[llvm] [DA] Dependence analysis does not handle array accesses of different sizes (PR #116630)

[Ryotaro Kasuga via llvm-commits]

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@@ -3625,16 +3621,15 @@ DependenceInfo::depends(Instruction *Src, Instruction *Dst,
     break; // The underlying objects alias; test accesses for dependence.
   }
 
-  // establish loop nesting levels
-  establishNestingLevels(Src, Dst);
-  LLVM_DEBUG(dbgs() << "    common nesting levels = " << CommonLevels << "\n");
-  LLVM_DEBUG(dbgs() << "    maximum nesting levels = " << MaxLevels << "\n");
-
-  FullDependence Result(Src, Dst, PossiblyLoopIndependent, CommonLevels);
-  ++TotalArrayPairs;
+  if (DstLoc.Size != SrcLoc.Size) {
+    // The dependence test gets confused if the size of the memory accesses
+    // differ.
+    LLVM_DEBUG(dbgs() << "can't analyze must alias with different sizes\n");
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kasuga-fj wrote:

Only "must alias"?

https://github.com/llvm/llvm-project/pull/116630