[IR] Introduce `llvm.errno.tbaa` metadata for errno alias disambiguation

Add a new named module-level frontend-annotated metadata that
specifies the TBAA node for an integer access, for which, C/C++
`errno` accesses are guaranteed to use (under strict aliasing).
This should allow LLVM to prove the involved memory location/
accesses may not alias `errno`; thus, to perform optimizations
around errno-writing libcalls (store-to-load forwarding amongst
others).

Previous discussion: https://discourse.llvm.org/t/rfc-modelling-errno-memory-effects/82972.

1 files changed, 1 insertions, 1 deletions

diff --git a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
index 22a0d0f..832aa9f 100644
--- a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -7024,7 +7024,7 @@ Error BitcodeReader::materialize(GlobalValue *GV) {
   if (!MDLoader->isStrippingTBAA()) {
     for (auto &I : instructions(F)) {
       MDNode *TBAA = I.getMetadata(LLVMContext::MD_tbaa);
-      if (!TBAA || TBAAVerifyHelper.visitTBAAMetadata(I, TBAA))
+      if (!TBAA || TBAAVerifyHelper.visitTBAAMetadata(&I, TBAA))
         continue;
       MDLoader->setStripTBAA(true);
       stripTBAA(F->getParent());