GlobalISel: translate "unreachable" (into nothing)

Easiest instruction ever!

llvm-svn: 277225

llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp

@@ -269,6 +269,9 @@ bool IRTranslator::translate(const Instruction &Inst) {
   case Instruction::Alloca:
     return translateStaticAlloca(cast<AllocaInst>(Inst));
 
+  case Instruction::Unreachable:
+    return true;
+
   default:
     llvm_unreachable("Opcode not supported");
   }

llvm/test/CodeGen/AArch64/GlobalISel/arm64-irtranslator.ll

@@ -271,3 +271,13 @@ define void @intrinsics(i32 %cur, i32 %bits) {
   call void @llvm.aarch64.neon.st2.v8i8.p0i8(<8 x i8> %vec, <8 x i8> %vec, i8* %ptr)
   ret void
 }
+
+
+; CHECK-LABEL: name: unreachable
+; CHECK: G_ADD
+; CHECK-NEXT: {{^$}}
+; CHECK-NEXT: ...
+define void @unreachable(i32 %a) {
+  %sum = add i32 %a, %a
+  unreachable
+}