[PATCH] D46581: [DAGCombine] Change store merge candidates check cut off to 1024

[Amara Emerson via Phabricator via llvm-commits]

aemerson added a comment.

The actual problem here seems to be superlinear performance with this cutoff value. The 5x I mentioned was inappropriate as that was over a whole compile and compared to an old version of LLVM, before the store merging after legalisation patch for AArch64 was landed in December. The actual problem in my test case, which is admittedly a very large one, is that with the original value of 8192, I get around 330s runtime for my test case, at Max=2048 its 189s, Max=1024 its 34s, Max=512 21s, Max=256 20s. So somewhere between 512 and 1024 we start to see this superlinear compile time.

Unfortunately I can't share the test case, but something is definitely not O(N).


Repository:
  rL LLVM

https://reviews.llvm.org/D46581