Removing a variable that is initialized but never read. The original author has been...

[oota-llvm.git] / lib / Target / R600 / SILowerControlFlow.cpp

diff --git a/lib/Target/R600/SILowerControlFlow.cpp b/lib/Target/R600/SILowerControlFlow.cpp
index 59270ee062ee7bda3e884d4a530d5592766daf42..aaf91ea828168d1c7a433993ab27c87c98e5fdb6 100644 (file)
--- a/lib/Target/R600/SILowerControlFlow.cpp
+++ b/lib/Target/R600/SILowerControlFlow.cpp
@@ -88,7 +88,6 @@ private:
   void Kill(MachineInstr &MI);
   void Branch(MachineInstr &MI);
 
-  void InitM0ForLDS(MachineBasicBlock::iterator MI);
   void LoadM0(MachineInstr &MI, MachineInstr *MovRel);
   void IndirectSrc(MachineInstr &MI);
   void IndirectDst(MachineInstr &MI);
@@ -325,14 +324,6 @@ void SILowerControlFlowPass::Kill(MachineInstr &MI) {
   MI.eraseFromParent();
 }
 
-/// The m0 register stores the maximum allowable address for LDS reads and
-/// writes.  Its value must be at least the size in bytes of LDS allocated by
-/// the shader.  For simplicity, we set it to the maximum possible value.
-void SILowerControlFlowPass::InitM0ForLDS(MachineBasicBlock::iterator MI) {
-    BuildMI(*MI->getParent(), MI, MI->getDebugLoc(),  TII->get(AMDGPU::S_MOV_B32),
-            AMDGPU::M0).addImm(0xffffffff);
-}
-
 void SILowerControlFlowPass::LoadM0(MachineInstr &MI, MachineInstr *MovRel) {
 
   MachineBasicBlock &MBB = *MI.getParent();
@@ -391,12 +382,6 @@ void SILowerControlFlowPass::LoadM0(MachineInstr &MI, MachineInstr *MovRel) {
             .addReg(Save);
 
   }
-  // FIXME: Are there any values other than the LDS address clamp that need to
-  // be stored in the m0 register and may be live for more than a few
-  // instructions?  If so, we should save the m0 register at the beginning
-  // of this function and restore it here.
-  // FIXME: Add support for LDS direct loads.
-  InitM0ForLDS(&MI);
   MI.eraseFromParent();
 }
 
@@ -450,7 +435,6 @@ bool SILowerControlFlowPass::runOnMachineFunction(MachineFunction &MF) {
   SIMachineFunctionInfo *MFI = MF.getInfo<SIMachineFunctionInfo>();
 
   bool HaveKill = false;
-  bool NeedM0 = false;
   bool NeedWQM = false;
   bool NeedFlat = false;
   unsigned Depth = 0;
@@ -464,16 +448,12 @@ bool SILowerControlFlowPass::runOnMachineFunction(MachineFunction &MF) {
       Next = std::next(I);
 
       MachineInstr &MI = *I;
-      if (TII->isDS(MI.getOpcode())) {
-        NeedM0 = true;
+      if (TII->isDS(MI.getOpcode()))
         NeedWQM = true;
-      }
 
       // Flat uses m0 in case it needs to access LDS.
-      if (TII->isFLAT(MI.getOpcode())) {
-        NeedM0 = true;
+      if (TII->isFLAT(MI.getOpcode()))
         NeedFlat = true;
-      }
 
       switch (MI.getOpcode()) {
         default: break;
@@ -544,13 +524,6 @@ bool SILowerControlFlowPass::runOnMachineFunction(MachineFunction &MF) {
     }
   }
 
-  if (NeedM0) {
-    MachineBasicBlock &MBB = MF.front();
-    // Initialize M0 to a value that won't cause LDS access to be discarded
-    // due to offset clamping
-    InitM0ForLDS(MBB.getFirstNonPHI());
-  }
-
   if (NeedWQM && MFI->getShaderType() == ShaderType::PIXEL) {
     MachineBasicBlock &MBB = MF.front();
     BuildMI(MBB, MBB.getFirstNonPHI(), DebugLoc(), TII->get(AMDGPU::S_WQM_B64),
@@ -586,6 +559,8 @@ bool SILowerControlFlowPass::runOnMachineFunction(MachineFunction &MF) {
     MachineBasicBlock::iterator Start = MBB.getFirstNonPHI();
     const MCInstrDesc &SMovK = TII->get(AMDGPU::S_MOVK_I32);
 
+    assert(isInt<16>(StackOffset) && isInt<16>(StackSizeBytes));
+
     BuildMI(MBB, Start, NoDL, SMovK, AMDGPU::FLAT_SCR_LO)
       .addImm(StackOffset);