[llvm] [SPIRV] Support G_IS_FPCLASS (PR #148637)

[Dmitry Sidorov via llvm-commits]

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+; RUN: llc -verify-machineinstrs -O0 -mtriple=spirv64-unknown-unknown %s -o - | FileCheck %s
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MrSidims wrote:

Please also have a test with more-than-one masks used at once. I suspect there might be redundant/duplicating OpBitwiseAnd instructions generated.

https://github.com/llvm/llvm-project/pull/148637