[clang] [Clang][Interp] Implement constexpr vector unary operators +, -, ~, ! (PR #105996)

[Timm Baeder via cfe-commits]

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@@ -5312,6 +5314,149 @@ bool Compiler<Emitter>::VisitComplexUnaryOperator(const UnaryOperator *E) {
   return true;
 }
 
+template <class Emitter>
+bool Compiler<Emitter>::VisitVectorUnaryOp(const UnaryOperator *E) {
+  const Expr *SubExpr = E->getSubExpr();
+  assert(SubExpr->getType()->isVectorType());
+
+  if (DiscardResult)
+    return this->discard(SubExpr);
+
+  std::optional<PrimType> ResT = classify(E);
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tbaederr wrote:

`ResT` is unused except for in `prepareResult`. In what cases is `ResT` unset?

https://github.com/llvm/llvm-project/pull/105996