[PATCH] D100802: [PassManager] add late LICM to LTO pipeline to undo InstCombine sinking

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri added inline comments.


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Comment at: llvm/test/Other/opt-LTO-pipeline.ll:179-190
+; CHECK-NEXT:     Basic Alias Analysis (stateless AA impl)
+; CHECK-NEXT:     Function Alias Analysis Results
+; CHECK-NEXT:     Memory SSA
+; CHECK-NEXT:     Natural Loop Information
+; CHECK-NEXT:     Canonicalize natural loops
+; CHECK-NEXT:     LCSSA Verifier
+; CHECK-NEXT:     Loop-Closed SSA Form Pass
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The problem here is that we do this after the `FunctionPass Manager` finishes.
This seems suboptimal from cache locality perspective,
and that is my only guess as to why we are seeing such huge compile-time regression
in full LTO only, because full lto results in *huge* modules
with lots of functions.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D100802/new/

https://reviews.llvm.org/D100802