[llvm] [AMDGPU] Restore SP from saved-FP or saved-BP (PR #124007)

[Matt Arsenault via llvm-commits]

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@@ -525,8 +525,7 @@ Register SIRegisterInfo::getFrameRegister(const MachineFunction &MF) const {
 bool SIRegisterInfo::hasBasePointer(const MachineFunction &MF) const {
   // When we need stack realignment, we can't reference off of the
   // stack pointer, so we reserve a base pointer.
-  const MachineFrameInfo &MFI = MF.getFrameInfo();
-  return MFI.getNumFixedObjects() && shouldRealignStack(MF);
+  return shouldRealignStack(MF);
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arsenm wrote:

Add a fix to undo this and we use too many base pointers 

https://github.com/llvm/llvm-project/pull/124007