AMDGPU: Fix not preserving CSR VGPR if used for SGPR spills

Before this was not done if the function had no calls in it. This
is still a possible issue with any callable function, regardless
of calls present.

llvm-svn: 328659

1 files changed, 3 insertions, 4 deletions

diff --git a/llvm/lib/Target/AMDGPU/SIMachineFunctionInfo.cpp b/llvm/lib/Target/AMDGPU/SIMachineFunctionInfo.cpp
index 2534ad02478..f78578ad9c8 100644
--- a/llvm/lib/Target/AMDGPU/SIMachineFunctionInfo.cpp
+++ b/llvm/lib/Target/AMDGPU/SIMachineFunctionInfo.cpp
@@ -273,10 +273,9 @@ bool SIMachineFunctionInfo::allocateSGPRSpillToVGPR(MachineFunction &MF,
       }
 
       Optional<int> CSRSpillFI;
-      if (FrameInfo.hasCalls() && CSRegs && isCalleeSavedReg(CSRegs, LaneVGPR)) {
-        // TODO: Should this be a CreateSpillStackObject? This is technically a
-        // weird CSR spill.
-        CSRSpillFI = FrameInfo.CreateStackObject(4, 4, false);
+      if ((FrameInfo.hasCalls() || !isEntryFunction()) && CSRegs &&
+          isCalleeSavedReg(CSRegs, LaneVGPR)) {
+        CSRSpillFI = FrameInfo.CreateSpillStackObject(4, 4);
       }
 
       SpillVGPRs.push_back(SGPRSpillVGPRCSR(LaneVGPR, CSRSpillFI));