It's not necessary to do rounding for alloca operations when the requested
alignment is equal to the stack alignment.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@40004 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/Alpha/AlphaInstrInfo.cpp b/lib/Target/Alpha/AlphaInstrInfo.cpp
new file mode 100644
index 0000000..718587d
--- /dev/null
+++ b/lib/Target/Alpha/AlphaInstrInfo.cpp
@@ -0,0 +1,266 @@
+//===- AlphaInstrInfo.cpp - Alpha Instruction Information -------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains the Alpha implementation of the TargetInstrInfo class.
+//
+//===----------------------------------------------------------------------===//
+
+#include "Alpha.h"
+#include "AlphaInstrInfo.h"
+#include "AlphaGenInstrInfo.inc"
+#include "llvm/CodeGen/MachineInstrBuilder.h"
+using namespace llvm;
+
+AlphaInstrInfo::AlphaInstrInfo()
+  : TargetInstrInfo(AlphaInsts, sizeof(AlphaInsts)/sizeof(AlphaInsts[0])),
+    RI(*this) { }
+
+
+bool AlphaInstrInfo::isMoveInstr(const MachineInstr& MI,
+                                 unsigned& sourceReg,
+                                 unsigned& destReg) const {
+  MachineOpCode oc = MI.getOpcode();
+  if (oc == Alpha::BISr   || 
+      oc == Alpha::CPYSS  || 
+      oc == Alpha::CPYST  ||
+      oc == Alpha::CPYSSt || 
+      oc == Alpha::CPYSTs) {
+    // or r1, r2, r2 
+    // cpys(s|t) r1 r2 r2
+    assert(MI.getNumOperands() >= 3 &&
+           MI.getOperand(0).isRegister() &&
+           MI.getOperand(1).isRegister() &&
+           MI.getOperand(2).isRegister() &&
+           "invalid Alpha BIS instruction!");
+    if (MI.getOperand(1).getReg() == MI.getOperand(2).getReg()) {
+      sourceReg = MI.getOperand(1).getReg();
+      destReg = MI.getOperand(0).getReg();
+      return true;
+    }
+  }
+  return false;
+}
+
+unsigned 
+AlphaInstrInfo::isLoadFromStackSlot(MachineInstr *MI, int &FrameIndex) const {
+  switch (MI->getOpcode()) {
+  case Alpha::LDL:
+  case Alpha::LDQ:
+  case Alpha::LDBU:
+  case Alpha::LDWU:
+  case Alpha::LDS:
+  case Alpha::LDT:
+    if (MI->getOperand(1).isFrameIndex()) {
+      FrameIndex = MI->getOperand(1).getFrameIndex();
+      return MI->getOperand(0).getReg();
+    }
+    break;
+  }
+  return 0;
+}
+
+unsigned 
+AlphaInstrInfo::isStoreToStackSlot(MachineInstr *MI, int &FrameIndex) const {
+  switch (MI->getOpcode()) {
+  case Alpha::STL:
+  case Alpha::STQ:
+  case Alpha::STB:
+  case Alpha::STW:
+  case Alpha::STS:
+  case Alpha::STT:
+    if (MI->getOperand(1).isFrameIndex()) {
+      FrameIndex = MI->getOperand(1).getFrameIndex();
+      return MI->getOperand(0).getReg();
+    }
+    break;
+  }
+  return 0;
+}
+
+static bool isAlphaIntCondCode(unsigned Opcode) {
+  switch (Opcode) {
+  case Alpha::BEQ: 
+  case Alpha::BNE: 
+  case Alpha::BGE: 
+  case Alpha::BGT: 
+  case Alpha::BLE: 
+  case Alpha::BLT: 
+  case Alpha::BLBC: 
+  case Alpha::BLBS:
+    return true;
+  default:
+    return false;
+  }
+}
+
+unsigned AlphaInstrInfo::InsertBranch(MachineBasicBlock &MBB,MachineBasicBlock *TBB,
+                                  MachineBasicBlock *FBB,
+                                  const std::vector<MachineOperand> &Cond)const{
+  assert(TBB && "InsertBranch must not be told to insert a fallthrough");
+  assert((Cond.size() == 2 || Cond.size() == 0) && 
+         "Alpha branch conditions have two components!");
+
+  // One-way branch.
+  if (FBB == 0) {
+    if (Cond.empty())   // Unconditional branch
+      BuildMI(&MBB, get(Alpha::BR)).addMBB(TBB);
+    else                // Conditional branch
+      if (isAlphaIntCondCode(Cond[0].getImm()))
+        BuildMI(&MBB, get(Alpha::COND_BRANCH_I))
+          .addImm(Cond[0].getImm()).addReg(Cond[1].getReg()).addMBB(TBB);
+      else
+        BuildMI(&MBB, get(Alpha::COND_BRANCH_F))
+          .addImm(Cond[0].getImm()).addReg(Cond[1].getReg()).addMBB(TBB);
+    return 1;
+  }
+  
+  // Two-way Conditional Branch.
