Allow users to ignore optimization changes

Authored by dfeuer on Dec 11 2017, 12:03 PM.

Description

Allow users to ignore optimization changes

  • Add a new flag, -fignore-optim-changes, allowing them to avoid recompilation if the only changes are to the -O level or to flags controlling optimizations.
  • When -fignore-optim-changes is *off*, recompile when optimization flags (e.g., -fno-full-laziness) change. Previously, we ignored these unconditionally when deciding whether to recompile a module.

Reviewers: austin, bgamari, simonmar

Reviewed By: simonmar

Subscribers: duog, carter, simonmar, rwbarton, thomie

GHC Trac Issues: Trac #13604

Differential Revision: https://phabricator.haskell.org/D4123

(cherry picked from commit 708ed9ca4dbf372817fe84a2fe486940123bddfb)