[llvm-branch-commits] [llvm] [amdgpu-cfi: 7/9]: [AMDGPU] Implement CFI for CSR spills (PR #183150)

[Matt Arsenault via llvm-branch-commits]

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@@ -2242,12 +2242,59 @@ bool SIFrameLowering::spillCalleeSavedRegisters(
     ArrayRef<CalleeSavedInfo> CSI, const TargetRegisterInfo *TRI) const {
   MachineFunction *MF = MBB.getParent();
   const GCNSubtarget &ST = MF->getSubtarget<GCNSubtarget>();
-  if (!ST.useVGPRBlockOpsForCSR())
-    return false;
+  const SIInstrInfo *TII = ST.getInstrInfo();
+  const MachineRegisterInfo &MRI = MF->getRegInfo();
+
+  if (!ST.useVGPRBlockOpsForCSR()) {
+    SparseBitVector<> LiveInRoots;
+    if (MRI.tracksLiveness()) {
+      for (const auto &LI : MBB.liveins()) {
+        for (MCRegUnitMaskIterator MI(LI.PhysReg, TRI); MI.isValid(); ++MI) {
+          auto [Unit, UnitLaneMask] = *MI;
+          if ((LI.LaneMask & UnitLaneMask).none())
+            continue;
+          for (MCRegUnitRootIterator RI(Unit, TRI); RI.isValid(); ++RI)
+            LiveInRoots.set(*RI);
+        }
+      }
+    }
+
+    auto UpdateLiveInCheckCanKill = [&](MCRegister Reg) {
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arsenm wrote:

Make this not a lambda 

https://github.com/llvm/llvm-project/pull/183150