[llvm] [PowerPC] Utilize getReservedRegs to find asm clobberable registers. (PR #107863)

[Lei Huang via llvm-commits]

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@@ -3434,6 +3434,8 @@ SDValue PPCTargetLowering::LowerGlobalTLSAddressAIX(SDValue Op,
   if (Subtarget.hasAIXShLibTLSModelOpt())
     updateForAIXShLibTLSModelOpt(Model, DAG, getTargetMachine());
 
+  setUsesTOCBasePtr(DAG);
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lei137 wrote:

Can we add a comment here as to why this is now needed?

https://github.com/llvm/llvm-project/pull/107863