ARM "rrx" shift operands do not have an immediate. PR7790.

[oota-llvm.git] / lib / Target / ARM / Thumb2SizeReduction.cpp

diff --git a/lib/Target/ARM/Thumb2SizeReduction.cpp b/lib/Target/ARM/Thumb2SizeReduction.cpp
index 2bc75f28d50397ea551f9faf0dfc09ee22473792..ba392f36d946424fab03cc0fbc615b943dab1acb 100644 (file)
--- a/lib/Target/ARM/Thumb2SizeReduction.cpp
+++ b/lib/Target/ARM/Thumb2SizeReduction.cpp
@@ -451,11 +451,18 @@ Thumb2SizeReduce::ReduceTo2Addr(MachineBasicBlock &MBB, MachineInstr *MI,
   if (ReduceLimit2Addr != -1 && ((int)Num2Addrs >= ReduceLimit2Addr))
     return false;
 
-  const TargetInstrDesc &TID = MI->getDesc();
   unsigned Reg0 = MI->getOperand(0).getReg();
   unsigned Reg1 = MI->getOperand(1).getReg();
-  if (Reg0 != Reg1)
-    return false;
+  if (Reg0 != Reg1) {
+    // Try to commute the operands to make it a 2-address instruction.
+    unsigned CommOpIdx1, CommOpIdx2;
+    if (!TII->findCommutedOpIndices(MI, CommOpIdx1, CommOpIdx2) ||
+        CommOpIdx1 != 1 || MI->getOperand(CommOpIdx2).getReg() != Reg0)
+      return false;
+    MachineInstr *CommutedMI = TII->commuteInstruction(MI);
+    if (!CommutedMI)
+      return false;
+  }
   if (Entry.LowRegs2 && !isARMLowRegister(Reg0))
     return false;
   if (Entry.Imm2Limit) {
@@ -484,6 +491,7 @@ Thumb2SizeReduce::ReduceTo2Addr(MachineBasicBlock &MBB, MachineInstr *MI,
 
   bool HasCC = false;
   bool CCDead = false;
+  const TargetInstrDesc &TID = MI->getDesc();
   if (TID.hasOptionalDef()) {
     unsigned NumOps = TID.getNumOperands();
     HasCC = (MI->getOperand(NumOps-1).getReg() == ARM::CPSR);
@@ -656,15 +664,8 @@ static bool UpdateCPSRUse(MachineInstr &MI, bool LiveCPSR) {
 bool Thumb2SizeReduce::ReduceMBB(MachineBasicBlock &MBB) {
   bool Modified = false;
 
-  bool LiveCPSR = false;
   // Yes, CPSR could be livein.
-  for (MachineBasicBlock::const_livein_iterator I = MBB.livein_begin(),
-         E = MBB.livein_end(); I != E; ++I) {
-    if (*I == ARM::CPSR) {
-      LiveCPSR = true;
-      break;
-    }
-  }
+  bool LiveCPSR = MBB.isLiveIn(ARM::CPSR);
 
   MachineBasicBlock::iterator MII = MBB.begin(), E = MBB.end();
   MachineBasicBlock::iterator NextMII;
@@ -696,7 +697,7 @@ bool Thumb2SizeReduce::ReduceMBB(MachineBasicBlock &MBB) {
         goto ProcessNext;
       }
 
-      // Try to transform ro a 16-bit non-two-address instruction.
+      // Try to transform to a 16-bit non-two-address instruction.
       if (Entry.NarrowOpc1 && ReduceToNarrow(MBB, MI, Entry, LiveCPSR)) {
         Modified = true;
         MachineBasicBlock::iterator I = prior(NextMII);