[PATCH] D111032: Testing instcombine/licm pass order...

[Alina Sbirlea via Phabricator via llvm-commits]

asbirlea added inline comments.


================
Comment at: llvm/lib/Passes/PassBuilderPipelines.cpp:561
+      LICMPass(PTO.LicmMssaOptCap, PTO.LicmMssaNoAccForPromotionCap),
+      /*UseMemorySSA=*/true, /*UseBlockFrequencyInfo=*/true));
   invokePeepholeEPCallbacks(FPM, Level);
----------------
mnadeem wrote:
> nikic wrote:
> > This LICM run is currently placed to reuse the MSSA analysis computed for MemCpyOpt and DSE. While the LTO change looks reasonable to me, the compile-time impact of this move is unlikely to be worthwhile under global consideration.
> Looking at the changes in `clang/test/CodeGen/thinlto-distributed-newpm.ll` it does not look like MemorySSA is being run again.
> 
> Does simplifycfg or instcombine invalidate the MSSA analysis?
Neither simplifycfg nor instcombine updates MSSA.


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  https://reviews.llvm.org/D111032/new/

https://reviews.llvm.org/D111032