[PATCH] D146776: [llvm] Preliminary fat-lto-objects support

[Paul Kirth via Phabricator via llvm-commits]

paulkirth added inline comments.


================
Comment at: llvm/lib/Passes/PassBuilderPipelines.cpp:1489
+      buildModuleSimplificationPipeline(Level, ThinOrFullLTOPhase::None));
+  MPM.addPass(buildModuleOptimizationPipeline(Level, ThinOrFullLTOPhase::None,
+                                              /*IsFatLto*/ true));
----------------
tejohnson wrote:
> Why pass in phase None for these calls to module simplification and optimization passes, instead of the corresponding post-LTO link phase? I would think we would want the complement of the phase provided earlier. I'm pretty sure there are some passes that are configured to run in exactly one of these phases, and we might end up duplicating them if running a pre-LTO link phase + a default (non-LTO) phase optimization pipeline.
The intent there was to closely mimic the non-lto pipeline. For now I've attempted to just split everything, but I'm not sure I love the approach. It's certainly simple, but I didn't like giving a pass its own passmanager... plus its does seem to be a bit wasteful to run two complete pipelines on the module.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D146776/new/

https://reviews.llvm.org/D146776