[llvm] [AMDGPU] Update base addr of dyn alloca considering GrowingUp stack (PR #119822)

[via llvm-commits]

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@@ -4023,10 +4024,20 @@ SDValue SITargetLowering::lowerDYNAMIC_STACKALLOCImpl(SDValue Op,
   Chain = DAG.getCALLSEQ_START(Chain, 0, 0, dl);
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easyonaadit wrote:

This is also used in the default implementation. 
All the DAG nodes emitted to modify the stack pointer do have a chain dependency and ideally the scheduler should not insert any other stack pointer manipulation between them. I assume the CALLSEQ_START/CALLSEQ_END is a sort of "additional precaution". 
However, should it be removed? I'm not sure. 
@arsenm 

https://github.com/llvm/llvm-project/pull/119822