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(), "expected 16-bit signed immediate");
   }
   return 0;
 }
diff --git a/llvm/test/MC/Mips/reloc-implicit-constraints-error.s b/llvm/test/MC/Mips/reloc-implicit-constraints-error.s
new file mode 100644
--- /dev/null
+++ b/llvm/test/MC/Mips/reloc-implicit-constraints-error.s
@@ -0,0 +1,15 @@
+# RUN: not llvm-mc -triple mips-unknown-linux-gnu -filetype obj -o /dev/null %s 2>%t1
+# RUN: FileCheck %s < %t1
+
+# RUN: not llvm-mc -triple mips64-unknown-linux-gnu -filetype obj -o /dev/null %s 2>%t1
+# RUN: FileCheck %s < %t1
+
+# Check that implicit constraints error
+
+  ori  $4, $4, start            # CHECK: [[@LINE]]:{{[0-9]+}}: error: expected 16-bit signed immediate
+  ori  $4, $4, (start - .)      # CHECK: [[@LINE]]:{{[0-9]+}}: error: expected 16-bit signed immediate
+
+  addiu  $4, $4, start          # CHECK: [[@LINE]]:{{[0-9]+}}: error: expected 16-bit signed immediate
+  addiu  $4, $4, (start - .)    # CHECK: [[@LINE]]:{{[0-9]+}}: error: expected 16-bit signed immediate
+
+start: