1 files changed, 105 insertions, 0 deletions
diff --git a/contrib/llvm/lib/Target/X86/X86VZeroUpper.cpp b/contrib/llvm/lib/Target/X86/X86VZeroUpper.cpp
new file mode 100644
index 0000000..3958494
--- /dev/null
+++ b/contrib/llvm/lib/Target/X86/X86VZeroUpper.cpp
@@ -0,0 +1,105 @@
+//===-- X86VZeroUpper.cpp - AVX vzeroupper instruction inserter -----------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines the pass which inserts x86 AVX vzeroupper instructions
+// before calls to SSE encoded functions. This avoids transition latency
+// penalty when tranfering control between AVX encoded instructions and old
+// SSE encoding mode.
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "x86-codegen"
+#include "X86.h"
+#include "X86InstrInfo.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/CodeGen/Passes.h"
+#include "llvm/GlobalValue.h"
+#include "llvm/Target/TargetInstrInfo.h"
+using namespace llvm;
+
+STATISTIC(NumVZU, "Number of vzeroupper instructions inserted");
+
+namespace {
+  struct VZeroUpperInserter : public MachineFunctionPass {
+    static char ID;
+    VZeroUpperInserter() : MachineFunctionPass(ID) {}
+
+    virtual bool runOnMachineFunction(MachineFunction &MF);
+
+    bool processBasicBlock(MachineFunction &MF, MachineBasicBlock &MBB);
+
+    virtual const char *getPassName() const { return "X86 vzeroupper inserter";}
+
+  private:
+    const TargetInstrInfo *TII; // Machine instruction info.
+    MachineBasicBlock *MBB;     // Current basic block
+  };
+  char VZeroUpperInserter::ID = 0;
+}
+
+FunctionPass *llvm::createX86IssueVZeroUpperPass() {
+  return new VZeroUpperInserter();
+}
+
+/// runOnMachineFunction - Loop over all of the basic blocks, inserting
+/// vzero upper instructions before function calls.
+bool VZeroUpperInserter::runOnMachineFunction(MachineFunction &MF) {
+  TII = MF.getTarget().getInstrInfo();
+  bool Changed = false;
+
+  // Process any unreachable blocks in arbitrary order now.
+  for (MachineFunction::iterator BB = MF.begin(), E = MF.end(); BB != E; ++BB)
+    Changed |= processBasicBlock(MF, *BB);
+
+  return Changed;
+}
+
+static bool isCallToModuleFn(const MachineInstr *MI) {
+  assert(MI->getDesc().isCall() && "Isn't a call instruction");
+
+  for (int i = 0, e = MI->getNumOperands(); i != e; ++i) {
+    const MachineOperand &MO = MI->getOperand(i);
+
+    if (!MO.isGlobal())
+      continue;
+
+    const GlobalValue *GV = MO.getGlobal();
+    GlobalValue::LinkageTypes LT = GV->getLinkage();
+    if (GV->isInternalLinkage(LT) || GV->isPrivateLinkage(LT) ||
+        (GV->isExternalLinkage(LT) && !GV->isDeclaration()))
+      return true;
+
+    return false;
+  }
+  return false;
+}
+
+/// processBasicBlock - Loop over all of the instructions in the basic block,
+/// inserting vzero upper instructions before function calls.
+bool VZeroUpperInserter::processBasicBlock(MachineFunction &MF,
+                                           MachineBasicBlock &BB) {
+  bool Changed = false;
+  MBB = &BB;
+
+  for (MachineBasicBlock::iterator I = BB.begin(); I != BB.end(); ++I) {
+    MachineInstr *MI = I;
+    DebugLoc dl = I->getDebugLoc();
+
+    // Insert a vzeroupper instruction before each control transfer
+    // to functions outside this module
+    if (MI->getDesc().isCall() && !isCallToModuleFn(MI)) {
+      BuildMI(*MBB, I, dl, TII->get(X86::VZEROUPPER));
+      ++NumVZU;
+    }
+  }
+
+  return Changed;
+}