1 files changed, 98 insertions, 0 deletions
diff --git a/lib/Target/X86/SSEDomainFix.cpp b/lib/Target/X86/SSEDomainFix.cpp
new file mode 100644
index 0000000000..261b40c5ab
--- /dev/null
+++ b/lib/Target/X86/SSEDomainFix.cpp
@@ -0,0 +1,98 @@
+//===- SSEDomainFix.cpp - Use proper int/float domain for SSE ---*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains the SSEDomainFix pass.
+//
+// Some SSE instructions like mov, and, or, xor are available in different
+// variants for different operand types. These variant instructions are
+// equivalent, but on Nehalem and newer cpus there is extra latency
+// transferring data between integer and floating point domains.
+//
+// This pass changes the variant instructions to minimize domain crossings.
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "sse-domain-fix"
+#include "X86InstrInfo.h"
+#include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
+#include "llvm/ADT/DepthFirstIterator.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
+
+using namespace llvm;
+
+namespace {
+class SSEDomainFixPass : public MachineFunctionPass {
+  static char ID;
+  const X86InstrInfo *TII;
+
+  MachineFunction *MF;
+  MachineBasicBlock *MBB;
+public:
+  SSEDomainFixPass() : MachineFunctionPass(&ID) {}
+
+  virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+    AU.setPreservesAll();
+    MachineFunctionPass::getAnalysisUsage(AU);
+  }
+
+  virtual bool runOnMachineFunction(MachineFunction &MF);
+
+  virtual const char *getPassName() const {
+    return "SSE execution domain fixup";
+  }
+
+private:
+  void enterBasicBlock(MachineBasicBlock *MBB);
+};
+}
+
+char SSEDomainFixPass::ID = 0;
+
+void SSEDomainFixPass::enterBasicBlock(MachineBasicBlock *mbb) {
+  MBB = mbb;
+  DEBUG(dbgs() << "Entering MBB " << MBB->getName() << "\n");
+}
+
+bool SSEDomainFixPass::runOnMachineFunction(MachineFunction &mf) {
+  MF = &mf;
+  TII = static_cast<const X86InstrInfo*>(MF->getTarget().getInstrInfo());
+
+  // If no XMM registers are used in the function, we can skip it completely.
+  bool XMMIsUsed = false;
+  for (TargetRegisterClass::const_iterator I = X86::VR128RegClass.begin(),
+         E = X86::VR128RegClass.end(); I != E; ++I)
+    if (MF->getRegInfo().isPhysRegUsed(*I)) {
+      XMMIsUsed = true;
+      break;
+    }
+  if (!XMMIsUsed) return false;
+
+  MachineBasicBlock *Entry = MF->begin();
+  SmallPtrSet<MachineBasicBlock*, 16> Visited;
+  for (df_ext_iterator<MachineBasicBlock*,
+         SmallPtrSet<MachineBasicBlock*, 16> >
+         DFI = df_ext_begin(Entry, Visited), DFE = df_ext_end(Entry, Visited);
+       DFI != DFE; ++DFI) {
+    enterBasicBlock(*DFI);
+    for (MachineBasicBlock::iterator I = MBB->begin(), E = MBB->end(); I != E;
+        ++I) {
+      MachineInstr *MI = I;
+      const unsigned *equiv = 0;
+      X86InstrInfo::SSEDomain domain = TII->GetSSEDomain(MI, equiv);
+      DEBUG(dbgs() << "-isd"[domain] << (equiv ? "* " : "  ") << *MI);
+    }
+  }
+  return false;
+}
+
+FunctionPass *llvm::createSSEDomainFixPass() {
+  return new SSEDomainFixPass();
+}