NVPTX: Don't even create a regalloc if we're not going to use it.

[oota-llvm.git] / lib / Target / Hexagon / HexagonFrameLowering.cpp

diff --git a/lib/Target/Hexagon/HexagonFrameLowering.cpp b/lib/Target/Hexagon/HexagonFrameLowering.cpp
index 50db2a6d56cea5fed172d8120ce079217a9746a9..2b04f25dd677eea57bc1a4b9c642dd3a9393702a 100644 (file)
--- a/lib/Target/Hexagon/HexagonFrameLowering.cpp
+++ b/lib/Target/Hexagon/HexagonFrameLowering.cpp
@@ -25,14 +25,14 @@
 #include "llvm/CodeGen/MachineModuleInfo.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/CodeGen/RegisterScavenging.h"
-#include "llvm/Function.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/Type.h"
 #include "llvm/MC/MCAsmInfo.h"
 #include "llvm/MC/MachineLocation.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Target/TargetInstrInfo.h"
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/Target/TargetOptions.h"
-#include "llvm/Type.h"
 
 using namespace llvm;
 
@@ -76,17 +76,12 @@ void HexagonFrameLowering::determineFrameLayout(MachineFunction &MF) const {
 void HexagonFrameLowering::emitPrologue(MachineFunction &MF) const {
   MachineBasicBlock &MBB = MF.front();
   MachineFrameInfo *MFI = MF.getFrameInfo();
-  MachineModuleInfo &MMI = MF.getMMI();
   MachineBasicBlock::iterator MBBI = MBB.begin();
   const HexagonRegisterInfo *QRI =
     static_cast<const HexagonRegisterInfo *>(MF.getTarget().getRegisterInfo());
   DebugLoc dl = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
   determineFrameLayout(MF);
 
-  // Check if frame moves are needed for EH.
-  bool needsFrameMoves = MMI.hasDebugInfo() ||
-    !MF.getFunction()->needsUnwindTableEntry();
-
   // Get the number of bytes to allocate from the FrameInfo.
   int NumBytes = (int) MFI->getStackSize();
 
@@ -113,28 +108,6 @@ void HexagonFrameLowering::emitPrologue(MachineFunction &MF) const {
     MO.setImm(MFI->getMaxCallFrameSize());
   }
 
- std::vector<MachineMove> &Moves = MMI.getFrameMoves();
-
- if (needsFrameMoves) {
-   // Advance CFA. DW_CFA_def_cfa
-   unsigned FPReg = QRI->getFrameRegister();
-   unsigned RAReg = QRI->getRARegister();
-
-   MachineLocation Dst(MachineLocation::VirtualFP);
-   MachineLocation Src(FPReg, -8);
-   Moves.push_back(MachineMove(0, Dst, Src));
-
-   // R31 = (R31 - #4)
-   MachineLocation LRDst(RAReg, -4);
-   MachineLocation LRSrc(RAReg);
-   Moves.push_back(MachineMove(0, LRDst, LRSrc));
-
-   // R30 = (R30 - #8)
-   MachineLocation SPDst(FPReg, -8);
-   MachineLocation SPSrc(FPReg);
-   Moves.push_back(MachineMove(0, SPDst, SPSrc));
- }
-
   //
   // Only insert ALLOCFRAME if we need to.
   //
@@ -166,37 +139,63 @@ bool HexagonFrameLowering::hasTailCall(MachineBasicBlock &MBB) const {
   MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
   unsigned RetOpcode = MBBI->getOpcode();
 
-  return RetOpcode == Hexagon::TCRETURNtg || RetOpcode == Hexagon::TCRETURNtext;}
+  return RetOpcode == Hexagon::TCRETURNtg || RetOpcode == Hexagon::TCRETURNtext;
+}
 
 void HexagonFrameLowering::emitEpilogue(MachineFunction &MF,
                                      MachineBasicBlock &MBB) const {
   MachineBasicBlock::iterator MBBI = prior(MBB.end());
   DebugLoc dl = MBBI->getDebugLoc();
   //
-  // Only insert deallocframe if we need to.
+  // Only insert deallocframe if we need to.  Also at -O0.  See comment
+  // in emitPrologue above.
   //
-  if (hasFP(MF)) {
+  if (hasFP(MF) || MF.getTarget().getOptLevel() == CodeGenOpt::None) {
     MachineBasicBlock::iterator MBBI = prior(MBB.end());
     MachineBasicBlock::iterator MBBI_end = MBB.end();
-    //
-    // For Hexagon, we don't need the frame size.
-    //
-    MachineFrameInfo *MFI = MF.getFrameInfo();
-    int NumBytes = (int) MFI->getStackSize();
 
