[PATCH] D113214: [IR][ShuffleVector] Introduce `isReplicationMask()` matcher

[Jordan Rupprecht via Phabricator via llvm-commits]

rupprecht added inline comments.


================
Comment at: llvm/unittests/IR/InstructionsTest.cpp:1133
+
+TEST(InstructionsTest, ShuffleMaskIsReplicationMask_undef) {
+  for (int ReplicationFactor : seq_inclusive(1, 6)) {
----------------
rupprecht wrote:
> lebedev.ri wrote:
> > rupprecht wrote:
> > > These two exhaustive test cases take an extremely long time to test (3+ minutes for each one). Would it make sense to use `#ifdef EXPENSIVE_CHECKS` for these two?
> > They take 1 and 2 seconds for me.
> > How long do tests in `ConstantRangeTest.cpp` take for you?
> Weird. `ConstantRangeTest` takes 23 seconds in total, most test cases being <.5s but a few being ~2 seconds.
> 
> ```
> $ ./unittests/IR/IRTests --gtest_filter='InstructionsTest.ShuffleMask*'
> Note: Google Test filter = InstructionsTest.ShuffleMask*
> [==========] Running 4 tests from 1 test suite.
> [----------] Global test environment set-up.
> [----------] 4 tests from InstructionsTest
> [ RUN      ] InstructionsTest.ShuffleMaskQueries
> [       OK ] InstructionsTest.ShuffleMaskQueries (2 ms)
> [ RUN      ] InstructionsTest.ShuffleMaskIsReplicationMask
> [       OK ] InstructionsTest.ShuffleMaskIsReplicationMask (0 ms)
> [ RUN      ] InstructionsTest.ShuffleMaskIsReplicationMask_undef
> [       OK ] InstructionsTest.ShuffleMaskIsReplicationMask_undef (227553 ms)
> [ RUN      ] InstructionsTest.ShuffleMaskIsReplicationMask_Exhaustive_Correctness
> [       OK ] InstructionsTest.ShuffleMaskIsReplicationMask_Exhaustive_Correctness (203930 ms)
> [----------] 4 tests from InstructionsTest (431486 ms total)
> 
> [----------] Global test environment tear-down
> [==========] 4 tests from 1 test suite ran. (431486 ms total)
> [  PASSED  ] 4 tests.
> ```
> 
> I'm running a debug build. I would expect performance to be degraded, but not this much. I'll see if release build makes a difference.
Yep, a release build is **much** faster:

```
$ ./unittests/IR/IRTests --gtest_filter='InstructionsTest.ShuffleMask*'
Note: Google Test filter = InstructionsTest.ShuffleMask*
[==========] Running 4 tests from 1 test suite.
[----------] Global test environment set-up.
[----------] 4 tests from InstructionsTest
[ RUN      ] InstructionsTest.ShuffleMaskQueries
[       OK ] InstructionsTest.ShuffleMaskQueries (1 ms)
[ RUN      ] InstructionsTest.ShuffleMaskIsReplicationMask
[       OK ] InstructionsTest.ShuffleMaskIsReplicationMask (0 ms)
[ RUN      ] InstructionsTest.ShuffleMaskIsReplicationMask_undef
[       OK ] InstructionsTest.ShuffleMaskIsReplicationMask_undef (4884 ms)
[ RUN      ] InstructionsTest.ShuffleMaskIsReplicationMask_Exhaustive_Correctness
[       OK ] InstructionsTest.ShuffleMaskIsReplicationMask_Exhaustive_Correctness (2030 ms)
[----------] 4 tests from InstructionsTest (6915 ms total)

[----------] Global test environment tear-down
[==========] 4 tests from 1 test suite ran. (6915 ms total)
[  PASSED  ] 4 tests.
```

I wonder what is so horrendously bad about this test case that the optimizer is able to get rid of so much?


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D113214/new/

https://reviews.llvm.org/D113214