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60146 Commits

Author SHA1 Message Date
Simon Pilgrim
26f9e0a715 [X86] Add SimplifyDemandedBitsForTargetNode support for PEXTRB/PEXTRW
Improved constant folding for PEXTRB/PEXTRW will be added in a future commit

llvm-svn: 356324
2019-03-16 14:29:50 +00:00
Heejin Ahn
aaf0cbd6bc [WebAssembly] Make rethrow take an except_ref type argument
Summary:
In the new wasm EH proposal, `rethrow` takes an `except_ref` argument.
This change was missing in r352598.

This patch adds `llvm.wasm.rethrow.in.catch` intrinsic. This is an
intrinsic that's gonna eventually be lowered to wasm `rethrow`
instruction, but this intrinsic can appear only within a catchpad or a
cleanuppad scope. Also this intrinsic needs to be invokable - otherwise
EH pad successor for it will not be correctly generated in clang.

This also adds lowering logic for this intrinsic in
`SelectionDAGBuilder::visitInvoke`. This routine is basically a
specialized and simplified version of
`SelectionDAGBuilder::visitTargetIntrinsic`, but we can't use it
because if is only for `CallInst`s.

This deletes the previous `llvm.wasm.rethrow` intrinsic and related
tests, which was meant to be used within a `__cxa_rethrow` library
function. Turned out this needs some more logic, so the intrinsic for
this purpose will be added later.

LateEHPrepare takes a result value of `catch` and inserts it into
matching `rethrow` as an argument.

`RETHROW_IN_CATCH` is a pseudo instruction that serves as a link between
`llvm.wasm.rethrow.in.catch` and the real wasm `rethrow` instruction. To
generate a `rethrow` instruction, we need an `except_ref` argument,
which is generated from `catch` instruction. But `catch` instrutions are
added in LateEHPrepare pass, so we use `RETHROW_IN_CATCH`, which takes
no argument, until we are able to correctly lower it to `rethrow` in
LateEHPrepare.

Reviewers: dschuff

Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D59352

llvm-svn: 356316
2019-03-16 05:38:57 +00:00
Heejin Ahn
19f40769e5 [WebAssembly] Irreducible control flow rewrite
Summary:
Rewrite WebAssemblyFixIrreducibleControlFlow to a simpler and cleaner
design, which directly computes reachability and other properties
itself. This avoids previous complexity and bugs. (The new graph
analyses are very similar to how the Relooper algorithm would find loop
entries and so forth.)

This fixes a few bugs, including where we had a false positive and
thought fannkuch was irreducible when it was not, which made us much
larger and slower there, and a reverse bug where we missed
irreducibility. On fannkuch, we used to be 44% slower than asm2wasm and
are now 4% faster.

Reviewers: aheejin

Subscribers: jdoerfert, mgrang, dschuff, sbc100, jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D58919

Patch by Alon Zakai (kripken)

llvm-svn: 356313
2019-03-16 03:00:19 +00:00
Fedor Sergeev
0b5a016873 [TimePasses] allow -time-passes reporting into a custom stream
TimePassesHandler object (implementation of time-passes for new pass manager)
gains ability to report into a stream customizable per-instance (per pipeline).

Intended use is to specify separate time-passes output stream per each compilation,
setting up TimePasses member of StandardInstrumentation during PassBuilder setup.
That allows to get independent non-overlapping pass-times reports for parallel
independent compilations (in JIT-like setups).

By default it still puts timing reports into the info-output-file stream
(created by CreateInfoOutputFile every time report is requested).

Unit-test added for non-default case, and it also allowed to discover that print() does not work
as declared - it did not reset the timers, leading to yet another report being printed into the default stream.
Fixed print() to actually reset timers according to what was declared in print's comments before.

Reviewed By: philip.pfaffe
Differential Revision: https://reviews.llvm.org/D59366

llvm-svn: 356305
2019-03-15 22:15:23 +00:00
Eli Friedman
83b587811f [ARM] Add MachineVerifier logic for some Thumb1 instructions.
tMOVr and tPUSH/tPOP/tPOP_RET have register constraints which can't be
expressed in TableGen, so check them explicitly. I've unfortunately run
into issues with both of these recently; hopefully this saves some time
for someone else in the future.

Differential Revision: https://reviews.llvm.org/D59383

llvm-svn: 356303
2019-03-15 21:44:49 +00:00
Roman Lebedev
6d79f08f21 [X86] X86ISelLowering::combineSextInRegCmov(): also handle i8 CMOV's
Summary:
As noted by @andreadb in https://reviews.llvm.org/D59035#inline-525780

If we have `sext (trunc (cmov C0, C1) to i8)`,
we can instead do `cmov (sext (trunc C0 to i8)), (sext (trunc C1 to i8))`

Reviewers: craig.topper, andreadb, RKSimon

Reviewed By: craig.topper

Subscribers: llvm-commits, andreadb

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D59412

llvm-svn: 356301
2019-03-15 21:18:05 +00:00
Roman Lebedev
e207952556 [X86] Promote i8 CMOV's (PR40965)
Summary:
@mclow.lists brought up this issue up in IRC, it came up during
implementation of libc++ `std::midpoint()` implementation (D59099)
https://godbolt.org/z/oLrHBP

Currently LLVM X86 backend only promotes i8 CMOV if it came from 2x`trunc`.
This differential proposes to always promote i8 CMOV.

There are several concerns here:
* Is this actually more performant, or is it just the ASM that looks cuter?
* Does this result in partial register stalls?
* What about branch predictor?

