Index: lib/Target/Mips/AsmParser/MipsAsmParser.cpp
===================================================================
--- lib/Target/Mips/AsmParser/MipsAsmParser.cpp
+++ lib/Target/Mips/AsmParser/MipsAsmParser.cpp
@@ -6297,6 +6297,9 @@
   return false;
 }
 
+static std::string MipsMnemonicSpellCheck(StringRef S, uint64_t FBS,
+                                          unsigned VariantID = 0);
+
 bool MipsAsmParser::ParseInstruction(ParseInstructionInfo &Info, StringRef Name,
                                      SMLoc NameLoc, OperandVector &Operands) {
   MCAsmParser &Parser = getParser();
@@ -6307,7 +6310,9 @@
 
   // Check if we have valid mnemonic
   if (!mnemonicIsValid(Name, 0)) {
-    return Error(NameLoc, "unknown instruction");
+    uint64_t FBS = ComputeAvailableFeatures(getSTI().getFeatureBits());
+    std::string Suggestion = MipsMnemonicSpellCheck(Name, FBS);
+    return Error(NameLoc, "unknown instruction" + Suggestion);
   }
   // First operand in MCInst is instruction mnemonic.
   Operands.push_back(MipsOperand::CreateToken(Name, NameLoc, *this));
@@ -8002,6 +8007,7 @@
 
 #define GET_REGISTER_MATCHER
 #define GET_MATCHER_IMPLEMENTATION
+#define GET_MNEMONIC_SPELL_CHECKER
 #include "MipsGenAsmMatcher.inc"
 
 bool MipsAsmParser::mnemonicIsValid(StringRef Mnemonic, unsigned VariantID) {
Index: test/MC/Mips/invalid-instructions-spellcheck.s
===================================================================
--- /dev/null
+++ test/MC/Mips/invalid-instructions-spellcheck.s
@@ -0,0 +1,45 @@
+# RUN: not llvm-mc -triple mips-unknown-unknown \
+# RUN:             -mattr=micromips -show-encoding < %s 2>&1 | FileCheck %s
+
+# This tests the mnemonic spell checker.
+
+# First check what happens when an instruction is omitted:
+
+$2, $1, $25
+
+# CHECK:      error: unexpected token at start of statement
+# CHECK-NEXT: $2, $1, $25
+# CHECK-NEXT:  ^
+
+# We don't want to see a suggestion here; the edit distance is too large to
+# give sensible suggestions:
+
+aaaaaaaaaaaaaaa $2, $1, $25
+
+# CHECK:      error: unknown instruction
+# CHECK-NEXT: aaaaaaaaaaaaaaa $2, $1, $25
+# CHECK-NEXT: ^
+
+# Check that we get one suggestion: 'addiuspi' is 1 edit away, i.e. an deletion.
+
+addiuspi -16
+
+# CHECK:      error: unknown instruction, did you mean: addiusp?
+# CHECK-NEXT: addiuspi -16
+# CHECK-NEXT: ^
+
+# Check edit distance 1 and 2, just insertions:
+
+addru $9, $6, 17767
+
+# CHECK:      error: unknown instruction, did you mean: add, addiu, addu, maddu?
+# CHECK-NEXT: addru $9, $6, 17767
+# CHECK-NEXT: ^
+
+# Check an instruction that is 2 edits away, and also has a lot of candidates:
+
+culE.d  $fcc7, $f24, $f18
+
+# CHECK:      error: unknown instruction, did you mean: c.le.d, c.ule.d?
+# CHECK-NEXT: culE.d  $fcc7, $f24, $f18
+# CHECK-NEXT: ^