[llvm] [IR] Initial introduction of memset_pattern (PR #97583)

[Alex Bradbury via llvm-commits]

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@@ -1249,6 +1252,21 @@ class MemSetInlineInst : public MemSetInst {
   }
 };
 
+/// This class wraps the llvm.memset.pattern intrinsic.
+class MemSetPatternInst : public MemSetInst {
+public:
+  ConstantInt *getLength() const {
+    return cast<ConstantInt>(MemSetInst::getLength());
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asb wrote:

Yes this was a holdover from before I'd removed that restriction. Now removed.

https://github.com/llvm/llvm-project/pull/97583