[PATCH] D38768: Add remarks describing when a pass changes the IR instruction count of a module

[Jessica Paquette via Phabricator via llvm-commits]

paquette updated this revision to Diff 147357.
paquette added a comment.

A few changes here after running this on some more complicated code.

- I had entirely forgotten to implement it for loop passes in this patch. Added that. ("Why is instcombine making this module 50% bigger? Oh; it's loop unrolling.")

- `Changed` and `LocalChanged` aren't reliable for this sort of task. Removed the reliance on that from emitting remarks.

- Getting the initial size of the module at the entry to `runOnBlah` is unreliable due to missing initialization steps/passes. Moved this down to near where the remark is emitted.

- Added documentation to the test to explain what it's doing, what behaviour it tests, why/why not.

- Made the test enforce that instruction counts and deltas must be within a certain range, and not just any old number.


https://reviews.llvm.org/D38768

Files:
  include/llvm/IR/Function.h
  include/llvm/IR/LegacyPassManagers.h
  include/llvm/IR/Module.h
  lib/Analysis/CallGraphSCCPass.cpp
  lib/Analysis/LoopPass.cpp
  lib/IR/Function.cpp
  lib/IR/LegacyPassManager.cpp
  lib/IR/Module.cpp
  test/Other/size-remarks.ll

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