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140809 Commits

Author SHA1 Message Date
Esme-Yi
f754a1db1b Revert "[PowerPC] Extend folding RLWINM + RLWINM to post-RA."
This reverts commit 119ab2181e6ed823849c93d55af8e989c28c9f3c.
2020-11-03 16:34:02 +00:00
Tim Renouf
83e3834a8d [AMDGPU] Add gfx1033 target
Differential Revision: https://reviews.llvm.org/D90447

Change-Id: If2650fc7f31bbdd49c76e74a9ca8e3734d769761
2020-11-03 16:27:48 +00:00
Tim Renouf
2a63696860 [AMDGPU] Add gfx90c target
This differentiates the Ryzen 4000/4300/4500/4700 series APUs that were
previously included in gfx909.

Differential Revision: https://reviews.llvm.org/D90419

Change-Id: Ia901a7157eb2f73ccd9f25dbacec38427312377d
2020-11-03 16:27:43 +00:00
Jay Foad
d6e4e20e6b [AMDGPU] Fix ds_read2/write2 with unaligned offsets
These instructions use a scaled offset. We were wrongly selecting them
even when the required offset was not a multiple of the scale factor.

Differential Revision: https://reviews.llvm.org/D90607
2020-11-03 15:16:10 +00:00
Jameson Nash
11a667f122 make the AsmPrinterHandler array public
This lets external consumers customize the output, similar to how
AssemblyAnnotationWriter lets the caller define callbacks when printing
IR. The array of handlers already existed, this just cleans up the code
so that it can be exposed publically.

Replaces https://reviews.llvm.org/D74158

Differential Revision: https://reviews.llvm.org/D89613
2020-11-03 10:02:09 -05:00
Simon Pilgrim
fc543f8a95 [DAG] computeKnownBits - Move (most) ISD::SHL handling into KnownBits::shl
As discussed on D90527, we should be be trying to move shift handling functionality into KnownBits to avoid code duplication in SelectionDAG/GlobalISel/ValueTracking.

The refactor to use the KnownBits fixed/min/max constant helpers allows us to hit a couple of cases that we were missing before.

We still need the getValidMinimumShiftAmountConstant case as KnownBits doesn't handle per-element vector cases.
2020-11-03 14:22:28 +00:00
Sanjay Patel
d761b7c23c [x86] update cost table comments for maxnum; NFC
Follow-up suggested in D90613.
2020-11-03 08:09:59 -05:00
Roman Lebedev
67e1befafc [InstCombine] Perform C-(X+C2) --> (C-C2)-X transform before using Negator
In particular, it makes it fire for C=0, because negator doesn't want
to perform that fold since in general it's not beneficial.
2020-11-03 16:06:52 +03:00
Roman Lebedev
ca79221be4 [InstCombine] Negator: - (C - %x) --> %x - C (PR47997)
This relaxes one-use restriction on that `sub` fold,
since apparently the addition of Negator broke
preexisting `C-(C2-X) --> X+(C-C2)` (with C=0) fold.
2020-11-03 16:06:51 +03:00
Florian Hahn
8985e25f47 [SCCP] Handle bitcast of vector constants.
Vectors where all elements have the same known constant range are treated as a
single constant range in the lattice. When bitcasting such vectors, there is a
mis-match between the width of the lattice value (single constant range) and
the original operands (vector). Go to overdefined in that case.

Fixes PR47991.
2020-11-03 12:58:39 +00:00
David Green
be5f4f896c [ARM] Remove unused variable. NFC 2020-11-03 12:58:10 +00:00
Hans Wennborg
0be5551915 Revert "[CodeGen] [WinException] Only produce handler data at the end of the function if needed"
This caused an explosion in ICF times during linking on Windows when libfuzzer
instrumentation is enabled. For a small binary we see ICF time go from ~0 to
~10 s. For a large binary it goes from ~1 s to forevert (I gave up after 30
minutes).

See comment on the code review.

