[llvm] [SPIRV] Add FPVariant tracking for floating-point registers in SPIR-V (PR #156871)

[Dmitry Sidorov via llvm-commits]

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@@ -88,6 +92,11 @@ class SPIRVGlobalRegistry : public SPIRVIRMapping {
   // map of aliasing decorations to aliasing metadata
   std::unordered_map<const MDNode *, MachineInstr *> AliasInstMDMap;
 
+  // Maps floating point Registers to their FPVariant (float type kind), given
+  // the MachineFunction.
+  DenseMap<const MachineFunction *, DenseMap<Register, FPVariant>>
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MrSidims wrote:

Why it's not enough to use VRegToTypeMap?

https://github.com/llvm/llvm-project/pull/156871