From a17768f5822ab62bc18608e5ba473187bf726b84 Mon Sep 17 00:00:00 2001
From: Jakob Stoklund Olesen <stoklund@2pi.dk>
Date: Thu, 14 Oct 2010 23:49:52 +0000
Subject: Create a new LiveRangeEdit class to keep track of the new registers
 created when splitting or spillling, and to help with rematerialization.

Use LiveRangeEdit in InlineSpiller and SplitKit. This will eventually make it
possible to share remat code between InlineSpiller and SplitKit.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@116543 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/LiveRangeEdit.cpp | 64 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 64 insertions(+)
 create mode 100644 lib/CodeGen/LiveRangeEdit.cpp

(limited to 'lib/CodeGen/LiveRangeEdit.cpp')

diff --git a/lib/CodeGen/LiveRangeEdit.cpp b/lib/CodeGen/LiveRangeEdit.cpp
new file mode 100644
index 0000000000..8a123fbe70
--- /dev/null
+++ b/lib/CodeGen/LiveRangeEdit.cpp
@@ -0,0 +1,64 @@
+//===--- LiveRangeEdit.cpp - Basic tools for editing a register live range --===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// The LiveRangeEdit class represents changes done to a virtual register when it
+// is spilled or split.
+//===----------------------------------------------------------------------===//
+
+#include "LiveRangeEdit.h"
+#include "VirtRegMap.h"
+#include "llvm/CodeGen/LiveIntervalAnalysis.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
+
+using namespace llvm;
+
+LiveInterval &LiveRangeEdit::create(MachineRegisterInfo &mri,
+                                    LiveIntervals &lis,
+                                    VirtRegMap &vrm) {
+  const TargetRegisterClass *RC = mri.getRegClass(parent_.reg);
+  unsigned VReg = mri.createVirtualRegister(RC);
+  vrm.grow();
+  LiveInterval &li = lis.getOrCreateInterval(VReg);
+  newRegs_.push_back(&li);
+  return li;
+}
+
+/// allUsesAvailableAt - Return true if all registers used by OrigMI at
+/// OrigIdx are also available with the same value at UseIdx.
+bool LiveRangeEdit::allUsesAvailableAt(const MachineInstr *OrigMI,
+                                       SlotIndex OrigIdx,
+                                       SlotIndex UseIdx,
+                                       LiveIntervals &lis) {
+  OrigIdx = OrigIdx.getUseIndex();
+  UseIdx = UseIdx.getUseIndex();
+  for (unsigned i = 0, e = OrigMI->getNumOperands(); i != e; ++i) {
+    const MachineOperand &MO = OrigMI->getOperand(i);
+    if (!MO.isReg() || !MO.getReg() || MO.getReg() == getReg())
+      continue;
+    // Reserved registers are OK.
+    if (MO.isUndef() || !lis.hasInterval(MO.getReg()))
+      continue;
+    // We don't want to move any defs.
+    if (MO.isDef())
+      return false;
+    // We cannot depend on virtual registers in uselessRegs_.
+    for (unsigned ui = 0, ue = uselessRegs_.size(); ui != ue; ++ui)
+      if (uselessRegs_[ui]->reg == MO.getReg())
+        return false;
+
+    LiveInterval &li = lis.getInterval(MO.getReg());
+    const VNInfo *OVNI = li.getVNInfoAt(OrigIdx);
+    if (!OVNI)
+      continue;
+    if (OVNI != li.getVNInfoAt(UseIdx))
+      return false;
+  }
+  return true;
+}
+
-- 
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