[llvm] [SPIR-V] Re-implement switch and improve validation of forward calls (PR #87823)

[Alexey Bader via llvm-commits]

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@@ -112,7 +114,7 @@ void SPIRVAsmPrinter::emitEndOfAsmFile(Module &M) {
   // TODO: calculate Bound more carefully from maximum used register number,
   // accounting for generated OpLabels and other related instructions if
   // needed.
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bader wrote:

Don't we need to update this comment?

https://github.com/llvm/llvm-project/pull/87823