PowerPC: Avoid implicit iterator conversions, NFC

Avoid implicit conversions from MachineInstrBundleIterator to
MachineInstr* in the PowerPC backend, mainly by preferring MachineInstr&
over MachineInstr* when a pointer isn't nullable and using range-based
for loops.

There was one piece of questionable code in PPCInstrInfo::AnalyzeBranch,
where a condition checked a pointer converted from an iterator for
nullptr.  Since this case is impossible (moreover, the code above
guarantees that the iterator is valid), I removed the check when I
changed the pointer to a reference.

Despite that case, there should be no functionality change here.

llvm-svn: 276864

1 files changed, 13 insertions, 15 deletions

diff --git a/llvm/lib/Target/PowerPC/PPCVSXCopy.cpp b/llvm/lib/Target/PowerPC/PPCVSXCopy.cpp
index 60f1ad5585f..e4989e5687f 100644
--- a/llvm/lib/Target/PowerPC/PPCVSXCopy.cpp
+++ b/llvm/lib/Target/PowerPC/PPCVSXCopy.cpp
@@ -89,14 +89,12 @@ protected:
       bool Changed = false;
 
       MachineRegisterInfo &MRI = MBB.getParent()->getRegInfo();
-      for (MachineBasicBlock::iterator I = MBB.begin(), IE = MBB.end();
-           I != IE; ++I) {
-        MachineInstr *MI = I;
-        if (!MI->isFullCopy())
+      for (MachineInstr &MI : MBB) {
+        if (!MI.isFullCopy())
           continue;
 
-        MachineOperand &DstMO = MI->getOperand(0);
-        MachineOperand &SrcMO = MI->getOperand(1);
+        MachineOperand &DstMO = MI.getOperand(0);
+        MachineOperand &SrcMO = MI.getOperand(1);
 
         if ( IsVSReg(DstMO.getReg(), MRI) &&
             !IsVSReg(SrcMO.getReg(), MRI)) {
@@ -113,13 +111,13 @@ protected:
                  "Unknown source for a VSX copy");
 
           unsigned NewVReg = MRI.createVirtualRegister(SrcRC);
-          BuildMI(MBB, MI, MI->getDebugLoc(),
+          BuildMI(MBB, MI, MI.getDebugLoc(),
                   TII->get(TargetOpcode::SUBREG_TO_REG), NewVReg)
-            .addImm(1) // add 1, not 0, because there is no implicit clearing
-                       // of the high bits.
-            .addOperand(SrcMO)
-            .addImm(IsVRReg(SrcMO.getReg(), MRI) ? PPC::sub_128 :
-                                                   PPC::sub_64);
+              .addImm(1) // add 1, not 0, because there is no implicit clearing
+                         // of the high bits.
+              .addOperand(SrcMO)
+              .addImm(IsVRReg(SrcMO.getReg(), MRI) ? PPC::sub_128
+                                                   : PPC::sub_64);
 
           // The source of the original copy is now the new virtual register.
           SrcMO.setReg(NewVReg);
@@ -139,9 +137,9 @@ protected:
 
           // Copy the VSX value into a new VSX register of the correct subclass.
           unsigned NewVReg = MRI.createVirtualRegister(DstRC);
-          BuildMI(MBB, MI, MI->getDebugLoc(),
-                  TII->get(TargetOpcode::COPY), NewVReg)
-            .addOperand(SrcMO);
+          BuildMI(MBB, MI, MI.getDebugLoc(), TII->get(TargetOpcode::COPY),
+                  NewVReg)
+              .addOperand(SrcMO);
 
           // Transform the original copy into a subregister extraction copy.
           SrcMO.setReg(NewVReg);