# Indeed, performance should be the main point here.
Let's look at a simple microbenchmark: {F8412076}
```
#include "benchmark/benchmark.h"

#include <algorithm>
#include <cmath>
#include <cstdint>
#include <iterator>
#include <limits>
#include <random>
#include <type_traits>
#include <utility>
#include <vector>

// Future preliminary libc++ code, from Marshall Clow.
namespace std {
template <class _Tp>
__inline _Tp midpoint(_Tp __a, _Tp __b) noexcept {
  using _Up = typename std::make_unsigned<typename remove_cv<_Tp>::type>::type;

  int __sign = 1;
  _Up __m = __a;
  _Up __M = __b;
  if (__a > __b) {
    __sign = -1;
    __m = __b;
    __M = __a;
  }
  return __a + __sign * _Tp(_Up(__M - __m) >> 1);
}
}  // namespace std

template <typename T>
std::vector<T> getVectorOfRandomNumbers(size_t count) {
  std::random_device rd;
  std::mt19937 gen(rd());
  std::uniform_int_distribution<T> dis(std::numeric_limits<T>::min(),
                                       std::numeric_limits<T>::max());
  std::vector<T> v;
  v.reserve(count);
  std::generate_n(std::back_inserter(v), count,
                  [&dis, &gen]() { return dis(gen); });
  assert(v.size() == count);
  return v;
}

struct RandRand {
  template <typename T>
  static std::pair<std::vector<T>, std::vector<T>> Gen(size_t count) {
    return std::make_pair(getVectorOfRandomNumbers<T>(count),
                          getVectorOfRandomNumbers<T>(count));
  }
};
struct ZeroRand {
  template <typename T>
  static std::pair<std::vector<T>, std::vector<T>> Gen(size_t count) {
    return std::make_pair(std::vector<T>(count, T(0)),
                          getVectorOfRandomNumbers<T>(count));
  }
};

template <class T, class Gen>
void BM_StdMidpoint(benchmark::State& state) {
  const size_t Length = state.range(0);

  const std::pair<std::vector<T>, std::vector<T>> Data =
      Gen::template Gen<T>(Length);
  const std::vector<T>& a = Data.first;
  const std::vector<T>& b = Data.second;
  assert(a.size() == Length && b.size() == a.size());

  benchmark::ClobberMemory();
  benchmark::DoNotOptimize(a);
  benchmark::DoNotOptimize(a.data());
  benchmark::DoNotOptimize(b);
  benchmark::DoNotOptimize(b.data());

  for (auto _ : state) {
    for (size_t i = 0; i < Length; i++) {
      const auto calculated = std::midpoint(a[i], b[i]);
      benchmark::DoNotOptimize(calculated);
    }
  }
  state.SetComplexityN(Length);
  state.counters["midpoints"] =
      benchmark::Counter(Length, benchmark::Counter::kIsIterationInvariant);
  state.counters["midpoints/sec"] =
      benchmark::Counter(Length, benchmark::Counter::kIsIterationInvariantRate);
  const size_t BytesRead = 2 * sizeof(T) * Length;
  state.counters["bytes_read/iteration"] =
      benchmark::Counter(BytesRead, benchmark::Counter::kDefaults,
                         benchmark::Counter::OneK::kIs1024);
  state.counters["bytes_read/sec"] = benchmark::Counter(
      BytesRead, benchmark::Counter::kIsIterationInvariantRate,
      benchmark::Counter::OneK::kIs1024);
}

template <typename T>
static void CustomArguments(benchmark::internal::Benchmark* b) {
  const size_t L2SizeBytes = 2 * 1024 * 1024;
  // What is the largest range we can check to always fit within given L2 cache?
  const size_t MaxLen = L2SizeBytes / /*total bufs*/ 2 /
                        /*maximal elt size*/ sizeof(T) / /*safety margin*/ 2;
  b->RangeMultiplier(2)->Range(1, MaxLen)->Complexity(benchmark::oN);
}

// Both of the values are random.
// The comparison is unpredictable.
BENCHMARK_TEMPLATE(BM_StdMidpoint, int32_t, RandRand)
    ->Apply(CustomArguments<int32_t>);
BENCHMARK_TEMPLATE(BM_StdMidpoint, uint32_t, RandRand)
    ->Apply(CustomArguments<uint32_t>);
BENCHMARK_TEMPLATE(BM_StdMidpoint, int64_t, RandRand)
    ->Apply(CustomArguments<int64_t>);
BENCHMARK_TEMPLATE(BM_StdMidpoint, uint64_t, RandRand)
    ->Apply(CustomArguments<uint64_t>);
BENCHMARK_TEMPLATE(BM_StdMidpoint, int16_t, RandRand)
    ->Apply(CustomArguments<int16_t>);
BENCHMARK_TEMPLATE(BM_StdMidpoint, uint16_t, RandRand)
    ->Apply(CustomArguments<uint16_t>);
BENCHMARK_TEMPLATE(BM_StdMidpoint, int8_t, RandRand)
    ->Apply(CustomArguments<int8_t>);
BENCHMARK_TEMPLATE(BM_StdMidpoint, uint8_t, RandRand)
    ->Apply(CustomArguments<uint8_t>);

// One value is always zero, and another is bigger or equal than zero.
// The comparison is predictable.
BENCHMARK_TEMPLATE(BM_StdMidpoint, uint32_t, ZeroRand)
    ->Apply(CustomArguments<uint32_t>);
BENCHMARK_TEMPLATE(BM_StdMidpoint, uint64_t, ZeroRand)
    ->Apply(CustomArguments<uint64_t>);
BENCHMARK_TEMPLATE(BM_StdMidpoint, uint16_t, ZeroRand)
    ->Apply(CustomArguments<uint16_t>);
BENCHMARK_TEMPLATE(BM_StdMidpoint, uint8_t, ZeroRand)
    ->Apply(CustomArguments<uint8_t>);
```

```
$ ~/src/googlebenchmark/tools/compare.py --no-utest benchmarks ./llvm-cmov-bench-OLD ./llvm-cmov-bench-NEW
RUNNING: ./llvm-cmov-bench-OLD --benchmark_out=/tmp/tmp5a5qjm
2019-03-06 21:53:31
Running ./llvm-cmov-bench-OLD
Run on (8 X 4000 MHz CPU s)
CPU Caches:
  L1 Data 16K (x8)
  L1 Instruction 64K (x4)
  L2 Unified 2048K (x4)
  L3 Unified 8192K (x1)
Load Average: 1.78, 1.81, 1.36
----------------------------------------------------------------------------------------------------
Benchmark                                          Time             CPU   Iterations UserCounters<...>