> If we are going to write handler data (that is written as variable
> length data following after the unwind info in .xdata), we need to
> emit the handler data immediately, but for cases where no such
> info is going to be written, skip emitting it right away. (Unwind
> info for all remaining functions that hasn't gotten it emitted
> directly is emitted at the end.)
>
> This does slightly change the ordering of sections (triggering a
> bunch of updates to DebugInfo/COFF tests), but the change should be
> benign.
>
> This also matches GCC's assembly output, which doesn't output
> .seh_handlerdata unless it actually is needed.
>
> For ARM64, the unwind info can be packed into the runtime function
> entry itself (leaving no data in the .xdata section at all), but
> that can only be done if there's no follow-on data in the .xdata
> section. If emission of the unwind info is triggered via
> EmitWinEHHandlerData (or the .seh_handlerdata directive), which
> implicitly switches to the .xdata section, there's a chance of the
> caller wanting to pass further data there, so the packed format
> can't be used in that case.
>
> Differential Revision: https://reviews.llvm.org/D87448

This reverts commit 36c64af9d7f97414d48681b74352c9684077259b.
2020-11-03 13:12:10 +01:00
Stefan Gränitz
07d8c057bd [JITLink][ELF] Implement R_X86_64_PLT32 relocations
Basic implementation for call and jmp branches with 32 bit offset. Branches to local targets produce
Branch32 edges that are resolved like a regular PCRel32 relocations. Branches to external (undefined)
targets produce Branch32ToStub edges and go through a PLT entry by default. If the target happens to
get resolved within the 32 bit range from the callsite, the edge is relaxed during post-allocation
optimization. There is a test for each of these cases.

Reviewed By: lhames

Differential Revision: https://reviews.llvm.org/D90331
2020-11-03 12:05:54 +00:00
David Green
1b81a85e7e [ARM] Treat memcpy/memset/memmove as call instructions for low overhead loops
If an instruction will be lowered to a call there is no advantage of
using a low overhead loop as the LR register will need to be spilled and
reloaded around the call, and the low overhead will end up being
reverted. This teaches our hardware loop lowering that these memory
intrinsics will be calls under certain situations.

Differential Revision: https://reviews.llvm.org/D90439
2020-11-03 11:53:09 +00:00
Simon Pilgrim
63512b001b [AggressiveInstCombine] Generalize foldGuardedRotateToFunnelShift to generic funnel shifts
The fold currently only handles rotation patterns, but with the maturation of backend funnel shift handling we can now realistically handle all funnel shift patterns.

This should allow us to begin resolving PR46896 et al.

Differential Revision: https://reviews.llvm.org/D90625
2020-11-03 10:49:49 +00:00
Florian Hahn
3a9ee235ce [SLP] Pass VecPred argument to getCmpSelInstrCost.
Check if all compares in VL have the same predicate and pass it to
getCmpSelInstrCost, to improve cost-modeling on targets that only
support compare/select combinations for certain uniform predicates.

This leads to additional vectorization in some cases

```
Same hash: 217 (filtered out)
Remaining: 19
Metric: SLP.NumVectorInstructions

Program                                        base    slp2    diff
 test-suite...marks/SciMark2-C/scimark2.test    11.00   26.00  136.4%
 test-suite...T2006/445.gobmk/445.gobmk.test    79.00  135.00  70.9%
 test-suite...ediabench/gsm/toast/toast.test    54.00   71.00  31.5%
 test-suite...telecomm-gsm/telecomm-gsm.test    54.00   71.00  31.5%
 test-suite...CI_Purple/SMG2000/smg2000.test   426.00  542.00  27.2%
 test-suite...ch/g721/g721encode/encode.test    30.00   24.00  -20.0%
 test-suite...000/186.crafty/186.crafty.test   116.00  138.00  19.0%
 test-suite...ications/JM/ldecod/ldecod.test   697.00  765.00   9.8%
 test-suite...6/464.h264ref/464.h264ref.test   822.00  886.00   7.8%
 test-suite...chmarks/MallocBench/gs/gs.test   154.00  162.00   5.2%
 test-suite...nsumer-lame/consumer-lame.test   621.00  651.00   4.8%
 test-suite...lications/ClamAV/clamscan.test   223.00  231.00   3.6%
 test-suite...marks/7zip/7zip-benchmark.test   680.00  695.00   2.2%
 test-suite...CFP2000/177.mesa/177.mesa.test   2121.00 2129.00  0.4%
 test-suite...:: External/Povray/povray.test   2406.00 2412.00  0.2%
 test-suite...TimberWolfMC/timberwolfmc.test   634.00  634.00   0.0%
 test-suite...CFP2006/433.milc/433.milc.test   1036.00 1036.00  0.0%
 test-suite.../Benchmarks/nbench/nbench.test   321.00  321.00   0.0%
 test-suite...ctions-flt/Reductions-flt.test    NaN      5.00   nan%
```

