Add DEBUG message.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@113614 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/RegAllocFast.cpp b/lib/CodeGen/RegAllocFast.cpp
index fc150d5..8301402 100644
--- a/lib/CodeGen/RegAllocFast.cpp
+++ b/lib/CodeGen/RegAllocFast.cpp
@@ -798,9 +798,11 @@
             setPhysReg(MI, i, LRI->second.PhysReg);
           else {
             int SS = StackSlotForVirtReg[Reg];
-            if (SS == -1)
+            if (SS == -1) {
               // We can't allocate a physreg for a DebugValue, sorry!
+              DEBUG(dbgs() << "Unable to allocate vreg used by DBG_VALUE");
               MO.setReg(0);
+            }
             else {
               // Modify DBG_VALUE now that the value is in a spill slot.
               int64_t Offset = MI->getOperand(1).getImm();
@@ -817,9 +819,11 @@
                 MI = NewDV;
                 ScanDbgValue = true;
                 break;
-              } else
+              } else {
                 // We can't allocate a physreg for a DebugValue; sorry!
+                DEBUG(dbgs() << "Unable to allocate vreg used by DBG_VALUE");
                 MO.setReg(0);
+              }
             }
           }
         }