----------------------------------------------------------------------------------------------------
<...>
BM_StdMidpoint<int32_t, RandRand>/131072      300398 ns       300404 ns         2330 bytes_read/iteration=1024k bytes_read/sec=3.25083G/s midpoints=305.398M midpoints/sec=436.319M/s
BM_StdMidpoint<int32_t, RandRand>_BigO          2.29 N          2.29 N
BM_StdMidpoint<int32_t, RandRand>_RMS              2 %             2 %
<...>
BM_StdMidpoint<uint32_t, RandRand>/131072     300433 ns       300433 ns         2330 bytes_read/iteration=1024k bytes_read/sec=3.25052G/s midpoints=305.398M midpoints/sec=436.278M/s
BM_StdMidpoint<uint32_t, RandRand>_BigO         2.29 N          2.29 N
BM_StdMidpoint<uint32_t, RandRand>_RMS             2 %             2 %
<...>
BM_StdMidpoint<int64_t, RandRand>/65536       169857 ns       169858 ns         4121 bytes_read/iteration=1024k bytes_read/sec=5.74929G/s midpoints=270.074M midpoints/sec=385.828M/s
BM_StdMidpoint<int64_t, RandRand>_BigO          2.59 N          2.59 N
BM_StdMidpoint<int64_t, RandRand>_RMS              3 %             3 %
<...>
BM_StdMidpoint<uint64_t, RandRand>/65536      169770 ns       169771 ns         4125 bytes_read/iteration=1024k bytes_read/sec=5.75223G/s midpoints=270.336M midpoints/sec=386.026M/s
BM_StdMidpoint<uint64_t, RandRand>_BigO         2.59 N          2.59 N
BM_StdMidpoint<uint64_t, RandRand>_RMS             3 %             3 %
<...>
BM_StdMidpoint<int16_t, RandRand>/262144      591169 ns       591179 ns         1182 bytes_read/iteration=1024k bytes_read/sec=1.65189G/s midpoints=309.854M midpoints/sec=443.426M/s
BM_StdMidpoint<int16_t, RandRand>_BigO          2.25 N          2.25 N
BM_StdMidpoint<int16_t, RandRand>_RMS              1 %             1 %
<...>
BM_StdMidpoint<uint16_t, RandRand>/262144     591264 ns       591274 ns         1184 bytes_read/iteration=1024k bytes_read/sec=1.65162G/s midpoints=310.378M midpoints/sec=443.354M/s
BM_StdMidpoint<uint16_t, RandRand>_BigO         2.25 N          2.25 N
BM_StdMidpoint<uint16_t, RandRand>_RMS             1 %             1 %
<...>
BM_StdMidpoint<int8_t, RandRand>/524288      2983669 ns      2983689 ns          235 bytes_read/iteration=1024k bytes_read/sec=335.156M/s midpoints=123.208M midpoints/sec=175.718M/s
BM_StdMidpoint<int8_t, RandRand>_BigO           5.69 N          5.69 N
BM_StdMidpoint<int8_t, RandRand>_RMS               0 %             0 %
<...>
BM_StdMidpoint<uint8_t, RandRand>/524288     2668398 ns      2668419 ns          262 bytes_read/iteration=1024k bytes_read/sec=374.754M/s midpoints=137.363M midpoints/sec=196.479M/s
BM_StdMidpoint<uint8_t, RandRand>_BigO          5.09 N          5.09 N
BM_StdMidpoint<uint8_t, RandRand>_RMS              0 %             0 %
<...>
BM_StdMidpoint<uint32_t, ZeroRand>/131072     300887 ns       300887 ns         2331 bytes_read/iteration=1024k bytes_read/sec=3.24561G/s midpoints=305.529M midpoints/sec=435.619M/s
BM_StdMidpoint<uint32_t, ZeroRand>_BigO         2.29 N          2.29 N
BM_StdMidpoint<uint32_t, ZeroRand>_RMS             2 %             2 %
<...>
BM_StdMidpoint<uint64_t, ZeroRand>/65536      169634 ns       169634 ns         4102 bytes_read/iteration=1024k bytes_read/sec=5.75688G/s midpoints=268.829M midpoints/sec=386.338M/s
BM_StdMidpoint<uint64_t, ZeroRand>_BigO         2.59 N          2.59 N
BM_StdMidpoint<uint64_t, ZeroRand>_RMS             3 %             3 %
<...>
BM_StdMidpoint<uint16_t, ZeroRand>/262144     592252 ns       592255 ns         1182 bytes_read/iteration=1024k bytes_read/sec=1.64889G/s midpoints=309.854M midpoints/sec=442.62M/s
BM_StdMidpoint<uint16_t, ZeroRand>_BigO         2.26 N          2.26 N
BM_StdMidpoint<uint16_t, ZeroRand>_RMS             1 %             1 %
<...>
BM_StdMidpoint<uint8_t, ZeroRand>/524288      987295 ns       987309 ns          711 bytes_read/iteration=1024k bytes_read/sec=1012.85M/s midpoints=372.769M midpoints/sec=531.028M/s
BM_StdMidpoint<uint8_t, ZeroRand>_BigO          1.88 N          1.88 N
BM_StdMidpoint<uint8_t, ZeroRand>_RMS              1 %             1 %
RUNNING: ./llvm-cmov-bench-NEW --benchmark_out=/tmp/tmpPvwpfW
2019-03-06 21:56:58
Running ./llvm-cmov-bench-NEW
Run on (8 X 4000 MHz CPU s)
CPU Caches:
  L1 Data 16K (x8)
  L1 Instruction 64K (x4)
  L2 Unified 2048K (x4)
  L3 Unified 8192K (x1)
Load Average: 1.17, 1.46, 1.30
----------------------------------------------------------------------------------------------------
Benchmark                                          Time             CPU   Iterations UserCounters<...>
----------------------------------------------------------------------------------------------------
<...>
BM_StdMidpoint<int32_t, RandRand>/131072      300878 ns       300880 ns         2324 bytes_read/iteration=1024k bytes_read/sec=3.24569G/s midpoints=304.611M midpoints/sec=435.629M/s
BM_StdMidpoint<int32_t, RandRand>_BigO          2.29 N          2.29 N
BM_StdMidpoint<int32_t, RandRand>_RMS              2 %             2 %
<...>
BM_StdMidpoint<uint32_t, RandRand>/131072     300231 ns       300226 ns         2330 bytes_read/iteration=1024k bytes_read/sec=3.25276G/s midpoints=305.398M midpoints/sec=436.578M/s
BM_StdMidpoint<uint32_t, RandRand>_BigO         2.29 N          2.29 N
BM_StdMidpoint<uint32_t, RandRand>_RMS             2 %             2 %
<...>
