `br` instuction, and it still can be
widened by replacing the result of `@llvm.experimental.widenable.condition()`
with `and` with any arbitrary boolean value (as long as the branch that is taken when
it is `false` has a deopt and has no side-effects).

For more motivation, please check llvm-dev discussion "[llvm-dev] Giving up using
implicit control flow in guards".

This patch introduces this new intrinsic with respective LangRef changes and a pass
that converts old-style guards (expressed as intrinsics) into the new form.

The naming discussion is still ungoing. Merging this to unblock further items. We can
later change the name of this intrinsic.

Reviewed By: reames, fedor.sergeev, sanjoy
Differential Revision: https://reviews.llvm.org/D51207

llvm-svn: 348593
2018-12-07 14:39:46 +00:00
Tim Northover
906154f438 ARM: use correct offset from base pointer (r6) in call frame regions.
When we had dynamic call frames (i.e. sp adjustment around each call) we
were including that adjustment into offsets calculated based on r6, even
though it's only sp that changes. This led to incorrect stack slot
accesses.

llvm-svn: 348591
2018-12-07 13:43:55 +00:00
David Green
76448ad394 [Targets] Add errors for tiny and kernel codemodel on targets that don't support them
Adds fatal errors for any target that does not support the Tiny or Kernel
codemodels by rejigging the getEffectiveCodeModel calls.

Differential Revision: https://reviews.llvm.org/D50141

llvm-svn: 348585
2018-12-07 12:10:23 +00:00
Simon Pilgrim
690edaebad Fix gcc7.3 -Wparentheses warning. NFCI.
llvm-svn: 348581
2018-12-07 11:10:03 +00:00
Xing GUO
4b00eac7d0 [yaml2obj] format some codes NFC.
Summary: This line is longer than 80 characters.

Subscribers: llvm-commits, jakehehrlich

Differential Revision: https://reviews.llvm.org/D55419

llvm-svn: 348580
2018-12-07 11:04:22 +00:00
Xing GUO
9441a3469b [yaml2obj] revert bad change
llvm-svn: 348579
2018-12-07 10:50:29 +00:00
Xing GUO
11cd73c5fb [yaml2obj] format some codes NFC.
Summary: This line is longer than 80 characters.

Subscribers: llvm-commits, jakehehrlich

Differential Revision: https://reviews.llvm.org/D55419

llvm-svn: 348578
2018-12-07 10:31:34 +00:00
Hans Wennborg
cacd663e58 Fix test/tools/llvm-mca/AArch64/Exynos/direct-branch.s on Mac
It was failing as below. Adding a triple seems to help.

--
: 'RUN: at line 2';   /work/llvm.combined/build.release/bin/llvm-mca -march=aarch64 -mcpu=exynos-m1 -resource-pressure=false < /work/llvm.combined/llvm/test/tools/llvm-mca/AArch64/Exynos/direct-branch.s | /work/llvm.combined/build.release/bin/FileCheck /work/llvm.combined/llvm/test/tools/llvm-mca/AArch64/Exynos/direct-branch.s -check-prefixes=ALL,M1
: 'RUN: at line 3';   /work/llvm.combined/build.release/bin/llvm-mca -march=aarch64 -mcpu=exynos-m3 -resource-pressure=false < /work/llvm.combined/llvm/test/tools/llvm-mca/AArch64/Exynos/direct-branch.s | /work/llvm.combined/build.release/bin/FileCheck /work/llvm.combined/llvm/test/tools/llvm-mca/AArch64/Exynos/direct-branch.s -check-prefixes=ALL,M3
--
Exit Code: 1

Command Output (stderr):
--
/work/llvm.combined/llvm/test/tools/llvm-mca/AArch64/Exynos/direct-branch.s:36:12: error: M1-NEXT: expected string not found in input
           ^
<stdin>:21:2: note: scanning from here
 1 0 0.25 b Ltmp0
 ^

--

llvm-svn: 348577
2018-12-07 09:58:33 +00:00
Roger Ferrer Ibanez
b8655608cc [utils] Use operator "in" instead of bound function "has_key"
has_key has been removed in Python 3. The in comparison operator can be used
instead.

Differential Revision: https://reviews.llvm.org/D55310

llvm-svn: 348576
2018-12-07 09:49:21 +00:00
Simon Pilgrim
66e4940592 [X86] Add ivybridge to llvm-exegesis PFM counter mappings
llvm-svn: 348575
2018-12-07 09:27:35 +00:00
Simon Pilgrim
344bd94c69 [SelectionDAG] Don't pass on DemandedElts when handling SCALAR_TO_VECTOR
Fixes an assertion:

llc: lib/CodeGen/SelectionDAG/SelectionDAG.cpp:2200: llvm::KnownBits llvm::SelectionDAG::computeKnownBits(llvm::SDValue, const llvm::APInt&, unsigned int) const: Assertion `(!Op.getValueType().isVector() || NumElts == Op.getValueType().getVectorNumElements()) && "Unexpected vector size"' failed.

