[PATCH] D22744: CodeExtractor : Add ability to preserve profile data.

[River Riddle via llvm-commits]

rriddle added inline comments.

================
Comment at: lib/Transforms/Utils/CodeExtractor.cpp:693
@@ +692,3 @@
+  for (auto &Weight : ExitWeights) {
+    if (Weight.second.getFrequency() == 0) {
+      HasValidWeights = false;
----------------
davidxl wrote:
> rriddle wrote:
> > rriddle wrote:
> > > davidxl wrote:
> > > > This check does not look correct. It is possible for the frequency to be zero
> > > Yeah, that was my understanding. Thanks for the sanity check! I need to add the weights without using the current methods given that they do not allow for weights of 0.
> > Although, can you help clarify on what I should be doing in the case of a 0 frequency? I am unsure on whether the branch weight can be set to a hard 0 or if it needs to be modified to always have a non zero weight? 
> zero weight is fine -- BFI will always adds 1 to it if it sees it due to some limitation (it is less than ideal -- a better way to is to fix BPI (which will be fixed in the near future).
> 
> One the other hand if the total weight is zero, you may want to treat it as invalid.
Awesome. Thanks for the clarification!


https://reviews.llvm.org/D22744