BM_StdMidpoint<int64_t, RandRand>/65536       170819 ns       170777 ns         4115 bytes_read/iteration=1024k bytes_read/sec=5.71835G/s midpoints=269.681M midpoints/sec=383.752M/s
BM_StdMidpoint<int64_t, RandRand>_BigO          2.60 N          2.60 N
BM_StdMidpoint<int64_t, RandRand>_RMS              3 %             3 %
<...>
BM_StdMidpoint<uint64_t, RandRand>/65536      171705 ns       171708 ns         4106 bytes_read/iteration=1024k bytes_read/sec=5.68733G/s midpoints=269.091M midpoints/sec=381.671M/s
BM_StdMidpoint<uint64_t, RandRand>_BigO         2.62 N          2.62 N
BM_StdMidpoint<uint64_t, RandRand>_RMS             3 %             3 %
<...>
BM_StdMidpoint<int16_t, RandRand>/262144      592510 ns       592516 ns         1182 bytes_read/iteration=1024k bytes_read/sec=1.64816G/s midpoints=309.854M midpoints/sec=442.425M/s
BM_StdMidpoint<int16_t, RandRand>_BigO          2.26 N          2.26 N
BM_StdMidpoint<int16_t, RandRand>_RMS              1 %             1 %
<...>
BM_StdMidpoint<uint16_t, RandRand>/262144     614823 ns       614823 ns         1180 bytes_read/iteration=1024k bytes_read/sec=1.58836G/s midpoints=309.33M midpoints/sec=426.373M/s
BM_StdMidpoint<uint16_t, RandRand>_BigO         2.33 N          2.33 N
BM_StdMidpoint<uint16_t, RandRand>_RMS             4 %             4 %
<...>
BM_StdMidpoint<int8_t, RandRand>/524288      1073181 ns      1073201 ns          650 bytes_read/iteration=1024k bytes_read/sec=931.791M/s midpoints=340.787M midpoints/sec=488.527M/s
BM_StdMidpoint<int8_t, RandRand>_BigO           2.05 N          2.05 N
BM_StdMidpoint<int8_t, RandRand>_RMS               1 %             1 %
BM_StdMidpoint<uint8_t, RandRand>/524288     1071010 ns      1071020 ns          653 bytes_read/iteration=1024k bytes_read/sec=933.689M/s midpoints=342.36M midpoints/sec=489.522M/s
BM_StdMidpoint<uint8_t, RandRand>_BigO          2.05 N          2.05 N
BM_StdMidpoint<uint8_t, RandRand>_RMS              1 %             1 %
<...>
BM_StdMidpoint<uint32_t, ZeroRand>/131072     300413 ns       300416 ns         2330 bytes_read/iteration=1024k bytes_read/sec=3.2507G/s midpoints=305.398M midpoints/sec=436.302M/s
BM_StdMidpoint<uint32_t, ZeroRand>_BigO         2.29 N          2.29 N
BM_StdMidpoint<uint32_t, ZeroRand>_RMS             2 %             2 %
<...>
BM_StdMidpoint<uint64_t, ZeroRand>/65536      169667 ns       169669 ns         4123 bytes_read/iteration=1024k bytes_read/sec=5.75568G/s midpoints=270.205M midpoints/sec=386.257M/s
BM_StdMidpoint<uint64_t, ZeroRand>_BigO         2.59 N          2.59 N
BM_StdMidpoint<uint64_t, ZeroRand>_RMS             3 %             3 %
<...>
BM_StdMidpoint<uint16_t, ZeroRand>/262144     591396 ns       591404 ns         1184 bytes_read/iteration=1024k bytes_read/sec=1.65126G/s midpoints=310.378M midpoints/sec=443.257M/s
BM_StdMidpoint<uint16_t, ZeroRand>_BigO         2.26 N          2.26 N
BM_StdMidpoint<uint16_t, ZeroRand>_RMS             1 %             1 %
<...>
BM_StdMidpoint<uint8_t, ZeroRand>/524288     1069421 ns      1069413 ns          655 bytes_read/iteration=1024k bytes_read/sec=935.092M/s midpoints=343.409M midpoints/sec=490.258M/s
BM_StdMidpoint<uint8_t, ZeroRand>_BigO          2.04 N          2.04 N
BM_StdMidpoint<uint8_t, ZeroRand>_RMS              0 %             0 %
Comparing ./llvm-cmov-bench-OLD to ./llvm-cmov-bench-NEW
Benchmark                                                   Time             CPU      Time Old      Time New       CPU Old       CPU New
----------------------------------------------------------------------------------------------------------------------------------------
<...>
BM_StdMidpoint<int32_t, RandRand>/131072                 +0.0016         +0.0016        300398        300878        300404        300880
<...>
BM_StdMidpoint<uint32_t, RandRand>/131072                -0.0007         -0.0007        300433        300231        300433        300226
<...>
BM_StdMidpoint<int64_t, RandRand>/65536                  +0.0057         +0.0054        169857        170819        169858        170777
<...>
BM_StdMidpoint<uint64_t, RandRand>/65536                 +0.0114         +0.0114        169770        171705        169771        171708
<...>
BM_StdMidpoint<int16_t, RandRand>/262144                 +0.0023         +0.0023        591169        592510        591179        592516
<...>
BM_StdMidpoint<uint16_t, RandRand>/262144                +0.0398         +0.0398        591264        614823        591274        614823
<...>
BM_StdMidpoint<int8_t, RandRand>/524288                  -0.6403         -0.6403       2983669       1073181       2983689       1073201
<...>
BM_StdMidpoint<uint8_t, RandRand>/524288                 -0.5986         -0.5986       2668398       1071010       2668419       1071020
<...>
BM_StdMidpoint<uint32_t, ZeroRand>/131072                -0.0016         -0.0016        300887        300413        300887        300416
<...>
BM_StdMidpoint<uint64_t, ZeroRand>/65536                 +0.0002         +0.0002        169634        169667        169634        169669
<...>
BM_StdMidpoint<uint16_t, ZeroRand>/262144                -0.0014         -0.0014        592252        591396        592255        591404
<...>
BM_StdMidpoint<uint8_t, ZeroRand>/524288                 +0.0832         +0.0832        987295       1069421        987309       1069413
```

