Use make_range(rbegin(), rend()) to allow foreach loops. NFC.

Instead of the pattern

for (auto I = x.rbegin(), E = x.end(); I != E; ++I)

we can use make_range to construct the reverse range and iterate using
that instead.

llvm-svn: 243163

1 files changed, 6 insertions, 9 deletions

diff --git a/llvm/lib/CodeGen/DeadMachineInstructionElim.cpp b/llvm/lib/CodeGen/DeadMachineInstructionElim.cpp
index 941129b5cc9..39c259d7c79 100644
--- a/llvm/lib/CodeGen/DeadMachineInstructionElim.cpp
+++ b/llvm/lib/CodeGen/DeadMachineInstructionElim.cpp
@@ -101,26 +101,23 @@ bool DeadMachineInstructionElim::runOnMachineFunction(MachineFunction &MF) {
   // Loop over all instructions in all blocks, from bottom to top, so that it's
   // more likely that chains of dependent but ultimately dead instructions will
   // be cleaned up.
-  for (MachineFunction::reverse_iterator I = MF.rbegin(), E = MF.rend();
-       I != E; ++I) {
-    MachineBasicBlock *MBB = &*I;
-
+  for (MachineBasicBlock &MBB : make_range(MF.rbegin(), MF.rend())) {
     // Start out assuming that reserved registers are live out of this block.
     LivePhysRegs = MRI->getReservedRegs();
 
     // Add live-ins from sucessors to LivePhysRegs. Normally, physregs are not
     // live across blocks, but some targets (x86) can have flags live out of a
     // block.
-    for (MachineBasicBlock::succ_iterator S = MBB->succ_begin(),
-           E = MBB->succ_end(); S != E; S++)
+    for (MachineBasicBlock::succ_iterator S = MBB.succ_begin(),
+           E = MBB.succ_end(); S != E; S++)
       for (MachineBasicBlock::livein_iterator LI = (*S)->livein_begin();
            LI != (*S)->livein_end(); LI++)
         LivePhysRegs.set(*LI);
 
     // Now scan the instructions and delete dead ones, tracking physreg
     // liveness as we go.
-    for (MachineBasicBlock::reverse_iterator MII = MBB->rbegin(),
-         MIE = MBB->rend(); MII != MIE; ) {
+    for (MachineBasicBlock::reverse_iterator MII = MBB.rbegin(),
+         MIE = MBB.rend(); MII != MIE; ) {
       MachineInstr *MI = &*MII;
 
       // If the instruction is dead, delete it!
@@ -132,7 +129,7 @@ bool DeadMachineInstructionElim::runOnMachineFunction(MachineFunction &MF) {
         MI->eraseFromParentAndMarkDBGValuesForRemoval();
         AnyChanges = true;
         ++NumDeletes;
-        MIE = MBB->rend();
+        MIE = MBB.rend();
         // MII is now pointing to the next instruction to process,
         // so don't increment it.
         continue;