Reviewed By: RKSimon

Differential Revision: https://reviews.llvm.org/D90124
2020-11-03 10:16:43 +00:00
Nicholas Guy
8b3116b36c [AArch64] Redundant masks in downcast long multiply
Adds patterns to catch masks preceeding a long multiply,
and generating a single umull/smull instruction instead.

Differential revision: https://reviews.llvm.org/D89956
2020-11-03 10:12:28 +00:00
David Green
41688b499e [CostModel] Make target intrinsics cheap by default
This patch changes the intrinsics cost model to assume that by default
target intrinsics are cheap. This didn't seem to be the case for all
intrinsics, and is potentially an MVE problem due to our scalarization
overheads. Cheap seems to be a good default in general though.

Differential Revision: https://reviews.llvm.org/D90597
2020-11-03 09:58:28 +00:00
Petar Avramovic
cf35e6aad4 AMDGPU/GlobalISel: Use same builder/observer in post-legalizer-combiner
Change match/apply functions into methods of new target specific combiner
helper class. Use reference to MachineIRBuilder from helper instead of
constructing new MachineIRBuilder each time new instruction needs to made.
Allows correct tracking of newly created instructions.

Differential Revision: https://reviews.llvm.org/D90623
2020-11-03 09:24:50 +01:00
Max Kazantsev
9c353872bf [NFC] Refactor code in IndVars, preparing for further improvement 2020-11-03 15:08:12 +07:00
Esme-Yi
cc2de8bfa9 [PowerPC] Extend folding RLWINM + RLWINM to post-RA.
Summary: This patch depends on D89846. We have the patterns to fold 2 RLWINMs in ppc-mi-peephole, while some RLWINM will be generated after RA, for example rGc4690b007743. If the RLWINM generated after RA followed by another RLWINM, we expect to perform the optimization after RA, too.

Reviewed By: shchenz, steven.zhang

Differential Revision: https://reviews.llvm.org/D89855
2020-11-03 07:44:11 +00:00
Max Kazantsev
6a18756c16 [NFC] Split lambda into 2 parts for further reuse 2020-11-03 14:13:55 +07:00
Craig Topper
3eb7636233 [RISCV] Remove isel patterns for fshl/fshr with same inputs. NFC
These were being selected to ROL/ROR, but DAG combine should
canonicalize fshl/fshr with same inputs to rotl/rotr which we
also have patterns for.
2020-11-02 23:12:18 -08:00
Max Kazantsev
b0c85eefb0 [IndVars] Use knowledge about execution on last iteration when removing checks
If we know that some check will not be executed on the last iteration, we can use this
fact to eliminate its check.

Differential Revision: https://reviews.llvm.org/D88210
Reviwed By: ebrevnov
2020-11-03 13:38:58 +07:00
Esme-Yi
04514155d5 [NFC][PowerPC] Move the folding RLWINMs from ppc-mi-peephole to PPCInstrInfo.
Summary: We have the patterns to fold 2 RLWINMs in ppc-mi-peephole, while some RLWINM will be generated after RA, for example D88274. If the RLWINM generated after RA followed by another RLWINM, we expect to perform the optimization after RA, too.
This is a NFC patch to move the folding patterns to PPCInstrInfo, and the follow-up works will be calling it in pre-emit-peephole and expand the patterns to handle more cases.