What can we tell from the benchmark?
* `BM_StdMidpoint<[u]int8_t, RandRand>` indeed has the worst performance.
* All `BM_StdMidpoint<uint{8,16,32}_t, ZeroRand>` are all performant, even the 8-bit case.
  That is because there we are computing mid point between zero and some random number,
  thus if the branch predictor is in use, it is in optimal situation.
* Promoting 8-bit CMOV did improve performance of `BM_StdMidpoint<[u]int8_t, RandRand>`, by -59%..-64%.

# What about branch predictor?
* `BM_StdMidpoint<uint8_t, ZeroRand>` was faster than `BM_StdMidpoint<uint{16,32,64}_t, ZeroRand>`,
  which may mean that well-predicted branch is better than `cmov`.
* Promoting 8-bit CMOV degraded performance of `BM_StdMidpoint<uint8_t, ZeroRand>`,
  `cmov` is up to +10% worse than well-predicted branch.
* However, i do not believe this is a concern. If the branch is well predicted,  then the PGO
  will also say that it is well predicted, and LLVM will happily expand cmov back into branch:
  https://godbolt.org/z/P5ufig

# What about partial register stalls?
I'm not really able to answer that.
What i can say is that if the branch is unpredictable (if it is predictable, then use PGO and you'll have branch)
in ~50% of cases you will have to pay branch misprediction penalty.
```
$ grep -i MispredictPenalty X86Sched*.td
X86SchedBroadwell.td:  let MispredictPenalty = 16;
X86SchedHaswell.td:  let MispredictPenalty = 16;
X86SchedSandyBridge.td:  let MispredictPenalty = 16;
X86SchedSkylakeClient.td:  let MispredictPenalty = 14;
X86SchedSkylakeServer.td:  let MispredictPenalty = 14;
X86ScheduleBdVer2.td:  let MispredictPenalty = 20; // Minimum branch misdirection penalty.
X86ScheduleBtVer2.td:  let MispredictPenalty = 14; // Minimum branch misdirection penalty
X86ScheduleSLM.td:  let MispredictPenalty = 10;
X86ScheduleZnver1.td:  let MispredictPenalty = 17;
```
.. which it can be as small as 10 cycles and as large as 20 cycles.
Partial register stalls do not seem to be an issue for AMD CPU's.
For intel CPU's, they should be around ~5 cycles?
Is that actually an issue here? I'm not sure.

In short, i'd say this is an improvement, at least on this microbenchmark.

Fixes [[ https://bugs.llvm.org/show_bug.cgi?id=40965 | PR40965 ]].

Reviewers: craig.topper, RKSimon, spatel, andreadb, nikic

Reviewed By: craig.topper, andreadb

Subscribers: jfb, jdoerfert, llvm-commits, mclow.lists

Tags: #llvm, #libc

Differential Revision: https://reviews.llvm.org/D59035

llvm-svn: 356300
2019-03-15 21:17:53 +00:00
Nikita Popov
b965ccb2fd [AArch64] Turn BIC immediate creation into a DAG combine
Switch BIC immediate creation for vector ANDs from custom lowering
to a DAG combine, which gives generic DAG combines a change to
apply first. In particular this avoids (and x, -1) being turned into
a (bic x, 0) instead of being eliminated entirely.

Differential Revision: https://reviews.llvm.org/D59187

llvm-svn: 356299
2019-03-15 21:04:34 +00:00
Changpeng Fang
3a3129c593 AMDGPU: Fix a SIAnnotateControlFlow issue when there are multiple backedges.
Summary:
At the exit of the loop, the compiler uses a register to remember and accumulate
the number of threads that have already exited. When all active threads exit the
loop, this register is used to restore the exec mask, and the execution continues
for the post loop code.

When there is a "continue" in the loop, the compiler made a mistake to reset the
register to 0 when the "continue" backedge is taken. This will result in some
threads not executing the post loop code as they are supposed to.

This patch fixed the issue.

Reviewers:
  nhaehnle, arsenm

Differential Revision:
  https://reviews.llvm.org/D59312

llvm-svn: 356298
2019-03-15 21:02:48 +00:00
Philip Reames
3116bccced [SimplifyDemandedVec] Strengthen handling all undef lanes (particularly GEPs)
A change of two parts:
1) A generic enhancement for all callers of SDVE to exploit the fact that if all lanes are undef, the result is undef.
2) A GEP specific piece to strengthen/fix the vector index undef element handling, and call into the generic infrastructure when visiting the GEP.

The result is that we replace a vector gep with at least one undef in each lane with a undef.  We can also do the same for vector intrinsics.  Once the masked.load patch (D57372) has landed, I'll update to include call tests as well.

