[llvm] [SROA] Rewrite invariant group intrinsics after splitting alloca (PR #107557)

[Nikita Popov via llvm-commits]

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@@ -3531,8 +3531,19 @@ class AllocaSliceRewriter : public InstVisitor<AllocaSliceRewriter, bool> {
       return true;
     }
 
-    if (II.isLaunderOrStripInvariantGroup())
+    if (II.isLaunderOrStripInvariantGroup()) {
+      Value *AdjustedPtr = getNewAllocaSlicePtr(IRB, OldPtr->getType());
+      Value *New = nullptr;
+      if (II.getIntrinsicID() == Intrinsic::launder_invariant_group)
+        New = IRB.CreateLaunderInvariantGroup(AdjustedPtr);
+      else if (II.getIntrinsicID() == Intrinsic::strip_invariant_group)
+        New = IRB.CreateStripInvariantGroup(AdjustedPtr);
+
+      New->takeName(&II);
+      II.replaceAllUsesWith(New);
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nikic wrote:

The case I have in mind is something like memcpy_after_laundering_alloca but where we end up with two memcpys rather than one. I expect you'll get incorrect pointers in that case.

https://github.com/llvm/llvm-project/pull/107557