[llvm] 6439fde - [DSE] Bail out from getLocForWriteEx if call is not argmemonly/inacc_mem.

[Florian Hahn via llvm-commits]

Author: Florian Hahn
Date: 2020-10-20T14:37:53+01:00
New Revision: 6439fde6d403d3e01e265fb84b0beffe67f745c5

URL: https://github.com/llvm/llvm-project/commit/6439fde6d403d3e01e265fb84b0beffe67f745c5
DIFF: https://github.com/llvm/llvm-project/commit/6439fde6d403d3e01e265fb84b0beffe67f745c5.diff

LOG: [DSE] Bail out from getLocForWriteEx if call is not argmemonly/inacc_mem.

This change should currently not have any impact, but guard against
further inconsistencies between MemoryLocation and function attributes.

Added: 
    

Modified: 
    llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp

Removed: 
    


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diff  --git a/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp b/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
index f0eb520f9332..58deceaba60f 100644
--- a/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
+++ b/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
@@ -1701,6 +1701,11 @@ struct DSEState {
       return {MemoryLocation::getForDest(MTI)};
 
     if (auto *CB = dyn_cast<CallBase>(I)) {
+      // If the functions may write to memory we do not know about, bail out.
+      if (!CB->onlyAccessesArgMemory() &&
+          !CB->onlyAccessesInaccessibleMemOrArgMem())
+        return None;
+
       LibFunc LF;
       if (TLI.getLibFunc(*CB, LF) && TLI.has(LF)) {
         switch (LF) {