Differential Revision: https://reviews.llvm.org/D57468

llvm-svn: 356293
2019-03-15 19:54:06 +00:00
Simon Pilgrim
c607b9dd60 [X86][SSE] Fold scalar_to_vector(i64 anyext(x)) -> bitcast(scalar_to_vector(i32 anyext(x)))
Reduce the size of an any-extended i64 scalar_to_vector source to i32 - the any_extend nodes are often introduced by SimplifyDemandedBits.

llvm-svn: 356292
2019-03-15 19:14:28 +00:00
Sanjay Patel
69185cd19c [InstCombine] add tests for logic of NaN fcmps; NFC
llvm-svn: 356287
2019-03-15 18:14:25 +00:00
Philip Reames
4b688aacf8 [tests] Add a test for constexpr mask as requested in D57372
llvm-svn: 356285
2019-03-15 18:06:32 +00:00
Sanjay Patel
217449bbd9 [InstCombine] add tests for masked store/scatter; NFC
Baseline tests for D57247

llvm-svn: 356283
2019-03-15 18:00:28 +00:00
Amara Emerson
af364080e2 [AArch64][GlobalISel] Regbankselect: Fix G_BUILD_VECTOR trying to use s16 gpr sources.
Since we can't insert s16 gprs as we don't have 16 bit GPR registers, we need to
teach RBS to assign them to the FPR bank so our selector works.

llvm-svn: 356282
2019-03-15 18:00:01 +00:00
Philip Reames
63be0dc80c [X86][GlobalISEL] Support lowering aligned unordered atomics
The existing lowering code is accidentally correct for unordered atomics as far as I can tell. An unordered atomic has no memory ordering, and simply requires the actual load or store to be done as a single well aligned instruction. As such, relax the restriction while adding tests to ensure the lowering remains correct in the future.

Differential Revision: https://reviews.llvm.org/D57803

llvm-svn: 356280
2019-03-15 17:50:30 +00:00
Yonghong Song
24ad14dc25 [BPF] handle external global properly
Previous commit 6bc58e6d3dbd ("[BPF] do not generate unused local/global types")
tried to exclude global variable from type generation. The condition is:
     if (Global.hasExternalLinkage())
       continue;
This is not right. It also excluded initialized globals.

The correct condition (from AssemblyWriter::printGlobal()) is:
  if (!GV->hasInitializer() && GV->hasExternalLinkage())
    Out << "external ";

Let us do the same in BTF type generation. Also added a test for it.

Signed-off-by: Yonghong Song <yhs@fb.com>
llvm-svn: 356279
2019-03-15 17:39:10 +00:00
Simon Pilgrim
118118e6bc [AArch64] Regenerate build vector tests
llvm-svn: 356274
2019-03-15 17:17:37 +00:00
Simon Pilgrim
82dd9e6590 [SelectionDAG] Add SimplifyDemandedBits handling for ISD::SCALAR_TO_VECTOR
Fixes a lot of constant folding mismatches between i686 and x86_64

llvm-svn: 356273
2019-03-15 17:00:55 +00:00
Simon Pilgrim
b806341f27 [X86] Add SimplifyDemandedBitsForTargetNode support for PINSRB/PINSRW
llvm-svn: 356270
2019-03-15 16:16:49 +00:00
Teresa Johnson
2274d19c8e [ThinLTO] Restructure AliasSummary to contain ValueInfo of Aliasee
Summary:
The AliasSummary previously contained the AliaseeGUID, which was only
populated when reading the summary from bitcode. This patch changes it
to instead hold the ValueInfo of the aliasee, and always populates it.
This enables more efficient access to the ValueInfo (specifically in the
recent patch r352438 which needed to perform an index hash table lookup
using the aliasee GUID).

As noted in the comments in AliasSummary, we no longer technically need
to keep a pointer to the corresponding aliasee summary, since it could
be obtained by walking the list of summaries on the ValueInfo looking
for the summary in the same module. However, I am concerned that this
would be inefficient when walking through the index during the thin
link for various analyses. That can be reevaluated in the future.

By always populating this new field, we can remove the guard and special
handling for a 0 aliasee GUID when dumping the dot graph of the summary.

An additional improvement in this patch is when reading the summaries
from LLVM assembly we now set the AliaseeSummary field to the aliasee
summary in that same module, which makes it consistent with the behavior
when reading the summary from bitcode.

Reviewers: pcc, mehdi_amini

Subscribers: inglorion, eraman, steven_wu, dexonsmith, arphaman, llvm-commits

Differential Revision: https://reviews.llvm.org/D57470

llvm-svn: 356268
2019-03-15 15:11:38 +00:00
Simon Pilgrim
44c4f80ee4 [Hexagon] Remove icmp undef from reduced tests
Pre-commit for D59363 (Add icmp UNDEF handling to SelectionDAG::FoldSetCC)

Approved by @kparzysz (Krzysztof Parzyszek)

llvm-svn: 356267
2019-03-15 15:07:44 +00:00
Mircea Trofin
639b1173c3 [llvm] Skip over empty line table entries.
Summary:
This is similar to how addr2line handles consecutive entries with the
same address - pick the last one.

Reviewers: dblaikie, friss, JDevlieghere

Reviewed By: dblaikie

Subscribers: eugenis, vitalybuka, echristo, JDevlieghere, probinson, aprantl, hiraditya, rupprecht, jdoerfert, llvm-commits

Tags: #llvm, #debug-info

Differential Revision: https://reviews.llvm.org/D58952

llvm-svn: 356265
2019-03-15 15:00:12 +00:00
Mikael Holmen
9f277da942 [CodeGenPrepare] avoid crashing from replacing a phi twice
Summary:
This is a fix to bug 41052:
https://bugs.llvm.org/show_bug.cgi?id=41052

While trying to optimize a memory instruction in a dead basic block, we end up registering the same phi for replacement twice. This patch avoids registering more than the first replacement candidate for a phi.

Patch by: JesperAntonsson

Reviewers: skatkov, aprantl

Reviewed By: aprantl

Subscribers: jdoerfert, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D59358

llvm-svn: 356260
2019-03-15 13:51:05 +00:00
Sam Parker
26b46594cf [ARM] Remove EarlyCSE from backend
There is an issue with early CSE hitting an assert, so temporarily
remove the pass from the Arm backend.
    