Reviewed By: shchenz

Differential Revision: https://reviews.llvm.org/D89846
2020-11-03 06:28:56 +00:00
Jessica Clarke
d022c319e8 [CodeGen] Fix regression from D83655
Arm EHABI has a null LSDASection as it does its own thing, so we should
continue to return null in that case rather than try and cast it.
2020-11-03 03:57:46 +00:00
Jessica Clarke
7b1a5513ca [RISCV] Only return DestSourcePair from isCopyInstrImpl for registers
ADDI often has a frameindex in operand 1, but consumers of this
interface, such as MachineSink, tend to call getReg() on the Destination
and Source operands, leading to the following crash when building
FreeBSD after this implementation was added in 8cf6778d30:

```
clang: llvm/include/llvm/CodeGen/MachineOperand.h:359: llvm::Register llvm::MachineOperand::getReg() const: Assertion `isReg() && "This is not a register operand!"' failed.
PLEASE submit a bug report to https://bugs.llvm.org/ and include the crash backtrace, preprocessed source, and associated run script.
Stack dump:
 #0 0x00007f4286f9b4d0 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) llvm/lib/Support/Unix/Signals.inc:563:0
 #1 0x00007f4286f9b587 PrintStackTraceSignalHandler(void*) llvm/lib/Support/Unix/Signals.inc:630:0
 #2 0x00007f4286f9926b llvm::sys::RunSignalHandlers() llvm/lib/Support/Signals.cpp:71:0
 #3 0x00007f4286f9ae52 SignalHandler(int) llvm/lib/Support/Unix/Signals.inc:405:0
 #4 0x00007f428646ffd0 (/lib/x86_64-linux-gnu/libc.so.6+0x3efd0)
 #5 0x00007f428646ff47 raise /build/glibc-2ORdQG/glibc-2.27/signal/../sysdeps/unix/sysv/linux/raise.c:51:0
 #6 0x00007f42864718b1 abort /build/glibc-2ORdQG/glibc-2.27/stdlib/abort.c:81:0
 #7 0x00007f428646142a __assert_fail_base /build/glibc-2ORdQG/glibc-2.27/assert/assert.c:89:0
 #8 0x00007f42864614a2 (/lib/x86_64-linux-gnu/libc.so.6+0x304a2)
 #9 0x00007f428d4078e2 llvm::MachineOperand::getReg() const llvm/include/llvm/CodeGen/MachineOperand.h:359:0
#10 0x00007f428d8260e7 attemptDebugCopyProp(llvm::MachineInstr&, llvm::MachineInstr&) llvm/lib/CodeGen/MachineSink.cpp:862:0
#11 0x00007f428d826442 performSink(llvm::MachineInstr&, llvm::MachineBasicBlock&, llvm::MachineInstrBundleIterator<llvm::MachineInstr, false>, llvm::SmallVectorImpl<llvm::MachineInstr*>&) llvm/lib/CodeGen/MachineSink.cpp:918:0
#12 0x00007f428d826e27 (anonymous namespace)::MachineSinking::SinkInstruction(llvm::MachineInstr&, bool&, std::map<llvm::MachineBasicBlock*, llvm::SmallVector<llvm::MachineBasicBlock*, 4u>, std::less<llvm::MachineBasicBlock*>, std::allocator<std::pair<llvm::MachineBasicBlock* const, llvm::SmallVector<llvm::MachineBasicBlock*, 4u> > > >&) llvm/lib/CodeGen/MachineSink.cpp:1073:0
#13 0x00007f428d824a2c (anonymous namespace)::MachineSinking::ProcessBlock(llvm::MachineBasicBlock&) llvm/lib/CodeGen/MachineSink.cpp:410:0
#14 0x00007f428d824513 (anonymous namespace)::MachineSinking::runOnMachineFunction(llvm::MachineFunction&) llvm/lib/CodeGen/MachineSink.cpp:340:0
```

Thus, check that operand 1 is also a register in the condition.

