[PATCH] D128452: [PGL][LTO] Make PGL work with FLTO (PR #56185)

Wed Jun 29 14:22:49 PDT 2022

MaskRay accepted this revision.
MaskRay added a comment.
This revision is now accepted and ready to land.

Please expand uncommon abbreviations: PGL, FLTO, and TLTO.

> TLTO is not affected as the passes are added (correctly) via a different path

Be more precise about why ThinLTO is unaffected: buildModuleOptimizationPipeline called by it runs CGProfilePass.

================
Comment at: llvm/lib/Passes/PassBuilderPipelines.cpp:1274

-  if (PTO.CallGraphProfile)
+  if (PTO.CallGraphProfile && !LTOPreLink)
     MPM.addPass(CGProfilePass());
----------------
Perhaps move after GlobalDCEPass/ConstantMergePass similar to buildLTODefaultPipeline.

GlobalDCEPass may discard some functions and these functions don't need to run CGProfilePass. Though the speed-up is almost assuredly negligible.

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