GlobalISel: set correct regclass for LOAD_STACK_GUARD.

Since it's not actually a generic MI, its register operands need a RegClass,
which is conveniently the target's pointer RegClass.

llvm-svn: 293335
diff --git a/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp b/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
index ce3e682..9382de7 100644
--- a/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
@@ -477,6 +477,8 @@
 
 void IRTranslator::getStackGuard(unsigned DstReg,
                                  MachineIRBuilder &MIRBuilder) {
+  const TargetRegisterInfo *TRI = MF->getSubtarget().getRegisterInfo();
+  MRI->setRegClass(DstReg, TRI->getPointerRegClass(*MF));
   auto MIB = MIRBuilder.buildInstr(TargetOpcode::LOAD_STACK_GUARD);
   MIB.addDef(DstReg);