[llvm] [clang] [SPARC] Support reserving arbitrary general purpose registers (PR #74927)

[Sergei Barannikov via cfe-commits]

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@@ -1125,6 +1130,19 @@ Register SparcTargetLowering::getRegisterByName(const char* RegName, LLT VT,
     .Case("g4", SP::G4).Case("g5", SP::G5).Case("g6", SP::G6).Case("g7", SP::G7)
     .Default(0);
 
+  const SparcRegisterInfo *MRI = Subtarget->getRegisterInfo();
+  unsigned DwarfRegNum = MRI->getDwarfRegNum(Reg, false);
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s-barannikov wrote:

It looks strange to check dwarf register numbers here. Why don't compare register ids directly? E.g.
`IsG = Reg >= SP::G0 && Reg <= SP::G7`.


https://github.com/llvm/llvm-project/pull/74927