[PATCH] D139970: [llvm][CallBrPrepare] use SSAUpdater to use intrinsic value

[Eli Friedman via Phabricator via llvm-commits]

efriedma added inline comments.


================
Comment at: llvm/lib/CodeGen/CallBrPrepare.cpp:182
+
+    for (Use &U : CBR->uses()) {
+      if (!Visited.insert(&U).second)
----------------
You can't iterate this way if you're going to modify the uses, I think?  Once you rewrite a use, it refers to a different use-list, so the iterator's increment won't do the right thing.


================
Comment at: llvm/lib/CodeGen/CallBrPrepare.cpp:204
+      SSAUpdate.AddAvailableValue(LandingPad, Intrinsic);
+      SSAUpdate.RewriteUse(U);
+    }
----------------
This usage of SSAUpdater seems a little strange.  It would be more efficient to construct one SSAUpdater per callbr, instead of one SSAUpdater per use.  You can construct the SSAUpdater, AddAvailableValue all the intrinsic call for that callbr, then rewrite all the relevant uses using that SSAUpdater.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D139970/new/

https://reviews.llvm.org/D139970