Committed on behalf of: @pendingchaos (Rhys Perry)

Differential Revision: https://reviews.llvm.org/D55223

llvm-svn: 348574
2018-12-07 09:18:44 +00:00
Stefan Granitz
fc767a4720 [CMake] Add support for NO_INSTALL_RPATH argument in llvm_add_library()
Summary:
Allow clients to suppress setup of default RPATHs in designated library targets. This is used in LLDB when emitting liblldb as a framework bundle, which itself doesn't load further RPATH-dependent libraries.
This follows the approach in add_llvm_executable().

Reviewers: aprantl, JDevlieghere, davide, friss

Reviewed By: aprantl

Subscribers: mgorny, lldb-commits, llvm-commits, #lldb

Differential Revision: https://reviews.llvm.org/D55316

llvm-svn: 348573
2018-12-07 09:12:54 +00:00
Ranjeet Singh
377ecd93ee [IR] Don't assume all functions are 4 byte aligned
In some cases different alignments for function might be used to save
space e.g. thumb mode with -Oz will try to use 2 byte function
alignment. Similar patch that fixed this in other areas exists here
https://reviews.llvm.org/D46110

This was approved previously https://reviews.llvm.org/D55115 (r348215)
but when committed it caused failures on the sanitizer buildbots when
building llvm with clang (containing this patch). This is now fixed
because I've added a check to see if getting the parent module returns
null if it does then set the alignment to 0.

Differential Revision: https://reviews.llvm.org/D55115

llvm-svn: 348571
2018-12-07 08:34:59 +00:00
Markus Lavin
6da1480917 [PM] Port LoadStoreVectorizer to the new pass manager.
Differential Revision: https://reviews.llvm.org/D54848

llvm-svn: 348570
2018-12-07 08:23:37 +00:00
Max Kazantsev
dafa7c4e1d [LoopSimplifyCFG] Do not deal with loops with irreducible CFG inside
The current algorithm that collects live/dead/inloop blocks relies on some invariants
related to RPO and PO traversals. In particular, the important fact it requires is that
the only loop's latch is the first block in PO traversal. It also relies on fact that during
RPO we visit all prececessors of a block before we visit this block (backedges ignored).

If a loop has irreducible non-loop cycle inside, both these assumptions may break.
This patch adds detection for this situation and prohibits the terminator folding
for loops with irreducible CFG.

We can in theory support this later, for this some algorithmic changes are needed.
Besides, irreducible CFG is not a frequent situation and we can just don't bother.

Thanks @uabelho for finding this!

Differential Revision: https://reviews.llvm.org/D55357
Reviewed By: skatkov

llvm-svn: 348567
2018-12-07 05:44:45 +00:00
Zi Xuan Wu
699d18eb82 [PowerPC] Fix assert from machine verify pass that missing undef register flag
Fix assert about using an undefined physical register in machine instruction verify pass. 
The reason is that register flag undef is missing when doing transformation from If Conversion Pass.

```
Bad machine code: Using an undefined physical register 
- function:    func_65
- basic block: %bb.0 entry (0x10024740738)
- instruction: BCLR killed $cr5lt, implicit $lr8, implicit $rm, implicit undef $x3
- operand 0:   killed $cr5lt
LLVM ERROR: Found 1 machine code errors.
```

There are also other existing testcases with same issue. So I add -verify-machineinstrs option to open verifying.

Differential Revision: https://reviews.llvm.org/D55408

llvm-svn: 348566
2018-12-07 05:25:16 +00:00
Evandro Menezes
dd16b36e31 [llvm-mca] Improve test (NFC)
Add more instructions to the test for Cortex.

llvm-svn: 348565
2018-12-07 03:23:36 +00:00
Evandro Menezes
f9084248b9 [llvm-mca] Improve test (NFC)
Add a label to make explicit that the branch is short for Exynos.

llvm-svn: 348564
2018-12-07 03:23:14 +00:00
Vedant Kumar
a5d628103d [CodeExtractor] Store outputs at the first valid insertion point
When CodeExtractor outlines values which are used by the original
function, it must store those values in some in-out parameter. This
store instruction must not be inserted in between a PHI and an EH pad
instruction, as that results in invalid IR.

