Merge remote-tracking branch 'upstream/master' into merge-llvm

Conflicts:
	lib/CodeGen/AsmPrinter/AsmPrinter.cpp
	lib/CodeGen/AsmPrinter/AsmPrinterInlineAsm.cpp
	lib/MC/MCAssembler.cpp
	lib/Support/Atomic.cpp
	lib/Support/Memory.cpp
	lib/Target/ARM/ARMJITInfo.cpp

Change-Id: Ib339baf88df5b04870c8df1bedcfe1f877ccab8d

1 files changed, 331 insertions, 0 deletions

diff --git a/lib/Target/R600/SILowerControlFlow.cpp b/lib/Target/R600/SILowerControlFlow.cpp
new file mode 100644
index 0000000..3fbe653
--- /dev/null
+++ b/lib/Target/R600/SILowerControlFlow.cpp
@@ -0,0 +1,331 @@
+//===-- SILowerControlFlow.cpp - Use predicates for control flow ----------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+/// \file
+/// \brief This pass lowers the pseudo control flow instructions to real
+/// machine instructions.
+///
+/// All control flow is handled using predicated instructions and
+/// a predicate stack.  Each Scalar ALU controls the operations of 64 Vector
+/// ALUs.  The Scalar ALU can update the predicate for any of the Vector ALUs
+/// by writting to the 64-bit EXEC register (each bit corresponds to a
+/// single vector ALU).  Typically, for predicates, a vector ALU will write
+/// to its bit of the VCC register (like EXEC VCC is 64-bits, one for each
+/// Vector ALU) and then the ScalarALU will AND the VCC register with the
+/// EXEC to update the predicates.
+///
+/// For example:
+/// %VCC = V_CMP_GT_F32 %VGPR1, %VGPR2
+/// %SGPR0 = SI_IF %VCC
+///   %VGPR0 = V_ADD_F32 %VGPR0, %VGPR0
+/// %SGPR0 = SI_ELSE %SGPR0
+///   %VGPR0 = V_SUB_F32 %VGPR0, %VGPR0
+/// SI_END_CF %SGPR0
+///
+/// becomes:
+///
+/// %SGPR0 = S_AND_SAVEEXEC_B64 %VCC  // Save and update the exec mask
+/// %SGPR0 = S_XOR_B64 %SGPR0, %EXEC  // Clear live bits from saved exec mask
+/// S_CBRANCH_EXECZ label0            // This instruction is an optional
+///                                   // optimization which allows us to
+///                                   // branch if all the bits of
+///                                   // EXEC are zero.
+/// %VGPR0 = V_ADD_F32 %VGPR0, %VGPR0 // Do the IF block of the branch
+///
+/// label0:
+/// %SGPR0 = S_OR_SAVEEXEC_B64 %EXEC   // Restore the exec mask for the Then block
+/// %EXEC = S_XOR_B64 %SGPR0, %EXEC    // Clear live bits from saved exec mask
+/// S_BRANCH_EXECZ label1              // Use our branch optimization
+///                                    // instruction again.
+/// %VGPR0 = V_SUB_F32 %VGPR0, %VGPR   // Do the THEN block
+/// label1:
+/// %EXEC = S_OR_B64 %EXEC, %SGPR0     // Re-enable saved exec mask bits
+//===----------------------------------------------------------------------===//
+
+#include "AMDGPU.h"
+#include "SIInstrInfo.h"
+#include "SIMachineFunctionInfo.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
+
+using namespace llvm;
+
+namespace {
+
+class SILowerControlFlowPass : public MachineFunctionPass {
+
+private:
+  static const unsigned SkipThreshold = 12;
+
+  static char ID;
+  const TargetInstrInfo *TII;
+
+  void Skip(MachineInstr &MI, MachineOperand &To);
+
+  void If(MachineInstr &MI);
+  void Else(MachineInstr &MI);
+  void Break(MachineInstr &MI);
+  void IfBreak(MachineInstr &MI);
+  void ElseBreak(MachineInstr &MI);
+  void Loop(MachineInstr &MI);
+  void EndCf(MachineInstr &MI);
+
+  void Branch(MachineInstr &MI);
+
+public:
+  SILowerControlFlowPass(TargetMachine &tm) :
