[GlobalIsel] Add llvm.invariant.start and llvm.invariant.end

Port over the implementation in SelectionDAGBuilder.cpp into the IRTranslator
and update the arm64-irtranslator test.

These were causing fallbacks in CTMark/Bullet (-Rpass-missed=gisel-select),
and this patch fixes that.

https://reviews.llvm.org/D52945

llvm-svn: 343885

1 files changed, 8 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp b/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
index ff1ad712f93..709965ba151 100644
--- a/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
@@ -955,6 +955,14 @@ bool IRTranslator::translateKnownIntrinsic(const CallInst &CI, Intrinsic::ID ID,
         .addUse(getOrCreateVReg(*CI.getArgOperand(0)));
     return true;
   }
+  case Intrinsic::invariant_start: {
+    LLT PtrTy = getLLTForType(*CI.getArgOperand(0)->getType(), *DL);
+    unsigned Undef = MRI->createGenericVirtualRegister(PtrTy);
+    MIRBuilder.buildUndef(Undef);
+    return true;
+  }
+  case Intrinsic::invariant_end:
+    return true;
   }
   return false;
 }