[PATCH] D99707: Remove "Rewrite Symbols" from codegen pipeline

[Arthur Eubanks via Phabricator via llvm-commits]

aeubanks added inline comments.


================
Comment at: llvm/lib/Target/ARM/ARMTargetMachine.cpp:466
     addPass(createMVETailPredicationPass());
+    addPass(createBarrierNoopPass());
   }
----------------
SjoerdMeijer wrote:
> Thanks for adding us. I am unfamiliar with this BarriesNoopPass. @dmgreen, do you know more about this by any chance?
typically if we have a bunch of function passes in a row, the pass manager will run all of them on one function, then the next function, etc
by adding a module pass somewhere in the middle of the function passes, we'll end up running the first half of the function passes on each function, then the second half. this accomplishes what's mentioned in the description

e.g. if we have two functions f1 and f2, and four function passes FP1-4, normally it'd be
FP1 on f1
FP2 on f1
FP3 on f1
FP4 on f1
FP1 on f2
FP2 on f2
FP3 on f2
FP4 on f2

but with the barrier between FP2 and FP3, we get

FP1 on f1
FP2 on f1
FP1 on f2
FP2 on f2
barrier
FP3 on f1
FP4 on f1
FP3 on f2
FP4 on f2


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  https://reviews.llvm.org/D99707/new/

https://reviews.llvm.org/D99707