+    MachineFunctionPass(ID), TII(tm.getInstrInfo()) { }
+
+  virtual bool runOnMachineFunction(MachineFunction &MF);
+
+  const char *getPassName() const {
+    return "SI Lower control flow instructions";
+  }
+
+};
+
+} // End anonymous namespace
+
+char SILowerControlFlowPass::ID = 0;
+
+FunctionPass *llvm::createSILowerControlFlowPass(TargetMachine &tm) {
+  return new SILowerControlFlowPass(tm);
+}
+
+void SILowerControlFlowPass::Skip(MachineInstr &From, MachineOperand &To) {
+  unsigned NumInstr = 0;
+
+  for (MachineBasicBlock *MBB = *From.getParent()->succ_begin();
+       NumInstr < SkipThreshold && MBB != To.getMBB() && !MBB->succ_empty();
+       MBB = *MBB->succ_begin()) {
+
+    for (MachineBasicBlock::iterator I = MBB->begin(), E = MBB->end();
+         NumInstr < SkipThreshold && I != E; ++I) {
+
+      if (I->isBundle() || !I->isBundled())
+        ++NumInstr;
+    }
+  }
+
+  if (NumInstr < SkipThreshold)
+    return;
+
+  DebugLoc DL = From.getDebugLoc();
+  BuildMI(*From.getParent(), &From, DL, TII->get(AMDGPU::S_CBRANCH_EXECZ))
+          .addOperand(To)
+          .addReg(AMDGPU::EXEC);
+}
+
+void SILowerControlFlowPass::If(MachineInstr &MI) {
+  MachineBasicBlock &MBB = *MI.getParent();
+  DebugLoc DL = MI.getDebugLoc();
+  unsigned Reg = MI.getOperand(0).getReg();
+  unsigned Vcc = MI.getOperand(1).getReg();
+
+  BuildMI(MBB, &MI, DL, TII->get(AMDGPU::S_AND_SAVEEXEC_B64), Reg)
+          .addReg(Vcc);
+
+  BuildMI(MBB, &MI, DL, TII->get(AMDGPU::S_XOR_B64), Reg)
+          .addReg(AMDGPU::EXEC)
+          .addReg(Reg);
+
+  Skip(MI, MI.getOperand(2));
+
+  MI.eraseFromParent();
+}
+
+void SILowerControlFlowPass::Else(MachineInstr &MI) {
+  MachineBasicBlock &MBB = *MI.getParent();
+  DebugLoc DL = MI.getDebugLoc();
+  unsigned Dst = MI.getOperand(0).getReg();
+  unsigned Src = MI.getOperand(1).getReg();
+
+  BuildMI(MBB, &MI, DL, TII->get(AMDGPU::S_OR_SAVEEXEC_B64), Dst)
+          .addReg(Src); // Saved EXEC
+
+  BuildMI(MBB, &MI, DL, TII->get(AMDGPU::S_XOR_B64), AMDGPU::EXEC)
+          .addReg(AMDGPU::EXEC)
+          .addReg(Dst);
+
+  Skip(MI, MI.getOperand(2));
+
+  MI.eraseFromParent();
+}
+
+void SILowerControlFlowPass::Break(MachineInstr &MI) {
+  MachineBasicBlock &MBB = *MI.getParent();
+  DebugLoc DL = MI.getDebugLoc();
+
+  unsigned Dst = MI.getOperand(0).getReg();
+  unsigned Src = MI.getOperand(1).getReg();
+ 
+  BuildMI(MBB, &MI, DL, TII->get(AMDGPU::S_OR_B64), Dst)
+          .addReg(AMDGPU::EXEC)
+          .addReg(Src);
+
+  MI.eraseFromParent();
+}
+
+void SILowerControlFlowPass::IfBreak(MachineInstr &MI) {
+  MachineBasicBlock &MBB = *MI.getParent();
+  DebugLoc DL = MI.getDebugLoc();
+
+  unsigned Dst = MI.getOperand(0).getReg();
+  unsigned Vcc = MI.getOperand(1).getReg();
+  unsigned Src = MI.getOperand(2).getReg();
+ 
+  BuildMI(MBB, &MI, DL, TII->get(AMDGPU::S_OR_B64), Dst)
+          .addReg(Vcc)
+          .addReg(Src);
+
+  MI.eraseFromParent();
+}
+
+void SILowerControlFlowPass::ElseBreak(MachineInstr &MI) {
+  MachineBasicBlock &MBB = *MI.getParent();
+  DebugLoc DL = MI.getDebugLoc();
+
+  unsigned Dst = MI.getOperand(0).getReg();
+  unsigned Saved = MI.getOperand(1).getReg();
+  unsigned Src = MI.getOperand(2).getReg();
+ 
+  BuildMI(MBB, &MI, DL, TII->get(AMDGPU::S_OR_B64), Dst)
+          .addReg(Saved)
+          .addReg(Src);
+
+  MI.eraseFromParent();
+}
+
+void SILowerControlFlowPass::Loop(MachineInstr &MI) {