This fixes the following verifier failure seen while outlining within
ObjC methods with live exit values:

  The unwind destination does not have an exception handling instruction!
    %call35 = invoke i8* bitcast (i8* (i8*, i8*, ...)* @objc_msgSend to i8* (i8*, i8*)*)(i8* %exn.adjusted, i8* %1)
            to label %invoke.cont34 unwind label %lpad33, !dbg !4183
  The unwind destination does not have an exception handling instruction!
    invoke void @objc_exception_throw(i8* %call35) #12
            to label %invoke.cont36 unwind label %lpad33, !dbg !4184
  LandingPadInst not the first non-PHI instruction in the block.
    %3 = landingpad { i8*, i32 }
            catch i8* null, !dbg !1411

rdar://46540815

llvm-svn: 348562
2018-12-07 03:01:54 +00:00
Armando Montanez
101947bd66 Revert "[llvm-tapi] Don't override SequenceTraits for std::string"
Revert r348551 since it triggered some warnings that don't appear to have a quick fix.

llvm-svn: 348560
2018-12-07 01:31:28 +00:00
Nikita Popov
80f672ac7f Revert "[DemandedBits][BDCE] Support vectors of integers"
This reverts commit r348549. Causing assertion failures during
clang build.

llvm-svn: 348558
2018-12-07 00:42:03 +00:00
Sanjay Patel
c041183d75 [DAGCombiner] use root SDLoc for all nodes created by logic fold
If this is not a valid way to assign an SDLoc, then we get this
wrong all over SDAG.

I don't know enough about the SDAG to explain this. IIUC, theoretically,
debug info is not supposed to affect codegen. But here it has clearly
affected 3 different targets, and the x86 change is an actual improvement.

llvm-svn: 348552
2018-12-07 00:01:57 +00:00
Armando Montanez
2801d1750e [llvm-tapi] Don't override SequenceTraits for std::string
Change the ELF YAML implementation of TextAPI so NeededLibs uses flow
sequence vector correctly instead of overriding the YAML implementation
for std::vector<std::string>>.

This should fix the test failure with the LLVM_LINK_LLVM_DYLIB build mentioned in D55381.

Still passes existing tests that cover this.

Differential Revision: https://reviews.llvm.org/D55390

llvm-svn: 348551
2018-12-06 23:59:32 +00:00
Sanjay Patel
9e9c307c6d [DAGCombiner] don't bother saving a SDLoc for a node that's dead; NFCI
We shouldn't care about the debug location for a node that
we're creating, but attaching the root of the pattern should
be the best effort. (If this is not true, then we are doing
it wrong all over the SDAG).

This is no-functional-change-intended, and there are no
regression test diffs...and that's what I expected. But
there's a similar line above this diff, where those
assumptions apparently do not hold.

llvm-svn: 348550
2018-12-06 23:53:58 +00:00
Nikita Popov
4b01d392e0 [DemandedBits][BDCE] Support vectors of integers
DemandedBits and BDCE currently only support scalar integers. This
patch extends them to also handle vector integer operations. In this
case bits are not tracked for individual vector elements, instead a
bit is demanded if it is demanded for any of the elements. This matches
the behavior of computeKnownBits in ValueTracking and
SimplifyDemandedBits in InstCombine.

The getDemandedBits() method can now only be called on instructions that
have integer or vector of integer type. Previously it could be called on
any sized instruction (even if it was not particularly useful). The size
of the return value is now always the scalar size in bits (while
previously it was the type size in bits).

Differential Revision: https://reviews.llvm.org/D55297

llvm-svn: 348549
2018-12-06 23:50:32 +00:00
Nikita Popov
a4fb132929 [BDCE] Add tests for BDCE applied to vector instructions; NFC
These are baseline tests for D55297.

llvm-svn: 348548
2018-12-06 23:50:19 +00:00
Sanjay Patel
cbfbd67626 [DAGCombiner] more clean up in hoistLogicOpWithSameOpcodeHands(); NFC
This code can still misbehave.

llvm-svn: 348547
2018-12-06 23:39:28 +00:00
Nico Weber
bcee0107a7 Run git ls-files '*.gn' '*.gni' | xargs -n 1 gn format.
llvm-svn: 348539
2018-12-06 22:40:05 +00:00
Nico Weber
eeb1f9b2da [gn build] merge r348505.
llvm-svn: 348537
2018-12-06 22:36:16 +00:00
Craig Topper
7381e47ad5 [X86] Directly create ADC/SBB nodes instead of using ADD/SUB with (and SETCC_CARRY, 1)
This addresses a FIXME and avoids depending on an isel pattern match I think. I've remove the isel patterns too since he have no lit tests left that cover them. Hopefully that really means they are unused.

I'm trying to decide if we need SETCC_CARRY. This removes one of its usages.

Differential Revision: https://reviews.llvm.org/D55355

llvm-svn: 348536
2018-12-06 22:26:59 +00:00
Sanjay Patel
ea83a1d238 [DAGCombiner] don't group bswap with casts in logic hoisting fold
This was probably organized as it was because bswap is a unary op.
But that's where the similarity to the other opcodes ends. We should
not limit this transform to scalars, and we should not try it if
either input has other uses. This is another step towards trying to
clean this whole function up to prevent it from causing infinite loops
and memory explosions. 

