[PATCH] D67359: [IVUser] Limit the iterations to check whether a loop has dedicated exits for extreme large case

Mon Sep 23 16:02:55 PDT 2019

wmi added a comment.

Sorry for taking a while to get back. Upload a testfile 1.cc: F10054736: 1.cc <https://reviews.llvm.org/F10054736>.

~/workarea/llvm-r371746/rbuild/bin/clang -O2 -S 1.cc
Without the patch, it took 52s to compile.
With the patch, it took 2s to compile.
gcc took 9s to compile.

And for the testcase, disabling LSR didn't help much, so it is not an IVUser specific problem. It took so long mainly because of hasDedicatedExits.

Repository:
  rL LLVM

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D67359/new/

https://reviews.llvm.org/D67359