[PATCH] D83699: [Bitcode] Drop invalid branch_weight in BitcodeReader

[Adrian Prantl via Phabricator via llvm-commits]

aprantl added inline comments.


================
Comment at: llvm/lib/Bitcode/Reader/BitcodeReader.cpp:5397
 
+  // Check the branch weight on the instructions are correct. If not, drop them.
+  for (auto &I : instructions(F)) {
----------------
Perhaps even more explicit:
`// "Upgrade" older incorrect branch weights by dropping them.`


================
Comment at: llvm/lib/Bitcode/Reader/BitcodeReader.cpp:5400
+    if (auto *MD = I.getMetadata(LLVMContext::MD_prof)) {
+      if (MD->getNumOperands() >= 2 || MD->getOperand(0) != nullptr ||
+          isa<MDString>(MD->getOperand(0))) {
----------------
Are the || operators correct here?

I feel like this should be 

`MD->getOperand(0) != nullptr && isa<MDString>(MD->getOperand(0)` ?


================
Comment at: llvm/lib/Bitcode/Reader/BitcodeReader.cpp:5405
+        // Check consistency of !prof branch_weights metadata.
+        if (ProfName.equals("branch_weights")) {
+          unsigned ExpectedNumOperands = 0;
----------------
if (!ProfName.equals("branch_weights"))
  continue;


================
Comment at: llvm/lib/Bitcode/Reader/BitcodeReader.cpp:5420
+
+          // If branch weight doens't match, just strip branch weight.
+          if (MD->getNumOperands() != 1 + ExpectedNumOperands)
----------------
doesn't


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D83699/new/

https://reviews.llvm.org/D83699