[llvm] [DAG] computeKnownFPClass - add ISD::FNEG handling + test coverage (PR #190325)

[Simon Pilgrim via llvm-commits]

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@@ -0,0 +1,60 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 6
+; RUN: llc < %s -mtriple=riscv64 -mattr=+v,+f,+d | FileCheck %s
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RKSimon wrote:

Worth just adding these to combine-is_fpclass.ll ?

https://github.com/llvm/llvm-project/pull/190325