[PATCH] D124196: [AMDGPU][SILowerSGPRSpills] Spill SGPRs to virtual VGPRs

[Christudasan Devadasan via Phabricator via llvm-commits]

cdevadas added inline comments.


================
Comment at: llvm/lib/Target/AMDGPU/SIMachineFunctionInfo.cpp:283
   if (!LaneIndex) {
-    LaneVGPR = TRI->findUnusedRegister(MRI, &AMDGPU::VGPR_32RegClass, MF);
-    if (LaneVGPR == AMDGPU::NoRegister) {
-      // We have no VGPRs left for spilling SGPRs. Reset because we will not
-      // partially spill the SGPR to VGPRs.
-      SGPRToVGPRSpills.erase(FI);
-
-      // FIXME: We can run out of free registers with split allocation if
-      // IPRA is enabled and a called function already uses every VGPR.
-#if 0
-        DiagnosticInfoResourceLimit DiagOutOfRegs(MF.getFunction(),
-                                                  "VGPRs for SGPR spilling",
-                                                  0, DS_Error);
-        MF.getFunction().getContext().diagnose(DiagOutOfRegs);
-#endif
-      return false;
-    }
-
+    LaneVGPR = MRI.createVirtualRegister(&AMDGPU::VGPR_32RegClass);
     SpillVGPRs.push_back(LaneVGPR);
----------------
arsenm wrote:
> As part of the follow up to allow spill slot sharing, I think we can move all of this allocation stuff out of SIMachineFunctionInfo and into SILowerSGPRSpills
Ya, will try to move it entirely out of SIMachineFunctionInfo. 


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D124196/new/

https://reviews.llvm.org/D124196