+  MachineBasicBlock &MBB = *MI.getParent();
+  DebugLoc DL = MI.getDebugLoc();
+  unsigned Src = MI.getOperand(0).getReg();
+
+  BuildMI(MBB, &MI, DL, TII->get(AMDGPU::S_ANDN2_B64), AMDGPU::EXEC)
+          .addReg(AMDGPU::EXEC)
+          .addReg(Src);
+
+  BuildMI(MBB, &MI, DL, TII->get(AMDGPU::S_CBRANCH_EXECNZ))
+          .addOperand(MI.getOperand(1))
+          .addReg(AMDGPU::EXEC);
+
+  MI.eraseFromParent();
+}
+
+void SILowerControlFlowPass::EndCf(MachineInstr &MI) {
+  MachineBasicBlock &MBB = *MI.getParent();
+  DebugLoc DL = MI.getDebugLoc();
+  unsigned Reg = MI.getOperand(0).getReg();
+
+  BuildMI(MBB, MBB.getFirstNonPHI(), DL,
+          TII->get(AMDGPU::S_OR_B64), AMDGPU::EXEC)
+          .addReg(AMDGPU::EXEC)
+          .addReg(Reg);
+
+  MI.eraseFromParent();
+}
+
+void SILowerControlFlowPass::Branch(MachineInstr &MI) {
+  MachineBasicBlock *Next = MI.getParent()->getNextNode();
+  MachineBasicBlock *Target = MI.getOperand(0).getMBB();
+  if (Target == Next)
+    MI.eraseFromParent();
+  else
+    assert(0);
+}
+
+bool SILowerControlFlowPass::runOnMachineFunction(MachineFunction &MF) {
+  bool HaveCf = false;
+
+  for (MachineFunction::iterator BI = MF.begin(), BE = MF.end();
+       BI != BE; ++BI) {
+
+    MachineBasicBlock &MBB = *BI;
+    for (MachineBasicBlock::iterator I = MBB.begin(), Next = llvm::next(I);
+         I != MBB.end(); I = Next) {
+
+      Next = llvm::next(I);
+      MachineInstr &MI = *I;
+      switch (MI.getOpcode()) {
+        default: break;
+        case AMDGPU::SI_IF:
+          If(MI);
+          break;
+
+        case AMDGPU::SI_ELSE:
+          Else(MI);
+          break;
+
+        case AMDGPU::SI_BREAK:
+          Break(MI);
+          break;
+
+        case AMDGPU::SI_IF_BREAK:
+          IfBreak(MI);
+          break;
+
+        case AMDGPU::SI_ELSE_BREAK:
+          ElseBreak(MI);
+          break;
+
+        case AMDGPU::SI_LOOP:
+          Loop(MI);
+          break;
+
+        case AMDGPU::SI_END_CF:
+          HaveCf = true;
+          EndCf(MI);
+          break;
+
+        case AMDGPU::S_BRANCH:
+          Branch(MI);
+          break;
+      }
+    }
+  }
+
+  // TODO: What is this good for?
+  unsigned ShaderType = MF.getInfo<SIMachineFunctionInfo>()->ShaderType;
+  if (HaveCf && ShaderType == ShaderType::PIXEL) {
+    for (MachineFunction::iterator BI = MF.begin(), BE = MF.end();
+         BI != BE; ++BI) {
+
+      MachineBasicBlock &MBB = *BI;
+      if (MBB.succ_empty()) {
+
+        MachineInstr &MI = *MBB.getFirstNonPHI();
+        DebugLoc DL = MI.getDebugLoc();
+
+        // If the exec mask is non-zero, skip the next two instructions
+        BuildMI(MBB, &MI, DL, TII->get(AMDGPU::S_CBRANCH_EXECNZ))
+               .addImm(3)
+               .addReg(AMDGPU::EXEC);
+
+        // Exec mask is zero: Export to NULL target...
+        BuildMI(MBB, &MI, DL, TII->get(AMDGPU::EXP))
+                .addImm(0)
+                .addImm(0x09) // V_008DFC_SQ_EXP_NULL
+                .addImm(0)
+                .addImm(1)
+                .addImm(1)
+                .addReg(AMDGPU::SREG_LIT_0)
+                .addReg(AMDGPU::SREG_LIT_0)
+                .addReg(AMDGPU::SREG_LIT_0)
+                .addReg(AMDGPU::SREG_LIT_0);
+
+        // ... and terminate wavefront
+        BuildMI(MBB, &MI, DL, TII->get(AMDGPU::S_ENDPGM));
+      }
+    }
+  }
+
+  return true;
+}