[llvm] [AMDGPU] Support block load/store for CSR (PR #130013)

[Matt Arsenault via llvm-commits]

================
@@ -239,6 +240,36 @@ const MCExpr *AMDGPUAsmPrinter::lowerConstant(const Constant *CV) {
   return AsmPrinter::lowerConstant(CV);
 }
 
+static void emitVGPRBlockComment(const MachineInstr *MI, MCStreamer &OS) {
+  // The instruction will only transfer a subset of the registers in the block,
+  // based on the mask that is stored in m0. We could search for the instruction
+  // that sets m0, but most of the time we'll already have the mask stored in
+  // the machine function info. Try to use that. This assumes that we only use
+  // block loads/stores for CSR spills.
+  const MachineFunction *MF = MI->getParent()->getParent();
+  const SIMachineFunctionInfo *MFI = MF->getInfo<SIMachineFunctionInfo>();
+  const TargetRegisterInfo &TRI = *MF->getSubtarget().getRegisterInfo();
+  const SIInstrInfo *TII = MF->getSubtarget<GCNSubtarget>().getInstrInfo();
----------------
arsenm wrote:

Pass these in without chasing through the instruction, the parent context should have them already 

https://github.com/llvm/llvm-project/pull/130013