From bbea044c7d9057b1a1e8ee26408adbeafecf9955 Mon Sep 17 00:00:00 2001
From: shylie <shylie@shylie.info>
Date: Mon, 6 Apr 2026 22:06:00 -0400
Subject: [PATCH] Add rules to restore RRA

---
 llvm/lib/Target/Foot/FootFrameLowering.cpp | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/llvm/lib/Target/Foot/FootFrameLowering.cpp b/llvm/lib/Target/Foot/FootFrameLowering.cpp
index 2fe1dc811895..f1d74a9df659 100644
--- a/llvm/lib/Target/Foot/FootFrameLowering.cpp
+++ b/llvm/lib/Target/Foot/FootFrameLowering.cpp
@@ -21,9 +21,10 @@ void FootFrameLowering::emitPrologue(MachineFunction &MF,
 
   int FI = MF.getInfo<FootMachineFunctionInfo>()->getReturnAddressFrameIndex();
 
-  unsigned CFIIndex = MF.addFrameInst(MCCFIInstruction::createDefCfaRegister(
-      nullptr, MF.getRegInfo().getTargetRegisterInfo()->getDwarfRegNum(
-                   Foot::RSP, true)));
+  unsigned int CFIIndex =
+      MF.addFrameInst(MCCFIInstruction::createDefCfaRegister(
+          nullptr, MF.getRegInfo().getTargetRegisterInfo()->getDwarfRegNum(
+                       Foot::RSP, true)));
   BuildMI(MBB, MBB.begin(), DebugLoc(), TII->get(TargetOpcode::CFI_INSTRUCTION))
       .addCFIIndex(CFIIndex);
 
@@ -31,6 +32,13 @@ void FootFrameLowering::emitPrologue(MachineFunction &MF,
       .addFrameIndex(FI)
       .addReg(Foot::RRA)
       .addImm(0);
+  unsigned int RRADwarfRegNum =
+      MF.getRegInfo().getTargetRegisterInfo()->getDwarfRegNum(Foot::RRA, false);
+  int Offset = MFI.getObjectOffset(FI);
+  CFIIndex = MF.addFrameInst(
+      MCCFIInstruction::createOffset(nullptr, RRADwarfRegNum, Offset));
+  BuildMI(MBB, MBB.begin(), DebugLoc(), TII->get(TargetOpcode::CFI_INSTRUCTION))
+      .addCFIIndex(CFIIndex);
 
   unsigned NumBytes = MFI.getStackSize();
 
@@ -51,11 +59,11 @@ void FootFrameLowering::emitPrologue(MachineFunction &MF,
           .addImm(NumBytes);
     }
 
-    unsigned int CFIOffsetIndex = MF.addFrameInst(
+    CFIIndex = MF.addFrameInst(
         MCCFIInstruction::createAdjustCfaOffset(nullptr, NumBytes));
     BuildMI(MBB, MBB.getFirstTerminator(), DebugLoc(),
             TII->get(TargetOpcode::CFI_INSTRUCTION))
-        .addCFIIndex(CFIOffsetIndex);
+        .addCFIIndex(CFIIndex);
   }
 }
 
@@ -132,6 +140,7 @@ void FootFrameLowering::determineCalleeSaves(MachineFunction &MF,
   TargetFrameLowering::determineCalleeSaves(MF, SavedRegs, RS);
 
   SavedRegs.set(Foot::RSP);
+  SavedRegs.set(Foot::RRA);
 
   MachineFrameInfo &MFI = MF.getFrameInfo();