[llvm] 86d817d - [DSE,MemorySSA] Skip defs without analyzable write locations.

[Florian Hahn via llvm-commits]

Author: Florian Hahn
Date: 2020-08-30T21:56:25+01:00
New Revision: 86d817d7cf29750dfed1892d51110f44fc499c94

URL: https://github.com/llvm/llvm-project/commit/86d817d7cf29750dfed1892d51110f44fc499c94
DIFF: https://github.com/llvm/llvm-project/commit/86d817d7cf29750dfed1892d51110f44fc499c94.diff

LOG: [DSE,MemorySSA] Skip defs without analyzable write locations.

Similar to other checks above, if there is no write location for a def,
it cannot be considered for elimination and can be skipped.

Added: 
    

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

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp b/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
index b2613697bfa5..7e4ef1ed9cd8 100644
--- a/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
+++ b/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
@@ -1896,9 +1896,13 @@ struct DSEState {
         continue;
       }
 
+      // If Current does not have an analyzable write location, skip it
       auto CurrentLoc = getLocForWriteEx(CurrentI);
-      if (!CurrentLoc)
-        break;
+      if (!CurrentLoc) {
+        StepAgain = true;
+        Current = CurrentDef->getDefiningAccess();
+        continue;
+      }
 
       if (IsMemTerm) {
         // If the killing def is a memory terminator (e.g. lifetime.end), check