[llvm] [RISCV] Add CFI information for vector callee-saved registers (PR #86811)

[Craig Topper via llvm-commits]

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@@ -452,29 +478,39 @@ static MCCFIInstruction createDefCFAExpression(const TargetRegisterInfo &TRI,
   else
     Comment << printReg(Reg, &TRI);
 
-  uint8_t buffer[16];
-  if (FixedOffset) {
-    Expr.push_back(dwarf::DW_OP_consts);
-    Expr.append(buffer, buffer + encodeSLEB128(FixedOffset, buffer));
-    Expr.push_back((uint8_t)dwarf::DW_OP_plus);
-    Comment << " + " << FixedOffset;
-  }
+  appendScalableVectorExpression(Expr, FixedOffset, ScalableOffset,
+                                 TRI.getDwarfRegNum(RISCV::VLENB, true),
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topperc wrote:

Why is the caller responsible for calling `TRI.getDwarfRegNum(RISCV::VLENB, true)`? Can we sink that into the function?

https://github.com/llvm/llvm-project/pull/86811