[llvm] [VectorUtils] Improve mask*All(Ones|Zero)OrUndef (NFC) (PR #168388)

[Simon Pilgrim via llvm-commits]

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@@ -1289,7 +1289,7 @@ bool llvm::maskIsAllOneOrUndef(Value *Mask) {
   auto *ConstMask = dyn_cast<Constant>(Mask);
   if (!ConstMask)
     return false;
-  if (ConstMask->isAllOnesValue() || isa<UndefValue>(ConstMask))
+  if (match(ConstMask, m_CombineOr(m_AllOnes(), m_Undef())))
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RKSimon wrote:

isAllOnesValue can see through ConstantFP - can m_AllOnes()?

https://github.com/llvm/llvm-project/pull/168388