Add a comment to this change, requested by Eric Christopher.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185853 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/ARM/ARMISelDAGToDAG.cpp

@@ -3491,6 +3491,10 @@ SDNode *ARMDAGToDAGISel::SelectInlineAsm(SDNode *N){
     else
       continue;
 
+    // Immediate operands to inline asm in the SelectionDAG are modeled with
+    // two operands. The first is a constant of value InlineAsm::Kind_Imm, and
+    // the second is a constant with the value of the immediate. If we get here
+    // and we have a Kind_Imm, skip the next operand, and continue.
     if (Kind == InlineAsm::Kind_Imm) {
       SDValue op = N->getOperand(++i);
       AsmNodeOperands.push_back(op);

test/CodeGen/ARM/arm-modifier.ll

@@ -66,6 +66,7 @@ entry:
   ret i64 %0
 }
 
+; PR16490
 define void @f5(i64 %__pu_val) {
   call void asm sideeffect "$1", "r,i"(i64 %__pu_val, i32 -14)
   ret void