Reviewed By: arichardson, luismarques

Differential Revision: https://reviews.llvm.org/D89090
2020-11-03 03:55:47 +00:00
Qiu Chaofan
fd9800defc [PowerPC] Skip IEEE 128-bit FP type in FastISel
Vector types, quadword integers and f128 currently cannot be handled in
FastISel. We did not skip f128 type in lowering arguments, which causes
a crash. This patch will fix it.

Reviewed By: steven.zhang

Differential Revision: https://reviews.llvm.org/D90206
2020-11-03 11:17:11 +08:00
Qiu Chaofan
07283aa0c6 [PowerPC] [NFC] Rename VCMPo to VCMP_rec
Reviewed By: jsji

Differential Revision: https://reviews.llvm.org/D90581
2020-11-03 11:10:59 +08:00
Alina Sbirlea
c3d75ade94 [LICM] Add assert of AST/MSSA exclusiveness.
The API `canSinkOrHoistInst` may be called by LoopSink. Add assert to
avoid having two analyses passed in.
2020-11-02 18:04:43 -08:00
Akira Hatanaka
a14d53181f Remove unused parameter 2020-11-02 17:40:06 -08:00
Fangrui Song
c6463c4b94 [PowerPC] Parse and ignore .machine ppc64
In the wild, kexec-tools purgatory/arch/ppc64/v2wrap.S and hvcall.S
use this directive.
2020-11-02 16:49:57 -08:00
Gaurav Jain
4f8e5f73dc [NFC] Use [MC]Register in Live-ness tracking
Differential Revision: https://reviews.llvm.org/D90611
2020-11-02 15:46:13 -08:00
Jonas Devlieghere
6989bc45bd [MachO] Also recongize __swift_ast as a debug info section
Address post-commit review from Adrian.
2020-11-02 14:49:57 -08:00
Fangrui Song
4be7087bf0 [AsmPrinter] Split up .gcc_except_table
MC currently produces monolithic .gcc_except_table section. GCC can split up .gcc_except_table:

* if comdat: `.section .gcc_except_table._Z6comdatv,"aG",@progbits,_Z6comdatv,comdat`
* otherwise, if -ffunction-sections: `.section .gcc_except_table._Z3fooi,"a",@progbits`

This ensures that (a) non-prevailing copies are discarded and (b)
.gcc_except_table associated to discarded text sections can be discarded by a
.gcc_except_table-aware linker (GNU ld, but not gold or LLD)

This patches matches the GCC behavior. If -fno-unique-section-names is
specified, we don't append the suffix. If -ffunction-sections is additionally specified,
use `.section ...,unique`.

Note, if clang driver communicates that the linker is LLD and we know it
is new (11.0.0 or later) we can use SHF_LINK_ORDER to avoid string table
costs, at least in the -fno-unique-section-names case. We cannot use it on GNU
ld because as of binutils 2.35 it does not support mixed SHF_LINK_ORDER &
non-SHF_LINK_ORDER components in an output section
https://sourceware.org/bugzilla/show_bug.cgi?id=26256

For RISC-V -mrelax, this patch additionally fixes an assembler-linker
interaction problem: because a section is shrinkable, the length of a call-site
code range is not a constant. Relocations referencing the associated text
section (STT_SECTION) are needed. However, a STB_LOCAL relocation referencing a
discarded section group member from outside the group is disallowed by the ELF
specification (PR46675):

```
// a.cc
inline int comdat() { try { throw 1; } catch (int) { return 1; } return 0; }
int main() { return comdat(); }

// b.cc
inline int comdat() { try { throw 1; } catch (int) { return 1; } return 0; }
int foo() { return comdat(); }

clang++ -target riscv64-linux -c a.cc b.cc -fPIC -mno-relax
ld.lld -shared a.o b.o => ld.lld: error: relocation refers to a symbol in a discarded section:
```

-fbasic-block-sections= is similar to RISC-V -mrelax: there are outstanding relocations.

