CodeGen: Use MachineInstr& in TargetInstrInfo, NFC

This is mostly a mechanical change to make TargetInstrInfo API take
MachineInstr& (instead of MachineInstr* or MachineBasicBlock::iterator)
when the argument is expected to be a valid MachineInstr.  This is a
general API improvement.

Although it would be possible to do this one function at a time, that
would demand a quadratic amount of churn since many of these functions
call each other.  Instead I've done everything as a block and just
updated what was necessary.

This is mostly mechanical fixes: adding and removing `*` and `&`
operators.  The only non-mechanical change is to split
ARMBaseInstrInfo::getOperandLatencyImpl out from
ARMBaseInstrInfo::getOperandLatency.  Previously, the latter took a
`MachineInstr*` which it updated to the instruction bundle leader; now,
the latter calls the former either with the same `MachineInstr&` or the
bundle leader.

As a side effect, this removes a bunch of MachineInstr* to
MachineBasicBlock::iterator implicit conversions, a necessary step
toward fixing PR26753.

Note: I updated WebAssembly, Lanai, and AVR (despite being
off-by-default) since it turned out to be easy.  I couldn't run tests
for AVR since llc doesn't link with it turned on.

llvm-svn: 274189

1 files changed, 3 insertions, 4 deletions

diff --git a/llvm/lib/CodeGen/MachineCSE.cpp b/llvm/lib/CodeGen/MachineCSE.cpp
index b8283eaf9e2..1209f73d960 100644
--- a/llvm/lib/CodeGen/MachineCSE.cpp
+++ b/llvm/lib/CodeGen/MachineCSE.cpp
@@ -389,7 +389,7 @@ bool MachineCSE::isProfitableToCSE(unsigned CSReg, unsigned Reg,
   // Heuristics #1: Don't CSE "cheap" computation if the def is not local or in
   // an immediate predecessor. We don't want to increase register pressure and
   // end up causing other computation to be spilled.
-  if (TII->isAsCheapAsAMove(MI)) {
+  if (TII->isAsCheapAsAMove(*MI)) {
     MachineBasicBlock *CSBB = CSMI->getParent();
     MachineBasicBlock *BB = MI->getParent();
     if (CSBB != BB && !CSBB->isSuccessor(BB))
@@ -478,8 +478,7 @@ bool MachineCSE::ProcessBlock(MachineBasicBlock *MBB) {
     // Commute commutable instructions.
     bool Commuted = false;
     if (!FoundCSE && MI->isCommutable()) {
-      MachineInstr *NewMI = TII->commuteInstruction(MI);
-      if (NewMI) {
+      if (MachineInstr *NewMI = TII->commuteInstruction(*MI)) {
         Commuted = true;
         FoundCSE = VNT.count(NewMI);
         if (NewMI != MI) {
@@ -488,7 +487,7 @@ bool MachineCSE::ProcessBlock(MachineBasicBlock *MBB) {
           Changed = true;
         } else if (!FoundCSE)
           // MI was changed but it didn't help, commute it back!
-          (void)TII->commuteInstruction(MI);
+          (void)TII->commuteInstruction(*MI);
       }
     }