[GISel] Pass MD_callees metadata down in call lowering.

Summary:
This will make it possible to improve IPRA by taking into account
register usage in indirect calls.

NFC yet; this is just laying the groundwork to start building
up patches to take advantage of the information for improved register
allocation.

Reviewers: aditya_nandakumar, volkan, qcolombet, arsenm, rovka, aemerson, paquette

Subscribers: sdardis, wdng, javed.absar, hiraditya, jrtc27, atanasyan, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D65488

llvm-svn: 367476

1 files changed, 5 insertions, 1 deletions

diff --git a/llvm/lib/CodeGen/GlobalISel/CallLowering.cpp b/llvm/lib/CodeGen/GlobalISel/CallLowering.cpp
index a5d8205a34a..9f950131c85 100644
--- a/llvm/lib/CodeGen/GlobalISel/CallLowering.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/CallLowering.cpp
@@ -19,6 +19,7 @@
 #include "llvm/CodeGen/TargetLowering.h"
 #include "llvm/IR/DataLayout.h"
 #include "llvm/IR/Instructions.h"
+#include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Module.h"
 
 #define DEBUG_TYPE "call-lowering"
@@ -61,8 +62,11 @@ bool CallLowering::lowerCall(MachineIRBuilder &MIRBuilder, ImmutableCallSite CS,
   if (!OrigRet.Ty->isVoidTy())
     setArgFlags(OrigRet, AttributeList::ReturnIndex, DL, CS);
 
+  const MDNode *KnownCallees =
+      CS.getInstruction()->getMetadata(LLVMContext::MD_callees);
+
   return lowerCall(MIRBuilder, CS.getCallingConv(), Callee, OrigRet, OrigArgs,
-                   SwiftErrorVReg);
+                   SwiftErrorVReg, KnownCallees);
 }
 
 template <typename FuncInfoTy>