pr6480: Don't try producing ld/st-multiple instructions when the address is

an undef value.  This is only going to come up for bugpoint-reduced tests --
correct programs will not access memory at undefined addresses -- so it's not
worth the effort of doing anything more aggressive.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97745 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/ARM/ARMLoadStoreOptimizer.cpp

@@ -761,6 +761,11 @@ static bool isMemoryOp(const MachineInstr *MI) {
       MI->getOperand(0).isUndef())
     return false;
 
+  // Likewise don't mess with references to undefined addresses.
+  if (MI->getNumOperands() > 1 && MI->getOperand(1).isReg() &&
+      MI->getOperand(1).isUndef())
+    return false;
+
   int Opcode = MI->getOpcode();
   switch (Opcode) {
   default: break;