diff --git a/lib/CodeGen/RegAllocBasic.cpp b/lib/CodeGen/RegAllocBasic.cpp
index d92d80f181f..32cb62223b5 100644
--- a/lib/CodeGen/RegAllocBasic.cpp
+++ b/lib/CodeGen/RegAllocBasic.cpp
@@ -321,6 +321,23 @@ void RegAllocBase::allocatePhysRegs() {
     VirtRegVec SplitVRegs;
     unsigned AvailablePhysReg = selectOrSplit(*VirtReg, SplitVRegs);
 
+    if (AvailablePhysReg == ~0u) {
+      // selectOrSplit failed to find a register!
+      std::string msg;
+      raw_string_ostream Msg(msg);
+      Msg << "Ran out of registers during register allocation!"
+             "\nCannot allocate: " << *VirtReg;
+      for (MachineRegisterInfo::reg_iterator I = MRI->reg_begin(VirtReg->reg);
+      MachineInstr *MI = I.skipInstruction();) {
+        if (!MI->isInlineAsm())
+          continue;
+        Msg << "\nPlease check your inline asm statement for "
+          "invalid constraints:\n";
+        MI->print(Msg, &VRM->getMachineFunction().getTarget());
+      }
+      report_fatal_error(Msg.str());
+    }
+
     if (AvailablePhysReg)
       assign(*VirtReg, AvailablePhysReg);
 
@@ -498,8 +515,11 @@ unsigned RABasic::selectOrSplit(LiveInterval &VirtReg,
     // Tell the caller to allocate to this newly freed physical register.
     return *PhysRegI;
   }
+
   // No other spill candidates were found, so spill the current VirtReg.
   DEBUG(dbgs() << "spilling: " << VirtReg << '\n');
+  if (!VirtReg.isSpillable())
+    return ~0u;
   LiveRangeEdit LRE(VirtReg, SplitVRegs);
   spiller().spill(LRE);
 
diff --git a/lib/CodeGen/RegAllocGreedy.cpp b/lib/CodeGen/RegAllocGreedy.cpp
index 053344f46e8..e9920b82712 100644
--- a/lib/CodeGen/RegAllocGreedy.cpp
+++ b/lib/CodeGen/RegAllocGreedy.cpp
@@ -1380,7 +1380,10 @@ unsigned RAGreedy::selectOrSplit(LiveInterval &VirtReg,
     return 0;
   }
 
-  assert(Stage < RS_Spill && "Cannot allocate after spilling");
+  // If we couldn't allocate a register from spilling, there is probably some
+  // invalid inline assembly. The base class wil report it.
+  if (Stage >= RS_Spill)
+    return ~0u;
 
   // Try splitting VirtReg or interferences.
   unsigned PhysReg = trySplit(VirtReg, Order, NewVRegs);
diff --git a/test/CodeGen/X86/inline-asm-error.ll b/test/CodeGen/X86/inline-asm-error.ll
new file mode 100644
index 00000000000..29c5ae51cf8
--- /dev/null
+++ b/test/CodeGen/X86/inline-asm-error.ll
@@ -0,0 +1,17 @@
+; RUN: not llc -march x86 -regalloc=fast       < %s 2> %t1
+; RUN: not llc -march x86 -regalloc=basic      < %s 2> %t2
+; RUN: not llc -march x86 -regalloc=greedy     < %s 2> %t3
+; RUN: FileCheck %s < %t1
+; RUN: FileCheck %s < %t2
+; RUN: FileCheck %s < %t3
+
+; The register allocator must fail on this function, and it should print the
+; inline asm in the diagnostic.
+; CHECK: LLVM ERROR: Ran out of registers during register allocation!
+; CHECK: INLINEASM <es:hello world>
+
+define void @f(i32 %x0, i32 %x1, i32 %x2, i32 %x3, i32 %x4, i32 %x5, i32 %x6, i32 %x7, i32 %x8, i32 %x9) nounwind ssp {
+entry:
+  tail call void asm sideeffect "hello world", "r,r,r,r,r,r,r,r,r,r,~{dirflag},~{fpsr},~{flags}"(i32 %x0, i32 %x1, i32 %x2, i32 %x3, i32 %x4, i32 %x5, i32 %x6, i32 %x7, i32 %x8, i32 %x9) nounwind
+  ret void
+}