Rebased PNaCl localmods in LLVM to 223109

lib/Target/ARM/ARMLoadStoreOptimizer.cpp

 //===-- ARMLoadStoreOptimizer.cpp - ARM load / store opt. pass ------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file contains a pass that performs load / store related peephole
@@ skipping 1053 matching lines @@
 ///
 /// stmia rn, <ra, rb, rc>
 /// rn := rn + 4 * 3;
 /// =>
 /// stmia rn!, <ra, rb, rc>
 ///
 /// rn := rn - 4 * 3;
 /// ldmia rn, <ra, rb, rc>
 /// =>
 /// ldmdb rn!, <ra, rb, rc>
+/// @LOCALMOD This is especially useful for rn == sp
 bool ARMLoadStoreOpt::MergeBaseUpdateLSMultiple(MachineBasicBlock &MBB,
                                                MachineBasicBlock::iterator MBBI,
                                                bool &Advance,
                                                MachineBasicBlock::iterator &I) {
   // Thumb1 is already using updating loads/stores.
   if (isThumb1) return false;
 
   MachineInstr *MI = MBBI;
   unsigned Base = MI->getOperand(0).getReg();
   bool BaseKill = MI->getOperand(0).isKill();
@@ skipping 664 matching lines @@
 /// MergeReturnIntoLDM - If this is a exit BB, try merging the return ops
 /// ("bx lr" and "mov pc, lr") into the preceding stack restore so it
 /// directly restore the value of LR into pc.
 ///   ldmfd sp!, {..., lr}
 ///   bx lr
 /// or
 ///   ldmfd sp!, {..., lr}
 ///   mov pc, lr
 /// =>
 ///   ldmfd sp!, {..., pc}
+// @LOCALMOD for sfi we do not want this to happen
 bool ARMLoadStoreOpt::MergeReturnIntoLDM(MachineBasicBlock &MBB) {
+  // @LOCALMOD-START
+  // For NaCl, do not load into PC directly for a return, since NaCl requires
+  // masking the address first.
+  if (STI->isTargetNaCl()) {
+    return false;
+  }
+  // @LOCALMOD-END
+
   // Thumb1 LDM doesn't allow high registers.
   if (isThumb1) return false;
   if (MBB.empty()) return false;
 
   MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
   if (MBBI != MBB.begin() &&
       (MBBI->getOpcode() == ARM::BX_RET ||
        MBBI->getOpcode() == ARM::tBX_RET ||
        MBBI->getOpcode() == ARM::MOVPCLR)) {
     MachineInstr *PrevMI = std::prev(MBBI);
@@ skipping 499 matching lines @@
 }
 
 
 /// createARMLoadStoreOptimizationPass - returns an instance of the load / store
 /// optimization pass.
 FunctionPass *llvm::createARMLoadStoreOptimizationPass(bool PreAlloc) {
   if (PreAlloc)
     return new ARMPreAllocLoadStoreOpt();
   return new ARMLoadStoreOpt();
 }