[llvm] [DAG] computeKnownFPClass - add ISD::EXTRACT_VECTOR_ELT handling (PR #190307)

[Xinlong Chen via llvm-commits]

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@@ -22,6 +22,61 @@ define i8 @iszero_constant_v4f32() nounwind {
   ret i8 %r
 }
 
+define i1 @extract_nonconst_idx_const_vec_isnan(i32 %idx) nounwind {
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Xinlong-Chen wrote:

Done. Updated the tests to use a mixed-class vector (`<QNaN, 2.0, +Inf, -Inf>`) 

https://github.com/llvm/llvm-project/pull/190307