Bug: https://bugs.llvm.org/show_bug.cgi?id=41081

Differential Revision: https://reviews.llvm.org/D59410

llvm-svn: 356259
2019-03-15 13:36:37 +00:00
Michael Liao
fc9ff6e8cb [AMDGPU] Fix SGPR fixing through SCC chaining
Summary:
- During the fixing of SGPR copying from VGPR, ensure users of SCC is
  properly propagated, i.e.
  * only propagate through live def of SCC,
  * skip the SCC-def inst itself, and
  * stop the propagation on the other SCC-def inst after checking its
    SCC-use first.

Subscribers: arsenm, kzhuravl, jvesely, wdng, nhaehnle, yaxunl, dstuttard, tpr, t-tye, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D59362

llvm-svn: 356258
2019-03-15 12:42:21 +00:00
Florian Hahn
aef0241562 [LSR] Update test from rL356256 after rebase.
llvm-svn: 356257
2019-03-15 12:37:50 +00:00
Florian Hahn
e9781212b4 [LSR] Check for signed overflow in NarrowSearchSpaceByDetectingSupersets.
We are adding a sign extended IR value to an int64_t, which can cause
signed overflows, as in the attached test case, where we have a formula
with BaseOffset = -1 and a constant with numeric_limits<int64_t>::min().

If the addition would overflow, skip the simplification for this
formula. Note that the target triple is required to trigger the failure.

Reviewers: qcolombet, gilr, kparzysz, efriedma

Reviewed By: efriedma

Differential Revision: https://reviews.llvm.org/D59211

llvm-svn: 356256
2019-03-15 12:17:36 +00:00
Simon Pilgrim
30acd71a23 [SPARC] Regenerate label test for D59363
llvm-svn: 356253
2019-03-15 11:24:17 +00:00
Simon Pilgrim
6ab6556262 [ARM] Remove icmp undef from reduced tests
Pre-commit for D59363 (Add icmp UNDEF handling to SelectionDAG::FoldSetCC)

Approved by @efriedma (Eli Friedman)

llvm-svn: 356252
2019-03-15 11:14:59 +00:00
Simon Pilgrim
09b2bf7406 [WebAssembly] Remove icmp undef in stackify test
Pre-commit for D59363 (Add icmp UNDEF handling to SelectionDAG::FoldSetCC)

Approved by @tlively (Thomas Lively)

llvm-svn: 356251
2019-03-15 11:13:26 +00:00
Simon Pilgrim
c1fde1c9b1 [X86][SSE] Attempt to convert SSE shift-by-var to shift-by-imm.
Prep work for PR40203

llvm-svn: 356249
2019-03-15 11:05:42 +00:00
James Henderson
cccf1bdc3a [yaml2obj]Allow explicit setting of p_filesz, p_memsz, and p_offset
yaml2obj currently derives the p_filesz, p_memsz, and p_offset values of
program headers from their sections. This makes writing tests for
certain formats more complex, and sometimes impossible. This patch
allows setting these fields explicitly, overriding the default value,
when relevant.

Reviewed by: jakehehrlich, Higuoxing

Differential Revision: https://reviews.llvm.org/D59372

llvm-svn: 356247
2019-03-15 10:35:27 +00:00
Sam Parker
1a293b1c13 [ARM][ParallelDSP] Disable for big-endian
Bail early when we don't have a preheader and also if the target is
big endian because it's written with only little endian in mind!

Differential Revision: https://reviews.llvm.org/D59368

llvm-svn: 356243
2019-03-15 10:19:32 +00:00
Petar Avramovic
9f97fe13bc [MIPS GlobalISel] Improve selection of constants
Certain 32 bit constants can be generated with a single instruction
instead of two. Implement materialize32BitImm function for MIPS32.

Differential Revision: https://reviews.llvm.org/D59369

llvm-svn: 356238
2019-03-15 07:07:50 +00:00
Yonghong Song
c6159d464d [BPF] do not generate unused local/global types
The kernel currently has a limit for # of types to be 64KB and
the size of string subsection to be 64KB. A simple bcc tool
runqlat.py generates:
  . the size of ~33KB type section, roughly ~10K types
  . the size of ~17KB string section

The majority type is from the types referenced by local
variables in the bpf program. For example, the kernel "task_struct"
itself recursively brings in ~900 other types.
This patch did the following optimization to avoid generating
unused types:
  . do not generate types for local variables unless they are
    function arguments.
  . do not generate types for external globals.

If an external global is not used in the program, llvm
already removes it from IR, so global variable saving is
typical small. For runqlat.py, only one variable "llvm.used"
is the external global.

The types for locals and external globals can be added back
once there is a usage for them.

After the above optimization, the runqlat.py generates:
  . the size of ~1.5KB type section, roughtly 500 types
  . the size of ~0.7KB string section

UPDATE:
  resubmitted the patch after previous revert with
  the following fix:
  use Global.hasExternalLinkage() to test "external"
  linkage instead of using Global.getInitializer(),
  which will assert on external variables.

Signed-off-by: Yonghong Song <yhs@fb.com>
llvm-svn: 356234
2019-03-15 05:51:25 +00:00
Yonghong Song
efb38e2269 Revert "[BPF] do not generate unused local/global types"
This reverts commit r356232.

Reason: test failure with ASSERT on enabled build.
llvm-svn: 356233
2019-03-15 05:02:19 +00:00
Yonghong Song
c572b095fb [BPF] do not generate unused local/global types
The kernel currently has a limit for # of types to be 64KB and
the size of string subsection to be 64KB. A simple bcc tool
runqlat.py generates:
  . the size of ~33KB type section, roughly ~10K types
  . the size of ~17KB string section

The majority type is from the types referenced by local
variables in the bpf program. For example, the kernel "task_struct"
itself recursively brings in ~900 other types.
This patch did the following optimization to avoid generating
unused types:
  . do not generate types for local variables unless they are
    function arguments.
  . do not generate types for external globals.