+  if (isAlphaIntCondCode(Cond[0].getImm()))
+    BuildMI(&MBB, get(Alpha::COND_BRANCH_I))
+      .addImm(Cond[0].getImm()).addReg(Cond[1].getReg()).addMBB(TBB);
+  else
+    BuildMI(&MBB, get(Alpha::COND_BRANCH_F))
+      .addImm(Cond[0].getImm()).addReg(Cond[1].getReg()).addMBB(TBB);
+  BuildMI(&MBB, get(Alpha::BR)).addMBB(FBB);
+  return 2;
+}
+
+static unsigned AlphaRevCondCode(unsigned Opcode) {
+  switch (Opcode) {
+  case Alpha::BEQ: return Alpha::BNE;
+  case Alpha::BNE: return Alpha::BEQ;
+  case Alpha::BGE: return Alpha::BLT;
+  case Alpha::BGT: return Alpha::BLE;
+  case Alpha::BLE: return Alpha::BGT;
+  case Alpha::BLT: return Alpha::BGE;
+  case Alpha::BLBC: return Alpha::BLBS;
+  case Alpha::BLBS: return Alpha::BLBC;
+  case Alpha::FBEQ: return Alpha::FBNE;
+  case Alpha::FBNE: return Alpha::FBEQ;
+  case Alpha::FBGE: return Alpha::FBLT;
+  case Alpha::FBGT: return Alpha::FBLE;
+  case Alpha::FBLE: return Alpha::FBGT;
+  case Alpha::FBLT: return Alpha::FBGE;
+  default:
+    assert(0 && "Unknown opcode");
+  }
+}
+
+// Branch analysis.
+bool AlphaInstrInfo::AnalyzeBranch(MachineBasicBlock &MBB,MachineBasicBlock *&TBB,
+                                 MachineBasicBlock *&FBB,
+                                 std::vector<MachineOperand> &Cond) const {
+  // If the block has no terminators, it just falls into the block after it.
+  MachineBasicBlock::iterator I = MBB.end();
+  if (I == MBB.begin() || !isUnpredicatedTerminator(--I))
+    return false;
+
+  // Get the last instruction in the block.
+  MachineInstr *LastInst = I;
+  
+  // If there is only one terminator instruction, process it.
+  if (I == MBB.begin() || !isUnpredicatedTerminator(--I)) {
+    if (LastInst->getOpcode() == Alpha::BR) {
+      TBB = LastInst->getOperand(0).getMachineBasicBlock();
+      return false;
+    } else if (LastInst->getOpcode() == Alpha::COND_BRANCH_I ||
+               LastInst->getOpcode() == Alpha::COND_BRANCH_F) {
+      // Block ends with fall-through condbranch.
+      TBB = LastInst->getOperand(2).getMachineBasicBlock();
+      Cond.push_back(LastInst->getOperand(0));
+      Cond.push_back(LastInst->getOperand(1));
+      return false;
+    }
+    // Otherwise, don't know what this is.
+    return true;
+  }
+  
+  // Get the instruction before it if it's a terminator.
+  MachineInstr *SecondLastInst = I;
+
+  // If there are three terminators, we don't know what sort of block this is.
+  if (SecondLastInst && I != MBB.begin() &&
+      isUnpredicatedTerminator(--I))
+    return true;
+  
+  // If the block ends with Alpha::BR and Alpha::COND_BRANCH_*, handle it.
+  if ((SecondLastInst->getOpcode() == Alpha::COND_BRANCH_I ||
+      SecondLastInst->getOpcode() == Alpha::COND_BRANCH_F) && 
+      LastInst->getOpcode() == Alpha::BR) {
+    TBB =  SecondLastInst->getOperand(2).getMachineBasicBlock();
+    Cond.push_back(SecondLastInst->getOperand(0));
+    Cond.push_back(SecondLastInst->getOperand(1));
+    FBB = LastInst->getOperand(0).getMachineBasicBlock();
+    return false;
+  }
+  
+  // If the block ends with two Alpha::BRs, handle it.  The second one is not
+  // executed, so remove it.
+  if (SecondLastInst->getOpcode() == Alpha::BR && 
+      LastInst->getOpcode() == Alpha::BR) {
+    TBB = SecondLastInst->getOperand(0).getMachineBasicBlock();
+    I = LastInst;
+    I->eraseFromParent();
+    return false;
+  }
+
+  // Otherwise, can't handle this.
+  return true;
+}
+
+unsigned AlphaInstrInfo::RemoveBranch(MachineBasicBlock &MBB) const {
+  MachineBasicBlock::iterator I = MBB.end();
+  if (I == MBB.begin()) return 0;
+  --I;
+  if (I->getOpcode() != Alpha::BR && 
+      I->getOpcode() != Alpha::COND_BRANCH_I &&
+      I->getOpcode() != Alpha::COND_BRANCH_F)
+    return 0;
+  
+  // Remove the branch.
+  I->eraseFromParent();
+  
+  I = MBB.end();
+
+  if (I == MBB.begin()) return 1;
+  --I;
+  if (I->getOpcode() != Alpha::COND_BRANCH_I && 
+      I->getOpcode() != Alpha::COND_BRANCH_F)
+    return 1;
+  
+  // Remove the branch.
+  I->eraseFromParent();
+  return 2;
+}
+
+void AlphaInstrInfo::insertNoop(MachineBasicBlock &MBB, 
+                                MachineBasicBlock::iterator MI) const {
+  BuildMI(MBB, MI, get(Alpha::BISr), Alpha::R31).addReg(Alpha::R31)
+    .addReg(Alpha::R31);
+}
+
+bool AlphaInstrInfo::BlockHasNoFallThrough(MachineBasicBlock &MBB) const {
+  if (MBB.empty()) return false;
+  
+  switch (MBB.back().getOpcode()) {
+  case Alpha::RETDAG: // Return.
+  case Alpha::RETDAGp:
+  case Alpha::BR:     // Uncond branch.
+  case Alpha::JMP:  // Indirect branch.
+    return true;
+  default: return false;
+  }
+}
+bool AlphaInstrInfo::
+ReverseBranchCondition(std::vector<MachineOperand> &Cond) const {
+  assert(Cond.size() == 2 && "Invalid Alpha branch opcode!");
+  Cond[0].setImm(AlphaRevCondCode(Cond[0].getImm()));
+  return false;
+}
+