     const TargetInstrInfo &TII = *MF.getTarget().getInstrInfo();
-
+    // Handle EH_RETURN.
+    if (MBBI->getOpcode() == Hexagon::EH_RETURN_JMPR) {
+      assert(MBBI->getOperand(0).isReg() && "Offset should be in register!");
+      BuildMI(MBB, MBBI, dl, TII.get(Hexagon::DEALLOCFRAME));
+      BuildMI(MBB, MBBI, dl, TII.get(Hexagon::ADD_rr),
+              Hexagon::R29).addReg(Hexagon::R29).addReg(Hexagon::R28);
+      return;
+    }
     // Replace 'jumpr r31' instruction with dealloc_return for V4 and higher
     // versions.
-    if (STI.hasV4TOps() && MBBI->getOpcode() == Hexagon::JMPR
+    if (STI.hasV4TOps() && MBBI->getOpcode() == Hexagon::JMPret
                         && !DisableDeallocRet) {
-      // Remove jumpr node.
-      MBB.erase(MBBI);
+      // Check for RESTORE_DEALLOC_RET_JMP_V4 call. Don't emit an extra DEALLOC
+      // instruction if we encounter it.
+      MachineBasicBlock::iterator BeforeJMPR =
+        MBB.begin() == MBBI ? MBBI : prior(MBBI);
+      if (BeforeJMPR != MBBI &&
+          BeforeJMPR->getOpcode() == Hexagon::RESTORE_DEALLOC_RET_JMP_V4) {
+        // Remove the JMPR node.
+        MBB.erase(MBBI);
+        return;
+      }
+
       // Add dealloc_return.
-      BuildMI(MBB, MBBI_end, dl, TII.get(Hexagon::DEALLOC_RET_V4))
-        .addImm(NumBytes);
-    } else { // Add deallocframe for V2 and V3.
-      BuildMI(MBB, MBBI, dl, TII.get(Hexagon::DEALLOCFRAME)).addImm(NumBytes);
+      MachineInstrBuilder MIB =
+        BuildMI(MBB, MBBI_end, dl, TII.get(Hexagon::DEALLOC_RET_V4));
+      // Transfer the function live-out registers.
+      MIB->copyImplicitOps(*MBB.getParent(), &*MBBI);
+      // Remove the JUMPR node.
+      MBB.erase(MBBI);
+    } else { // Add deallocframe for V2 and V3, and V4 tail calls.
+      // Check for RESTORE_DEALLOC_BEFORE_TAILCALL_V4. We don't need an extra
+      // DEALLOCFRAME instruction after it.
+      MachineBasicBlock::iterator Term = MBB.getFirstTerminator();
+      MachineBasicBlock::iterator I =
+        Term == MBB.begin() ?  MBB.end() : prior(Term);
+      if (I != MBB.end() &&
+          I->getOpcode() == Hexagon::RESTORE_DEALLOC_BEFORE_TAILCALL_V4)
+        return;
+
+      BuildMI(MBB, MBBI, dl, TII.get(Hexagon::DEALLOCFRAME));
     }
   }
 }
@@ -326,6 +325,21 @@ bool HexagonFrameLowering::restoreCalleeSavedRegisters(
   return true;
 }
 
+void HexagonFrameLowering::
+eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
+                              MachineBasicBlock::iterator I) const {
+  MachineInstr &MI = *I;
+
+  if (MI.getOpcode() == Hexagon::ADJCALLSTACKDOWN) {
+    // Hexagon_TODO: add code
+  } else if (MI.getOpcode() == Hexagon::ADJCALLSTACKUP) {
+    // Hexagon_TODO: add code
+  } else {
+    llvm_unreachable("Cannot handle this call frame pseudo instruction");
+  }
+  MBB.erase(I);
+}
+
 int HexagonFrameLowering::getFrameIndexOffset(const MachineFunction &MF,
                                               int FI) const {
   return MF.getFrameInfo()->getObjectOffset(FI);