AMDGPU: Remove SIPrepareScratchRegs

[oota-llvm.git] / lib / Target / AMDGPU / SIFrameLowering.cpp

diff --git a/lib/Target/AMDGPU/SIFrameLowering.cpp b/lib/Target/AMDGPU/SIFrameLowering.cpp
index a2d8fa1b0a1080c4e306e341e916e28929c868be..6aff4b5700d4a45f2efaa3f0dbaee839bebf3558 100644 (file)
--- a/lib/Target/AMDGPU/SIFrameLowering.cpp
+++ b/lib/Target/AMDGPU/SIFrameLowering.cpp
@@ -8,17 +8,89 @@
 //==-----------------------------------------------------------------------===//
 
 #include "SIFrameLowering.h"
+#include "SIInstrInfo.h"
+#include "SIMachineFunctionInfo.h"
 #include "SIRegisterInfo.h"
 #include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineInstrBuilder.h"
 #include "llvm/CodeGen/RegisterScavenging.h"
 
 using namespace llvm;
 
+
+static bool hasOnlySGPRSpills(const SIMachineFunctionInfo *FuncInfo,
+                              const MachineFrameInfo *FrameInfo) {
+  if (!FuncInfo->hasSpilledSGPRs())
+    return false;
+
+  if (FuncInfo->hasSpilledVGPRs())
+    return false;
+
+  for (int I = FrameInfo->getObjectIndexBegin(),
+         E = FrameInfo->getObjectIndexEnd(); I != E; ++I) {
+    if (!FrameInfo->isSpillSlotObjectIndex(I))
+      return false;
+  }
+
+  return true;
+}
+
+void SIFrameLowering::emitPrologue(MachineFunction &MF,
+                                   MachineBasicBlock &MBB) const {
+  if (!MF.getFrameInfo()->hasStackObjects())
+    return;
+
+  assert(&MF.front() == &MBB && "Shrink-wrapping not yet supported");
+
+  const SIMachineFunctionInfo *MFI = MF.getInfo<SIMachineFunctionInfo>();
+
+  // If we only have SGPR spills, we won't actually be using scratch memory
+  // since these spill to VGPRs.
+  //
+  // FIXME: We should be cleaning up these unused SGPR spill frame indices
+  // somewhere.
+  if (hasOnlySGPRSpills(MFI, MF.getFrameInfo()))
+    return;
+
+  const SIInstrInfo *TII =
+      static_cast<const SIInstrInfo *>(MF.getSubtarget().getInstrInfo());
+  const SIRegisterInfo *TRI = &TII->getRegisterInfo();
+
+  // We need to insert initialization of the scratch resource descriptor.
+  unsigned ScratchRsrcReg = MFI->getScratchRSrcReg();
+  assert(ScratchRsrcReg != AMDGPU::NoRegister);
+
+  uint64_t Rsrc23 = TII->getScratchRsrcWords23();
+  MachineBasicBlock::iterator I = MBB.begin();
+  DebugLoc DL;
+
+  unsigned Rsrc0 = TRI->getSubReg(ScratchRsrcReg, AMDGPU::sub0);
+  unsigned Rsrc1 = TRI->getSubReg(ScratchRsrcReg, AMDGPU::sub1);
+  unsigned Rsrc2 = TRI->getSubReg(ScratchRsrcReg, AMDGPU::sub2);
+  unsigned Rsrc3 = TRI->getSubReg(ScratchRsrcReg, AMDGPU::sub3);
+
+  BuildMI(MBB, I, DL, TII->get(AMDGPU::S_MOV_B32), Rsrc0)
+    .addExternalSymbol("SCRATCH_RSRC_DWORD0");
+
+  BuildMI(MBB, I, DL, TII->get(AMDGPU::S_MOV_B32), Rsrc1)
+    .addExternalSymbol("SCRATCH_RSRC_DWORD1");
+
+  BuildMI(MBB, I, DL, TII->get(AMDGPU::S_MOV_B32), Rsrc2)
+    .addImm(Rsrc23 & 0xffffffff);
+
+  BuildMI(MBB, I, DL, TII->get(AMDGPU::S_MOV_B32), Rsrc3)
+    .addImm(Rsrc23 >> 32);
+}
+
 void SIFrameLowering::processFunctionBeforeFrameFinalized(
   MachineFunction &MF,
   RegScavenger *RS) const {
   MachineFrameInfo *MFI = MF.getFrameInfo();
+
+  if (!MFI->hasStackObjects())
+    return;
+
   bool MayNeedScavengingEmergencySlot = MFI->hasStackObjects();
 
   assert((RS || !MayNeedScavengingEmergencySlot) &&