Fix pr4091: Add support for "m" constraint in ARM inline assembly.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@72105 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMISelDAGToDAG.cpp b/lib/Target/ARM/ARMISelDAGToDAG.cpp
index 3bc5ae9..ca3a9cb 100644
--- a/lib/Target/ARM/ARMISelDAGToDAG.cpp
+++ b/lib/Target/ARM/ARMISelDAGToDAG.cpp
@@ -89,6 +89,13 @@
   
   // Include the pieces autogenerated from the target description.
 #include "ARMGenDAGISel.inc"
+
+private:
+    /// SelectInlineAsmMemoryOperand - Implement addressing mode selection for
+    /// inline asm expressions.
+    virtual bool SelectInlineAsmMemoryOperand(const SDValue &Op,
+                                              char ConstraintCode,
+                                              std::vector<SDValue> &OutOps);
 };
 }
 
@@ -881,6 +888,21 @@
   return SelectCode(Op);
 }
 
+bool ARMDAGToDAGISel::
+SelectInlineAsmMemoryOperand(const SDValue &Op, char ConstraintCode,
+                             std::vector<SDValue> &OutOps) {
+  assert(ConstraintCode == 'm' && "unexpected asm memory constraint");
+
+  SDValue Base, Offset, Opc;
+  if (!SelectAddrMode2(Op, Op, Base, Offset, Opc))
+    return true;
+  
+  OutOps.push_back(Base);
+  OutOps.push_back(Offset);
+  OutOps.push_back(Opc);
+  return false;
+}
+
 /// createARMISelDag - This pass converts a legalized DAG into a
 /// ARM-specific DAG, ready for instruction scheduling.
 ///