Fixes to be upstreamed - Preserve SlotIndexes in AMDGPURewriteAGPRCopyMFMA for NPM

AMDGPURewriteAGPRCopyMFMAPass claimed to preserve LiveIntervalsAnalysis
but did not preserve its dependency, SlotIndexesAnalysis. Under NPM, this
causes LiveIntervals to be invalidated and recomputed. Fix by explicitly
preserving SlotIndexesAnalysis.

Author: PrasoonMishra

llvm/lib/Target/AMDGPU/AMDGPURewriteAGPRCopyMFMA.cpp

@@ -32,6 +32,7 @@
 #include "llvm/CodeGen/LiveStacks.h"
 #include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/CodeGen/SlotIndexes.h"
 #include "llvm/CodeGen/VirtRegMap.h"
 #include "llvm/InitializePasses.h"
 
@@ -662,6 +663,7 @@ AMDGPURewriteAGPRCopyMFMAPass::run(MachineFunction &MF,
   PA.preserveSet<CFGAnalyses>()
     .preserve<LiveStacksAnalysis>()
     .preserve<VirtRegMapAnalysis>()
+    .preserve<SlotIndexesAnalysis>()
     .preserve<LiveIntervalsAnalysis>()
     .preserve<LiveRegMatrixAnalysis>();
   return PA;