Earlier commits in this series:
rL348501
rL348508
rL348518

llvm-svn: 348534
2018-12-06 22:10:44 +00:00
Sanjay Patel
c93f0d3fcd [x86] add test for vector bitwise-logic-of-bswaps; NFC
llvm-svn: 348530
2018-12-06 21:56:30 +00:00
Sanjay Patel
27dc1910bb [DAGCombiner] reduce indent; NFC
Unlike some of the folds in hoistLogicOpWithSameOpcodeHands()
above this shuffle transform, this has the expected hasOneUse()
checks in place.

llvm-svn: 348523
2018-12-06 20:02:47 +00:00
Andrea Di Biagio
c49870284c [DagCombiner][X86] Simplify a ConcatVectors of a scalar_to_vector with undef.
This patch introduces a new DAGCombiner rule to simplify concat_vectors nodes:

concat_vectors( bitcast (scalar_to_vector %A), UNDEF)
    --> bitcast (scalar_to_vector %A)

This patch only partially addresses PR39257. In particular, it is enough to fix
one of the two problematic cases mentioned in PR39257. However, it is not enough
to fix the original test case posted by Craig; that particular case would
probably require a more complicated approach (and knowledge about used bits).

Before this patch, we used to generate the following code for function PR39257
(-mtriple=x86_64 , -mattr=+avx):

vmovsd  (%rdi), %xmm0           # xmm0 = mem[0],zero
vxorps  %xmm1, %xmm1, %xmm1
vblendps        $3, %xmm0, %xmm1, %xmm0 # xmm0 = xmm0[0,1],xmm1[2,3]
vmovaps %ymm0, (%rsi)
vzeroupper
retq

Now we generate this:

vmovsd  (%rdi), %xmm0           # xmm0 = mem[0],zero
vmovaps %ymm0, (%rsi)
vzeroupper
retq

As a side note: that VZEROUPPER is completely redundant...

I guess the vzeroupper insertion pass doesn't realize that the definition of
%xmm0 from vmovsd is already zeroing the upper half of %ymm0. Note that on
%-mcpu=btver2, we don't get that vzeroupper because pass vzeroupper insertion
%pass is disabled.

Differential Revision: https://reviews.llvm.org/D55274

llvm-svn: 348522
2018-12-06 19:55:38 +00:00
Sanjay Patel
504d614e86 [DAGCombiner] don't hoist logic op if operands have other uses, part 2
The PPC test with 2 extra uses seems clearly better by avoiding this transform. 
With 1 extra use, we also prevent an extra register move (although that might
be an RA problem). The general rule should be to only make a change here if
it is always profitable. The x86 diffs are all neutral.

llvm-svn: 348518
2018-12-06 19:18:56 +00:00
Simon Pilgrim
61ddd35ee0 Fix Wdocumentation warning. NFCI.
llvm-svn: 348517
2018-12-06 19:17:28 +00:00
Sanjay Patel
d725fcf246 [PowerPC] add tests for hoisting bitwise logic; NFC
llvm-svn: 348516
2018-12-06 19:05:19 +00:00
Adrian Prantl
7e7967478b Reapply "Adapt gcov to changes in CFE."
This reverts commit r348203 and reapplies D55085 with an additional
GCOV bugfix to make the change NFC for relative file paths in .gcno files.

Thanks to Ilya Biryukov for additional testing!

Original commit message:

    Update Diagnostic handling for changes in CFE.

    The clang frontend no longer emits the current working directory for
    DIFiles containing an absolute path in the filename: and will move the
    common prefix between current working directory and the file into the
    directory: component.

    https://reviews.llvm.org/D55085

llvm-svn: 348512
2018-12-06 18:44:48 +00:00
Evandro Menezes
ee698790d2 [AArch64] Fix Exynos predicate
Fix predicate for arithmetic instructions with shift and/or extend.

llvm-svn: 348510
2018-12-06 18:25:37 +00:00
Sanjay Patel
8ba52a75ed [DAGCombiner] don't hoist logic op if operands have other uses
The AVX512 diffs are neutral, but the bswap test shows a clear overreach in 
hoistLogicOpWithSameOpcodeHands(). If we don't check for other uses, we can 
increase the instruction count.

This could also fight with transforms trying to go in the opposite direction 
and possibly blow up/infinite loop. This might be enough to solve the bug 
noted here:
http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20181203/608593.html

I did not add the hasOneUse() checks to all opcodes because I see a perf 
regression for at least one opcode. We may decide that's irrelevant in the
face of potential compiler crashing, but I'll see if I can salvage that first.

llvm-svn: 348508
2018-12-06 18:16:32 +00:00