GlobalISel: Add CallBase to CallLoweringInfo

The DAG version has this, and is necessary for call lowering to take
advantage of any attributes at the call site.

llvm/include/llvm/CodeGen/GlobalISel/CallLowering.h

@@ -116,6 +116,9 @@ public:
     /// vreg that the swifterror should be copied into after the call.
     Register SwiftErrorVReg;
 
+    /// Original IR callsite corresponding to this call, if available.
+    const CallBase *CB = nullptr;
+
     MDNode *KnownCallees = nullptr;
 
     /// True if the call must be tail call optimized.

llvm/lib/CodeGen/GlobalISel/CallLowering.cpp

@@ -139,6 +139,7 @@ bool CallLowering::lowerCall(MachineIRBuilder &MIRBuilder, const CallBase &CB,
   if (!Info.OrigRet.Ty->isVoidTy())
     setArgFlags(Info.OrigRet, AttributeList::ReturnIndex, DL, CB);
 
+  Info.CB = &CB;
   Info.KnownCallees = CB.getMetadata(LLVMContext::MD_callees);
   Info.CallConv = CallConv;
   Info.SwiftErrorVReg = SwiftErrorVReg;