If an external global is not used in the program, llvm
already removes it from IR, so global variable saving is
typical small. For runqlat.py, only one variable "llvm.used"
is the external global.

The types for locals and external globals can be added back
once there is a usage for them.

After the above optimization, the runqlat.py generates:
  . the size of ~1.5KB type section, roughtly 500 types
  . the size of ~0.7KB string section

Signed-off-by: Yonghong Song <yhs@fb.com>
llvm-svn: 356232
2019-03-15 04:42:01 +00:00
Matt Arsenault
0af2addce0 AMDGPU: Remove intrinsic operand assert
Before r355981, this was under LLVM_DEBUG. I don't think the assert is
quite right, but this really should be a verifier check. Instcombine
should not be asserting on this sort of thing.

llvm-svn: 356219
2019-03-14 23:45:09 +00:00
Sanjay Patel
8077e56c1a [CGP] add another bailout for degenerate code (PR41064)
This is almost the same as:
rL355345
...and should prevent any potential crashing from examples like:
https://bugs.llvm.org/show_bug.cgi?id=41064
...although the bug was masked by:
rL355823
...and I'm not sure how to repro the problem after that change.

llvm-svn: 356218
2019-03-14 23:14:31 +00:00
Paul Robinson
4112c6c281 Tighten up tests that use -debugify as a shortcut. NFC
These now verify that a given instruction has a specific source
location, rather than any old location. We want to make sure we
propagate the correct locations from one instruction to another.

llvm-svn: 356217
2019-03-14 23:09:17 +00:00
Eli Friedman
4d25420fc8 [MC] Sort FDEs by the associated CIE before emitting them.
This isn't necessary according to the DWARF standard, but it matches the
.eh_frame sections emitted by other tools in practice, and the Android
libunwindstack rejects .eh_frame sections where an FDE refers to a CIE
other than the closest previous CIE. So match the other tools and also
sort accordingly.

I consider this a bug in libunwindstack, but it's easy enough to emit
a compatible .eh_frame section for compatibility with installed
operating systems.

Differential Revision: https://reviews.llvm.org/D58266

llvm-svn: 356216
2019-03-14 23:08:19 +00:00
Matt Arsenault
571a94ef5d MIR: Allow targets to serialize MachineFunctionInfo
This has been a very painful missing feature that has made producing
reduced testcases difficult. In particular the various registers
determined for stack access during function lowering were necessary to
avoid undefined register errors in a large percentage of
cases. Implement a subset of the important fields that need to be
preserved for AMDGPU.

Most of the changes are to support targets parsing register fields and
properly reporting errors. The biggest sort-of bug remaining is for
fields that can be initialized from the IR section will be overwritten
by a default initialized machineFunctionInfo section. Another
remaining bug is the machineFunctionInfo section is still printed even
if empty.

llvm-svn: 356215
2019-03-14 22:54:43 +00:00
Jessica Paquette
5fc1e87953 [AArch64][GlobalISel] Add isel support for G_UADDO on s32s and s64s
This adds instruction selection support for G_UADDO on s32s and s64s.

Also
- Add an instruction selection test
- Update the arm64-xaluo.ll test to show that we generate the correct assembly

Differential Revision: https://reviews.llvm.org/D58734

llvm-svn: 356214
2019-03-14 22:54:29 +00:00
Amara Emerson
6da5735cc0 [AArch64][GlobalISel] Implement selection for G_UNMERGE of vectors to vectors.
This re-uses the previous support for extract vector elt to extract the
subvectors.

Differential Revision: https://reviews.llvm.org/D59390

llvm-svn: 356213
2019-03-14 22:48:18 +00:00
Amara Emerson
90869d8494 [AArch64][GlobalISel] Add some support for G_CONCAT_VECTORS.
Handles concatenating 2 x v2s32 and 2 x v4s16

Differential Revision: https://reviews.llvm.org/D59390

llvm-svn: 356212
2019-03-14 22:48:15 +00:00
Jordan Rupprecht
48ffd0d44c [llvm-strip] Hook up (unimplemented) --only-keep-debug
For ELF, we accept but ignore --only-keep-debug. Do the same for llvm-strip.

COFF does implement this, so update the test that it is supported.

llvm-svn: 356207
2019-03-14 21:51:42 +00:00
Adrian Prantl
c4c39636f1 Add test I forgot to git-add in r356163.
llvm-svn: 356205
2019-03-14 21:23:52 +00:00
Nikita Popov
915ab4173b [InstCombine] Add tests for range-based saturing math overflow; NFC
Tests for cases where overflow can be determined, but not based on
known bits.

llvm-svn: 356203
2019-03-14 21:06:46 +00:00
Pete Couperus
84f781f880 [ARC] Add more load/store variants.
On ARC ISA, general format of load instruction is this:

    LD<zz><.x><.aa><.di> a, [b,c]
And general format of store is this:
    ST<zz><.aa><.di> c, [b,s9]
Where:

<zz> is data size field and can be one of
  <empty> (bits 00) - Word (32-bit), default behavior
  B             (bits 01) - Byte
  H             (bits 10) - Half-word (16-bit)

 <.x> is data extend mode:
  <empty> (bit 0) - If size is not Word(32-bit), then data is zero extended
  X       (bit 1) - If size is not Word(32-bit), then data is sign extended

 <.aa> is address write-back mode:
  <empty> (bits 00) - no write-back
  .AW  (bits 01) - Preincrement, base register updated pre memory transaction
  .AB  (bits 10) - Postincrement, base register updated post memory transaction

 <.di> is cache bypass mode:
  <empty> (bit 0) - Cached memory access, default mode
  .DI     (bit 1) - Non-cached data memory access

  This patch adds these load/store instruction variants to the ARC backend.

Patch By Denis Antrushin! <denis@synopsys.com>

Differential Revision: https://reviews.llvm.org/D58980

llvm-svn: 356200
2019-03-14 20:50:54 +00:00