[llvm] Add optimisation for SVE intrinsics with no active lanes (PR #73964)

[Mark Harley via llvm-commits]

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@@ -1406,9 +1406,30 @@ static std::optional<Instruction *> instCombineSVEAllActive(IntrinsicInst &II,
   return &II;
 }
 
+// Optimize operations that take an all false predicate or send them for
+// canonicalization.
+static std::optional<Instruction *>
+instCombineSVEAllOrNoActive(InstCombiner &IC, IntrinsicInst &II,
+                            Intrinsic::ID IID) {
+  if (match(II.getOperand(0), m_ZeroInt())) {
+    if (II.getIntrinsicID() != IID)
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MarkAHarley wrote:

Fixed

https://github.com/llvm/llvm-project/pull/73964