[PATCH] D97414: [ThinLTO][NewPM] Clean up dead code under -O0

[Teresa Johnson via Phabricator via llvm-commits]

tejohnson added inline comments.


================
Comment at: llvm/lib/Passes/PassBuilder.cpp:1542
 
-  if (Level == OptimizationLevel::O0)
+  if (Level == OptimizationLevel::O0) {
+    // Drop available_externally and unreferenced globals. This is necessary
----------------
aeubanks wrote:
> tejohnson wrote:
> > Looking at the old PM, we also call:
> > MPM.add(createLowerTypeTestsPass(nullptr, nullptr, true));
> > 
> > to drop any leftover type tests. Thinking that should probably get added here too (it's normally done below in the ModuleSimplificationPipeline, but of course that doesn't get reached for O0).
> It's already added right above, but only when we have an ImportSummary. Should another be added when we don't have an ImportSummary?
Note the args are different - LTT needs to be called a second time with the third parameter set to true to remove all the type tests that the first call leaves behind for potential use in optimization.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D97414/new/

https://reviews.llvm.org/D97414