diff --git a/llvm/test/TableGen/MnemonicAlias.td b/llvm/test/TableGen/MnemonicAlias.td
new file mode 100644
index 000000000000..518454a7ca63
--- /dev/null
+++ b/llvm/test/TableGen/MnemonicAlias.td
@@ -0,0 +1,41 @@
+// RUN: llvm-tblgen -gen-asm-matcher -I %p/../../include %s | FileCheck %s
+
+include "llvm/Target/Target.td"
+
+def ArchInstrInfo : InstrInfo { }
+
+def Arch : Target {
+  let InstructionSet = ArchInstrInfo;
+}
+
+def Reg : Register<"reg">;
+def RegClass : RegisterClass<"foo", [i32], 0, (add Reg)>;
+
+def AsmCond1 : SubtargetFeature<"cond1", "cond1", "true", "">;
+def AsmCond2 : SubtargetFeature<"cond2", "cond2", "true", "">;
+
+def Subtarget1 : Predicate<"Pred1">, AssemblerPredicate<(all_of AsmCond1)>;
+def Subtarget2 : Predicate<"Pred2">, AssemblerPredicate<(all_of AsmCond2)>;
+
+multiclass DefInstruction<string name, dag outs, dag ins, Predicate pred> {
+  def "" : Instruction {
+    let Size = 2;
+    let OutOperandList = outs;
+    let InOperandList = ins;
+    let AsmString = name;
+    let Predicates = [pred];
+  }
+  def : MnemonicAlias<name # "_alias", name>;
+}
+
+defm FooInst1 : DefInstruction<"foo", (outs), (ins), Subtarget1>;
+
+defm FooInst2 : DefInstruction<"foo", (outs), (ins), Subtarget2>;
+
+// Check that applyMnemonicAliases maps "foo_alias" to "foo" once only and
+// without checking any predicates.
+
+// CHECK:      if (memcmp(Mnemonic.data()+0, "foo_alias", 9) != 0)
+// CHECK-NEXT:   break;
+// CHECK-NEXT: Mnemonic = "foo";        // "foo_alias"
+// CHECK-NEXT: return;
diff --git a/llvm/utils/TableGen/AsmMatcherEmitter.cpp b/llvm/utils/TableGen/AsmMatcherEmitter.cpp
index 96159a60c665..00bdd127e3c2 100644
--- a/llvm/utils/TableGen/AsmMatcherEmitter.cpp
+++ b/llvm/utils/TableGen/AsmMatcherEmitter.cpp
@@ -2749,10 +2749,14 @@ static void emitMnemonicAliasVariant(raw_ostream &OS,const AsmMatcherInfo &Info,
       // If this unconditionally matches, remember it for later and diagnose
       // duplicates.
       if (FeatureMask.empty()) {
-        if (AliasWithNoPredicate != -1) {
-          // We can't have two aliases from the same mnemonic with no predicate.
-          PrintError(ToVec[AliasWithNoPredicate]->getLoc(),
-                     "two MnemonicAliases with the same 'from' mnemonic!");
+        if (AliasWithNoPredicate != -1 &&
+            R->getValueAsString("ToMnemonic") !=
+                ToVec[AliasWithNoPredicate]->getValueAsString("ToMnemonic")) {
+          // We can't have two different aliases from the same mnemonic with no
+          // predicate.
+          PrintError(
+              ToVec[AliasWithNoPredicate]->getLoc(),
+              "two different MnemonicAliases with the same 'from' mnemonic!");
           PrintFatalError(R->getLoc(), "this is the other MnemonicAlias.");
         }