llvm-project/llvm/unittests/Transforms
Alina Sbirlea 2312a06c87 [SCEV] Add option to forget everything in SCEV.
Summary:
Create a method to forget everything in SCEV.
Add a cl::opt and PassManagerBuilder option to use this in LoopUnroll.

Motivation: Certain Halide applications spend a very long time compiling in forgetLoop, and prefer to forget everything and rebuild SCEV from scratch.
Sample difference in compile time reduction: 21.04 to 14.78 using current ToT release build.
Testcase showcasing this cannot be opensourced and is fairly large.

The option disabled by default, but it may be desirable to enable by
default. Evidence in favor (two difference runs on different days/ToT state):

File Before (s) After (s)
clang-9.bc 7267.91 6639.14
llvm-as.bc 194.12 194.12
llvm-dis.bc 62.50 62.50
opt.bc 1855.85 1857.53

File Before (s) After (s)
clang-9.bc 8588.70 7812.83
llvm-as.bc 196.20 194.78
llvm-dis.bc 61.55 61.97
opt.bc 1739.78 1886.26

Reviewers: sanjoy

Subscribers: mehdi_amini, jlebar, zzheng, javed.absar, dmgreen, jdoerfert, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D60144

llvm-svn: 358304
2019-04-12 19:16:07 +00:00
..
IPO Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
Scalar [MemorySSA & LoopPassManager] Add remaining book keeping [NFCI]. 2019-02-12 23:48:02 +00:00
Utils [SCEV] Add option to forget everything in SCEV. 2019-04-12 19:16:07 +00:00
Vectorize Update files that were mistakenly added with the old file header to the 2019-02-11 08:07:38 +00:00
CMakeLists.txt [VPlanRecipeBase] Add insertBefore helper. 2018-06-18 11:34:17 +00:00