[llvm] [InferAlignment] Do not use intrinsic align attributes as base pointer alignment (PR #221018)

[Stanislav Bardyuk via llvm-commits]

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@@ -80,8 +80,10 @@ static bool tryToImproveAlign(
     if (!Arg->getType()->isPointerTy())
       continue;
 
+    // The align attribute is not proof of an access (e.g. a zero-length
+    // memset), so it must not seed the base pointer alignment.
     Align OldAlign = II->getParamAlign(ArgNo).valueOrOne();
-    Align NewAlign = Fn(Arg, OldAlign, Align(1));
+    Align NewAlign = Fn(Arg, Align(1), Align(1));
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kodlan wrote:

done

https://github.com/llvm/llvm-project/pull/221018