[llvm] [PGO] Preserve analysis results when nothing was instrumented (PR #93421)

[Pavel Samolysov via llvm-commits]

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+; RUN: opt < %s -passes=pgo-instr-gen -S | FileCheck %s --implicit-check-not='__llvm_profile_raw_version'
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samolisov wrote:

Thank you for the questions, they let me get that the commit header and description were inaccurate. I've made them (at least I believe) a bit more precise.

https://github.com/llvm/llvm-project/pull/93421