[llvm] [PatternMatchHelpers] Introduce m_Unless (NFC) (PR #212454)

[Luke Lau via llvm-commits]

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@@ -208,7 +208,7 @@ template <typename Pred> struct Not {
 template <typename Pred> Not(const Pred &P) -> Not<Pred>;
 
 /// Match if the inner pattern does NOT match.
-template <typename Pred> inline Not<Pred> m_Unless(const Pred &P) {
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lukel97 wrote:

I gave nesting a try and it seems to work https://github.com/llvm/llvm-project/pull/213016

https://github.com/llvm/llvm-project/pull/212454