Reviewed By: jrtc27, rahmanl

Differential Revision: https://reviews.llvm.org/D83655
2020-11-02 14:36:25 -08:00
Fangrui Song
c9829bfb08 [LazyCallGraph] Build SCCs of the reference graph in order
```
// The legacy PM CGPassManager discovers SCCs this way:
for function in the source order
  tarjanSCC(function)

// While the new PM CGSCCPassManager does:
for function in the reversed source order [1]
  discover a reference graph SCC
  build call graph SCCs inside the reference graph SCC
```

In the common cases, reference graph ~= call graph, the new PM order is
undesired because for `a | b | c` (3 independent functions), the new PM will
process them in the reversed order: c, b, a. If `a <-> b <-> c`, we can see
that `-print-after-all` will report the sole SCC as `scc: (c, b, a)`.

This patch corrects the iteration order. The discovered SCC order will match
the legacy PM in the common cases.

For some tests (`Transforms/Inline/cgscc-*.ll` and
`unittests/Analysis/CGSCCPassManagerTest.cpp`), the behaviors are dependent on
the SCC discovery order and there are too many check lines for the particular
order.  This patch simply reverses the function order to avoid changing too many
check lines.

Differential Revision: https://reviews.llvm.org/D90566
2020-11-02 13:22:42 -08:00
Fangrui Song
f727ae92f5 [MC] Make MCStreamer aware of AsmParser's StartTokLoc
A SMLoc allows MCStreamer to report location-aware diagnostics, which
were previously done by adding SMLoc to various methods (e.g. emit*) in an ad-hoc way.

Since the file:line is most important, the column is less important and
the start token location suffices in many cases, this patch reverts
b7e7131af2dd7bdb03fa42a3bc1b4bc72ab95ce1

```
// old
symbol-binding-changed.s:6:8: error: local changed binding to STB_GLOBAL
.globl local
       ^
// new
symbol-binding-changed.s:6:1: error: local changed binding to STB_GLOBAL
.globl local
^
```

Reviewed By: rnk

Differential Revision: https://reviews.llvm.org/D90511
2020-11-02 12:32:07 -08:00
Krzysztof Parzyszek
13b75ea80b [Hexagon] Move isTypeForHVX from Hexagon TTI to HexagonSubtarget, NFC
It's useful outside of Hexagon TTI, and with how TTI is implemented,
it is not accessible outside of TTI.
2020-11-02 14:00:45 -06:00
Mircea Trofin
158d222d30 [NFC][regalloc] Use MCRegister appropriately
Differential Revision: https://reviews.llvm.org/D90506
2020-11-02 11:48:49 -08:00
Stanislav Mekhanoshin
d05e59d827 [AMDGPU] Improve FLAT scratch detection
We were useing too broad check for isFLATScratch() which also
includes FLAT global.

Differential Revision: https://reviews.llvm.org/D90505
2020-11-02 11:37:33 -08:00
Ettore Tiotto
157bbdf8a4 [PartialInliner]: Handle code regions in a switch stmt cases
This patch enhances computeOutliningColdRegionsInfo() to allow it to
consider regions containing a single basic block and a single
predecessor as candidate for partial inlining.

Reviewed By: fhann

Differential Revision: https://reviews.llvm.org/D89911
2020-11-02 14:32:45 -05:00
Alex Richardson
f7fe395a92 [AtomicExpand] Avoid creating an unnamed libcall
I recently modified this pass to better support CHERI-RISC-V and while
doing so I noticed that this pass was calling M->getOrInsertFunction()
with the result of TLI->getLibcallName(RTLibType). However, AMDGPU fills
the libcalls array with nullptr, so this creates an anonymous function
instead. This patch changes expandAtomicOpToLibcall to return false in
case the libcall does not exist and changes the assert() in the callees to
a report_fatal_error() instead.

Reviewed By: arsenm

Differential Revision: https://reviews.llvm.org/D88800
2020-11-02 17:52:37 +00:00
Craig Topper
dfd4863ad7 [RISCV] Make SelectRORIW handle the commutability of OR.
The SHL and SRL could be in opposite order so account for that.

