[llvm] [SPIR-V] Support SPV_INTEL_fp_max_error extension for `!fpmath` metadata (PR #130619)

[Viktoria Maximova via llvm-commits]

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@@ -307,6 +309,10 @@ SPIR-V backend, along with their descriptions and argument details.
      - None
      - `[Type, 32-bit Integer, Metadata]`
      - Assigns one of two memory aliasing decorations (specified by the second argument) to instructions using original aliasing metadata node. Not emitted directly but used to support SPIR-V representation in LLVM IR.
+   * - `int_spv_assign_fpmaxerror_decoration`
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vmaksimo wrote:

I like the idea, but it seems that we can't do that - `handleMIFlagDecoration` is "too late" in the stack, and we don't have FP accuracy saved in BE machine instructions. 

https://github.com/llvm/llvm-project/pull/130619