[llvm] ValueTracking: Handle constant structs in computeKnownFPClass (PR #184192)

[Matt Arsenault via llvm-commits]

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@@ -5058,6 +5058,21 @@ void computeKnownFPClass(const Value *V, const APInt &DemandedElts,
     return;
   }
 
+  if (const auto *CDS = dyn_cast<ConstantAggregate>(V)) {
+    Known.KnownFPClasses = fcNone;
+    for (const Use &Op : CDS->operands()) {
+      auto *CFP = dyn_cast<ConstantFP>(Op.get());
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arsenm wrote:

Left as a todo, I'm confused by the constant aggregate APIs 

https://github.com/llvm/llvm-project/pull/184192