[MIPS] Skip masking loads and stores via thread pointer.

lib/Target/Mips/MipsNaClRewritePass.cpp

 //===-- MipsNaClRewritePass.cpp - Native Client Rewrite Pass  -----*- C++ -*-=//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // Native Client Rewrite Pass
@@ skipping 191 matching lines @@
   case Mips::LW:
   case Mips::LWC1:
   case Mips::LDC1:
   case Mips::LL:
   case Mips::LWL:
   case Mips::LWR:
     *AddrIdx = 1;
     break;
   }
 
-  if (MI.getOperand(*AddrIdx).getReg() == Mips::SP) {
-    // The contents of SP do not require masking.
-    return false;
+  switch (MI.getOperand(*AddrIdx).getReg()) {
+    default: break;
+    // The contents of SP and thread pointer register do not require masking.
+    case Mips::SP:
+    case Mips::T8:
+      return false;
   }
 
   return true;
 }
 
 bool IsDangerousStore(const MachineInstr &MI, int *AddrIdx) {
   unsigned Opcode = MI.getOpcode();
   switch (Opcode) {
   default: return false;
 
   // Instructions with base address register in position 1
   case Mips::SB:
   case Mips::SH:
   case Mips::SW:
   case Mips::SWC1:
   case Mips::SDC1:
   case Mips::SWL:
   case Mips::SWR:
     *AddrIdx = 1;
     break;
 
   case Mips::SC:
     *AddrIdx = 2;
     break;
   }
 
-  if (MI.getOperand(*AddrIdx).getReg() == Mips::SP) {
-    // The contents of SP do not require masking.
-    return false;
+  switch (MI.getOperand(*AddrIdx).getReg()) {
+    default: break;
+    // The contents of SP and thread pointer register do not require masking.
+    case Mips::SP:
+    case Mips::T8:
+      return false;
   }
 
   return true;
 }
 
 bool MipsNaClRewritePass::SandboxLoadsInBlock(MachineBasicBlock &MBB) {
   bool Modified = false;
   for (MachineBasicBlock::iterator MBBI = MBB.begin(), E = MBB.end();
        MBBI != E;
        ++MBBI) {
@@ skipping 70 matching lines @@
   if (FlagSfiBranch)
     AlignAllJumpTargets(MF);
 
   return Modified;
 }
 
 /// createMipsNaClRewritePass - returns an instance of the NaClRewritePass.
 FunctionPass *llvm::createMipsNaClRewritePass() {
   return new MipsNaClRewritePass();
 }