Differential Revision: https://reviews.llvm.org/D90586
2020-11-02 09:32:54 -08:00
Paul C. Anagnostopoulos
e028635778 [TableGen] Fix a couple of minor issues regarding the paste operator.
Update the documentation to fully describe it.

Differential Revision: https://reviews.llvm.org/D90617
2020-11-02 12:21:54 -05:00
Sanjay Patel
389858bbc4 [x86] add AVX2 cost model entries for maxnum of 256-bit vectors
As noticed in D90554 ,
the AVX2 costs for 256-bit vectors did not include FMAXNUM entries,
so we fell back to AVX1 which assumes those ops will be split into
128-bit halves or something close to that.

Differential Revision: https://reviews.llvm.org/D90613
2020-11-02 12:20:17 -05:00
Craig Topper
d4f846d5af [RISCV] When matching RORIW, make sure the same input is given to both shifts.
The code is looking for (sext_inreg (or (shl X, C2), (shr (and Y, C3), C1))).
We need to ensure X and Y are the same.

Differential Revision: https://reviews.llvm.org/D90580
2020-11-02 09:12:40 -08:00
Simon Pilgrim
aeaa523af1 [AggressiveInstCombine] foldGuardedRotateToFunnelShift - generalize rotation to funnel shift matcher.
Replace matchRotate with a more general matchFunnelShift - at the moment this is still just used for rotation patterns.
2020-11-02 17:09:17 +00:00
Momchil Velikov
5fd1acbb48 [ARM][MachineOutliner] Do not overestimate LR liveness in return block
The `LiveRegUnits` utility (as well as `LivePhysRegs`) considers
callee-saved registers to be alive at the point after the return
instruction in a block. In the ARM backend, the `LR` register is
classified as callee-saved, which is not really correct (from an ARM
eABI or just common sense point of view).  These two conditions cause
the `MachineOutliner` to overestimate the liveness of `LR`, which
results in unnecessary saves/restores of `LR` around calls to outlined
sequences.  It also causes the `MachineVerifer` to crash in some
cases, because the save instruction reads a dead `LR`, for example
when the following program:

int h(int, int);

int f(int a, int b, int c, int d) {
  a = h(a + 1, b - 1);
  b = b + c;
  return 1 + (2 * a + b) * (c - d) / (a - b) * (c + d);
}

int g(int a, int b, int c, int d) {
  a = h(a - 1, b + 1);
  b = b + c;
  return 2 + (2 * a + b) * (c - d) / (a - b) * (c + d);
}

is compiled with `-target arm-eabi -march=armv7-m -Oz`.

This patch computes the liveness of `LR` in return blocks only, while
taking into account the few ARM instructions, which read `LR`, but
nevertheless the register is not mentioned (explicitly or implicitly)
in the instruction operands.

Differential Revision: https://reviews.llvm.org/D89189
2020-11-02 16:47:22 +00:00
Fangrui Song
6fba8f1f14 [Debugify] Port -debugify-each to NewPM
Preemptively switch 2 tests to the new PM

Reviewed By: aeubanks

Differential Revision: https://reviews.llvm.org/D90365
2020-11-02 08:16:43 -08:00
Florian Hahn
1db8566f5e Reland "[TTI] Add VecPred argument to getCmpSelInstrCost."
This reverts the revert commit 408c4408facc3a79ee4ff7e9983cc972f797e176.

This version of the patch includes a fix for a crash caused by
treating ICmp/FCmp constant expressions as instructions.

Original message:

On some targets, like AArch64, vector selects can be efficiently lowered
if the vector condition is a compare with a supported predicate.

This patch adds a new argument to getCmpSelInstrCost, to indicate the
predicate of the feeding select condition. Note that it is not
sufficient to use the context instruction when querying the cost of a
vector select starting from a scalar one, because the condition of the
vector select could be composed of compares with different predicates.

This change greatly improves modeling the costs of certain
compare/select patterns on AArch64.

I am also planning on putting up patches to make use of the new argument in
SLPVectorizer & LV.
2020-11-02 15:39:29 +00:00