diff --git a/llvm/lib/Target/Mips/MCTargetDesc/MipsMCCodeEmitter.cpp b/llvm/lib/Target/Mips/MCTargetDesc/MipsMCCodeEmitter.cpp
--- a/llvm/lib/Target/Mips/MCTargetDesc/MipsMCCodeEmitter.cpp
+++ b/llvm/lib/Target/Mips/MCTargetDesc/MipsMCCodeEmitter.cpp
@@ -724,19 +724,7 @@
   }
 
   if (Kind == MCExpr::SymbolRef) {
-    Mips::Fixups FixupKind = Mips::Fixups(0);
-
-    switch(cast<MCSymbolRefExpr>(Expr)->getKind()) {
-    default: llvm_unreachable("Unknown fixup kind!");
-      break;
-    case MCSymbolRefExpr::VK_None:
-      // FIXME: This is ok for O32/N32 but not N64.
-      FixupKind = Mips::fixup_Mips_32;
-      break;
-    } // switch
-
-    Fixups.push_back(MCFixup::create(0, Expr, MCFixupKind(FixupKind)));
-    return 0;
+    Ctx.reportError(Expr->getLoc(), "should use explicit constraints!");
   }
   return 0;
 }