[llvm] [mlir] [LLVM][Constants] Remove the option to disable vector ConstantFP support. (PR #197427)

[Matt Arsenault via llvm-commits]

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@@ -1665,24 +1659,25 @@ Constant *ConstantVector::getSplat(ElementCount EC, Constant *V) {
       return ConstantPointerNull::get(VTy);
   }
 
+  if (isa<ConstantByte>(V))
+    return ConstantByte::get(V->getContext(), EC,
+                             cast<ConstantByte>(V)->getValue());
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arsenm wrote:

dyn_cast instead of isa+cast 

https://github.com/llvm/llvm-project/pull/197427